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4. 以积木式编程制作网络应用程式 > 
相机
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该文档涵盖了使用相机的各个方面，包括 Web 应用程序的选择、访问、连接、使用和错误处理。

相机选择

允许 Web 应用访问您的相机

启用相机功能

{"blocks":"<xml xmlns=\"https://developers.google.com/blockly/xml\"><block type=\"Camera_enableCameraFeature\"><value name=\"enable\"><shadow type=\"logic_boolean\"><field name=\"BOOL\">FALSE</field></shadow></value></block></xml>"}

此块用于允许 Web 应用打开相机功能。

参数： 显示设置：布尔值 （True/False [Default]）
输出： N/A
示例代码：

{"blocks":"<xml xmlns=\"https://developers.google.com/blockly/xml\"><variables><variable>mainLayout</variable><variable>mainScreen</variable><variable>cameraControl</variable><variable>detectionAbortControl</variable></variables><block type=\"pxt-on-start\" x=\"0\" y=\"0\"><statement name=\"HANDLER\"><block type=\"variables_set\"><field name=\"VAR\">mainLayout</field><value name=\"VALUE\"><shadow type=\"math_number\"><field name=\"NUM\">0</field></shadow><block type=\"ScreenItem_createLayout\"/></value><next><block type=\"variables_set\"><field name=\"VAR\">mainScreen</field><value name=\"VALUE\"><shadow type=\"math_number\"><field name=\"NUM\">0</field></shadow><block type=\"Screen_create\"><value name=\"label\"><shadow type=\"text\"><field name=\"TEXT\">Main</field></shadow></value><value name=\"layout\"><block type=\"variables_get\"><field name=\"VAR\">mainLayout</field></block></value></block></value><next><block type=\"Camera_enableCameraFeature\"><value name=\"enable\"><shadow type=\"logic_boolean\"><field name=\"BOOL\">TRUE</field></shadow></value><next><block type=\"variables_set\"><field name=\"VAR\">cameraControl</field><value name=\"VALUE\"><shadow type=\"math_number\"><field name=\"NUM\">0</field></shadow><block type=\"Camera_getCameraControl\"/></value><next><block type=\"Control_OptionList_setMultiple\"><value name=\"this\"><block type=\"variables_get\"><field name=\"VAR\">cameraControl</field></block></value><value name=\"isMultiple\"><shadow type=\"logic_boolean\"><field name=\"BOOL\">TRUE</field></shadow></value><next><block type=\"ScreenItem_Layout_add\"><value name=\"this\"><block type=\"variables_get\"><field name=\"VAR\">mainLayout</field></block></value><value name=\"item\"><block type=\"variables_get\"><field name=\"VAR\">cameraControl</field></block></value><next><block type=\"variables_set\"><field name=\"VAR\">detectionAbortControl</field><value name=\"VALUE\"><shadow type=\"math_number\"><field name=\"NUM\">0</field></shadow><block type=\"Task_createAbortControl\"/></value></block></next></block></next></block></next></block></next></block></next></block></next></block></statement></block></xml>"}

当它设置为 false 时，输出：

启用相机功能 false - 输出

当设置为 true 时，输出：

启用相机功能 true - 输出启用相机功能 true - 输出

从设备中获取所有相机

获取摄像机控制权

{"blocks":"<xml xmlns=\"https://developers.google.com/blockly/xml\"><block type=\"Camera_getCameraControl\"/></xml>"}

此块用于从您的设备获取所有摄像头。

参数： N/A
输出： 屏幕项目
示例代码：

这用于设置变量以获取相机控制。

{"blocks":"<xml xmlns=\"https://developers.google.com/blockly/xml\"><block type=\"variables_set\"><field name=\"VAR\">cameraControl</field><value name=\"VALUE\"><shadow type=\"math_number\"><field name=\"NUM\">0</field></shadow><block type=\"Camera_getCameraControl\"/></value></block></xml>"}
{"blocks":"<xml xmlns=\"https://developers.google.com/blockly/xml\"><variables><variable>mainLayout</variable><variable>mainScreen</variable><variable>cameraControl</variable><variable>detectionAbortControl</variable></variables><block type=\"pxt-on-start\" x=\"0\" y=\"0\"><statement name=\"HANDLER\"><block type=\"variables_set\"><field name=\"VAR\">mainLayout</field><value name=\"VALUE\"><shadow type=\"math_number\"><field name=\"NUM\">0</field></shadow><block type=\"ScreenItem_createLayout\"/></value><next><block type=\"variables_set\"><field name=\"VAR\">mainScreen</field><value name=\"VALUE\"><shadow type=\"math_number\"><field name=\"NUM\">0</field></shadow><block type=\"Screen_create\"><value name=\"label\"><shadow type=\"text\"><field name=\"TEXT\">Main</field></shadow></value><value name=\"layout\"><block type=\"variables_get\"><field name=\"VAR\">mainLayout</field></block></value></block></value><next><block type=\"Camera_enableCameraFeature\"><value name=\"enable\"><shadow type=\"logic_boolean\"><field name=\"BOOL\">TRUE</field></shadow></value><next><block type=\"variables_set\"><field name=\"VAR\">cameraControl</field><value name=\"VALUE\"><shadow type=\"math_number\"><field name=\"NUM\">0</field></shadow><block type=\"Camera_getCameraControl\"/></value><next><block type=\"Control_OptionList_setMultiple\"><value name=\"this\"><block type=\"variables_get\"><field name=\"VAR\">cameraControl</field></block></value><value name=\"isMultiple\"><shadow type=\"logic_boolean\"><field name=\"BOOL\">TRUE</field></shadow></value><next><block type=\"ScreenItem_Layout_add\"><value name=\"this\"><block type=\"variables_get\"><field name=\"VAR\">mainLayout</field></block></value><value name=\"item\"><block type=\"variables_get\"><field name=\"VAR\">cameraControl</field></block></value><next><block type=\"variables_set\"><field name=\"VAR\">detectionAbortControl</field><value name=\"VALUE\"><shadow type=\"math_number\"><field name=\"NUM\">0</field></shadow><block type=\"Task_createAbortControl\"/></value></block></next></block></next></block></next></block></next></block></next></block></next></block></statement></block></xml>"}

输出：

获取摄像机控制 - 输出

更换摄像机时执行操作

相机控制已更改

{"blocks":"<xml xmlns=\"https://developers.google.com/blockly/xml\"><block type=\"Camera_setOnDeviceChanged\"><value name=\"HANDLER_DRAG_PARAM_connectedCameras\"><shadow type=\"variables_get_reporter\"><field name=\"VAR\">connectedCameras</field></shadow></value><value name=\"HANDLER_DRAG_PARAM_recentlyConnectedCameras\"><shadow type=\"variables_get_reporter\"><field name=\"VAR\">recentlyConnectedCameras</field></shadow></value><value name=\"HANDLER_DRAG_PARAM_recentlyDisconnectedCameras\"><shadow type=\"variables_get_reporter\"><field name=\"VAR\">recentlyDisconnectedCameras</field></shadow></value></block></xml>"}

此块用于在更换相机时执行某些操作。

参数：

  • selectedCameras： 您选择的摄像机。
  • recentlySelectedCameras： 您正在使用的相机。
  • 您选择的上一个摄像机。

输出： N/A
示例代码：

它将显示选定的相机。

{"blocks":"<xml xmlns=\"https://developers.google.com/blockly/xml\"><block type=\"Camera_setOnCameraControlChanged\"><value name=\"HANDLER_DRAG_PARAM_selectedCameras\"><shadow type=\"variables_get_reporter\"><field name=\"VAR\">selectedCameras</field></shadow></value><value name=\"HANDLER_DRAG_PARAM_recentlySelectedCameras\"><shadow type=\"variables_get_reporter\"><field name=\"VAR\">recentlySelectedCameras</field></shadow></value><value name=\"HANDLER_DRAG_PARAM_recentlyUnselectedCameras\"><shadow type=\"variables_get_reporter\"><field name=\"VAR\">recentlyUnselectedCameras</field></shadow></value><statement name=\"HANDLER\"><block type=\"pxt_controls_for_of\"><value name=\"VAR\"><shadow type=\"variables_get_reporter\"><field name=\"VAR\">value</field></shadow></value><value name=\"LIST\"><block type=\"variables_get\"><field name=\"VAR\">recentlyUnselectedCameras</field></block></value><statement name=\"DO\"><block type=\"ScreenItem_ScreenItem_remove\"><value name=\"this\"><block type=\"ScreenItem_ScreenItem_getParent\"><value name=\"this\"><block type=\"variables_get\"><field name=\"VAR\">value</field></block></value></block></value></block></statement></block></statement></block></xml>"}

它将删除未选择的相机。

{"blocks":"<xml xmlns=\"https://developers.google.com/blockly/xml\"><block type=\"Camera_setOnCameraControlChanged\"><value name=\"HANDLER_DRAG_PARAM_selectedCameras\"><shadow type=\"variables_get_reporter\"><field name=\"VAR\">selectedCameras</field></shadow></value><value name=\"HANDLER_DRAG_PARAM_recentlySelectedCameras\"><shadow type=\"variables_get_reporter\"><field name=\"VAR\">recentlySelectedCameras</field></shadow></value><value name=\"HANDLER_DRAG_PARAM_recentlyUnselectedCameras\"><shadow type=\"variables_get_reporter\"><field name=\"VAR\">recentlyUnselectedCameras</field></shadow></value><statement name=\"HANDLER\"><block type=\"pxt_controls_for_of\"><value name=\"VAR\"><shadow type=\"variables_get_reporter\"><field name=\"VAR\">value2</field></shadow></value><value name=\"LIST\"><block type=\"variables_get\"><field name=\"VAR\">recentlySelectedCameras</field></block></value><statement name=\"DO\"><block type=\"variables_set\"><field name=\"VAR\">cameraResultLayout</field><value name=\"VALUE\"><shadow type=\"math_number\"><field name=\"NUM\">0</field></shadow><block type=\"ScreenItem_createLayout\"/></value><next><block type=\"ScreenItem_Layout_add\"><value name=\"this\"><block type=\"variables_get\"><field name=\"VAR\">cameraResultLayout</field></block></value><value name=\"item\"><block type=\"lists_index_get\"><value name=\"LIST\"><block type=\"variables_get\"><field name=\"VAR\">recentlySelectedCameras</field></block></value><value name=\"INDEX\"><shadow type=\"math_number\"><field name=\"NUM\">0</field></shadow></value></block></value><next><block type=\"ScreenItem_Layout_add\"><value name=\"this\"><block type=\"variables_get\"><field name=\"VAR\">cameraLayout</field></block></value><value name=\"item\"><block type=\"variables_get\"><field name=\"VAR\">cameraResultLayout</field></block></value></block></next></block></next></block></statement></block></statement></block></xml>"}
{"blocks":"<xml xmlns=\"https://developers.google.com/blockly/xml\"><variables><variable>mainLayout</variable><variable>mainScreen</variable><variable>cameraLayout</variable><variable>cameraControl</variable><variable>selectedCameras</variable><variable>recentlySelectedCameras</variable><variable>recentlyUnselectedCameras</variable><variable>value</variable><variable>value2</variable><variable>cameraResultLayout</variable></variables><block type=\"pxt-on-start\" x=\"0\" y=\"0\"><statement name=\"HANDLER\"><block type=\"variables_set\"><field name=\"VAR\">mainLayout</field><value name=\"VALUE\"><shadow type=\"math_number\"><field name=\"NUM\">0</field></shadow><block type=\"ScreenItem_createLayout\"/></value><next><block type=\"variables_set\"><field name=\"VAR\">mainScreen</field><value name=\"VALUE\"><shadow type=\"math_number\"><field name=\"NUM\">0</field></shadow><block type=\"Screen_create\"><value name=\"label\"><shadow type=\"text\"><field name=\"TEXT\">Main</field></shadow></value><value name=\"layout\"><block type=\"variables_get\"><field name=\"VAR\">mainLayout</field></block></value></block></value><next><block type=\"Camera_enableCameraFeature\"><value name=\"enable\"><shadow type=\"logic_boolean\"><field name=\"BOOL\">TRUE</field></shadow></value><next><block type=\"variables_set\"><field name=\"VAR\">cameraLayout</field><value name=\"VALUE\"><shadow type=\"math_number\"><field name=\"NUM\">0</field></shadow><block type=\"ScreenItem_createLayout\"/></value><next><block type=\"variables_set\"><field name=\"VAR\">cameraControl</field><value name=\"VALUE\"><shadow type=\"math_number\"><field name=\"NUM\">0</field></shadow><block type=\"Camera_getCameraControl\"/></value><next><block type=\"Control_OptionList_setMultiple\"><value name=\"this\"><block type=\"variables_get\"><field name=\"VAR\">cameraControl</field></block></value><value name=\"isMultiple\"><shadow type=\"logic_boolean\"><field name=\"BOOL\">TRUE</field></shadow></value><next><block type=\"ScreenItem_Layout_add\"><value name=\"this\"><block type=\"variables_get\"><field name=\"VAR\">cameraLayout</field></block></value><value name=\"item\"><block type=\"variables_get\"><field name=\"VAR\">cameraControl</field></block></value><next><block type=\"ScreenItem_Layout_add\"><value name=\"this\"><block type=\"variables_get\"><field name=\"VAR\">mainLayout</field></block></value><value name=\"item\"><block type=\"variables_get\"><field name=\"VAR\">cameraLayout</field></block></value><next><block type=\"Camera_setOnCameraControlChanged\"><value name=\"HANDLER_DRAG_PARAM_selectedCameras\"><shadow type=\"variables_get_reporter\"><field name=\"VAR\">selectedCameras</field></shadow></value><value name=\"HANDLER_DRAG_PARAM_recentlySelectedCameras\"><shadow type=\"variables_get_reporter\"><field name=\"VAR\">recentlySelectedCameras</field></shadow></value><value name=\"HANDLER_DRAG_PARAM_recentlyUnselectedCameras\"><shadow type=\"variables_get_reporter\"><field name=\"VAR\">recentlyUnselectedCameras</field></shadow></value><statement name=\"HANDLER\"><block type=\"pxt_controls_for_of\"><value name=\"VAR\"><shadow type=\"variables_get_reporter\"><field name=\"VAR\">value</field></shadow></value><value name=\"LIST\"><block type=\"variables_get\"><field name=\"VAR\">recentlyUnselectedCameras</field></block></value><statement name=\"DO\"><block type=\"ScreenItem_ScreenItem_remove\"><value name=\"this\"><block type=\"ScreenItem_ScreenItem_getParent\"><value name=\"this\"><block type=\"variables_get\"><field name=\"VAR\">value</field></block></value></block></value></block></statement><next><block type=\"pxt_controls_for_of\"><value name=\"VAR\"><shadow type=\"variables_get_reporter\"><field name=\"VAR\">value2</field></shadow></value><value name=\"LIST\"><block type=\"variables_get\"><field name=\"VAR\">recentlySelectedCameras</field></block></value><statement name=\"DO\"><block type=\"variables_set\"><field name=\"VAR\">cameraResultLayout</field><value name=\"VALUE\"><shadow type=\"math_number\"><field name=\"NUM\">0</field></shadow><block type=\"ScreenItem_createLayout\"/></value><next><block type=\"ScreenItem_Layout_add\"><value name=\"this\"><block type=\"variables_get\"><field name=\"VAR\">cameraResultLayout</field></block></value><value name=\"item\"><block type=\"lists_index_get\"><value name=\"LIST\"><block type=\"variables_get\"><field name=\"VAR\">recentlySelectedCameras</field></block></value><value name=\"INDEX\"><shadow type=\"math_number\"><field name=\"NUM\">0</field></shadow></value></block></value><next><block type=\"ScreenItem_Layout_add\"><value name=\"this\"><block type=\"variables_get\"><field name=\"VAR\">cameraLayout</field></block></value><value name=\"item\"><block type=\"variables_get\"><field name=\"VAR\">cameraResultLayout</field></block></value></block></next></block></next></block></statement></block></next></block></statement></block></next></block></next></block></next></block></next></block></next></block></next></block></next></block></next></block></statement></block></xml>"}

单击第一个摄像头时，输出：

相机控制更改时 - 输出（第一台相机）

单击第三个摄像头时，输出：

相机控制更改时 - 输出（第三台相机）

更改连接的设备时执行操作

设备上已更改

{"blocks":"<xml xmlns=\"https://developers.google.com/blockly/xml\"><block type=\"Camera_setOnDeviceChanged\"><value name=\"HANDLER_DRAG_PARAM_connectedCameras\"><shadow type=\"variables_get_reporter\"><field name=\"VAR\">connectedCameras</field></shadow></value><value name=\"HANDLER_DRAG_PARAM_recentlyConnectedCameras\"><shadow type=\"variables_get_reporter\"><field name=\"VAR\">recentlyConnectedCameras</field></shadow></value><value name=\"HANDLER_DRAG_PARAM_recentlyDisconnectedCameras\"><shadow type=\"variables_get_reporter\"><field name=\"VAR\">recentlyDisconnectedCameras</field></shadow></value></block></xml>"}

当相应的相机断开连接时，它会做一些动作。

参数：

  • 连接Cammeras： 已连接的相机。
  • 最近ConnectedCameras： 正在使用和连接的相机。
  • 最近DiscounnectedCameras： 打折的相机。

输出： N/A
示例代码：

这用于移除断开连接的相机。

{"blocks":"<xml xmlns=\"https://developers.google.com/blockly/xml\"><block type=\"Camera_setOnCameraControlChanged\"><value name=\"HANDLER_DRAG_PARAM_selectedCameras\"><shadow type=\"variables_get_reporter\"><field name=\"VAR\">selectedCameras</field></shadow></value><value name=\"HANDLER_DRAG_PARAM_recentlySelectedCameras\"><shadow type=\"variables_get_reporter\"><field name=\"VAR\">recentlySelectedCameras</field></shadow></value><value name=\"HANDLER_DRAG_PARAM_recentlyUnselectedCameras\"><shadow type=\"variables_get_reporter\"><field name=\"VAR\">recentlyUnselectedCameras</field></shadow></value><statement name=\"HANDLER\"><block type=\"pxt_controls_for_of\"><value name=\"VAR\"><shadow type=\"variables_get_reporter\"><field name=\"VAR\">value</field></shadow></value><value name=\"LIST\"><block type=\"variables_get\"><field name=\"VAR\">recentlyUnselectedCameras</field></block></value><statement name=\"DO\"><block type=\"ScreenItem_ScreenItem_remove\"><value name=\"this\"><block type=\"ScreenItem_ScreenItem_getParent\"><value name=\"this\"><block type=\"variables_get\"><field name=\"VAR\">value</field></block></value></block></value></block></statement><next><block type=\"pxt_controls_for_of\"><value name=\"VAR\"><shadow type=\"variables_get_reporter\"><field name=\"VAR\">value2</field></shadow></value><value name=\"LIST\"><block type=\"variables_get\"><field name=\"VAR\">recentlySelectedCameras</field></block></value><statement name=\"DO\"><block type=\"variables_set\"><field name=\"VAR\">cameraResultLayout</field><value name=\"VALUE\"><shadow type=\"math_number\"><field name=\"NUM\">0</field></shadow><block type=\"ScreenItem_createLayout\"/></value><next><block type=\"ScreenItem_Layout_add\"><value name=\"this\"><block type=\"variables_get\"><field name=\"VAR\">cameraResultLayout</field></block></value><value name=\"item\"><block type=\"variables_get\"><field name=\"VAR\">value2</field></block></value><next><block type=\"ScreenItem_Layout_add\"><value name=\"this\"><block type=\"variables_get\"><field name=\"VAR\">cameraLayout</field></block></value><value name=\"item\"><block type=\"variables_get\"><field name=\"VAR\">cameraResultLayout</field></block></value><next><block type=\"Camera_setOnDeviceChanged\"><value name=\"HANDLER_DRAG_PARAM_connectedCameras\"><shadow type=\"variables_get_reporter\"><field name=\"VAR\">connectedCameras</field></shadow></value><value name=\"HANDLER_DRAG_PARAM_recentlyConnectedCameras\"><shadow type=\"variables_get_reporter\"><field name=\"VAR\">recentlyConnectedCameras</field></shadow></value><value name=\"HANDLER_DRAG_PARAM_recentlyDisconnectedCameras\"><shadow type=\"variables_get_reporter\"><field name=\"VAR\">recentlyDisconnectedCameras</field></shadow></value><statement name=\"HANDLER\"><block type=\"pxt_controls_for_of\"><value name=\"VAR\"><shadow type=\"variables_get_reporter\"><field name=\"VAR\">value3</field></shadow></value><value name=\"LIST\"><block type=\"variables_get\"><field name=\"VAR\">recentlyDisconnectedCameras</field></block></value><statement name=\"DO\"><block type=\"ScreenItem_ScreenItem_remove\"><value name=\"this\"><block type=\"ScreenItem_ScreenItem_getParent\"><value name=\"this\"><block type=\"variables_get\"><field name=\"VAR\">value3</field></block></value></block></value></block></statement></block></statement></block></next></block></next></block></next></block></statement></block></next></block></statement></block></xml>"}
{"blocks":"<xml xmlns=\"https://developers.google.com/blockly/xml\"><variables><variable>mainLayout</variable><variable>mainScreen</variable><variable>cameraLayout</variable><variable>cameraControl</variable><variable>selectedCameras</variable><variable>recentlySelectedCameras</variable><variable>recentlyUnselectedCameras</variable><variable>value</variable><variable>value2</variable><variable>cameraResultLayout</variable><variable>connectedCameras</variable><variable>recentlyConnectedCameras</variable><variable>recentlyDisconnectedCameras</variable><variable>value3</variable></variables><block type=\"pxt-on-start\" x=\"0\" y=\"0\"><statement name=\"HANDLER\"><block type=\"variables_set\"><field name=\"VAR\">mainLayout</field><value name=\"VALUE\"><shadow type=\"math_number\"><field name=\"NUM\">0</field></shadow><block type=\"ScreenItem_createLayout\"/></value><next><block type=\"variables_set\"><field name=\"VAR\">mainScreen</field><value name=\"VALUE\"><shadow type=\"math_number\"><field name=\"NUM\">0</field></shadow><block type=\"Screen_create\"><value name=\"label\"><shadow type=\"text\"><field name=\"TEXT\">Main</field></shadow></value><value name=\"layout\"><block type=\"variables_get\"><field name=\"VAR\">mainLayout</field></block></value></block></value><next><block type=\"Camera_enableCameraFeature\"><value name=\"enable\"><shadow type=\"logic_boolean\"><field name=\"BOOL\">TRUE</field></shadow></value><next><block type=\"variables_set\"><field name=\"VAR\">cameraLayout</field><value name=\"VALUE\"><shadow type=\"math_number\"><field name=\"NUM\">0</field></shadow><block type=\"ScreenItem_createLayout\"/></value><next><block type=\"variables_set\"><field name=\"VAR\">cameraControl</field><value name=\"VALUE\"><shadow type=\"math_number\"><field name=\"NUM\">0</field></shadow><block type=\"Camera_getCameraControl\"/></value><next><block type=\"Control_OptionList_setMultiple\"><value name=\"this\"><block type=\"variables_get\"><field name=\"VAR\">cameraControl</field></block></value><value name=\"isMultiple\"><shadow type=\"logic_boolean\"><field name=\"BOOL\">TRUE</field></shadow></value><next><block type=\"ScreenItem_Layout_add\"><value name=\"this\"><block type=\"variables_get\"><field name=\"VAR\">cameraLayout</field></block></value><value name=\"item\"><block type=\"variables_get\"><field name=\"VAR\">cameraControl</field></block></value><next><block type=\"ScreenItem_Layout_add\"><value name=\"this\"><block type=\"variables_get\"><field name=\"VAR\">mainLayout</field></block></value><value name=\"item\"><block type=\"variables_get\"><field name=\"VAR\">cameraLayout</field></block></value><next><block type=\"Camera_setOnCameraControlChanged\"><value name=\"HANDLER_DRAG_PARAM_selectedCameras\"><shadow type=\"variables_get_reporter\"><field name=\"VAR\">selectedCameras</field></shadow></value><value name=\"HANDLER_DRAG_PARAM_recentlySelectedCameras\"><shadow type=\"variables_get_reporter\"><field name=\"VAR\">recentlySelectedCameras</field></shadow></value><value name=\"HANDLER_DRAG_PARAM_recentlyUnselectedCameras\"><shadow type=\"variables_get_reporter\"><field name=\"VAR\">recentlyUnselectedCameras</field></shadow></value><statement name=\"HANDLER\"><block type=\"pxt_controls_for_of\"><value name=\"VAR\"><shadow type=\"variables_get_reporter\"><field name=\"VAR\">value</field></shadow></value><value name=\"LIST\"><block type=\"variables_get\"><field name=\"VAR\">recentlyUnselectedCameras</field></block></value><statement name=\"DO\"><block type=\"ScreenItem_ScreenItem_remove\"><value name=\"this\"><block type=\"ScreenItem_ScreenItem_getParent\"><value name=\"this\"><block type=\"variables_get\"><field name=\"VAR\">value</field></block></value></block></value></block></statement><next><block type=\"pxt_controls_for_of\"><value name=\"VAR\"><shadow type=\"variables_get_reporter\"><field name=\"VAR\">value2</field></shadow></value><value name=\"LIST\"><block type=\"variables_get\"><field name=\"VAR\">recentlySelectedCameras</field></block></value><statement name=\"DO\"><block type=\"variables_set\"><field name=\"VAR\">cameraResultLayout</field><value name=\"VALUE\"><shadow type=\"math_number\"><field name=\"NUM\">0</field></shadow><block type=\"ScreenItem_createLayout\"/></value><next><block type=\"ScreenItem_Layout_add\"><value name=\"this\"><block type=\"variables_get\"><field name=\"VAR\">cameraResultLayout</field></block></value><value name=\"item\"><block type=\"variables_get\"><field name=\"VAR\">value2</field></block></value><next><block type=\"ScreenItem_Layout_add\"><value name=\"this\"><block type=\"variables_get\"><field name=\"VAR\">cameraLayout</field></block></value><value name=\"item\"><block type=\"variables_get\"><field name=\"VAR\">cameraResultLayout</field></block></value><next><block type=\"Camera_setOnDeviceChanged\"><value name=\"HANDLER_DRAG_PARAM_connectedCameras\"><shadow type=\"variables_get_reporter\"><field name=\"VAR\">connectedCameras</field></shadow></value><value name=\"HANDLER_DRAG_PARAM_recentlyConnectedCameras\"><shadow type=\"variables_get_reporter\"><field name=\"VAR\">recentlyConnectedCameras</field></shadow></value><value name=\"HANDLER_DRAG_PARAM_recentlyDisconnectedCameras\"><shadow type=\"variables_get_reporter\"><field name=\"VAR\">recentlyDisconnectedCameras</field></shadow></value><statement name=\"HANDLER\"><block type=\"pxt_controls_for_of\"><value name=\"VAR\"><shadow type=\"variables_get_reporter\"><field name=\"VAR\">value3</field></shadow></value><value name=\"LIST\"><block type=\"variables_get\"><field name=\"VAR\">recentlyDisconnectedCameras</field></block></value><statement name=\"DO\"><block type=\"ScreenItem_ScreenItem_remove\"><value name=\"this\"><block type=\"ScreenItem_ScreenItem_getParent\"><value name=\"this\"><block type=\"variables_get\"><field name=\"VAR\">value3</field></block></value></block></value></block></statement></block></statement></block></next></block></next></block></next></block></statement></block></next></block></statement></block></next></block></next></block></next></block></next></block></next></block></next></block></next></block></next></block></statement></block></xml>"}

当所有摄像头都正常工作，并且用户选择第一个摄像头时，输出：

在设备更改时 - 输出（连接的第一个摄像头）

当第一个摄像头断开时，输出：

设备已更改 - 输出（断开第一个摄像头）

当用户选择另一台摄像机时，输出：

在设备更改时 - 输出（连接另一台相机）

选择选定的摄像机

获取选定的摄像机

{"blocks":"<xml xmlns=\"https://developers.google.com/blockly/xml\"><block type=\"Camera_getSelectedCameras\"/></xml>"}

此块用于显示选定的相机屏幕。

参数： N/A

输出： 屏幕项目
示例代码：

这是用来获取相应的相机的。

{"blocks":"<xml xmlns=\"https://developers.google.com/blockly/xml\"><block type=\"variables_set\"><field name=\"VAR\">selectedCameras</field><value name=\"VALUE\"><shadow type=\"math_number\"><field name=\"NUM\">0</field></shadow><block type=\"Camera_getSelectedCameras\"/></value></block></xml>"}
{"blocks":"<xml xmlns=\"https://developers.google.com/blockly/xml\"><variables><variable>mainLayout</variable><variable>mainScreen</variable><variable>cameraLayout</variable><variable>cameraControl</variable><variable>selectedCameras</variable><variable>recentlySelectedCameras</variable><variable>recentlyUnselectedCameras</variable><variable>value2</variable><variable>cameraResultLayout</variable><variable>resultTextBlock</variable></variables><block type=\"pxt-on-start\" x=\"0\" y=\"0\"><statement name=\"HANDLER\"><block type=\"variables_set\"><field name=\"VAR\">mainLayout</field><value name=\"VALUE\"><shadow type=\"math_number\"><field name=\"NUM\">0</field></shadow><block type=\"ScreenItem_createLayout\"/></value><next><block type=\"variables_set\"><field name=\"VAR\">mainScreen</field><value name=\"VALUE\"><shadow type=\"math_number\"><field name=\"NUM\">0</field></shadow><block type=\"Screen_create\"><value name=\"label\"><shadow type=\"text\"><field name=\"TEXT\">Main</field></shadow></value><value name=\"layout\"><block type=\"variables_get\"><field name=\"VAR\">mainLayout</field></block></value></block></value><next><block type=\"Camera_enableCameraFeature\"><value name=\"enable\"><shadow type=\"logic_boolean\"><field name=\"BOOL\">TRUE</field></shadow></value><next><block type=\"variables_set\"><field name=\"VAR\">cameraLayout</field><value name=\"VALUE\"><shadow type=\"math_number\"><field name=\"NUM\">0</field></shadow><block type=\"ScreenItem_createLayout\"/></value><next><block type=\"variables_set\"><field name=\"VAR\">cameraControl</field><value name=\"VALUE\"><shadow type=\"math_number\"><field name=\"NUM\">0</field></shadow><block type=\"Camera_getCameraControl\"/></value><next><block type=\"variables_set\"><field name=\"VAR\">selectedCameras</field><value name=\"VALUE\"><shadow type=\"math_number\"><field name=\"NUM\">0</field></shadow><block type=\"Camera_getSelectedCameras\"/></value><next><block type=\"Control_OptionList_setMultiple\"><value name=\"this\"><block type=\"variables_get\"><field name=\"VAR\">cameraControl</field></block></value><value name=\"isMultiple\"><shadow type=\"logic_boolean\"><field name=\"BOOL\">TRUE</field></shadow></value><next><block type=\"ScreenItem_Layout_add\"><value name=\"this\"><block type=\"variables_get\"><field name=\"VAR\">cameraLayout</field></block></value><value name=\"item\"><block type=\"variables_get\"><field name=\"VAR\">cameraControl</field></block></value><next><block type=\"ScreenItem_Layout_add\"><value name=\"this\"><block type=\"variables_get\"><field name=\"VAR\">mainLayout</field></block></value><value name=\"item\"><block type=\"variables_get\"><field name=\"VAR\">cameraLayout</field></block></value><next><block type=\"Camera_setOnCameraControlChanged\"><value name=\"HANDLER_DRAG_PARAM_selectedCameras\"><shadow type=\"variables_get_reporter\"><field name=\"VAR\">selectedCameras</field></shadow></value><value name=\"HANDLER_DRAG_PARAM_recentlySelectedCameras\"><shadow type=\"variables_get_reporter\"><field name=\"VAR\">recentlySelectedCameras</field></shadow></value><value name=\"HANDLER_DRAG_PARAM_recentlyUnselectedCameras\"><shadow type=\"variables_get_reporter\"><field name=\"VAR\">recentlyUnselectedCameras</field></shadow></value><statement name=\"HANDLER\"><block type=\"pxt_controls_for_of\"><value name=\"VAR\"><shadow type=\"variables_get_reporter\"><field name=\"VAR\">value2</field></shadow></value><value name=\"LIST\"><block type=\"variables_get\"><field name=\"VAR\">recentlySelectedCameras</field></block></value><statement name=\"DO\"><block type=\"variables_set\"><field name=\"VAR\">cameraResultLayout</field><value name=\"VALUE\"><shadow type=\"math_number\"><field name=\"NUM\">0</field></shadow><block type=\"ScreenItem_createLayout\"/></value><next><block type=\"ScreenItem_Layout_add\"><value name=\"this\"><block type=\"variables_get\"><field name=\"VAR\">cameraResultLayout</field></block></value><value name=\"item\"><block type=\"variables_get\"><field name=\"VAR\">value2</field></block></value><next><block type=\"variables_set\"><field name=\"VAR\">resultTextBlock</field><value name=\"VALUE\"><shadow type=\"math_number\"><field name=\"NUM\">0</field></shadow><block type=\"Control_createTextBlock\"><mutation xmlns=\"http://www.w3.org/1999/xhtml\" _expanded=\"0\" _input_init=\"false\"></mutation></block></value><next><block type=\"ScreenItem_Layout_add\"><value name=\"this\"><block type=\"variables_get\"><field name=\"VAR\">cameraResultLayout</field></block></value><value name=\"item\"><block type=\"variables_get\"><field name=\"VAR\">resultTextBlock</field></block></value><next><block type=\"ScreenItem_Layout_add\"><value name=\"this\"><block type=\"variables_get\"><field name=\"VAR\">cameraLayout</field></block></value><value name=\"item\"><block type=\"variables_get\"><field name=\"VAR\">cameraResultLayout</field></block></value></block></next></block></next></block></next></block></next></block></statement></block></statement></block></next></block></next></block></next></block></next></block></next></block></next></block></next></block></next></block></next></block></statement></block></xml>"}

选择第一台摄像机时，输出：

获取选定的摄像机 - 输出（第一台摄像机）

选择第三个摄像头时，输出：

获取选定的摄像机 - 输出（第三个摄像机）

连接相机

获取连接的摄像机

{"blocks":"<xml xmlns=\"https://developers.google.com/blockly/xml\"><block type=\"Camera_getConnectedCameras\"/></xml>"}

此块用于连接摄像机。

参数： N/A
输出： 屏幕项目
示例代码：

{"blocks":"<xml xmlns=\"https://developers.google.com/blockly/xml\"><variables><variable>mainLayout</variable><variable>mainScreen</variable><variable>cameraLayout</variable><variable>cameraControl</variable><variable>connectedCameras</variable></variables><block type=\"pxt-on-start\" x=\"0\" y=\"0\"><statement name=\"HANDLER\"><block type=\"variables_set\"><field name=\"VAR\">mainLayout</field><value name=\"VALUE\"><shadow type=\"math_number\"><field name=\"NUM\">0</field></shadow><block type=\"ScreenItem_createLayout\"/></value><next><block type=\"variables_set\"><field name=\"VAR\">mainScreen</field><value name=\"VALUE\"><shadow type=\"math_number\"><field name=\"NUM\">0</field></shadow><block type=\"Screen_create\"><value name=\"label\"><shadow type=\"text\"><field name=\"TEXT\">Main</field></shadow></value><value name=\"layout\"><block type=\"variables_get\"><field name=\"VAR\">mainLayout</field></block></value></block></value><next><block type=\"Camera_enableCameraFeature\"><value name=\"enable\"><shadow type=\"logic_boolean\"><field name=\"BOOL\">TRUE</field></shadow></value><next><block type=\"variables_set\"><field name=\"VAR\">cameraLayout</field><value name=\"VALUE\"><shadow type=\"math_number\"><field name=\"NUM\">0</field></shadow><block type=\"ScreenItem_createLayout\"/></value><next><block type=\"variables_set\"><field name=\"VAR\">cameraControl</field><value name=\"VALUE\"><shadow type=\"math_number\"><field name=\"NUM\">0</field></shadow><block type=\"Camera_getCameraControl\"/></value><next><block type=\"Control_OptionList_setMultiple\"><value name=\"this\"><block type=\"variables_get\"><field name=\"VAR\">cameraControl</field></block></value><value name=\"isMultiple\"><shadow type=\"logic_boolean\"><field name=\"BOOL\">TRUE</field></shadow></value><next><block type=\"variables_set\"><field name=\"VAR\">connectedCameras</field><value name=\"VALUE\"><shadow type=\"math_number\"><field name=\"NUM\">0</field></shadow><block type=\"Camera_getConnectedCameras\"/></value><next><block type=\"ScreenItem_Layout_add\"><value name=\"this\"><block type=\"variables_get\"><field name=\"VAR\">cameraLayout</field></block></value><value name=\"item\"><block type=\"variables_get\"><field name=\"VAR\">cameraControl</field></block></value><next><block type=\"ScreenItem_Layout_add\"><value name=\"this\"><block type=\"variables_get\"><field name=\"VAR\">cameraLayout</field></block></value><value name=\"item\"><block type=\"lists_index_get\"><value name=\"LIST\"><block type=\"variables_get\"><field name=\"VAR\">connectedCameras</field></block></value><value name=\"INDEX\"><shadow type=\"math_number\"><field name=\"NUM\">0</field></shadow></value></block></value><next><block type=\"ScreenItem_Layout_add\"><value name=\"this\"><block type=\"variables_get\"><field name=\"VAR\">mainLayout</field></block></value><value name=\"item\"><block type=\"variables_get\"><field name=\"VAR\">cameraLayout</field></block></value></block></next></block></next></block></next></block></next></block></next></block></next></block></next></block></next></block></next></block></statement></block></xml>"}

输出：

连接摄像机 - 输出

使用相机

检查是否包含指定的摄像头

有摄像头

{"blocks":"<xml xmlns=\"https://developers.google.com/blockly/xml\"><block type=\"Camera_hasCamera\"><value name=\"deviceId\"><shadow type=\"text\"><field name=\"TEXT\"/></shadow></value></block></xml>"}

此块用于检查它是否包含相应的摄像头。

参数： 字符串
输出： 屏幕项目
示例代码：

这用于检查它是否包含相应的摄像头。

{"blocks":"<xml xmlns=\"https://developers.google.com/blockly/xml\"><block type=\"controls_if\"><mutation else=\"1\"/><value name=\"IF0\"><shadow type=\"logic_boolean\"><field name=\"BOOL\">TRUE</field></shadow><block type=\"Camera_hasCamera\"><value name=\"deviceId\"><shadow type=\"text\"><field name=\"TEXT\">0a9c24fb5f5271cbef965ab36f48179f57402ea7aee8a50409c88c1363239e6f</field></shadow></value></block></value><statement name=\"DO0\"><block type=\"Control_TextBlock_setContent\"><value name=\"this\"><block type=\"variables_get\"><field name=\"VAR\">textBlock</field></block></value><value name=\"content\"><shadow type=\"text\"><field name=\"TEXT\">It contains USB Camera (0c45:6367)</field></shadow></value></block></statement><statement name=\"ELSE\"><block type=\"Control_TextBlock_setContent\"><value name=\"this\"><block type=\"variables_get\"><field name=\"VAR\">textBlock</field></block></value><value name=\"content\"><shadow type=\"text\"><field name=\"TEXT\">It doesn't contain USB Camera (0c45:6367)</field></shadow></value></block></statement></block></xml>"}
{"blocks":"<xml xmlns=\"https://developers.google.com/blockly/xml\"><variables><variable>mainLayout</variable><variable>mainScreen</variable><variable>cameraControl</variable><variable>selectedCameras</variable><variable>recentlySelectedCameras</variable><variable>recentlyUnselectedCameras</variable><variable>value</variable><variable>value2</variable><variable>deviceId</variable><variable>textBlock</variable></variables><block type=\"pxt-on-start\" x=\"0\" y=\"0\"><statement name=\"HANDLER\"><block type=\"variables_set\"><field name=\"VAR\">mainLayout</field><value name=\"VALUE\"><shadow type=\"math_number\"><field name=\"NUM\">0</field></shadow><block type=\"ScreenItem_createLayout\"/></value><next><block type=\"variables_set\"><field name=\"VAR\">mainScreen</field><value name=\"VALUE\"><shadow type=\"math_number\"><field name=\"NUM\">0</field></shadow><block type=\"Screen_create\"><value name=\"label\"><shadow type=\"text\"><field name=\"TEXT\">Main</field></shadow></value><value name=\"layout\"><block type=\"variables_get\"><field name=\"VAR\">mainLayout</field></block></value></block></value><next><block type=\"Camera_enableCameraFeature\"><value name=\"enable\"><shadow type=\"logic_boolean\"><field name=\"BOOL\">TRUE</field></shadow></value><next><block type=\"variables_set\"><field name=\"VAR\">cameraControl</field><value name=\"VALUE\"><shadow type=\"math_number\"><field name=\"NUM\">0</field></shadow><block type=\"Camera_getCameraControl\"/></value><next><block type=\"Control_OptionList_setMultiple\"><value name=\"this\"><block type=\"variables_get\"><field name=\"VAR\">cameraControl</field></block></value><value name=\"isMultiple\"><shadow type=\"logic_boolean\"><field name=\"BOOL\">TRUE</field></shadow></value><next><block type=\"ScreenItem_Layout_add\"><value name=\"this\"><block type=\"variables_get\"><field name=\"VAR\">mainLayout</field></block></value><value name=\"item\"><block type=\"variables_get\"><field name=\"VAR\">cameraControl</field></block></value><next><block type=\"Camera_setOnCameraControlChanged\"><value name=\"HANDLER_DRAG_PARAM_selectedCameras\"><shadow type=\"variables_get_reporter\"><field name=\"VAR\">selectedCameras</field></shadow></value><value name=\"HANDLER_DRAG_PARAM_recentlySelectedCameras\"><shadow type=\"variables_get_reporter\"><field name=\"VAR\">recentlySelectedCameras</field></shadow></value><value name=\"HANDLER_DRAG_PARAM_recentlyUnselectedCameras\"><shadow type=\"variables_get_reporter\"><field name=\"VAR\">recentlyUnselectedCameras</field></shadow></value><statement name=\"HANDLER\"><block type=\"pxt_controls_for_of\"><value name=\"VAR\"><shadow type=\"variables_get_reporter\"><field name=\"VAR\">value</field></shadow></value><value name=\"LIST\"><block type=\"variables_get\"><field name=\"VAR\">recentlyUnselectedCameras</field></block></value><statement name=\"DO\"><block type=\"ScreenItem_ScreenItem_remove\"><value name=\"this\"><block type=\"ScreenItem_ScreenItem_getParent\"><value name=\"this\"><block type=\"variables_get\"><field name=\"VAR\">value</field></block></value></block></value></block></statement><next><block type=\"pxt_controls_for_of\"><value name=\"VAR\"><shadow type=\"variables_get_reporter\"><field name=\"VAR\">value2</field></shadow></value><value name=\"LIST\"><block type=\"variables_get\"><field name=\"VAR\">recentlySelectedCameras</field></block></value><statement name=\"DO\"><block type=\"variables_set\"><field name=\"VAR\">deviceId</field><value name=\"VALUE\"><shadow type=\"math_number\"><field name=\"NUM\">0</field></shadow><block type=\"Control_createTextBlock\"><mutation xmlns=\"http://www.w3.org/1999/xhtml\" _expanded=\"0\" _input_init=\"false\"></mutation></block></value><next><block type=\"Control_TextBlock_setContent\"><value name=\"this\"><block type=\"variables_get\"><field name=\"VAR\">deviceId</field></block></value><value name=\"content\"><block type=\"Camera_Camera_getDeviceId\"><value name=\"this\"><block type=\"variables_get\"><field name=\"VAR\">value2</field></block></value></block></value><next><block type=\"ScreenItem_Layout_add\"><value name=\"this\"><block type=\"variables_get\"><field name=\"VAR\">mainLayout</field></block></value><value name=\"item\"><block type=\"variables_get\"><field name=\"VAR\">deviceId</field></block></value><next><block type=\"variables_set\"><field name=\"VAR\">textBlock</field><value name=\"VALUE\"><shadow type=\"math_number\"><field name=\"NUM\">0</field></shadow><block type=\"Control_createTextBlock\"><mutation xmlns=\"http://www.w3.org/1999/xhtml\" _expanded=\"0\" _input_init=\"false\"></mutation></block></value><next><block type=\"ScreenItem_Layout_add\"><value name=\"this\"><block type=\"variables_get\"><field name=\"VAR\">mainLayout</field></block></value><value name=\"item\"><block type=\"variables_get\"><field name=\"VAR\">textBlock</field></block></value><next><block type=\"ScreenItem_Layout_add\"><value name=\"this\"><block type=\"variables_get\"><field name=\"VAR\">mainLayout</field></block></value><value name=\"item\"><block type=\"variables_get\"><field name=\"VAR\">value2</field></block></value><next><block type=\"controls_if\"><mutation else=\"1\"/><value name=\"IF0\"><shadow type=\"logic_boolean\"><field name=\"BOOL\">TRUE</field></shadow><block type=\"Camera_hasCamera\"><value name=\"deviceId\"><shadow type=\"text\"><field name=\"TEXT\">0a9c24fb5f5271cbef965ab36f48179f57402ea7aee8a50409c88c1363239e6f</field></shadow></value></block></value><statement name=\"DO0\"><block type=\"Control_TextBlock_setContent\"><value name=\"this\"><block type=\"variables_get\"><field name=\"VAR\">textBlock</field></block></value><value name=\"content\"><shadow type=\"text\"><field name=\"TEXT\">It contains USB Camera (0c45:6367)</field></shadow></value></block></statement><statement name=\"ELSE\"><block type=\"Control_TextBlock_setContent\"><value name=\"this\"><block type=\"variables_get\"><field name=\"VAR\">textBlock</field></block></value><value name=\"content\"><shadow type=\"text\"><field name=\"TEXT\">It doesn't contain USB Camera (0c45:6367)</field></shadow></value></block></statement></block></next></block></next></block></next></block></next></block></next></block></next></block></statement></block></next></block></statement></block></next></block></next></block></next></block></next></block></next></block></next></block></statement></block></xml>"}

输出：

有摄像头 - 输出

获取指定的相机

获取相机

{"blocks":"<xml xmlns=\"https://developers.google.com/blockly/xml\"><block type=\"Camera_getCamera\"><value name=\"deviceId\"><shadow type=\"text\"><field name=\"TEXT\"/></shadow></value></block></xml>"}

此块用于通过在此块内输入摄像机的 ID 来获取摄像机。

参数： 字符串
输出： 屏幕项目
示例代码：

该变量将获取相机。

{"blocks":"<xml xmlns=\"https://developers.google.com/blockly/xml\"><block type=\"variables_set\"><field name=\"VAR\">getCamera</field><value name=\"VALUE\"><shadow type=\"math_number\"><field name=\"NUM\">0</field></shadow><block type=\"Camera_getCamera\"><value name=\"deviceId\"><shadow type=\"text\"><field name=\"TEXT\">7e2b0995f8a6d9df2958ed69edbb3757cfd0680da8b2fd6a0bcbb8b54987bb9d</field></shadow></value></block></value></block></xml>"}
{"blocks":"<xml xmlns=\"https://developers.google.com/blockly/xml\"><variables><variable>mainLayout</variable><variable>mainScreen</variable><variable>cameraLayout</variable><variable>cameraControl</variable><variable>deviceId</variable><variable>getCamera</variable></variables><block type=\"pxt-on-start\" x=\"0\" y=\"0\"><statement name=\"HANDLER\"><block type=\"variables_set\"><field name=\"VAR\">mainLayout</field><value name=\"VALUE\"><shadow type=\"math_number\"><field name=\"NUM\">0</field></shadow><block type=\"ScreenItem_createLayout\"/></value><next><block type=\"variables_set\"><field name=\"VAR\">mainScreen</field><value name=\"VALUE\"><shadow type=\"math_number\"><field name=\"NUM\">0</field></shadow><block type=\"Screen_create\"><value name=\"label\"><shadow type=\"text\"><field name=\"TEXT\">Main</field></shadow></value><value name=\"layout\"><block type=\"variables_get\"><field name=\"VAR\">mainLayout</field></block></value></block></value><next><block type=\"Camera_enableCameraFeature\"><value name=\"enable\"><shadow type=\"logic_boolean\"><field name=\"BOOL\">TRUE</field></shadow></value><next><block type=\"variables_set\"><field name=\"VAR\">cameraLayout</field><value name=\"VALUE\"><shadow type=\"math_number\"><field name=\"NUM\">0</field></shadow><block type=\"ScreenItem_createLayout\"/></value><next><block type=\"variables_set\"><field name=\"VAR\">cameraControl</field><value name=\"VALUE\"><shadow type=\"math_number\"><field name=\"NUM\">0</field></shadow><block type=\"Camera_getCameraControl\"/></value><next><block type=\"variables_set\"><field name=\"VAR\">deviceId</field><value name=\"VALUE\"><shadow type=\"math_number\"><field name=\"NUM\">0</field></shadow><block type=\"Control_createTextBlock\"><mutation xmlns=\"http://www.w3.org/1999/xhtml\" _expanded=\"0\" _input_init=\"false\"></mutation></block></value><next><block type=\"Control_OptionList_setMultiple\"><value name=\"this\"><block type=\"variables_get\"><field name=\"VAR\">cameraControl</field></block></value><value name=\"isMultiple\"><shadow type=\"logic_boolean\"><field name=\"BOOL\">TRUE</field></shadow></value><next><block type=\"ScreenItem_Layout_add\"><value name=\"this\"><block type=\"variables_get\"><field name=\"VAR\">cameraLayout</field></block></value><value name=\"item\"><block type=\"variables_get\"><field name=\"VAR\">cameraControl</field></block></value><next><block type=\"Control_TextBlock_setContent\"><value name=\"this\"><block type=\"variables_get\"><field name=\"VAR\">deviceId</field></block></value><value name=\"content\"><block type=\"Camera_Camera_getDeviceId\"><value name=\"this\"><block type=\"variables_get\"><field name=\"VAR\">getCamera</field></block></value></block></value><next><block type=\"variables_set\"><field name=\"VAR\">getCamera</field><value name=\"VALUE\"><shadow type=\"math_number\"><field name=\"NUM\">0</field></shadow><block type=\"Camera_getCamera\"><value name=\"deviceId\"><shadow type=\"text\"><field name=\"TEXT\">7e2b0995f8a6d9df2958ed69edbb3757cfd0680da8b2fd6a0bcbb8b54987bb9d</field></shadow></value></block></value><next><block type=\"ScreenItem_Layout_add\"><value name=\"this\"><block type=\"variables_get\"><field name=\"VAR\">cameraLayout</field></block></value><value name=\"item\"><block type=\"variables_get\"><field name=\"VAR\">deviceId</field></block></value><next><block type=\"ScreenItem_Layout_add\"><value name=\"this\"><block type=\"variables_get\"><field name=\"VAR\">cameraLayout</field></block></value><value name=\"item\"><block type=\"variables_get\"><field name=\"VAR\">getCamera</field></block></value><next><block type=\"ScreenItem_Layout_add\"><value name=\"this\"><block type=\"variables_get\"><field name=\"VAR\">mainLayout</field></block></value><value name=\"item\"><block type=\"variables_get\"><field name=\"VAR\">cameraLayout</field></block></value></block></next></block></next></block></next></block></next></block></next></block></next></block></next></block></next></block></next></block></next></block></next></block></next></block></statement></block></xml>"}

选择USB2.0高清UVC网络摄像头（13d3：56a8）时，输出：

相机ID为：7e2b0995f8a6d9df2958ed69edbb3757cfd0680da8b2fd6a0bcbb8b54987bb9d

获取相机 - 输出

显示摄像机 ID

相机获取设备 ID

{"blocks":"<xml xmlns=\"https://developers.google.com/blockly/xml\"><block type=\"Camera_Camera_getDeviceId\"><value name=\"this\"><block type=\"variables_get\"><field name=\"VAR\">camera</field></block></value></block></xml>"}

此块用于获取相机的 ID。

参数： 屏幕项目（相机）
输出： 屏幕项目
示例代码：

这将显示设备 ID 和相应的相机。

{"blocks":"<xml xmlns=\"https://developers.google.com/blockly/xml\"><block type=\"pxt_controls_for_of\"><value name=\"VAR\"><shadow type=\"variables_get_reporter\"><field name=\"VAR\">value2</field></shadow></value><value name=\"LIST\"><block type=\"variables_get\"><field name=\"VAR\">recentlySelectedCameras</field></block></value><statement name=\"DO\"><block type=\"variables_set\"><field name=\"VAR\">cameraResultLayout</field><value name=\"VALUE\"><shadow type=\"math_number\"><field name=\"NUM\">0</field></shadow><block type=\"ScreenItem_createLayout\"/></value><next><block type=\"ScreenItem_Layout_add\"><value name=\"this\"><block type=\"variables_get\"><field name=\"VAR\">cameraResultLayout</field></block></value><value name=\"item\"><block type=\"variables_get\"><field name=\"VAR\">value2</field></block></value><next><block type=\"variables_set\"><field name=\"VAR\">deviceId</field><value name=\"VALUE\"><shadow type=\"math_number\"><field name=\"NUM\">0</field></shadow><block type=\"Control_createTextBlock\"><mutation xmlns=\"http://www.w3.org/1999/xhtml\" _expanded=\"0\" _input_init=\"false\"></mutation></block></value><next><block type=\"Control_TextBlock_setContent\"><value name=\"this\"><block type=\"variables_get\"><field name=\"VAR\">deviceId</field></block></value><value name=\"content\"><block type=\"Camera_Camera_getDeviceId\"><value name=\"this\"><block type=\"variables_get\"><field name=\"VAR\">value2</field></block></value></block></value><next><block type=\"ScreenItem_Layout_add\"><value name=\"this\"><block type=\"variables_get\"><field name=\"VAR\">cameraLayout</field></block></value><value name=\"item\"><block type=\"variables_get\"><field name=\"VAR\">deviceId</field></block></value><next><block type=\"ScreenItem_Layout_add\"><value name=\"this\"><block type=\"variables_get\"><field name=\"VAR\">cameraLayout</field></block></value><value name=\"item\"><block type=\"variables_get\"><field name=\"VAR\">cameraResultLayout</field></block></value></block></next></block></next></block></next></block></next></block></next></block></statement></block></xml>"}
{"blocks":"<xml xmlns=\"https://developers.google.com/blockly/xml\"><variables><variable>mainLayout</variable><variable>mainScreen</variable><variable>cameraLayout</variable><variable>cameraControl</variable><variable>selectedCameras</variable><variable>recentlySelectedCameras</variable><variable>recentlyUnselectedCameras</variable><variable>value2</variable><variable>cameraResultLayout</variable><variable>deviceId</variable></variables><block type=\"pxt-on-start\" x=\"0\" y=\"0\"><statement name=\"HANDLER\"><block type=\"variables_set\"><field name=\"VAR\">mainLayout</field><value name=\"VALUE\"><shadow type=\"math_number\"><field name=\"NUM\">0</field></shadow><block type=\"ScreenItem_createLayout\"/></value><next><block type=\"variables_set\"><field name=\"VAR\">mainScreen</field><value name=\"VALUE\"><shadow type=\"math_number\"><field name=\"NUM\">0</field></shadow><block type=\"Screen_create\"><value name=\"label\"><shadow type=\"text\"><field name=\"TEXT\">Main</field></shadow></value><value name=\"layout\"><block type=\"variables_get\"><field name=\"VAR\">mainLayout</field></block></value></block></value><next><block type=\"Camera_enableCameraFeature\"><value name=\"enable\"><shadow type=\"logic_boolean\"><field name=\"BOOL\">TRUE</field></shadow></value><next><block type=\"variables_set\"><field name=\"VAR\">cameraLayout</field><value name=\"VALUE\"><shadow type=\"math_number\"><field name=\"NUM\">0</field></shadow><block type=\"ScreenItem_createLayout\"/></value><next><block type=\"variables_set\"><field name=\"VAR\">cameraControl</field><value name=\"VALUE\"><shadow type=\"math_number\"><field name=\"NUM\">0</field></shadow><block type=\"Camera_getCameraControl\"/></value><next><block type=\"Control_OptionList_setMultiple\"><value name=\"this\"><block type=\"variables_get\"><field name=\"VAR\">cameraControl</field></block></value><value name=\"isMultiple\"><shadow type=\"logic_boolean\"><field name=\"BOOL\">TRUE</field></shadow></value><next><block type=\"ScreenItem_Layout_add\"><value name=\"this\"><block type=\"variables_get\"><field name=\"VAR\">cameraLayout</field></block></value><value name=\"item\"><block type=\"variables_get\"><field name=\"VAR\">cameraControl</field></block></value><next><block type=\"ScreenItem_Layout_add\"><value name=\"this\"><block type=\"variables_get\"><field name=\"VAR\">mainLayout</field></block></value><value name=\"item\"><block type=\"variables_get\"><field name=\"VAR\">cameraLayout</field></block></value><next><block type=\"Camera_setOnCameraControlChanged\"><value name=\"HANDLER_DRAG_PARAM_selectedCameras\"><shadow type=\"variables_get_reporter\"><field name=\"VAR\">selectedCameras</field></shadow></value><value name=\"HANDLER_DRAG_PARAM_recentlySelectedCameras\"><shadow type=\"variables_get_reporter\"><field name=\"VAR\">recentlySelectedCameras</field></shadow></value><value name=\"HANDLER_DRAG_PARAM_recentlyUnselectedCameras\"><shadow type=\"variables_get_reporter\"><field name=\"VAR\">recentlyUnselectedCameras</field></shadow></value><statement name=\"HANDLER\"><block type=\"pxt_controls_for_of\"><value name=\"VAR\"><shadow type=\"variables_get_reporter\"><field name=\"VAR\">value2</field></shadow></value><value name=\"LIST\"><block type=\"variables_get\"><field name=\"VAR\">recentlySelectedCameras</field></block></value><statement name=\"DO\"><block type=\"variables_set\"><field name=\"VAR\">cameraResultLayout</field><value name=\"VALUE\"><shadow type=\"math_number\"><field name=\"NUM\">0</field></shadow><block type=\"ScreenItem_createLayout\"/></value><next><block type=\"ScreenItem_Layout_add\"><value name=\"this\"><block type=\"variables_get\"><field name=\"VAR\">cameraResultLayout</field></block></value><value name=\"item\"><block type=\"variables_get\"><field name=\"VAR\">value2</field></block></value><next><block type=\"variables_set\"><field name=\"VAR\">deviceId</field><value name=\"VALUE\"><shadow type=\"math_number\"><field name=\"NUM\">0</field></shadow><block type=\"Control_createTextBlock\"><mutation xmlns=\"http://www.w3.org/1999/xhtml\" _expanded=\"0\" _input_init=\"false\"></mutation></block></value><next><block type=\"Control_TextBlock_setContent\"><value name=\"this\"><block type=\"variables_get\"><field name=\"VAR\">deviceId</field></block></value><value name=\"content\"><block type=\"Camera_Camera_getDeviceId\"><value name=\"this\"><block type=\"variables_get\"><field name=\"VAR\">value2</field></block></value></block></value><next><block type=\"ScreenItem_Layout_add\"><value name=\"this\"><block type=\"variables_get\"><field name=\"VAR\">cameraLayout</field></block></value><value name=\"item\"><block type=\"variables_get\"><field name=\"VAR\">deviceId</field></block></value><next><block type=\"ScreenItem_Layout_add\"><value name=\"this\"><block type=\"variables_get\"><field name=\"VAR\">cameraLayout</field></block></value><value name=\"item\"><block type=\"variables_get\"><field name=\"VAR\">cameraResultLayout</field></block></value></block></next></block></next></block></next></block></next></block></next></block></statement></block></statement></block></next></block></next></block></next></block></next></block></next></block></next></block></next></block></next></block></statement></block></xml>"}

输出：

获取相机 - 输出

屏幕截图

相机捕捉图像

{"blocks":"<xml xmlns=\"https://developers.google.com/blockly/xml\"><block type=\"Camera_Camera_captureImage\"><value name=\"this\"><block type=\"variables_get\"><field name=\"VAR\">camera</field></block></value></block></xml>"}

此块用于捕获相机屏幕。

参数： 屏幕项目（相机）
输出： 屏幕项目
示例代码：

在单击按钮之前，它将显示相机屏幕。 您可以看到屏幕正在移动。 

{"blocks":"<xml xmlns=\"https://developers.google.com/blockly/xml\"><block type=\"ScreenItem_ScreenItem_onClick\"><value name=\"this\"><block type=\"variables_get\"><field name=\"VAR\">button</field></block></value><statement name=\"HANDLER\"><block type=\"ScreenItem_Layout_add\"><value name=\"this\"><block type=\"variables_get\"><field name=\"VAR\">cameraLayout</field></block></value><value name=\"item\"><block type=\"variables_get\"><field name=\"VAR\">captureImage</field></block></value></block></statement></block></xml>"}
{"blocks":"<xml xmlns=\"https://developers.google.com/blockly/xml\"><variables><variable>mainLayout</variable><variable>mainScreen</variable><variable>cameraLayout</variable><variable>cameraControl</variable><variable>getCamera</variable><variable>deviceId</variable><variable>text</variable><variable>button</variable><variable>captureImage</variable></variables><block type=\"pxt-on-start\" x=\"0\" y=\"0\"><statement name=\"HANDLER\"><block type=\"variables_set\"><field name=\"VAR\">mainLayout</field><value name=\"VALUE\"><shadow type=\"math_number\"><field name=\"NUM\">0</field></shadow><block type=\"ScreenItem_createLayout\"/></value><next><block type=\"variables_set\"><field name=\"VAR\">mainScreen</field><value name=\"VALUE\"><shadow type=\"math_number\"><field name=\"NUM\">0</field></shadow><block type=\"Screen_create\"><value name=\"label\"><shadow type=\"text\"><field name=\"TEXT\">Main</field></shadow></value><value name=\"layout\"><block type=\"variables_get\"><field name=\"VAR\">mainLayout</field></block></value></block></value><next><block type=\"Camera_enableCameraFeature\"><value name=\"enable\"><shadow type=\"logic_boolean\"><field name=\"BOOL\">TRUE</field></shadow></value><next><block type=\"variables_set\"><field name=\"VAR\">cameraLayout</field><value name=\"VALUE\"><shadow type=\"math_number\"><field name=\"NUM\">0</field></shadow><block type=\"ScreenItem_createLayout\"/></value><next><block type=\"variables_set\"><field name=\"VAR\">cameraControl</field><value name=\"VALUE\"><shadow type=\"math_number\"><field name=\"NUM\">0</field></shadow><block type=\"Camera_getCameraControl\"/></value><next><block type=\"variables_set\"><field name=\"VAR\">getCamera</field><value name=\"VALUE\"><shadow type=\"math_number\"><field name=\"NUM\">0</field></shadow><block type=\"Camera_getCamera\"><value name=\"deviceId\"><shadow type=\"text\"><field name=\"TEXT\">7e2b0995f8a6d9df2958ed69edbb3757cfd0680da8b2fd6a0bcbb8b54987bb9d</field></shadow></value></block></value><next><block type=\"variables_set\"><field name=\"VAR\">deviceId</field><value name=\"VALUE\"><shadow type=\"math_number\"><field name=\"NUM\">0</field></shadow><block type=\"Camera_Camera_getDeviceId\"><value name=\"this\"><block type=\"variables_get\"><field name=\"VAR\">getCamera</field></block></value></block></value><next><block type=\"variables_set\"><field name=\"VAR\">text</field><value name=\"VALUE\"><shadow type=\"math_number\"><field name=\"NUM\">0</field></shadow><block type=\"Control_createTextBlock\"><mutation xmlns=\"http://www.w3.org/1999/xhtml\" _expanded=\"0\" _input_init=\"false\"></mutation></block></value><next><block type=\"variables_set\"><field name=\"VAR\">button</field><value name=\"VALUE\"><shadow type=\"math_number\"><field name=\"NUM\">0</field></shadow><block type=\"Control_createButton\"><value name=\"content\"><shadow type=\"text\"><field name=\"TEXT\">Capture Image</field></shadow></value></block></value><next><block type=\"Control_OptionList_setMultiple\"><value name=\"this\"><block type=\"variables_get\"><field name=\"VAR\">cameraControl</field></block></value><value name=\"isMultiple\"><shadow type=\"logic_boolean\"><field name=\"BOOL\">TRUE</field></shadow></value><next><block type=\"ScreenItem_Layout_add\"><value name=\"this\"><block type=\"variables_get\"><field name=\"VAR\">cameraLayout</field></block></value><value name=\"item\"><block type=\"variables_get\"><field name=\"VAR\">cameraControl</field></block></value><next><block type=\"Control_TextBlock_setContent\"><value name=\"this\"><block type=\"variables_get\"><field name=\"VAR\">text</field></block></value><value name=\"content\"><block type=\"variables_get\"><field name=\"VAR\">deviceId</field></block></value><next><block type=\"ScreenItem_Layout_add\"><value name=\"this\"><block type=\"variables_get\"><field name=\"VAR\">cameraLayout</field></block></value><value name=\"item\"><block type=\"variables_get\"><field name=\"VAR\">text</field></block></value><next><block type=\"ScreenItem_Layout_add\"><value name=\"this\"><block type=\"variables_get\"><field name=\"VAR\">cameraLayout</field></block></value><value name=\"item\"><block type=\"variables_get\"><field name=\"VAR\">getCamera</field></block></value><next><block type=\"ScreenItem_Layout_add\"><value name=\"this\"><block type=\"variables_get\"><field name=\"VAR\">cameraLayout</field></block></value><value name=\"item\"><block type=\"variables_get\"><field name=\"VAR\">button</field></block></value><next><block type=\"ScreenItem_Layout_add\"><value name=\"this\"><block type=\"variables_get\"><field name=\"VAR\">mainLayout</field></block></value><value name=\"item\"><block type=\"variables_get\"><field name=\"VAR\">cameraLayout</field></block></value><next><block type=\"variables_set\"><field name=\"VAR\">captureImage</field><value name=\"VALUE\"><shadow type=\"math_number\"><field name=\"NUM\">0</field></shadow><block type=\"Camera_Camera_captureImage\"><value name=\"this\"><block type=\"variables_get\"><field name=\"VAR\">getCamera</field></block></value></block></value><next><block type=\"ScreenItem_ScreenItem_onClick\"><value name=\"this\"><block type=\"variables_get\"><field name=\"VAR\">button</field></block></value><statement name=\"HANDLER\"><block type=\"ScreenItem_Layout_add\"><value name=\"this\"><block type=\"variables_get\"><field name=\"VAR\">cameraLayout</field></block></value><value name=\"item\"><block type=\"variables_get\"><field name=\"VAR\">captureImage</field></block></value></block></statement></block></next></block></next></block></next></block></next></block></next></block></next></block></next></block></next></block></next></block></next></block></next></block></next></block></next></block></next></block></next></block></next></block></next></block></statement></block></xml>"}

输出：

摄像机捕获图像 - 移动输出
相机捕获图像 - 第二移动输出

单击按钮后，它将显示捕获图像。

输出：

相机捕获图像 - 捕获输出

更多相机

设置用于检测无相机壳的文本

设置未检测到摄像头的消息

{"blocks":"<xml xmlns=\"https://developers.google.com/blockly/xml\"><block type=\"Camera_setNoCameraDetectedMessage\"><value name=\"msg\"><shadow type=\"text\"><field name=\"TEXT\"/></shadow></value></block></xml>"}

设置设备不包含任何摄像头时的显示消息。

参数： 显示设置：字符串
输出： N/A
示例代码：

{"blocks":"<xml xmlns=\"https://developers.google.com/blockly/xml\"><variables><variable>mainLayout</variable><variable>mainScreen</variable><variable>cameraControl</variable></variables><block type=\"pxt-on-start\" x=\"0\" y=\"0\"><statement name=\"HANDLER\"><block type=\"variables_set\"><field name=\"VAR\">mainLayout</field><value name=\"VALUE\"><shadow type=\"math_number\"><field name=\"NUM\">0</field></shadow><block type=\"ScreenItem_createLayout\"/></value><next><block type=\"variables_set\"><field name=\"VAR\">mainScreen</field><value name=\"VALUE\"><shadow type=\"math_number\"><field name=\"NUM\">0</field></shadow><block type=\"Screen_create\"><value name=\"label\"><shadow type=\"text\"><field name=\"TEXT\">Main</field></shadow></value><value name=\"layout\"><block type=\"variables_get\"><field name=\"VAR\">mainLayout</field></block></value></block></value><next><block type=\"Camera_enableCameraFeature\"><value name=\"enable\"><shadow type=\"logic_boolean\"><field name=\"BOOL\">TRUE</field></shadow></value><next><block type=\"variables_set\"><field name=\"VAR\">cameraControl</field><value name=\"VALUE\"><shadow type=\"math_number\"><field name=\"NUM\">0</field></shadow><block type=\"Camera_getCameraControl\"/></value><next><block type=\"Camera_setNoCameraDetectedMessage\"><value name=\"msg\"><shadow type=\"text\"><field name=\"TEXT\">There is no camera.</field></shadow></value></block></next></block></next></block></next></block></next></block></statement></block></xml>"}

由于这些块没有获取检测消息输出，因此输出应为 none：

设置未检测到摄像头消息 - 输出

接收设备中没有摄像头的文本

获取未检测到摄像头的消息

{"blocks":"<xml xmlns=\"https://developers.google.com/blockly/xml\"><block type=\"Camera_getNoCameraDetectedMessage\"/></xml>"}

获取用于不包含摄像头的设备的内容消息。

参数： N/A
输出： 屏幕项目
示例代码：

{"blocks":"<xml xmlns=\"https://developers.google.com/blockly/xml\"><variables><variable>mainLayout</variable><variable>mainScreen</variable><variable>cameraControl</variable><variable>detectedMessage</variable></variables><block type=\"pxt-on-start\" x=\"0\" y=\"0\"><statement name=\"HANDLER\"><block type=\"variables_set\"><field name=\"VAR\">mainLayout</field><value name=\"VALUE\"><shadow type=\"math_number\"><field name=\"NUM\">0</field></shadow><block type=\"ScreenItem_createLayout\"/></value><next><block type=\"variables_set\"><field name=\"VAR\">mainScreen</field><value name=\"VALUE\"><shadow type=\"math_number\"><field name=\"NUM\">0</field></shadow><block type=\"Screen_create\"><value name=\"label\"><shadow type=\"text\"><field name=\"TEXT\">Main</field></shadow></value><value name=\"layout\"><block type=\"variables_get\"><field name=\"VAR\">mainLayout</field></block></value></block></value><next><block type=\"Camera_enableCameraFeature\"><value name=\"enable\"><shadow type=\"logic_boolean\"><field name=\"BOOL\">TRUE</field></shadow></value><next><block type=\"variables_set\"><field name=\"VAR\">cameraControl</field><value name=\"VALUE\"><shadow type=\"math_number\"><field name=\"NUM\">0</field></shadow><block type=\"Camera_getCameraControl\"/></value><next><block type=\"Camera_setNoCameraDetectedMessage\"><value name=\"msg\"><shadow type=\"text\"><field name=\"TEXT\">There is no camera.</field></shadow></value><next><block type=\"variables_set\"><field name=\"VAR\">detectedMessage</field><value name=\"VALUE\"><shadow type=\"math_number\"><field name=\"NUM\">0</field></shadow><block type=\"Camera_getNoCameraDetectedMessage\"/></value><next><block type=\"ScreenItem_Layout_add\"><value name=\"this\"><block type=\"variables_get\"><field name=\"VAR\">mainLayout</field></block></value><value name=\"item\"><block type=\"Control_createTextBlock\"><mutation xmlns=\"http://www.w3.org/1999/xhtml\" _expanded=\"1\" _input_init=\"true\"></mutation><value name=\"text\"><block type=\"variables_get\"><field name=\"VAR\">detectedMessage</field></block></value></block></value></block></next></block></next></block></next></block></next></block></next></block></next></block></statement></block></xml>"}

输出：

获取未检测到摄像头的消息 - 输出

目录