该文件说明了如何将元素滚动到可见范围、识别父元素、清除和删除屏幕项目中的值，以及向屏幕项目添加操作。

将元素滚动到可见区域

屏幕专案滚动到检视中

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

此块用于将指定的布局滚动到可见区域。

参数： 屏幕专案
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>scrollButton</variable><variable>secondChildLayout</variable><variable>firstChildLayout</variable><variable>screenItem</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=\"Styling_setFlexShorthand\"><field name=\"flexShorthand\">FlexShorthand.Auto</field><value name=\"item\"><block type=\"variables_get\"><field name=\"VAR\">mainLayout</field></block></value><next><block type=\"variables_set\"><field name=\"VAR\">scrollButton</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\">Scroll</field></shadow></value></block></value><next><block type=\"ScreenItem_ScreenItem_onClick\"><value name=\"this\"><block type=\"variables_get\"><field name=\"VAR\">scrollButton</field></block></value><statement name=\"HANDLER\"><block type=\"ScreenItem_ScreenItem_scrollIntoView\"><value name=\"this\"><block type=\"variables_get\"><field name=\"VAR\">secondChildLayout</field></block></value></block></statement><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\">scrollButton</field></block></value><next><block type=\"variables_set\"><field name=\"VAR\">firstChildLayout</field><value name=\"VALUE\"><shadow type=\"math_number\"><field name=\"NUM\">0</field></shadow><block type=\"ScreenItem_createLayout\"/></value><next><block type=\"Styling_setHeight\"><value name=\"item\"><block type=\"variables_get\"><field name=\"VAR\">firstChildLayout</field></block></value><value name=\"height\"><block type=\"CssValues_createLength\"><field name=\"unit\">CssLengthUnit.PX</field><value name=\"value\"><shadow type=\"math_number\"><field name=\"NUM\">1000</field></shadow></value></block></value><next><block type=\"Styling_setBackgroundColor\"><value name=\"item\"><block type=\"variables_get\"><field name=\"VAR\">firstChildLayout</field></block></value><value name=\"color\"><block type=\"CssValues_createColor\"><mutation xmlns=\"http://www.w3.org/1999/xhtml\" _expanded=\"0\" _input_init=\"false\"></mutation><value name=\"r\"><shadow type=\"math_number_minmax\"><mutation min=\"0\" max=\"255\" label=\"Number\" precision=\"0\"/><field name=\"SLIDER\">255</field></shadow></value><value name=\"g\"><shadow type=\"math_number_minmax\"><mutation min=\"0\" max=\"255\" label=\"Number\" precision=\"0\"/><field name=\"SLIDER\">255</field></shadow></value><value name=\"b\"><shadow type=\"math_number_minmax\"><mutation min=\"0\" max=\"255\" label=\"Number\" precision=\"0\"/><field name=\"SLIDER\">0</field></shadow></value></block></value><next><block type=\"variables_set\"><field name=\"VAR\">secondChildLayout</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\">mainLayout</field></block></value><value name=\"item\"><block type=\"variables_get\"><field name=\"VAR\">firstChildLayout</field></block></value><next><block type=\"Styling_setHeight\"><value name=\"item\"><block type=\"variables_get\"><field name=\"VAR\">secondChildLayout</field></block></value><value name=\"height\"><block type=\"CssValues_createLengthPercentage\"><value name=\"value\"><shadow type=\"math_number\"><field name=\"NUM\">100</field></shadow></value></block></value><next><block type=\"Styling_setBackgroundColor\"><value name=\"item\"><block type=\"variables_get\"><field name=\"VAR\">secondChildLayout</field></block></value><value name=\"color\"><block type=\"CssValues_createColor\"><mutation xmlns=\"http://www.w3.org/1999/xhtml\" _expanded=\"0\" _input_init=\"false\"></mutation><value name=\"r\"><shadow type=\"math_number_minmax\"><mutation min=\"0\" max=\"255\" label=\"Number\" precision=\"0\"/><field name=\"SLIDER\">0</field></shadow></value><value name=\"g\"><shadow type=\"math_number_minmax\"><mutation min=\"0\" max=\"255\" label=\"Number\" precision=\"0\"/><field name=\"SLIDER\">255</field></shadow></value><value name=\"b\"><shadow type=\"math_number_minmax\"><mutation min=\"0\" max=\"255\" label=\"Number\" precision=\"0\"/><field name=\"SLIDER\">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\">secondChildLayout</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></next></block></statement></block></xml>"}

原始输出：

点击“滚动”按钮后：

获取父元素

屏幕项 获取父屏幕项

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

此块用于获取父屏幕项。

参数： 屏幕项目
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>removeChildBtn</variable><variable>removeParentBtn</variable><variable>parent</variable><variable>child</variable><variable>screenItem</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=\"variables_set\"><field name=\"VAR\">removeChildBtn</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\">Remove Child</field></shadow></value></block></value><next><block type=\"variables_set\"><field name=\"VAR\">removeParentBtn</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\">Remove Parent</field></shadow></value></block></value><next><block type=\"variables_set\"><field name=\"VAR\">parent</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\">child</field><value name=\"VALUE\"><shadow type=\"math_number\"><field name=\"NUM\">0</field></shadow><block type=\"ScreenItem_createLayout\"/></value><next><block type=\"Styling_setFlexShorthand\"><field name=\"flexShorthand\">FlexShorthand.Auto</field><value name=\"item\"><block type=\"variables_get\"><field name=\"VAR\">mainLayout</field></block></value><next><block type=\"Styling_setBackgroundColor\"><value name=\"item\"><block type=\"variables_get\"><field name=\"VAR\">parent</field></block></value><value name=\"color\"><block type=\"CssValues_createColor\"><mutation xmlns=\"http://www.w3.org/1999/xhtml\" _expanded=\"0\" _input_init=\"false\"></mutation><value name=\"r\"><shadow type=\"math_number_minmax\"><mutation min=\"0\" max=\"255\" label=\"Number\" precision=\"0\"/><field name=\"SLIDER\">255</field></shadow></value><value name=\"g\"><shadow type=\"math_number_minmax\"><mutation min=\"0\" max=\"255\" label=\"Number\" precision=\"0\"/><field name=\"SLIDER\">255</field></shadow></value><value name=\"b\"><shadow type=\"math_number_minmax\"><mutation min=\"0\" max=\"255\" label=\"Number\" precision=\"0\"/><field name=\"SLIDER\">0</field></shadow></value></block></value><next><block type=\"Styling_setHeight\"><value name=\"item\"><block type=\"variables_get\"><field name=\"VAR\">parent</field></block></value><value name=\"height\"><block type=\"CssValues_createLength\"><field name=\"unit\">CssLengthUnit.PX</field><value name=\"value\"><shadow type=\"math_number\"><field name=\"NUM\">70</field></shadow></value></block></value><next><block type=\"Styling_setWidth\"><value name=\"item\"><block type=\"variables_get\"><field name=\"VAR\">parent</field></block></value><value name=\"width\"><block type=\"CssValues_createLength\"><field name=\"unit\">CssLengthUnit.PX</field><value name=\"value\"><shadow type=\"math_number\"><field name=\"NUM\">500</field></shadow></value></block></value><next><block type=\"Styling_setBackgroundColor\"><value name=\"item\"><block type=\"variables_get\"><field name=\"VAR\">child</field></block></value><value name=\"color\"><block type=\"CssValues_createColor\"><mutation xmlns=\"http://www.w3.org/1999/xhtml\" _expanded=\"0\" _input_init=\"false\"></mutation><value name=\"r\"><shadow type=\"math_number_minmax\"><mutation min=\"0\" max=\"255\" label=\"Number\" precision=\"0\"/><field name=\"SLIDER\">0</field></shadow></value><value name=\"g\"><shadow type=\"math_number_minmax\"><mutation min=\"0\" max=\"255\" label=\"Number\" precision=\"0\"/><field name=\"SLIDER\">0</field></shadow></value><value name=\"b\"><shadow type=\"math_number_minmax\"><mutation min=\"0\" max=\"255\" label=\"Number\" precision=\"0\"/><field name=\"SLIDER\">255</field></shadow></value></block></value><next><block type=\"Styling_setHeight\"><value name=\"item\"><block type=\"variables_get\"><field name=\"VAR\">child</field></block></value><value name=\"height\"><block type=\"CssValues_createLength\"><field name=\"unit\">CssLengthUnit.PX</field><value name=\"value\"><shadow type=\"math_number\"><field name=\"NUM\">40</field></shadow></value></block></value><next><block type=\"Styling_setWidth\"><value name=\"item\"><block type=\"variables_get\"><field name=\"VAR\">child</field></block></value><value name=\"width\"><block type=\"CssValues_createLength\"><field name=\"unit\">CssLengthUnit.PX</field><value name=\"value\"><shadow type=\"math_number\"><field name=\"NUM\">300</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\">removeChildBtn</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\">removeParentBtn</field></block></value><next><block type=\"ScreenItem_Layout_add\"><value name=\"this\"><block type=\"variables_get\"><field name=\"VAR\">parent</field></block></value><value name=\"item\"><block type=\"variables_get\"><field name=\"VAR\">child</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\">parent</field></block></value><next><block type=\"ScreenItem_ScreenItem_onClick\"><value name=\"this\"><block type=\"variables_get\"><field name=\"VAR\">removeChildBtn</field></block></value><statement name=\"HANDLER\"><block type=\"ScreenItem_ScreenItem_remove\"><value name=\"this\"><block type=\"variables_get\"><field name=\"VAR\">child</field></block></value></block></statement><next><block type=\"ScreenItem_ScreenItem_onClick\"><value name=\"this\"><block type=\"variables_get\"><field name=\"VAR\">removeParentBtn</field></block></value><statement name=\"HANDLER\"><block type=\"ScreenItem_ScreenItem_remove\"><value name=\"this\"><block type=\"ScreenItem_ScreenItem_getParent\"><value name=\"this\"><block type=\"variables_get\"><field name=\"VAR\">child</field></block></value></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></next></block></statement></block></xml>"}

输出：

当按键「删除子项」按钮时，子项（蓝色框）将被删除。

当单击“删除父项”按钮时，父项（黄色框）和父项内的子项（蓝色框）将被删除。

查找父屏幕专案

屏幕项具有父屏幕项

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

此块用于检查变量是否具有父屏幕项。

参数： 屏幕专案
输出： 布尔值 （True/False）
示例代码：

这里是使用一个if条件来删除屏幕专案。

{"blocks":"<xml xmlns=\"https://developers.google.com/blockly/xml\"><block type=\"controls_if\"><value name=\"IF0\"><shadow type=\"logic_boolean\"><field name=\"BOOL\">TRUE</field></shadow><block type=\"ScreenItem_ScreenItem_hasParent\"><value name=\"this\"><block type=\"variables_get\"><field name=\"VAR\">parent</field></block></value></block></value><statement name=\"DO0\"><block type=\"ScreenItem_ScreenItem_remove\"><value name=\"this\"><block type=\"variables_get\"><field name=\"VAR\">parent</field></block></value></block></statement></block></xml>"}

{"blocks":"<xml xmlns=\"https://developers.google.com/blockly/xml\"><variables><variable>mainLayout</variable><variable>mainScreen</variable><variable>removeParentBtn</variable><variable>removeChildBtn</variable><variable>parent</variable><variable>child</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=\"variables_set\"><field name=\"VAR\">removeParentBtn</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\">Remove Parent</field></shadow></value></block></value><next><block type=\"variables_set\"><field name=\"VAR\">removeChildBtn</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\">Remove Child</field></shadow></value></block></value><next><block type=\"variables_set\"><field name=\"VAR\">parent</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\">child</field><value name=\"VALUE\"><shadow type=\"math_number\"><field name=\"NUM\">0</field></shadow><block type=\"ScreenItem_createLayout\"/></value><next><block type=\"Styling_setFlexShorthand\"><field name=\"flexShorthand\">FlexShorthand.Auto</field><value name=\"item\"><block type=\"variables_get\"><field name=\"VAR\">mainLayout</field></block></value><next><block type=\"Styling_setBackgroundColor\"><value name=\"item\"><block type=\"variables_get\"><field name=\"VAR\">parent</field></block></value><value name=\"color\"><block type=\"CssValues_createColor\"><mutation xmlns=\"http://www.w3.org/1999/xhtml\" _expanded=\"0\" _input_init=\"false\"></mutation><value name=\"r\"><shadow type=\"math_number_minmax\"><mutation min=\"0\" max=\"255\" label=\"Number\" precision=\"0\"/><field name=\"SLIDER\">148</field></shadow></value><value name=\"g\"><shadow type=\"math_number_minmax\"><mutation min=\"0\" max=\"255\" label=\"Number\" precision=\"0\"/><field name=\"SLIDER\">0</field></shadow></value><value name=\"b\"><shadow type=\"math_number_minmax\"><mutation min=\"0\" max=\"255\" label=\"Number\" precision=\"0\"/><field name=\"SLIDER\">211</field></shadow></value></block></value><next><block type=\"Styling_setHeight\"><value name=\"item\"><block type=\"variables_get\"><field name=\"VAR\">parent</field></block></value><value name=\"height\"><block type=\"CssValues_createLength\"><field name=\"unit\">CssLengthUnit.PX</field><value name=\"value\"><shadow type=\"math_number\"><field name=\"NUM\">70</field></shadow></value></block></value><next><block type=\"Styling_setWidth\"><value name=\"item\"><block type=\"variables_get\"><field name=\"VAR\">parent</field></block></value><value name=\"width\"><block type=\"CssValues_createLength\"><field name=\"unit\">CssLengthUnit.PX</field><value name=\"value\"><shadow type=\"math_number\"><field name=\"NUM\">500</field></shadow></value></block></value><next><block type=\"Styling_setBackgroundColor\"><value name=\"item\"><block type=\"variables_get\"><field name=\"VAR\">child</field></block></value><value name=\"color\"><block type=\"CssValues_createColor\"><mutation xmlns=\"http://www.w3.org/1999/xhtml\" _expanded=\"0\" _input_init=\"false\"></mutation><value name=\"r\"><shadow type=\"math_number_minmax\"><mutation min=\"0\" max=\"255\" label=\"Number\" precision=\"0\"/><field name=\"SLIDER\">255</field></shadow></value><value name=\"g\"><shadow type=\"math_number_minmax\"><mutation min=\"0\" max=\"255\" label=\"Number\" precision=\"0\"/><field name=\"SLIDER\">165</field></shadow></value><value name=\"b\"><shadow type=\"math_number_minmax\"><mutation min=\"0\" max=\"255\" label=\"Number\" precision=\"0\"/><field name=\"SLIDER\">0</field></shadow></value></block></value><next><block type=\"Styling_setHeight\"><value name=\"item\"><block type=\"variables_get\"><field name=\"VAR\">child</field></block></value><value name=\"height\"><block type=\"CssValues_createLength\"><field name=\"unit\">CssLengthUnit.PX</field><value name=\"value\"><shadow type=\"math_number\"><field name=\"NUM\">40</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\">removeParentBtn</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\">removeChildBtn</field></block></value><next><block type=\"ScreenItem_Layout_add\"><value name=\"this\"><block type=\"variables_get\"><field name=\"VAR\">parent</field></block></value><value name=\"item\"><block type=\"variables_get\"><field name=\"VAR\">child</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\">parent</field></block></value><next><block type=\"ScreenItem_ScreenItem_onClick\"><value name=\"this\"><block type=\"variables_get\"><field name=\"VAR\">removeParentBtn</field></block></value><statement name=\"HANDLER\"><block type=\"controls_if\"><value name=\"IF0\"><shadow type=\"logic_boolean\"><field name=\"BOOL\">TRUE</field></shadow><block type=\"ScreenItem_ScreenItem_hasParent\"><value name=\"this\"><block type=\"variables_get\"><field name=\"VAR\">parent</field></block></value></block></value><statement name=\"DO0\"><block type=\"ScreenItem_ScreenItem_remove\"><value name=\"this\"><block type=\"variables_get\"><field name=\"VAR\">parent</field></block></value></block></statement></block></statement><next><block type=\"ScreenItem_ScreenItem_onClick\"><value name=\"this\"><block type=\"variables_get\"><field name=\"VAR\">removeChildBtn</field></block></value><statement name=\"HANDLER\"><block type=\"controls_if\"><value name=\"IF0\"><shadow type=\"logic_boolean\"><field name=\"BOOL\">TRUE</field></shadow><block type=\"ScreenItem_ScreenItem_hasParent\"><value name=\"this\"><block type=\"variables_get\"><field name=\"VAR\">child</field></block></value></block></value><statement name=\"DO0\"><block type=\"ScreenItem_ScreenItem_remove\"><value name=\"this\"><block type=\"variables_get\"><field name=\"VAR\">child</field></block></value></block></statement></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>"}

原始输出：

当单击“删除子项”按钮时，子项（橙色框）将被删除。

当单击“删除父项”按钮时，父项（紫色框）和父项内的子项（橙色框）将被删除。

取消屏幕项中的所有值

删除屏幕专案

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

此块用于删除屏幕中的所有值。

参数： 屏幕专案
输出： N/A
示例代码：

按下按钮后，此处将删除屏幕项中的所有值。

{"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_ScreenItem_remove\"><value name=\"this\"><block type=\"variables_get\"><field name=\"VAR\">mainLayout</field></block></value></block></statement></block></xml>"}

{"blocks":"<xml xmlns=\"https://developers.google.com/blockly/xml\"><variables><variable>mainLayout</variable><variable>mainScreen</variable><variable>button</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=\"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\">Remove Main Layout</field></shadow></value></block></value><next><block type=\"Styling_setFlexShorthand\"><field name=\"flexShorthand\">FlexShorthand.Auto</field><value name=\"item\"><block type=\"variables_get\"><field name=\"VAR\">mainLayout</field></block></value><next><block type=\"Styling_setBackgroundColor\"><value name=\"item\"><block type=\"variables_get\"><field name=\"VAR\">mainLayout</field></block></value><value name=\"color\"><block type=\"CssValues_createColor\"><mutation xmlns=\"http://www.w3.org/1999/xhtml\" _expanded=\"0\" _input_init=\"false\"></mutation><value name=\"r\"><shadow type=\"math_number_minmax\"><mutation min=\"0\" max=\"255\" label=\"Number\" precision=\"0\"/><field name=\"SLIDER\">255</field></shadow></value><value name=\"g\"><shadow type=\"math_number_minmax\"><mutation min=\"0\" max=\"255\" label=\"Number\" precision=\"0\"/><field name=\"SLIDER\">165</field></shadow></value><value name=\"b\"><shadow type=\"math_number_minmax\"><mutation min=\"0\" max=\"255\" label=\"Number\" precision=\"0\"/><field name=\"SLIDER\">0</field></shadow></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_ScreenItem_remove\"><value name=\"this\"><block type=\"variables_get\"><field name=\"VAR\">mainLayout</field></block></value></block></statement><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\">button</field></block></value></block></next></block></next></block></next></block></next></block></next></block></next></block></statement></block></xml>"}

原始输出：

当单击“删除主布局”按钮时，主布局（橙色区域）将被删除。

删除屏幕项目中的值

清除屏幕专案

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

此块用于清除相关布局中的所有值。

参数： 屏幕专案
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>removeChildBtn</variable><variable>childLayout</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=\"Styling_setFlexShorthand\"><field name=\"flexShorthand\">FlexShorthand.Auto</field><value name=\"item\"><block type=\"variables_get\"><field name=\"VAR\">mainLayout</field></block></value><next><block type=\"Styling_setBackgroundColor\"><value name=\"item\"><block type=\"variables_get\"><field name=\"VAR\">mainLayout</field></block></value><value name=\"color\"><block type=\"CssValues_createColor\"><mutation xmlns=\"http://www.w3.org/1999/xhtml\" _expanded=\"0\" _input_init=\"false\"></mutation><value name=\"r\"><shadow type=\"math_number_minmax\"><mutation min=\"0\" max=\"255\" label=\"Number\" precision=\"0\"/><field name=\"SLIDER\">255</field></shadow></value><value name=\"g\"><shadow type=\"math_number_minmax\"><mutation min=\"0\" max=\"255\" label=\"Number\" precision=\"0\"/><field name=\"SLIDER\">218</field></shadow></value><value name=\"b\"><shadow type=\"math_number_minmax\"><mutation min=\"0\" max=\"255\" label=\"Number\" precision=\"0\"/><field name=\"SLIDER\">185</field></shadow></value></block></value><next><block type=\"variables_set\"><field name=\"VAR\">removeChildBtn</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\">Remove content in child layout</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\">removeChildBtn</field></block></value><next><block type=\"variables_set\"><field name=\"VAR\">childLayout</field><value name=\"VALUE\"><shadow type=\"math_number\"><field name=\"NUM\">0</field></shadow><block type=\"ScreenItem_createLayout\"/></value><next><block type=\"Styling_setBackgroundColor\"><value name=\"item\"><block type=\"variables_get\"><field name=\"VAR\">childLayout</field></block></value><value name=\"color\"><block type=\"CssValues_createColor\"><mutation xmlns=\"http://www.w3.org/1999/xhtml\" _expanded=\"0\" _input_init=\"false\"></mutation><value name=\"r\"><shadow type=\"math_number_minmax\"><mutation min=\"0\" max=\"255\" label=\"Number\" precision=\"0\"/><field name=\"SLIDER\">0</field></shadow></value><value name=\"g\"><shadow type=\"math_number_minmax\"><mutation min=\"0\" max=\"255\" label=\"Number\" precision=\"0\"/><field name=\"SLIDER\">255</field></shadow></value><value name=\"b\"><shadow type=\"math_number_minmax\"><mutation min=\"0\" max=\"255\" label=\"Number\" precision=\"0\"/><field name=\"SLIDER\">191</field></shadow></value></block></value><next><block type=\"Styling_setHeight\"><value name=\"item\"><block type=\"variables_get\"><field name=\"VAR\">childLayout</field></block></value><value name=\"height\"><block type=\"CssValues_createLength\"><field name=\"unit\">CssLengthUnit.PX</field><value name=\"value\"><shadow type=\"math_number\"><field name=\"NUM\">40</field></shadow></value></block></value><next><block type=\"ScreenItem_Layout_add\"><value name=\"this\"><block type=\"variables_get\"><field name=\"VAR\">childLayout</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\"><shadow type=\"text\"><field name=\"TEXT\">Text inside the child layout.</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\">childLayout</field></block></value><next><block type=\"ScreenItem_ScreenItem_onClick\"><value name=\"this\"><block type=\"variables_get\"><field name=\"VAR\">removeChildBtn</field></block></value><statement name=\"HANDLER\"><block type=\"ScreenItem_ScreenItem_clear\"><value name=\"this\"><block type=\"variables_get\"><field name=\"VAR\">childLayout</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></statement></block></xml>"}

原始输出：

当单击“删除子布局中的内容”按钮时，文本将被删除。

使用屏幕项添加一些操作

控制点击

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

此块用于设置变量或布局的特定对齐方式。

参数： 屏幕专案
输出： N/A
示例代码：

{"blocks":"<xml xmlns=\"https://developers.google.com/blockly/xml\"><variables><variable>mainLayout</variable><variable>mainScreen</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=\"Task_runAfter\"><value name=\"ms\"><shadow type=\"math_number\"><field name=\"NUM\">5000</field></shadow></value><value name=\"abortSignal\"><block type=\"Task_createAbortControl\"/></value><statement name=\"HANDLER\"><block type=\"ScreenItem_ScreenItem_click\"><value name=\"this\"><block type=\"variables_get\"><field name=\"VAR\">mainLayout</field></block></value></block></statement><next><block type=\"ScreenItem_ScreenItem_onClick\"><value name=\"this\"><block type=\"variables_get\"><field name=\"VAR\">mainLayout</field></block></value><statement name=\"HANDLER\"><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\"><shadow type=\"text\"><field name=\"TEXT\">It clicked main layout after 5 second.</field></shadow></value></block></value></block></statement></block></next></block></next></block></next></block></statement></block></xml>"}

在单击主布局之前，输出：

点击主布局后，输出：