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4. 以積木式編程製作網絡應用程式
變數
變數

本文檔包含使用塊設置和修改變量值的說明和示例代碼。

更改變量的值

設置…自

{"blocks":"<xml xmlns=\"https://developers.google.com/blockly/xml\"><block type=\"variables_set\"><field name=\"VAR\">count</field><value name=\"VALUE\"><shadow type=\"math_number\"><field name=\"NUM\">0</field></shadow></value></block></xml>"}

此塊用於將變數設置為與值相同。

參數:

  • 屏幕物件
  • 條件:數字(預設值:0)

輸出: N/A
示例代碼:

{"blocks":"<xml xmlns=\"https://developers.google.com/blockly/xml\"><variables><variable>mainLayout</variable><variable>mainScreen</variable><variable>count</variable><variable>dateTimeOffset</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\">count</field><value name=\"VALUE\"><shadow type=\"math_number\"><field name=\"NUM\">3</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=\"Control_createTextBlock\"><mutation xmlns=\"http://www.w3.org/1999/xhtml\" _expanded=\"1\" _input_init=\"true\"></mutation><value name=\"text\"><block type=\"DateTime_DateTimeOffset_toString\"><value name=\"dateTimeOffset\"><block type=\"variables_get\"><field name=\"VAR\">count</field></block></value></block></value></block></value></block></next></block></next></block></next></block></statement></block></xml>"}

輸出:

將變數設定為 - 輸出

修改變量的值

改變…由

{"blocks":"<xml xmlns=\"https://developers.google.com/blockly/xml\"><block type=\"variables_change\"><field name=\"VAR\">count</field><value name=\"VALUE\"><shadow type=\"math_number\"><field name=\"NUM\">1</field></shadow></value></block></xml>"}

此塊用於按數字的數量更改變量。

參數:

  • 屏幕物件
  • 條件:數字(預設值:0)

輸出: N/A
示例代碼:

{"blocks":"<xml xmlns=\"https://developers.google.com/blockly/xml\"><variables><variable>mainLayout</variable><variable>mainScreen</variable><variable>count</variable><variable>dateTimeOffset</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\">count</field><value name=\"VALUE\"><shadow type=\"math_number\"><field name=\"NUM\">3</field></shadow></value><next><block type=\"variables_change\"><field name=\"VAR\">count</field><value name=\"VALUE\"><shadow type=\"math_number\"><field name=\"NUM\">1</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=\"Control_createTextBlock\"><mutation xmlns=\"http://www.w3.org/1999/xhtml\" _expanded=\"1\" _input_init=\"true\"></mutation><value name=\"text\"><block type=\"DateTime_DateTimeOffset_toString\"><value name=\"dateTimeOffset\"><block type=\"variables_get\"><field name=\"VAR\">count</field></block></value></block></value></block></value></block></next></block></next></block></next></block></next></block></statement></block></xml>"}

輸出:

更改變量值 - 輸出

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