输入验证

				
					{"blocks":"<xml xmlns=\"https://developers.google.com/blockly/xml\"><variables><variable>mainLayout</variable><variable>mainScreen</variable><variable>resultButton</variable><variable>validation</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=\"ScreenItem_Layout_add\"><value name=\"this\"><block type=\"variables_get\"><field name=\"VAR\">mainLayout</field></block></value><value name=\"item\"><block type=\"Control_createTextInput\"><field name=\"type\">TextInputType.URL</field></block></value><next><block type=\"variables_set\"><field name=\"VAR\">resultButton</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\">Show Result</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\">resultButton</field></block></value><next><block type=\"variables_set\"><field name=\"VAR\">validation</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\">validation</field></block></value><next><block type=\"ScreenItem_ScreenItem_onClick\"><value name=\"this\"><block type=\"variables_get\"><field name=\"VAR\">resultButton</field></block></value><statement name=\"HANDLER\"><block type=\"controls_if\"><mutation else=\"1\"/><value name=\"IF0\"><shadow type=\"logic_boolean\"><field name=\"BOOL\">TRUE</field></shadow><block type=\"Control_validateInputs\"><value name=\"layout\"><block type=\"variables_get\"><field name=\"VAR\">mainLayout</field></block></value></block></value><statement name=\"DO0\"><block type=\"Control_TextBlock_setContent\"><value name=\"this\"><block type=\"variables_get\"><field name=\"VAR\">validation</field></block></value><value name=\"content\"><shadow type=\"text\"><field name=\"TEXT\">The text is valid.</field></shadow></value></block></statement><statement name=\"ELSE\"><block type=\"Control_TextBlock_setContent\"><value name=\"this\"><block type=\"variables_get\"><field name=\"VAR\">validation</field></block></value><value name=\"content\"><shadow type=\"text\"><field name=\"TEXT\">The text is not valid.</field></shadow></value></block></statement></block></statement></block></next></block></next></block></next></block></next></block></next></block></next></block></next></block></statement></block></xml>"}