Dart syntax - initSate,Build,deactive, Dispose

   ☝initSate(){ super.initSate //放置一旦載入statefulwidget後就不需一直更新的物件。}

如字面的意思in it sate. 此功能好比statefulwidget 裡面的statelesswidget。  Called only once when the widget is created，只會執行一次，不像build() 一變動就自毀後重建。

☝Build(BuildContext context) {//放置載入後每次有任何變動就需更新的物件。}

        -Build the widget tree

        -A build is triggred every time we use setState() that re-triggre build().

☝deactive() {super.deactive //放置當statefulwight自毀換頁前跟著毀的物件。例如:釋放記憶空間。}

☝Dispose()

        - When the widget/state object is removed.