在flutter中更新现有的StatefulWidget类的小部件

Question

当用户按下onTapDown（）和onTapUP（在GestureDetector中）时，我想更新我的MaterialButton。但我无法做到这一点。我试过但没有成功。我在控制台中打印了一些信息，以检查我的代码是否正常工作，但成功完成所有工作而不更新我的MaterialButton小部件。请帮帮我一些代码如下： -

（此代码用于具有可变背景图像的按钮）。

Container(
color: Colors.amber,
alignment: Alignment.center,
padding: EdgeInsets.only(top: 15, bottom: 10),
child: Text(
   "CALL FUNTIONS",
    style: TextStyle(
       fontSize: 25,
       fontWeight: FontWeight.bold,
  ),
)),
Container(
padding: EdgeInsets.only(bottom: 10),
color: Colors.amber,
child: callFunctionsForLessThan600Pixel(),
),


Widget callFunctionsForLessThan600Pixel() {
return new Column(
  mainAxisAlignment: MainAxisAlignment.center,
  crossAxisAlignment: CrossAxisAlignment.center,
  children: <Widget>[
    Row(
      mainAxisAlignment: MainAxisAlignment.center,
      crossAxisAlignment: CrossAxisAlignment.center,
      children: <Widget>[
       lessThan600Pixel(Key("LockCallButton"),"button_default","locked"),
   lessThan600Pixel(Key("UnLockCallButton"),"button_default","unlocked"),
       lessThan600Pixel(Key("StatusCallButton"),"button_default","info"),
      ],
    ),
  ],
);
}

Widget lessThan600Pixel(Key key, String buttonName, String svgName) {
return MaterialButton(
  key: key,
  child: ConstrainedBox(
    constraints: BoxConstraints(
      maxHeight: 70,
      maxWidth: 70,
    ),
    child: GestureDetector(
      child: Stack(
        children: <Widget>[
          Image.asset("assets/images/$buttonName.png",),
          SvgPicture.asset(
            "assets/images/$svgName.svg",
            height: 30,
            width: 30,
            color: Colors.white,
          ),
        ],
        alignment: Alignment.center,
      ),
      onTapDown: (v) {
        buttonTappedDown(key, svgName);
      },
      onTapUp: (v) {
        buttonTappedDown(key, svgName);
      },
    ),
  ),
  onPressed: buttonPressed,
  elevation: 0,
  highlightElevation: 0,
  highlightColor: Colors.amber,
);
}



void buttonTappedDown(Key key, String svgName) {
setState(() {
  lessThan600Pixel(key, "button_pressed", svgName);
});
}

void buttonTappedUp(Key key, String svgName) {
setState(() {
  lessThan600Pixel(key, "button_default", svgName);
});
}

Answer 1

要拥有交互式UI，您需要将窗口小部件类设置为有状态，并且在onPressed函数上，您只需使用setState（）方法执行任何更改。通过这种方式，小部件知道必须刷新。

如果您的小部件是无状态的，它将永远不会更新。

以下是谷歌的入门教程，它教你良好的有状态逻辑：qazxsw poi

Answer 2

https://flutter.dev/docs/development/ui/interactive