flutter如何实现点击事件

在Android中，您可以通过调用方法setOnClickListener将OnClick绑定到按钮等view上。
在Flutter中，有两种方法:

1.如果Widget支持事件监听，则可以将一个函数传递给它并进行处理。例如，RaisedButton有一个onPressed参数

@override
Widget build(BuildContext context) {
  return new RaisedButton(
      onPressed: () {
        print("click");
      },
      child: new Text("Button"));
}

2.如果Widget不支持事件监听，则可以将该Widget包装到GestureDetector中，并将处理函数传递给onTap参数

class SampleApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return new Scaffold(
        body: new Center(
      child: new GestureDetector(
        child: new FlutterLogo(
          size: 200.0,
        ),
        onTap: () {
          print("tap");
        },
      ),
    ));
  }
}

2.1.使用GestureDetector，可以监听多种手势

（1）Tap

• onTapDown
• onTapUp
• onTap
• onTapCancel

(2)Double tap

• onDoubleTap 用户快速连续两次在同一位置轻敲屏幕

(3)长按

• onLongPress

(4)垂直拖动

• onVerticalDragStart
• onVerticalDragUpdate
• onVerticalDragEnd

(5)水平拖拽

• onHorizontalDragStart
• onHorizontalDragUpdate
• onHorizontalDragEnd

2.2.示例：监听FlutterLogo的双击事件，双击时使其旋转。

void main() => runApp(DemoApp());

class DemoApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return new MaterialApp(
      title: '导航演示1',
      home: new MyAppHome(),
    );
  }
}

class MyAppHome extends StatefulWidget{
  @override
  _MyAppHomeState createState() => _MyAppHomeState();

}
class _MyAppHomeState extends State<MyAppHome> with TickerProviderStateMixin{
  AnimationController controller;
  CurvedAnimation curve;

  @override
  void initState() {
    super.initState();
    controller = new AnimationController(
        duration: const Duration(milliseconds: 2000), vsync: this);
    curve = new CurvedAnimation(parent: controller, curve: Curves.easeIn);
  }

  @override
  Widget build(BuildContext context) {
    return new Scaffold(
        body: new Center(
      child: new GestureDetector(
        child: new RotationTransition(
            turns: curve,
            child: new FlutterLogo(
              size: 200.0,
            )),
        onDoubleTap: () {
          if (controller.isCompleted) {
            controller.reverse();
          } else {
            controller.forward();
          }
        },
      ),
    ));
  }
}