Flutter事件相关梳理(全网最全)

作者: StevenHu_Sir | 来源:发表于2019-12-01 22:13 被阅读0次

监听屏幕触摸事件(Listener)
PointerEvent(忽略事件)
GestureDetector 手势点击
拖拽控件
缩放识别
事件竞争机制
NotificationListener 监听滑动

1.监听屏幕触摸事件(Listener)

onPointerDown 点击
onPointerMove 移动
onPointerUp 离开
onPointerCancel 取消

Listener(
  child: Container(
    alignment: Alignment.center,
    color: Colors.blue,
    width: 240.0,
    height: 120.0,
    child: Text(
      _opName,
      style: TextStyle(color: Colors.white),
    ),
  ),
  onPointerDown: (PointerDownEvent event) =>
      _showEventText('onPointerDown'),
  onPointerMove: (PointerMoveEvent event) =>
      _showEventText('onPointerMove'),
  onPointerUp: (PointerUpEvent event) => _showEventText('onPointerUp'),
  onPointerCancel: (PointerCancelEvent event) =>
      _showEventText('onPointerCancel'),
)

2.PointerEvent(忽略事件)

IgnorePointer : ignoring是否忽略点击,默认true 不可以点击
AbsorbPointer : absorbing child 是否接受点击事件,默认true 可以点击

import 'package:flutter/material.dart';

class PointerEventIgnorePage extends StatefulWidget {
  @override
  _PointerEventIgnorePageState createState() =>
      new _PointerEventIgnorePageState();
}

class _PointerEventIgnorePageState extends State<PointerEventIgnorePage> {
  bool _ignore = true;

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(title: Text('忽略事件')),
      body: Container(
        alignment: AlignmentDirectional.center,
        child: Column(
          children: <Widget>[
            Switch(
              value: _ignore,
              onChanged: (value) {
                setState(() => _ignore = value);
              },
            ),
            GestureDetector(
              onTap: () => print('GestureDetector Clicked!'),
              child: IgnorePointer(
                ignoring: _ignore,
                child: RaisedButton(
                  onPressed: () => print('IgnorePointer Clicked!'),
                  child: Text('IgnorePointer'),
                ),
              ),
            ),
            GestureDetector(
              onTap: () => print('GestureDetector Clicked!'),
              child: AbsorbPointer(
                absorbing: _ignore,
                child: RaisedButton(
                  onPressed: () => print('AbsorbPointer Clicked!'),
                  child: Text('AbsorbPointer'),
                ),
              ),
            ),
          ],
        ),
      ),
    );
  }
}

3.GestureDetector 手势点击

onTap 点击
onTapUp
onTapDown
onTapCancel
onDoubleTap 双击
onLongPress 长按
onVerticalDragDown 拖拽
onVerticalDragStart
onVerticalDragUpdate
onVerticalDragEnd
onVerticalDragCancel
onHorizontalDragDown
onHorizontalDragStart
onHorizontalDragUpdate
onHorizontalDragEnd
onHorizontalDragCancel

class GestureDetectorPage extends StatefulWidget {
  @override
  _GestureDetectorState createState() => new _GestureDetectorState();
}

class _GestureDetectorState extends State<GestureDetectorPage> {
  String _opName = "未检测到操作";

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text("GestureDetector手势识别"),
      ),
      body: Center(
        child: GestureDetector(
          child: Container(
            alignment: Alignment.center,
            color: Colors.blue,
            width: 240.0,
            height: 120.0,
            child: Text(
              _opName,
              style: TextStyle(color: Colors.white),
            ),
          ),
          onTap: () => _showEventText("Tap"),
          onTapUp: (e) => _showEventText("TapUp"),
          onTapDown: (e) => _showEventText("TapDown"),
          onTapCancel: () => _showEventText("TapCancel"),
          onDoubleTap: () => _showEventText("DoubleTap"),
          onLongPress: () => _showEventText("LongPress"),
          onVerticalDragDown: (e) => _showEventText("onVerticalDragDown"),
          onVerticalDragStart: (e) => _showEventText("onVerticalDragStart"),
          onVerticalDragUpdate: (e) => _showEventText("onVerticalDragUpdate"),
          onVerticalDragEnd: (e) => _showEventText("onVerticalDragEnd"),
          onVerticalDragCancel: () => _showEventText("onVerticalDragCancel"),
          onHorizontalDragDown: (e) => _showEventText("onHorizontalDragDown"),
          onHorizontalDragStart: (e) => _showEventText("onHorizontalDragStart"),
          onHorizontalDragUpdate: (e) => _showEventText("onHorizontalDragUpdate"),
          onHorizontalDragEnd: (e) => _showEventText("onHorizontalDragEnd"),
          onHorizontalDragCancel: () => _showEventText("onHorizontalDragCancel"),
//          onPanDown: (e) => _showEventText("onPanDown"),
//          onPanStart: (e) => _showEventText("onPanStart"),
//          onPanUpdate: (e) => _showEventText("onPanUpdate"),
//          onPanEnd: (e) => _showEventText("onPanEnd"),
//          onScaleStart: (e) => _showEventText("onScaleStart"),
//          onScaleUpdate: (e) => _showEventText("onScaleUpdate"),
//          onScaleEnd: (e) => _showEventText("onScaleEnd"),
        ),
      ),
    );
  }

  void _showEventText(String text) {
    setState(() {
      _opName = text;
    });
    print(_opName);
  }
}

4.拖拽控件

效果图

拖拽

关键代码

import 'package:flutter/material.dart';

class DragPage extends StatefulWidget {
  @override
  _DragState createState() => new _DragState();
}

class _DragState extends State<DragPage> with SingleTickerProviderStateMixin {
  double _top = 0.0;
  double _left = 0.0;
  double _size = 100.0;

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text("拖拽控件"),
      ),
      body: Stack(
        children: <Widget>[
          Positioned(
            top: _top,
            left: _left,
            child: GestureDetector(
              child: FlutterLogo(
                size: _size,
              ),
              onPanUpdate: (e) {
                setState(() {
                  _left += e.delta.dx;
                  _top += e.delta.dy;
                });
              },
            ),
          )
        ],
      ),
    );
  }
}

5.缩放识别

import 'package:flutter/material.dart';

class ScalePage extends StatefulWidget {
  @override
  _ScaleState createState() => new _ScaleState();
}

class _ScaleState extends State<ScalePage> {
  double _size = 100.0;
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text("缩放识别"),
      ),
      body: Center(
        child: GestureDetector(
          child: Container(
            alignment: Alignment.center,
            child: FlutterLogo(size: _size,),
          ),
          onScaleUpdate: (ScaleUpdateDetails e) {
            setState(() {
              _size = 300 * e.scale.clamp(.5, 10.0);
            });
          },
        ),
      ),
    );
  }
}

6.GestureRecognizer(对于不带点击事件的Widget，例如RichText)

关键代码

recognizer: _tapGestureRecognizer
  ..onTap = () {
    showInSnackBar("built: 建造");
  },

import 'package:flutter/gestures.dart';
import 'package:flutter/material.dart';

class GestureRecognizerPage extends StatefulWidget {
  @override
  _GestureRecognizerState createState() => new _GestureRecognizerState();
}

class _GestureRecognizerState extends State<GestureRecognizerPage> {
  TapGestureRecognizer _tapGestureRecognizer = new TapGestureRecognizer();
  final GlobalKey<ScaffoldState> _scaffoldKey = new GlobalKey<ScaffoldState>();

  @override
  void dispose() {
    _tapGestureRecognizer.dispose();
    super.dispose();
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      key: _scaffoldKey,
      appBar: AppBar(
        title: Text("GestureRecognizer"),
      ),
      body: Padding(
        padding: EdgeInsets.all(10.0),
        child: Column(
          children: <Widget>[
            Text.rich(
              TextSpan(
                children: [
                  TextSpan(
                    text: "Room is not ",
                    style: TextStyle(fontSize: 25.0),
                  ),
                  TextSpan(
                    text: "built",
                    style: TextStyle(
                      fontSize: 25.0,
                      color: Colors.blue,
                      fontWeight: FontWeight.bold,
                      decoration: TextDecoration.underline,
                      decorationThickness: 3.0,
                      decorationColor: Colors.amber,
                      decorationStyle: TextDecorationStyle.solid,
                    ),
                    recognizer: _tapGestureRecognizer
                      ..onTap = () {
                        showInSnackBar("built: 建造");
                      },
                  ),
                  TextSpan(
                    text: " in one day.",
                    style: TextStyle(fontSize: 25.0),
                  ),
                ],
              ),
            ),
          ],
        ),
      ),
    );
  }

  void showInSnackBar(String value) {
    _scaffoldKey.currentState.showSnackBar(
      new SnackBar(
        content: new Text(
          value,
          style: TextStyle(fontSize: 25.0),
        ),
      ),
    );
  }
}

7.事件竞争机制

import 'package:flutter/gestures.dart';
import 'package:flutter/material.dart';

class BothDirectionPage extends StatefulWidget {
  @override
  _BothDirectionState createState() => new _BothDirectionState();
}
class _BothDirectionState extends State<BothDirectionPage> {
  double _top = 0.0;
  double _left = 0.0;

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text("事件竞争机制"),
      ),
      body: Stack(
        children: <Widget>[
          Positioned(
            top: _top,
            left: _left,
            child: GestureDetector(
              child: FlutterLogo(
                size: 100,
              ),
              onVerticalDragUpdate: (DragUpdateDetails e) {
                setState(() {
                  _top += e.delta.dy;
                });
                print("垂直胜出");
              },
              onHorizontalDragUpdate: (DragUpdateDetails e) {
                setState(() {
                  _left += e.delta.dx;
                });
                print("水平胜出");
              },
              onTapDown: (e) {
                print("按下");
              },
              onTapUp: (e) {
                print("松开");
              },
              onHorizontalDragEnd: (e) {
                print("水平移动结束");
              },
              onVerticalDragEnd: (e) {
                print("垂直移动结束");
              },
            ),
          )
        ],
      ),
    );
  }
}

8.NotificationListener

监听滚动通知`<ScrollNotification>`

Scroll Start
Scroll Update
Scroll End

效果图

通知中心

关键代码

import 'package:flutter/material.dart';

class ScrollStatusPage extends StatefulWidget {
  @override
  _ScrollStatusState createState() => new _ScrollStatusState();
}

class _ScrollStatusState extends State<ScrollStatusPage> {
  String message = "";

  _onStartScroll(ScrollMetrics metrics) {
    setState(() {
      message = "Scroll Start";
    });
  }

  _onUpdateScroll(ScrollMetrics metrics) {
    print(metrics.pixels);
    setState(() {
      message = "Scroll Update";
    });
  }

  _onEndScroll(ScrollMetrics metrics) {
    setState(() {
      message = "Scroll End";
    });
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text("NotificationListener"),
      ),
      body: Column(
        children: <Widget>[
          Container(
            height: 50.0,
            color: Colors.green,
            child: Center(
              child: Text(message),
            ),
          ),
          Expanded(
            child: NotificationListener<ScrollNotification>(
              onNotification: (scrollNotification) {
                if (scrollNotification is ScrollStartNotification) {
                  _onStartScroll(scrollNotification.metrics);
                } else if (scrollNotification is ScrollUpdateNotification) {
                  _onUpdateScroll(scrollNotification.metrics);
                } else if (scrollNotification is ScrollEndNotification) {
                  _onEndScroll(scrollNotification.metrics);
                }
              },
              child: ListView.builder(
                itemCount: 30,
                itemBuilder: (context, index) {
                  return ListTile(title: Text("Index : $index"));
                },
              ),
            ),
          ),
        ],
      ),
    );
  }
}

9.GestureDetector实现360展物

效果图

关键代码

import 'dart:async';

import 'package:flutter/material.dart';
class GestureDetectorPage extends StatefulWidget {
  GestureDetectorPage({Key key, this.title}) : super(key: key);

  final String title;

  @override
  _GestureDetectorPageState createState() => _GestureDetectorPageState();
}

class _GestureDetectorPageState extends State<GestureDetectorPage> {
  int index = 1; // 第一张图片
  int count = 72; // 图片总数
  double initial = 0.0;
  final int DIRECTION_ANTICLOCKWISE = 1; // 逆时针
  final int DIRECTION_CLOCKWISE = -1; // 顺时针
  int direction;
  Timer _timer;

  @override
  void initState() {
    super.initState();
    direction = DIRECTION_CLOCKWISE;
    _startTimer();
  }

  _startTimer() {
    _timer = Timer.periodic(new Duration(milliseconds: 90), (timer) {
      setState(() {});
      if (direction == DIRECTION_ANTICLOCKWISE) {
        if (index > 1) {
          index--;
          return;
        }
        // 重新回到第一张图
        index = count;
      } else if (direction == DIRECTION_CLOCKWISE) {
        if (index < count) {
          index++;
          return;
        }
        // 重新回到第一张图
        index = 1;
      }
    });
  }

  @override
  Widget build(BuildContext context) {
    var width = MediaQuery.of(context).size.width;
    var height = width;

    return Scaffold(
      appBar: AppBar(
        title: Text(widget.title),
      ),
      body: Center(
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: <Widget>[
            GestureDetector(
              onTap: () => _cancelTimer(),
              onPanStart: (e) => _cancelTimer(),
              onPanUpdate: (e) => _onTouchImage(e),
              // 在触屏结束之后，恢复自动旋转
              onPanEnd: (e) => _startTimer(),
              child: Image.asset(
                'assets/images/product00${index}.png',
                fit: BoxFit.cover,
                width: width,
                height: height,
                // 该属性防止图片快速切换时白屏发生，在新图出前时保持旧的图
                gaplessPlayback: true,
                excludeFromSemantics: true,
              ),
            )
          ],
        ),
      ),
    );
  }

  void _onTouchImage(e) {
    if (e.delta.dx < 0) {
      direction = DIRECTION_CLOCKWISE;
    }
    if (e.delta.dx > 0) {
      direction = DIRECTION_ANTICLOCKWISE;
    }
    setState(() {
      index -= e.delta.dx.toInt();
    });
    // 防止取到不存在的图片报错
    if (index < 1) index = 1;
    if (index > count) index = count;
  }

  @override
  void dispose() {
    super.dispose();
    _cancelTimer();
  }

  void _cancelTimer() {
    _timer?.cancel();
  }
}

Flutter事件相关梳理(全网最全)

1.监听屏幕触摸事件(Listener)

2.PointerEvent(忽略事件)

3.GestureDetector 手势点击

4.拖拽控件

效果图

关键代码

5.缩放识别

6.GestureRecognizer(对于不带点击事件的Widget，例如RichText)

关键代码

7.事件竞争机制

8.NotificationListener

监听滚动通知`<ScrollNotification>`

效果图

关键代码

9.GestureDetector实现360展物

效果图

关键代码

相关文章

网友评论

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深度阅读

栏目导航

热点阅读

Flutter学习

Flutter

Flutter

Flutter事件相关梳理(全网最全)

1.监听屏幕触摸事件(Listener)

2.PointerEvent(忽略事件)

3.GestureDetector 手势点击

4.拖拽控件

效果图

关键代码

5.缩放识别

6.GestureRecognizer(对于不带点击事件的Widget，例如RichText)

关键代码

7.事件竞争机制

8.NotificationListener

监听滚动通知<ScrollNotification>

效果图

关键代码

9.GestureDetector实现360展物

效果图

关键代码

相关文章

网友评论

延伸阅读

深度阅读

栏目导航

热点阅读

Flutter学习

Flutter

Flutter

监听滚动通知`<ScrollNotification>`