一雏逾、GestureDetector 的介紹

GestureDetector：是手勢(shì)識(shí)別的組件，可以識(shí)別點(diǎn)擊屑宠、雙擊仇让、長(zhǎng)按事件、拖動(dòng)卫玖、縮放等手勢(shì)

二踊淳、GestureDetector的源碼介紹

GestureDetector({
    Key key,
    this.child,
    this.onTapDown,//按下時(shí)回調(diào)
    this.onTapUp,//抬起時(shí)回調(diào)
    this.onTap,//點(diǎn)擊事件回調(diào)
    this.onTapCancel,//點(diǎn)擊取消事件回調(diào)
    this.onSecondaryTap,
    this.onSecondaryTapDown,
    this.onSecondaryTapUp,
    this.onSecondaryTapCancel,
    this.onTertiaryTapDown,
    this.onTertiaryTapUp,
    this.onTertiaryTapCancel,
    this.onDoubleTapDown,//短時(shí)間內(nèi)雙擊按下時(shí)回調(diào)
    this.onDoubleTap,//短時(shí)間內(nèi)雙擊回調(diào)
    this.onDoubleTapCancel,//短時(shí)間內(nèi)雙擊取消事件回調(diào)
    this.onLongPress,//長(zhǎng)按事件回調(diào)
    this.onLongPressStart,//長(zhǎng)按開(kāi)始事件回調(diào)
    this.onLongPressMoveUpdate,//長(zhǎng)按移動(dòng)事件回調(diào)
    this.onLongPressUp,//長(zhǎng)按抬起事件回調(diào)
    this.onLongPressEnd,//長(zhǎng)按結(jié)束事件回調(diào)
    this.onSecondaryLongPress,
    this.onSecondaryLongPressStart,
    this.onSecondaryLongPressMoveUpdate,
    this.onSecondaryLongPressUp,
    this.onSecondaryLongPressEnd,
    this.onVerticalDragDown,//垂直滑動(dòng)按下事件回調(diào)
    this.onVerticalDragStart,//垂直滑動(dòng)開(kāi)始事件回調(diào)
    this.onVerticalDragUpdate,//垂直滑動(dòng)更新事件回調(diào)
    this.onVerticalDragEnd,//垂直滑動(dòng)結(jié)束事件回調(diào)
    this.onVerticalDragCancel,//垂直滑動(dòng)取消事件回調(diào)
    this.onHorizontalDragDown,//水平滑動(dòng)按下事件回調(diào)
    this.onHorizontalDragStart,///水平滑動(dòng)開(kāi)始事件回調(diào)
    this.onHorizontalDragUpdate,//水平滑動(dòng)更新事件回調(diào)
    this.onHorizontalDragEnd,//水平滑動(dòng)結(jié)束事件回調(diào)
    this.onHorizontalDragCancel,//水平滑動(dòng)取消事件回調(diào)
    this.onForcePressStart,//回調(diào)函數(shù)只會(huì)在有壓力的設(shè)備上被觸發(fā)
    this.onForcePressPeak,
    this.onForcePressUpdate,
    this.onForcePressEnd,
    this.onPanDown,//按壓時(shí)回調(diào)
    this.onPanStart,//按壓拖動(dòng)開(kāi)始回調(diào)
    this.onPanUpdate,//按壓拖動(dòng)回調(diào)
    this.onPanEnd,//按壓拖動(dòng)結(jié)束回調(diào)
    this.onPanCancel,//按壓拖動(dòng)取消回調(diào)
    this.onScaleStart,//縮放開(kāi)始事件回調(diào)
    this.onScaleUpdate,//縮放更新事件回調(diào)
    this.onScaleEnd,//縮放結(jié)束事件回調(diào)
    this.behavior,//手勢(shì)檢測(cè)器在觸摸中應(yīng)該如何工作
    this.excludeFromSemantics = false,
    this.dragStartBehavior = DragStartBehavior.start,
  }) : assert(excludeFromSemantics != null),
       assert(dragStartBehavior != null),
       assert(() {
         final bool haveVerticalDrag = onVerticalDragStart != null || onVerticalDragUpdate != null || onVerticalDragEnd != null;
         final bool haveHorizontalDrag = onHorizontalDragStart != null || onHorizontalDragUpdate != null || onHorizontalDragEnd != null;
         final bool havePan = onPanStart != null || onPanUpdate != null || onPanEnd != null;
         final bool haveScale = onScaleStart != null || onScaleUpdate != null || onScaleEnd != null;
         if (havePan || haveScale) {
           if (havePan && haveScale) {
             throw FlutterError.fromParts(<DiagnosticsNode>[
               ErrorSummary('Incorrect GestureDetector arguments.'),
               ErrorDescription(
                 'Having both a pan gesture recognizer and a scale gesture recognizer is redundant; scale is a superset of pan.'
               ),
               ErrorHint('Just use the scale gesture recognizer.')
             ]);
           }
           final String recognizer = havePan ? 'pan' : 'scale';
           if (haveVerticalDrag && haveHorizontalDrag) {
             throw FlutterError(
               'Incorrect GestureDetector arguments.\n'
               'Simultaneously having a vertical drag gesture recognizer, a horizontal drag gesture recognizer, and a $recognizer gesture recognizer '
               'will result in the $recognizer gesture recognizer being ignored, since the other two will catch all drags.'
             );
           }
         }
         return true;
       }()),
       super(key: key);

三、GestureDetector的屬性介紹

四沿彭、一些觸摸事件，監(jiān)聽(tīng)的調(diào)用順序

4.1瞧柔、點(diǎn)擊屏幕：onPanDown--onPanCancel--onTapDown--onTapUp--onTap

4.2睦裳、點(diǎn)擊滑動(dòng)：onPanDown--onTapDown--onTapCancel--onPanStart--onPanUpdate--onPanEnd

4.3、雙擊屏幕：onPanDown--onPanCancel--onDoubleTapDown--onPanDown--onPanCancel--onDoubleTap

4.4哥蔚、長(zhǎng)按屏幕：onPanDown--onTapDown--onTapCancel--onPanCancel--onLongPressStart--onLongPress--onLongPressMoveUpdate--onLongPressEnd--onLongPressUp

4.5、手指左右滑動(dòng)：onVerticalDragDown--onHorizontalDragDown--onVerticalDragCancel--onHorizontalDragStart--onHorizontalDragUpdate--onHorizontalDragEnd

4.6糙箍、手指上下滑動(dòng)：onVerticalDragDown--onHorizontalDragDown--onHorizontalDragCancel--onVerticalDragStart--onVerticalDragUpdate--onVerticalDragEnd

4.7、縮放：onScaleStart--onScaleUpdate--onScaleEnd

五深夯、GestureDetector的demo

5.1塌西、給組件添加按鍵監(jiān)聽(tīng)

class _GestureDetectorFulState extends State<GestureDetectorFul> {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
        home: Scaffold(
      appBar: AppBar(
        title: Text("GestureDetector學(xué)習(xí)"),
      ),
      body: Center(
        child: GestureDetector(
          //一定要加（按鈕和文字之間的空白，也添加監(jiān)聽(tīng)了）
          behavior: HitTestBehavior.opaque,
          onPanDown: (value) {
            print("我是onPanDown");
          },
          child: Row(
            children: [
              OutlinedButton(
                child: Text("按鈕"),
                onPressed: () {
                  print("點(diǎn)擊了button");
                },
              ),
              SizedBox(width: 80),
              Text("文字")
            ],
          )
        ),
      )
    ));
  }
}