Untitled

  @override
  Widget build(BuildContext context) {
    var gestures = <Type, GestureRecognizerFactory>{
      TapGestureRecognizer: GestureRecognizerFactoryWithHandlers<TapGestureRecognizer>(
        () => TapGestureRecognizer(),
        (TapGestureRecognizer instance) {
          instance.onTapDown = _tapDown;
<!--more-->
          instance.onTapUp = _tapUp;
          instance.onTap = _tap;
          instance.onTapCancel = _tapCancel;
        },
      ),
    };
    return RawGestureDetector(
      gestures: gestures,
      child: Container(
          width: 100.0,
          height: 100.0,
          color: color,
          alignment: Alignment.center,
          child: Text(
            "action:$action",
            style: TextStyle(color: Colors.white),
          )),
    );
  }

RawGestureDetector

  @override
  void initState() {
    super.initState();
    _semantics = widget.semantics ?? _DefaultSemanticsGestureDelegate(this);
    _syncAll(widget.gestures);
  }
  
  @override
  Widget build(BuildContext context) {
    Widget result = Listener(
      onPointerDown: _handlePointerDown,
      onPointerPanZoomStart: _handlePointerPanZoomStart,
      behavior: widget.behavior ?? _defaultBehavior,
      child: widget.child,
    );
    if (!widget.excludeFromSemantics) {
      result = _GestureSemantics(
        behavior: widget.behavior ?? _defaultBehavior,
        assignSemantics: _updateSemanticsForRenderObject,
        child: result,
      );
    }
    return result;
  }
  
  点击事件会进入 _handlePointerDown 中
  
  void _handlePointerDown(PointerDownEvent event) {
    assert(_recognizers != null);
    for (final GestureRecognizer recognizer in _recognizers!.values) {
      recognizer.addPointer(event);
    }
  }
  

	到父类 GestureRecognizer 中
	
  void addPointer(PointerDownEvent event) {
    _pointerToKind[event.pointer] = event.kind;
    if (isPointerAllowed(event)) {
      addAllowedPointer(event);
    } else {
      handleNonAllowedPointer(event);
    }
  }
  
  
    @override
  void addAllowedPointer(PointerDownEvent event) {
    assert(event != null);
    if (state == GestureRecognizerState.ready) {
      // If there is no result in the previous gesture arena,
      // we ignore them and prepare to accept a new pointer.
      if (_down != null && _up != null) {
        assert(_down!.pointer == _up!.pointer);
        _reset();
      }

      assert(_down == null && _up == null);
      // `_down` must be assigned in this method instead of `handlePrimaryPointer`,
      // because `acceptGesture` might be called before `handlePrimaryPointer`,
      // which relies on `_down` to call `handleTapDown`.
      _down = event;
    }
    if (_down != null) {
      // This happens when this tap gesture has been rejected while the pointer
      // is down (i.e. due to movement), when another allowed pointer is added,
      // in which case all pointers are simply ignored. The `_down` being null
      // means that _reset() has been called, since it is always set at the
      // first allowed down event and will not be cleared except for reset(),
      super.addAllowedPointer(event);
    }
  }
  
  >>>>>>>>>> PrimaryPointerGestureRecognizer
  
  @override
  void addAllowedPointer(PointerDownEvent event) {
    super.addAllowedPointer(event);
    if (state == GestureRecognizerState.ready) {
      _state = GestureRecognizerState.possible;
      _primaryPointer = event.pointer;
      _initialPosition = OffsetPair(local: event.localPosition, global: event.position);
      if (deadline != null) {
        _timer = Timer(deadline!, () => didExceedDeadlineWithEvent(event));
      }
    }
  }
  
  >>>>>>>>>> OneSequenceGestureRecognizer
  
  @override
  @protected
  void addAllowedPointer(PointerDownEvent event) {
    startTrackingPointer(event.pointer, event.transform);
  }
  
  @protected
  void startTrackingPointer(int pointer, [Matrix4? transform]) {
    // 点击事件处理由 handleEvent 函数完成
    GestureBinding.instance.pointerRouter.addRoute(pointer, handleEvent, transform);
    _trackedPointers.add(pointer);
    assert(!_entries.containsValue(pointer));
    // _addPointerToArena(pointer) 应该是将 pointer 加入到手势竞技场中
    // _entries 里面有竞技场相关的东西，之后通过 pointer 取出竞技场开始竞争
    _entries[pointer] = _addPointerToArena(pointer);
  }

  GestureArenaEntry _addPointerToArena(int pointer) {
    if (_team != null) {
      return _team!.add(pointer, this);
    }
    return GestureBinding.instance.gestureArena.add(pointer, this);
  }

	// GestureBinding 中会初始化 GestureArenaManager
  GestureArenaEntry add(int pointer, GestureArenaMember member) {
    final _GestureArena state = _arenas.putIfAbsent(pointer, () {
      assert(_debugLogDiagnostic(pointer, '★ Opening new gesture arena.'));
      return _GestureArena();
    });
    state.add(member);
    assert(_debugLogDiagnostic(pointer, 'Adding: $member'));
    return GestureArenaEntry._(this, pointer, member);
  }


  之后再回到 PrimaryPointerGestureRecognizer 中的 addAllowedPointer 方法中
    
  @override
  void addAllowedPointer(PointerDownEvent event) {
    super.addAllowedPointer(event);
    if (state == GestureRecognizerState.ready) {
      _state = GestureRecognizerState.possible;
      _primaryPointer = event.pointer;
      _initialPosition = OffsetPair(local: event.localPosition, global: event.position);
      if (deadline != null) {
        // deadline = 100 ms
        // 就是说 100ms 之后会会执行 didExceedDeadlineWithEvent 这个方法
        _timer = Timer(deadline!, () => didExceedDeadlineWithEvent(event));
      }
    }
  }

  @protected
  void didExceedDeadlineWithEvent(PointerDownEvent event) {
    didExceedDeadline();
  }

  void _checkDown() {
    if (_sentTapDown) {
      return;
    }
    handleTapDown(down: _down!);
    _sentTapDown = true;
  }

  @protected
  @override
  void handleTapDown({required PointerDownEvent down}) {
    final TapDownDetails details = TapDownDetails(
      globalPosition: down.position,
      localPosition: down.localPosition,
      kind: getKindForPointer(down.pointer),
    );
    switch (down.buttons) {
      case kPrimaryButton:
        if (onTapDown != null) {
          // 执行 onTapDown 方法，也就是在一开始构造函数中传入的回调方法
          invokeCallback<void>('onTapDown', () => onTapDown!(details));
        }
        break;
			......
    }
  }


最后分析 OneSequenceGestureRecognizer 中 startTrackingPointer 方法中的 handleEvent 方法
  @override
  void handleEvent(PointerEvent event) {
    assert(state != GestureRecognizerState.ready);
    if (state == GestureRecognizerState.possible && event.pointer == primaryPointer) {
      // ！_gestureAccepted && 移动的距离大余 18
      final bool isPreAcceptSlopPastTolerance =
          !_gestureAccepted &&  // 接受手势或者停止检测才会是 true
          preAcceptSlopTolerance != null && // 18
          _getGlobalDistance(event) > preAcceptSlopTolerance!;
      // _gestureAccepted && 移动的距离大余 18
      final bool isPostAcceptSlopPastTolerance =
          _gestureAccepted &&
          postAcceptSlopTolerance != null && // 18
          _getGlobalDistance(event) > postAcceptSlopTolerance!;
			
      // 点击手势走 else ，移动手势走 if
      if (event is PointerMoveEvent && (isPreAcceptSlopPastTolerance || isPostAcceptSlopPastTolerance)) {
        resolve(GestureDisposition.rejected);
        stopTrackingPointer(primaryPointer!);
      } else {
        handlePrimaryPointer(event);
      }
    }
    stopTrackingIfPointerNoLongerDown(event);
  }

  @override
  void handlePrimaryPointer(PointerEvent event) {
    if (event is PointerUpEvent) {
      _up = event;
      // 回调构造时闯进来的回调函数，完成本次事件
      _checkUp();
    } else if (event is PointerCancelEvent) {
      resolve(GestureDisposition.rejected);
      if (_sentTapDown) {
        _checkCancel(event, '');
      }
      _reset();
    } else if (event.buttons != _down!.buttons) {
      resolve(GestureDisposition.rejected);
      stopTrackingPointer(primaryPointer!);
    }
  }