Question

我嵌套了GestureDetetor，但是问题是只有子GestureDetector的{{1}}被执行。我不想覆盖孩子的onTap，而是希望父母和孩子的onTap都执行。这是我的代码：

onTap

如何更改此名称以同时调用GestureDetector( onTap: () { todo1(); }, child: GestureDetector( onTap: () { todo2(); }, child: Text("Nested Gesture")))和todo1() onTap？

Answer 1

我做了一个快速的自定义手势识别器-仅当用户距离初始点击点太远时，它才会取消手势。

用法示例：

UniversalTapHandler(
  onTap: () {
    print("Tap 1");
  },
  child: UniversalTapHandler(
    onTap: () {
      print("Tap 2");
    },
    child: Text("Nested Gesture"),
  )
)

源代码：

class UniversalTapHandler extends RawGestureDetector {
  UniversalTapHandler({
    @required GestureTapCallback onTap,
    @required Widget child,
  }):
    super(
      gestures: <Type, GestureRecognizerFactory>{
        _UniversalPointerHandler: GestureRecognizerFactoryWithHandlers<_UniversalPointerHandler>(
          () => _UniversalPointerHandler(onTap: onTap),
          (_) {},
        ),
      },
      child: child,
    );
}

class _UniversalPointerHandler extends OneSequenceGestureRecognizer {
  _UniversalPointerHandler({
    @required this.onTap,
  }): super();

  final GestureTapCallback onTap;

  final _maxDistance = 18; // as in official recognizer by default
  Offset _startPosition;

  void _reset() {
    _startPosition = null;
  }

  @override
  void addPointer(PointerDownEvent event) {
    _startPosition = event.position;
    startTrackingPointer(event.pointer);
    resolve(GestureDisposition.accepted);
  }

  @override
  void handleEvent(PointerEvent event) {
    if (event is PointerUpEvent) {
      stopTrackingPointer(event.pointer);
      if (_startPosition != null) {
        onTap();
      }
    }
    if (event is PointerMoveEvent && _startPosition != null) {
      if ((event.position - _startPosition).distance > _maxDistance) {
        rejectGesture(event.pointer);
        _reset();
      }
    }
    if (event is PointerCancelEvent || event is PointerExitEvent || event is PointerRemovedEvent) {
      _reset();
    }
  }

  @override
  void resolve(GestureDisposition disposition) {
    if (disposition == GestureDisposition.rejected) {
      _reset();
    }
    super.resolve(disposition);
  }

  @override
  void didStopTrackingLastPointer(int pointer) {}

  @override
  String get debugDescription => "_UniversalPointerHandler: Custom Gesture Recognizer";
}

更新别忘了导入：

import 'package:flutter/gestures.dart';

Answer 2

您可以在嵌套的 onTap 回调中调用 todo1()：

  GestureDetector(
        onTap: () {
            todo1(); 
        },
        child: GestureDetector(
            onTap: () {
                todo2();
                todo1();
            },
            child: Text("Nested Gesture")))

嵌套的GestureDetector OnTap函数

2 个答案: