如何使用颤振在移动应用程序中禁用多点触控

问题描述

这个问题纯粹是基于GestureDetectorflutter.

This question is purely based on GestureDetector flutter.

例如:在应用程序中，实现了 GestureDetector 类，因此默认情况下它支持多点触控，现在需要禁用此多点触控，以便最好的解决方案.

For Example: In Application, GestureDetector class is implemented so here by-default it support multi-touch, now need to disable this multi-touch so what could be the best way of a solution.

GestureDetector 参考链接:https://docs.flutter.io/flutter/widgets/GestureDetector-class.html

推荐答案

创建 OnlyOnePointerRecognizerWidget 小部件的实例并将任何小部件作为子部件传递给它.OnlyOnePointerRecognizerWidget 只会识别一个指针.

Create instance of OnlyOnePointerRecognizerWidget widget and pass any Widget as child to it. OnlyOnePointerRecognizerWidget will recognize only one pointer.

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

class OnlyOnePointerRecognizer extends OneSequenceGestureRecognizer {
  int _p = 0;
  @override
  void addPointer(PointerDownEvent event) {
    startTrackingPointer(event.pointer);
    if (_p == 0) {
      resolve(GestureDisposition.rejected);
      _p = event.pointer;
    } else {
      resolve(GestureDisposition.accepted);
    }
  }

  @override
  String get debugDescription => 'only one pointer recognizer';

  @override
  void didStopTrackingLastPointer(int pointer) {}

  @override
  void handleEvent(PointerEvent event) {
    if (!event.down && event.pointer == _p) {
      _p = 0;
    }
  }
}

class OnlyOnePointerRecognizerWidget extends StatelessWidget {
  final Widget child;
  OnlyOnePointerRecognizerWidget({this.child});
  @override
  Widget build(BuildContext context) {
    return RawGestureDetector(
      gestures: <Type, GestureRecognizerFactory>{
        OnlyOnePointerRecognizer: GestureRecognizerFactoryWithHandlers<OnlyOnePointerRecognizer>(
          () => OnlyOnePointerRecognizer(),
          (OnlyOnePointerRecognizer instance) {},
        ),
      },
      child: child,
    );
  }
}

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