Question

我有一个GestureDetector，需要启动一个URL。但是，如果该手势获得了多次轻击，则多次被称为启动。

在当前代码中，im试图使用状态_isButtonTapped来控制抽头。但是.whenComplete是在启动执行之前以某种方式调用的吗？

    import numpy as np

Answer 1

尝试一下：

class _HomePageState extends State<HomePage> {
  bool _isButtonTapped = false;
  String _url = "https://google.ca";

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: Center(
        child: Container(
          color: Colors.blue,
          width: 100,
          height: 100,
          child: GestureDetector(
            onTap: () async {
              if (!_isButtonTapped) { // only allow click if it is false
                _isButtonTapped = true; // make it true when clicked
                if (await canLaunch(_url)) {
                  await launch(_url);
                  _isButtonTapped = false; // once url is launched successfully, we again make it false, allowing tapping again
                }
              }
            },
          ),
        ),
      ),
    );
  }
}

Answer 2

试试这个？它应该可以解决您的问题。

class SafeOnTap extends StatefulWidget {
  SafeOnTap({
    Key? key,
    required this.child,
    required this.onSafeTap,
    this.intervalMs = 500,
  }) : super(key: key);
  final Widget child;
  final GestureTapCallback onSafeTap;
  final int intervalMs;

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

class _SafeOnTapState extends State<SafeOnTap> {
  int lastTimeClicked = 0;

  @override
  Widget build(BuildContext context) {
    return GestureDetector(
      onTap: () {
        final now = DateTime.now().millisecondsSinceEpoch;
        if (now - lastTimeClicked < widget.intervalMs) {
          return;
        }
        lastTimeClicked = now;
        widget.onSafeTap();
      },
      child: widget.child,
    );
  }
}

如果需要，您可以包装任何类型的小部件。

class HomeScreen extends StatefulWidget {
  const HomeScreen({Key? key}) : super(key: key);

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

class _HomeScreenState extends State<HomeScreen> {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: SafeArea(
        child: Center(
          child: Column(
            children: [
              // every click need to wait for 500ms
              SafeOnTap(
                onSafeTap: () => log('500ms'),
                child: Container(
                  width: double.infinity,
                  height: 200,
                  child: Center(child: Text('500ms click me')),
                ),
              ),
              // every click need to wait for 2000ms
              SafeOnTap(
                intervalMs: 2000,
                onSafeTap: () => log('2000ms'),
                child: Container(
                  width: double.infinity,
                  height: 200,
                  child: Center(child: Text('2000ms click me')),
                ),
              ),
            ],
          ),
        ),
      ),
    );
  }
}

如何防止多次点击手势？

2 个答案: