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如何在3.2以下的iOS中获得长按手势的功能

发布于 2024-10-09 23:04:52 字数 122 浏览 6 评论 0原文

UILongPressGesture 在 ios 版本 3.2 及更高版本中可用。但我正在尝试开发应用程序以实现最大兼容性，因此针对 ios ver2.0

任何人都可以指导我如何在 ios v2.0 中完成长按手势

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瑕疵 2024-10-16 23:04:52

对于单个手指，这非常简单：在 touchesBegan 方法中启动一个计时器，并在计时器触发时触发一个操作。如果在触发之前收到 touchesEnded 消息，请取消计时器。下面是使用 performSelector:withObject:afterDelay: 方法的实现。

- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
    [self performSelector:@selector(fireLongPress)
               withObject:nil
               afterDelay:LONG_PRESS_THRESHOLD];
}

- (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event {
    [NSObject cancelPreviousPerformRequestsWithTarget:self];
}

- (void)fireLongPress {
    // do what you want to do
}

如果手指移动得太远，您可能还想终止计时器。

对于多点触控，情况会稍微复杂一些。您必须跟踪哪个触摸是哪个触摸，并决定要做什么，例如，当一个手指按下足够长的时间而另一根手指没有按下时（或者弄清楚UILongPressGestureRecognizer做了什么）。

For a single finger, it's pretty simple: Start a timer in the touchesBegan method and trigger an action when the timer fires. Cancel the timer if you get a touchesEnded before it fires. Here's an implementation that uses the performSelector:withObject:afterDelay: method.

- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
    [self performSelector:@selector(fireLongPress)
               withObject:nil
               afterDelay:LONG_PRESS_THRESHOLD];
}

- (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event {
    [NSObject cancelPreviousPerformRequestsWithTarget:self];
}

- (void)fireLongPress {
    // do what you want to do
}

You'll probably also want to kill the timer if the finger moves too far.

With multitouch, it's a bit more complicated. You'll have to keep track of which touch is which, and decide what to do e.g. when one finger has pressed long enough but the other hasn't (or figure out what UILongPressGestureRecognizer does).

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