xcode iOS - 双击 uibutton
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iOS - Double tap on uibutton
提问by Kerberos
I have a button and I'm testing the taps on it, with one tap it change a background color, with two taps another color and with three taps another color again. The code is:
我有一个按钮，我正在测试它的点击，点击它会改变背景颜色，点击两次另一种颜色，再次点击三下另一种颜色。代码是：
- (IBAction) button
{
UITapGestureRecognizer *tapOnce = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(tapOnce:)];
UITapGestureRecognizer *tapTwice = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(tapTwice:)];
UITapGestureRecognizer *tapTrice = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(tapTrice:)];
tapOnce.numberOfTapsRequired = 1;
tapTwice.numberOfTapsRequired = 2;
tapTrice.numberOfTapsRequired = 3;
//stops tapOnce from overriding tapTwice
[tapOnce requireGestureRecognizerToFail:tapTwice];
[tapTwice requireGestureRecognizerToFail:tapTrice];
//then need to add the gesture recogniser to a view - this will be the view that recognises the gesture
[self.view addGestureRecognizer:tapOnce];
[self.view addGestureRecognizer:tapTwice];
[self.view addGestureRecognizer:tapTrice];
}
- (void)tapOnce:(UIGestureRecognizer *)gesture
{
self.view.backgroundColor = [UIColor redColor];
}
- (void)tapTwice:(UIGestureRecognizer *)gesture
{
self.view.backgroundColor = [UIColor blackColor];
}
- (void)tapTrice:(UIGestureRecognizer *)gesture
{
self.view.backgroundColor = [UIColor yellowColor];
}
The problem is that the first tap don't works, the other yes. If I use this code without button it works perfectly. Thanks.
问题是第一个水龙头不起作用，另一个是。如果我在没有按钮的情况下使用此代码，它可以完美运行。谢谢。
回答by iDev
If you want the colors to change on tap of button, you should add these gestures on button in viewDidLoadmethod or so rather than on the same button action. The above code will repeatedly add gestures on tap of the button to the self.viewand not on button.
如果您希望点击按钮时颜色发生变化，您应该在按钮上添加这些手势，viewDidLoad而不是在相同的按钮操作上。上面的代码将在点击按钮时重复添加手势到self.view而不是 on button。
- (void)viewDidLoad {
[super viewDidLoad];
UITapGestureRecognizer *tapOnce = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(tapOnce:)];
UITapGestureRecognizer *tapTwice = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(tapTwice:)];
UITapGestureRecognizer *tapTrice = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(tapTrice:)];
tapOnce.numberOfTapsRequired = 1;
tapTwice.numberOfTapsRequired = 2;
tapTrice.numberOfTapsRequired = 3;
//stops tapOnce from overriding tapTwice
[tapOnce requireGestureRecognizerToFail:tapTwice];
[tapTwice requireGestureRecognizerToFail:tapTrice];
//then need to add the gesture recogniser to a view - this will be the view that recognises the gesture
[self.button addGestureRecognizer:tapOnce]; //remove the other button action which calls method `button`
[self.button addGestureRecognizer:tapTwice];
[self.button addGestureRecognizer:tapTrice];
}
