设置UISwipeGestureRecognizer的方向
我想添加简单的滑动手势识别到我的基于视图的iPhone项目。应该识别所有方向(右、下、左、上)的手势。
UISwipeGestureRecognizer的文档中说明了这一点：
您可以通过使用按位OR操作数指定多个UISwipeGestureRecognizerDirection常量来指定多个方向。默认方向为UISwipeGestureRecognizerDirectionRight。
然而，对我来说，它并不起作用。当所有四个方向都进行OR运算时，只能识别向左和向右的滑动。
- (void)viewDidLoad {
UISwipeGestureRecognizer *recognizer;
recognizer = [[UISwipeGestureRecognizer alloc] initWithTarget:self action:@selector(handleSwipeFrom:)];
[recognizer setDirection:(UISwipeGestureRecognizerDirectionRight | UISwipeGestureRecognizerDirectionDown | UISwipeGestureRecognizerDirectionLeft | UISwipeGestureRecognizerDirectionUp)];
[[self view] addGestureRecognizer:recognizer];
[recognizer release];
[super viewDidLoad];
}
-(void)handleSwipeFrom:(UISwipeGestureRecognizer *)recognizer {
NSLog(@"Swipe received.");
}我修复了这个问题，在视图中添加了四个识别器，但我很好奇为什么它没有像文档中宣传的那样工作？
- (void)viewDidLoad {
UISwipeGestureRecognizer *recognizer;
recognizer = [[UISwipeGestureRecognizer alloc] initWithTarget:self action:@selector(handleSwipeFrom:)];
[recognizer setDirection:(UISwipeGestureRecognizerDirectionRight)];
[[self view] addGestureRecognizer:recognizer];
[recognizer release];
recognizer = [[UISwipeGestureRecognizer alloc] initWithTarget:self action:@selector(handleSwipeFrom:)];
[recognizer setDirection:(UISwipeGestureRecognizerDirectionUp)];
[[self view] addGestureRecognizer:recognizer];
[recognizer release];
recognizer = [[UISwipeGestureRecognizer alloc] initWithTarget:self action:@selector(handleSwipeFrom:)];
[recognizer setDirection:(UISwipeGestureRecognizerDirectionDown)];
[[self view] addGestureRecognizer:recognizer];
[recognizer release];
recognizer = [[UISwipeGestureRecognizer alloc] initWithTarget:self action:@selector(handleSwipeFrom:)];
[recognizer setDirection:(UISwipeGestureRecognizerDirectionLeft)];
[[self view] addGestureRecognizer:recognizer];
[recognizer release];
[super viewDidLoad];
}
-(void)handleSwipeFrom:(UISwipeGestureRecognizer *)recognizer {
NSLog(@"Swipe received.");
}回答 12
Stack Overflow用户
发布于 2010-08-05 21:52:19
好像有个bug。您可以像以前一样指定允许的方向。但是，当您尝试访问在操作选择器方法中触发滑动的实际方向时，您仍然会获得最初设置的位掩码(对于允许的方向)。
这意味着当允许多个方向时，对实际方向的检查将始终失败。当你在选择器方法(即-(void)scrollViewSwiped:(UISwipeGestureRecognizer *)recognizer)中输出'direction‘的值时，你可以很容易地看到它。
已向Apple提交错误报告(#8276386)。
更新:我从苹果公司得到了一个答复，说这个行为是按照预期工作的。
例如，在表格视图中，您可以在表格视图单元格中向左或向右滑动以触发“删除”(这将使滑动手势的方向设置为左和右)
这意味着原始的变通方法是它应该使用的方式。direction属性只能用于正确识别手势，而不能用于在成功识别时执行的方法中，以便与触发识别的实际方向进行比较。
Stack Overflow用户
发布于 2010-07-29 06:02:41
我注意到左/右和上/下手势是成对工作的，所以你只需要指定两个手势识别器。而且文档看起来确实是错的。
Stack Overflow用户
发布于 2011-12-23 18:32:21
很糟糕，我通过添加两个手势解决了这个问题，就像Lars提到的那样，而且效果很好……
1)左/右2)上/下
UISwipeGestureRecognizer *swipeLeftRight = [[UISwipeGestureRecognizer alloc] initWithTarget:self action:@selector(handleGesture:)];
[swipeLeftRight setDirection:(UISwipeGestureRecognizerDirectionRight | UISwipeGestureRecognizerDirectionLeft )];
[self.view addGestureRecognizer:swipeLeftRight];
UISwipeGestureRecognizer *swipeUpDown = [[UISwipeGestureRecognizer alloc] initWithTarget:self action:@selector(handleGesture:)];
[swipeUpDown setDirection:(UISwipeGestureRecognizerDirectionUp | UISwipeGestureRecognizerDirectionDown )];
[self.view addGestureRecognizer:swipeUpDown];https://stackoverflow.com/questions/3319209
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