touchesBegan 并不总是响应

Question

我正在检测屏幕上的滑动，它完全按照我想要的方式工作。 唯一的问题是，在测试中，我不断地反复滑动，至少 90% 或更多的时间它在响应，但时不时地没有响应。

我用 NSLog 记录了一切以找到罪魁祸首，发现在这种情况发生的几次中根本没有检测到 touchesBegan。

这是我的代码，虽然 touchesBegan 甚至没有被调用，所以代码应该无关紧要：

- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
    NSLog(@"touches began!");
    UITouch *touch = [touches anyObject];
    CGPoint thisTouch = [touch locationInView:self.view];

    touchstartedX = thisTouch.x;
    touchstartedY = thisTouch.y;
}

- (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event {

    CGPoint p = [[touches anyObject] locationInView:self.view];

    if ((abs(p.y - touchstartedY)) < 120) {
        if ((p.x - touchstartedX) > 10) {
            [self goPrevious];
        } else if ((p.x - touchstartedX) < -10) {
            [self goNext];
        } 
    } else { NSLog(@"too much Y"); }
} 

有什么想法吗？

谢谢！

* 使用解决方案编辑 * 这是我根据 dredful 的建议探索 UISwipeGestureRecognizer 后最终使用的代码：

在.h中：

UIViewController <UIGestureRecognizerDelegate>

UISwipeGestureRecognizer *swipeLeft;
UISwipeGestureRecognizer *swipeRight;

@property (nonatomic, retain) UISwipeGestureRecognizer *swipeLeft;
@property (nonatomic, retain) UISwipeGestureRecognizer *swipeRight;

在.m:

@synthesize swipeLeft, swipeRight;

UIGestureRecognizer *recognizer;
    recognizer = [[UISwipeGestureRecognizer alloc] initWithTarget:self action:@selector(handleSwipeFrom:)];
    self.swipeLeft = (UISwipeGestureRecognizer *)recognizer;
    swipeLeft.direction = UISwipeGestureRecognizerDirectionLeft;
    self.swipeLeft = (UISwipeGestureRecognizer *)recognizer;
    [recognizer release];

    recognizer;
    recognizer = [[UISwipeGestureRecognizer alloc] initWithTarget:self action:@selector(handleSwipeFrom:)];
    self.swipeRight = (UISwipeGestureRecognizer *)recognizer;
    swipeRight.direction = UISwipeGestureRecognizerDirectionRight; 
    self.swipeRight = (UISwipeGestureRecognizer *)recognizer;
    [recognizer release];

    [self.view addGestureRecognizer:swipeLeft];    
    [self.view addGestureRecognizer:swipeRight];

- (void)handleSwipeFrom:(UISwipeGestureRecognizer *)recognizer {

    if (recognizer.direction == UISwipeGestureRecognizerDirectionLeft) {
        [self goNext];
    } else {
        [self goPrevious];
    }
}

- (void)dealloc
{
    [swipeLeft release];
    [swipeRight release];
    [super dealloc];
}

- (void)viewDidUnload
{
    [super viewDidUnload];
    // Release any retained subviews of the main view.
    // e.g. self.myOutlet = nil;
    self.swipeLeft = nil;
    self.swipeRight = nil;
}

Answer 1

使用苹果的UISwipeGestureRecognizer更容易

// add Swipe Left
UISwipeGestureRecognizer *swipeLeft = [[UISwipeGestureRecognizer alloc] initWithTarget:self action:@selector(handleSwipeLeft:)];
swipeLeft.direction = UISwipeGestureRecognizerDirectionLeft;
[self.view addGestureRecognizer:swipeLeft];
[swipeLeft release];

// add Swipe Right
UISwipeGestureRecognizer *swipeRight = [[UISwipeGestureRecognizer alloc] initWithTarget:self action:@selector(handleSwipeRight:)];
swipeRight.direction = UISwipeGestureRecognizerDirectionRight;
[self.view addGestureRecognizer:swipeRight];
[swipeRight release];


- (void)handleSwipeLeft:(UISwipeGestureRecognizer *)recognizer {
    //do something
}

- (void)handleSwipeRight:(UISwipeGestureRecognizer *)recognizer {
    //do something
}