禁用平移手势，如果超出检测范围
我有一个UIView我想上下移动屏幕，但是我只想让它平移，以便当它在正常位置（0，0）时不能拖动视图，
我试图检测识别器的中心何时不是视图高度的一半，然而视图是不可移动的，并且中心总是高度的一半（在这种情况下是230）。
有任何想法吗？
- (IBAction)panDetected:(UIPanGestureRecognizer *)recognizer { CGPoint translation = [recognizer translationInView:self.view]; NSLog(@"\ncenter.y: %f\ntranslation.y: %f\n", recognizer.view.center.y, translation.y); if (recognizer.view.center.y > ([[UIScreen mainScreen] bounds].size.height - 20)/2) { return; } recognizer.view.center = CGPointMake(recognizer.view.center.x, recognizer.view.center.y + translation.y); [recognizer setTranslation:CGPointMake(0, 0) inView:self.view]; } 而不是手动计算点是否在视图的边界内，使用CGRectContainsPoint(rect, point) 。 这对我来说是有用的，我喜欢它，因为它更短，更可读：
func handlePan(pan: UIPanGestureRecognizer) { switch pan.state { case .Began: if CGRectContainsPoint(self.pannableView.frame, pan.locationInView(self.pannableView)) { // Gesture started inside the pannable view. Do your thing. } }
CGPoint translation = [recognizer translationInView:self.view]; CGPoint finalpoint = CGPointMake(recognizer.view.center.x + translation.x, recognizer.view.center.y+ translation.y); //limit the boundary if ((recognizer.view.frame.origin.x>0 && translation.x > 0) || (recognizer.view.frame.origin.x + recognizer.view.frame.size.width<=320 && translation.x < 0)) finalpoint.x = recognizer.view.center.x; if ((recognizer.view.frame.origin.y>0 && translation.y > 0) || (recognizer.view.frame.origin.y + recognizer.view.frame.size.height<=self.view.frame.size.height && translation.y < 0)) finalpoint.y = recognizer.view.center.y; //set final position recognizer.view.center = finalpoint; [recognizer setTranslation:CGPointZero inView:self.view];
尝试
CGPoint translation = [recognizer translationInView:self.view]; if (translation.x+recognizer.view.frame.origin.x<0||translation.y+recognizer.view.frame.origin.y<0) { return; } recognizer.view.center = CGPointMake(recognizer.view.center.x, recognizer.view.center.y + translation.y); [recognizer setTranslation:CGPointMake(0, 0) inView:self.view];
recognizer.view.center = CGPointMake(recognizer.view.center.x, MAX(recognizer.view.center.y + translation.y, ([[UIScreen mainScreen] bounds].size.height - 20)/2));