Iphone UIPanGestureRecognizer的使用
我有一个使用UIPangestureRecognitor在屏幕上移动的小图像视图,但是当它从superview的边缘出来时,不会得到更多的触摸,因此无法再返回。如何防止图像从superview的边缘出来? 代码如下:Iphone UIPanGestureRecognizer的使用,iphone,objective-c,uigesturerecognizer,uipangesturerecognizer,Iphone,Objective C,Uigesturerecognizer,Uipangesturerecognizer,我有一个使用UIPangestureRecognitor在屏幕上移动的小图像视图,但是当它从superview的边缘出来时,不会得到更多的触摸,因此无法再返回。如何防止图像从superview的边缘出来? 代码如下: - (void)pan:(UIPanGestureRecognizer *)gestureRecognizer { if (inLongPress) { UIView *hitView = [gestureRecognizer view]; [self adjus
- (void)pan:(UIPanGestureRecognizer *)gestureRecognizer
{
if (inLongPress) {
UIView *hitView = [gestureRecognizer view];
[self adjustAnchorPointForGestureRecognizer:gestureRecognizer];
if (!(CGRectContainsRect(self.imageView.frame, hitView.frame))) {
[UIView beginAnimations:@"" context:NULL];
[hitView setCenter:CGPointMake(_prevCenter.x, _prevCenter.y)];
[UIView commitAnimations];
}
_prevCenter=hitView.center;
if ([gestureRecognizer state] == UIGestureRecognizerStateBegan || [gestureRecognizer state] == UIGestureRecognizerStateChanged) {
CGPoint translation = [gestureRecognizer translationInView:[hitView superview]];
[hitView setCenter:CGPointMake([hitView center].x + translation.x, [hitView center].y + translation.y)];
[gestureRecognizer setTranslation:CGPointZero inView:[hitView superview]];
}
if ([gestureRecognizer state] == UIGestureRecognizerStateEnded){
inLongPress=NO;
hitView.alpha=1.0;
}
}
}在视图控制器的viewDidLoad方法中,只需将superview的ClipToBounds属性设置为YES
[superview setClipsToBounds:是] 在视图控制器的viewDidLoad方法中,只需将superview的clipsToBounds属性设置为YES [superview setClipsToBounds:是] 如果将CGPoint限制在允许范围内,只需使用两个 类似这样的操作可确保无法将对象移动到视图之外:
CGFloat proposedX = location.x;
CGFloat proposedY = location.y;
CGRect objectFrame = hitView.frame;
CGFloat allowedXMin = 0 + objectFrame.size.width / 2.0f;
CGFloat allowedXMax = self.view.bounds.size.width - objectFrame.size.width / 2.0f;
CGFloat allowedYMin = 0 + objectFrame.size.height / 2.0f;
CGFloat allowedYMax = self.view.bounds.size.height - objectFrame.size.height / 2.0f;
if (proposedX < allowedXMin) {
proposedX = allowedXMin;
}
else if (proposedX > allowedXMax) {
proposedX = allowedXMax;
}
if (proposedY < allowedYMin) {
proposedY = allowedYMin;
}
else if (proposedY > allowedYMax) {
proposedY = allowedYMax;
}
location = CGPointMake(proposedX, proposedY);
hitView.center = location;
如果这将CGPoint限制在允许的范围内,只需使用几个
类似这样的操作可确保无法将对象移动到视图之外:
CGFloat proposedX = location.x;
CGFloat proposedY = location.y;
CGRect objectFrame = hitView.frame;
CGFloat allowedXMin = 0 + objectFrame.size.width / 2.0f;
CGFloat allowedXMax = self.view.bounds.size.width - objectFrame.size.width / 2.0f;
CGFloat allowedYMin = 0 + objectFrame.size.height / 2.0f;
CGFloat allowedYMax = self.view.bounds.size.height - objectFrame.size.height / 2.0f;
if (proposedX < allowedXMin) {
proposedX = allowedXMin;
}
else if (proposedX > allowedXMax) {
proposedX = allowedXMax;
}
if (proposedY < allowedYMin) {
proposedY = allowedYMin;
}
else if (proposedY > allowedYMax) {
proposedY = allowedYMax;
}
location = CGPointMake(proposedX, proposedY);
hitView.center = location;