[英]How to set minimum & maximum y value?
我在我的应用程序中实现了可拖动的UIView。 我的代码工作正常,但我想在UIView中设置一个可以移动的限制区域。
我的代码:
-(void) touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
{
UITouch *touch = [[event allTouches] anyObject];
if( [touch view] == camview)
{
CGPoint location = [touch locationInView:self.view;
startX = camview.center.x;
startY= location.y - camview.center.y;
}
}
- (void) touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event{
UITouch *touch = [[event allTouches] anyObject];
if( [touch view] == camview)
{
CGPoint location = [touch locationInView:self.view];
location.y =location.y - startY;
location.x = startX;
camview.center = location;
}
}
那么如何设置UIView可以拖动的最小和最大y值呢?
谢谢!
如果您有兴趣确保镜框不会超过或低于某个y值,则可以执行以下操作,
- (void) touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event{
CGFloat minY, maxY; //The position in your self.view you are interested in
UITouch *touch = [[event allTouches] anyObject];
if( [touch view] == camview)
{
CGPoint location = [touch locationInView:self.view];
location.y = location.y - startY;
location.y = MIN(location.y,maxY); //Always <= maxY
location.y = MAX(location.y,minY); //Always >= minY
location.x = startX;
camview.center = location;
}
}
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