How to set minimum & maximum y value? - iphone

Question

I am implementing a draggable UIView in my application. The codes I have worked fine but I would like to set a restricted area the UIView can be moved.
My codes:
-(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;
}
}
So how can I set the minimum and maximum y value that the UIView can be dragged?
Thanks!

Answer 1

If you are interested in making sure the view frame doesn't go over or under a certain y value you could do the following,
- (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;
}
}