iOS: Gesture recogniser for smooth scrolling and flicking a View
- by AppleDeveloper
I am building an iPad app where I needed to allow resizing views functionality using divider view provided between two views. This divider view is just a 20px height view between two half screen content views - please refer attached images. When user scrolls this divider view up or down, both content views changes their sizes appropriately. I have extended UIView and implemented this using touchMoved delegate as code given below in touchesMoved delegate. It works fine. The only thing is missing with TouchMoved is you can't flick divider view to top or bottom directly. You have to scroll all the way to top or bottom! To support flicking the view I have tried UIPanGestureRecognizer but I don't see smooth scrolling with it. When I handle split position change in UIGestureRecognizerStateChanged state, just touching divider view flick it to top or bottom. Handling split position change in UIGestureRecognizerStateEnded does the same but I don't see content view resizing with dividerview scrolling! Could someone please tell me how could I achieve both smooth scrolling of divider view with resizing content views(like touchMoved) and flicking the view. Any alternative approach would also fine. Thanks.
- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event {
UITouch *touch = [touches anyObject];
if (touch) {
CGPoint lastPt = [touch previousLocationInView:self];
CGPoint pt = [touch locationInView:self];
float offset = pt.y - lastPt.y;
self.parentViewController.splitPosition = self.parentViewController.splitPosition + offset;
}
}
- (void)handlePan:(UIPanGestureRecognizer*)recognizer {
CGPoint translation = [recognizer translationInView:recognizer.view];
CGPoint velocity = [recognizer velocityInView:recognizer.view];
if (recognizer.state == UIGestureRecognizerStateBegan) {
} else if (recognizer.state == UIGestureRecognizerStateChanged) {
// If I change split position here, I don't see smooth scrolling dividerview...it directly jumps to the top or bottom!
self.parentViewController.splitPosition = self.parentViewController.splitPosition + translation.y;
} else if (recognizer.state == UIGestureRecognizerStateEnded) {
// If I change split position here, the same thing happens at end and I don't see my divider view moving with my scrolling and resizing my views.
self.parentViewController.splitPosition = self.parentViewController.splitPosition + translation.y;
}
}
Initial screen
Increased top view size by scrolling divider view
Top view is totally hidden here but I have to scroll divider view all
the way to top. I want to flick the divider view so that it directly
goes from any position to top
