BFDragGestureRecognizer is a UIGestureRecognizer subclass that can be used to drag views inside a scroll view with automatic scrolling at the edges of the scroll view.
Create a Podfile, if you don't have one already. Add the following line.
pod 'BFDragGestureRecognizer'
Run the following command.
pod install
Alternatively, you can just drop the BFDragGestureRecognizer.{h,m} files into your project.
Add the gesture recognizer to the view(s) you want to drag:
BFDragGestureRecognizer *dragRecognizer = [[BFDragGestureRecognizer alloc] init];
[dragRecognizer addTarget:self action:@selector(dragRecognized:)];
[view addGestureRecognizer:dragRecognizer];Implement the gesture handler method. This is very similar to what you would do using a standard UIPanGestureRecognizer:
- (void)dragRecognized:(BFDragGestureRecognizer *)recognizer {
UIView *view = recognizer.view;
if (recognizer.state == UIGestureRecognizerStateBegan) {
// When the gesture starts, remember the current position.
_startCenter = view.center;
} else if (recognizer.state == UIGestureRecognizerStateChanged) {
// During the gesture, we just add the gesture's translation to the saved original position.
// The translation will account for the changes in contentOffset caused by auto-scrolling.
CGPoint translation = [recognizer translationInView:_contentView];
CGPoint center = CGPointMake(_startCenter.x + translation.x, _startCenter.y + translation.y);
view.center = center;
}
}New BSD License. For the full license text, see here.