Question

I have an app with an MGSplitView containing a table view and a UIWebView, which is fixed to landscape. The web view has a UITapGestureRecognizer (for a triple tap) attached to the web view. Taps in the left portion of the web view work; taps on the right side of the web view are lost – the action is not triggered, and the gesture delegate messages are not received.

The problem seems not to lie in the MGSplitViewController, as switching to a UISplitViewController has the same issues; changing from a tap to a long press also has the same results.

Tap locations are reported with the x coordinate at or close to the max width of the gesture.view, and yet are clearly made close to the centre of the display, which I expect has something to do with the root of the problem – and yet the web view contents are clearly visible and correctly placed.

All the view controllers involved implement shouldAutorotate and supportedInterfaceOrientations, so being stuck in portrait seems unlikely i.e. MGSplitViewController, my UITableView subclass (left hand panel) and UIViewController subclass for the right hand panel.

My gesture recognizer delegate and output from one triple-tap (the view in the right hand panel web view):

- (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldReceiveTouch:(UITouch *)touch {
    NSLog(@"%s", __PRETTY_FUNCTION__);
    NSLog(@"gestureRecognizer view frame: %@", NSStringFromCGRect(gestureRecognizer.view.frame));
    NSLog(@"location %@", NSStringFromCGPoint([gestureRecognizer locationInView:gestureRecognizer.view]));
    return YES;
}

-[DocumentBrowser gestureRecognizer:shouldReceiveTouch:]
gestureRecognizer view frame: {{0, 0}, {703, 704}}
location {703, -20}
-[DocumentBrowser gestureRecognizer:shouldReceiveTouch:]
gestureRecognizer view frame: {{0, 0}, {703, 704}}
location {414.5, 204.5}
-[DocumentBrowser gestureRecognizer:shouldReceiveTouch:]
gestureRecognizer view frame: {{0, 0}, {703, 704}}
location {414.5, 204.5}

The first location reported seems strange.

Answer 1

Check your orientation and view resizing mechanisms. I’ve seen this several times when something is wrong in these areas – if you log the touch locations, I think you will probably find that they stop at 768 points from the left-hand side, i.e. there is a view somewhere that thinks it is in portrait orientation.