Trying to make UITableViewCell slideable AND tappable, while also keeping the UITableView scrollable, why is my cell sliding only working sometimes?

Question

I have a UITableView, where its cells are subclasses of UITableViewCell that have a top UIView and a bottom UIView that allow the top UIView to be moved to the right and left if the user drags his/her finger. I got it working by adding a pan gesture recognizer to each UITableViewCell. Pretty easy stuff. But I only want horizontal pans, but it would detect vertical pans across the cell when it was intended to scroll up, which would cause the UITableView not to move. I tried to make it so the gesture would only be detected if the user panned his/her finger horizontally more than 5px, but it doesn't seem to be working. The scroll works fine, and I can tap the cell, but I slide ten times across a cell and it works maybe once. I can't figure out why. Relevant code: ``` - (BOOL)gestureRecognizerShouldBegin:(UIGestureRecognizer *)recognizer { if ([recognizer isKindOfClass:[UIPanGestureRecognizer class]]) { NSLog(@"hi"); CGPoint translation = [(UIPanGestureRecognizer *)recognizer translationI…

Accepted Answer

A nice way of doing this without messing about with only starting to pan when you've moved a certain value is to determine which direction the gesture recognizer has translated the most in and using that. It cuts down on the amount of code you need quite a bit and works fairly well in my testing.

```
- (BOOL)gestureRecognizerShouldBegin:(UIGestureRecognizer *)gestureRecognizer {
    if ([gestureRecognizer isKindOfClass:[UIPanGestureRecognizer class]]) {
        CGPoint translation = [(UIPanGestureRecognizer*)gestureRecognizer translationInView:self.superview];
        return fabsf(translation.x) > fabsf(translation.y)
    }

return YES;
}
```

And now your view sliding becomes simpler. This code allows you to drag in either direction.

```
- (void)drag:(UIPanGestureRecognizer *)sender {
    CGPoint translation = [sender translationInView:self.superview];
    CGRect frame = self.upperView.frame;

switch (sender.state) {
        case UIGestureRecognizerStateChanged:
            frame.origin.x = translation.x;
            [self.upperView setFrame:frame];
            break;
        case UIGestureRecognizerStateBegan:
        case UIGestureRecognizerStateEnded:
        case UIGestureRecognizerStateFailed:
        default:
            break;
    }
}
```

Additionally, you may want to allow your gesture recognizer to work along side others (as in, the recognizer that handles the scrolling of the table view) but the code in `gestureRecognizerShouldBegin:` seems to handle this without issue.

```
- (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldRecognizeSimultaneouslyWithGestureRecognizer:(UIGestureRecognizer *)otherGestureRecognizer {
    return YES;
}
```

Also note that I'm using `self.superview` instead of just `self` as you have. This is because of this line in the `translationInView:` section of the docs:

The view in whose coordinate system the translation of the pan gesture should be computed. If you want to adjust a view's location to keep it under the user's finger, request the translation in that view's superview's coordinate system.

Trying to make UITableViewCell slideable AND tappable, while also keeping the UITableView scrollable, why is my cell sliding only working sometimes?

Solution

Problem