How to detect touch on UICollectionView?

问题

I want to disable UICollectionViewController's autorotation whenever there's a finger on the screen, as the iPhone photo app does.

How to do that?

• If use tap gesture, how to distinguish different touch states? (The state should be touching, even after finger moving.)
• If use touchBegan:withEvent:, where to put that code? (The hit view can be any subview of UICollectionView.)

回答1:

I would set a flag in touchesBegan and clear it in touchesEnded. Then in your shouldAutoRotate method you can check the flag and return false if the flag is set.

Something like this:

// In your UICollectionView subclass:

-(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
{
    // Do stuff
    ...
    canRotate = NO;
}

-(void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event
{
    // Do stuff
    ...
    canRotate = YES;
}

// In your UICollectionViewController:

-(bool)shouldAutorotate
{
    return(canRotate);
}

来源：https://stackoverflow.com/questions/22487121/how-to-detect-touch-on-uicollectionview