Scrolling with two fingers with a UIScrollView

Question

I have an app where my main view accepts both touchesBegan and touchesMoved, and therefore takes in single finger touches, and drags. I want to implement a UIScrollView, and I have it working, but it overrides the drags, and therefore my contentView never receives them. I'd like to implement a UIScrollview, where a two finger drag indicates a scroll, and a one finger drag event gets passed to my content view, so it performs normally. Do I need create my own subclass of UIScrollView?

Here's my code from my appDelegate where I implement the UIScrollView.

@implementation MusicGridAppDelegate  @synthesize window; @synthesize viewController; @synthesize scrollView;   - (void)applicationDidFinishLaunching:(UIApplication *)application {          // Override point for customization after app launch         //[application setStatusBarHidden:YES animated:NO];     //[window addSubview:viewController.view];      scrollView.contentSize = CGSizeMake(720, 480);     scrollView.showsHorizontalScrollIndicator = YES;     scrollView.showsVerticalScrollIndicator = YES;     scrollView.delegate = self;     [scrollView addSubview:viewController.view];     [window makeKeyAndVisible]; }   - (void)dealloc {     [viewController release];     [scrollView release];     [window release];     [super dealloc]; } 

Answer 1

In SDK 3.2 the touch handling for UIScrollView is handled using Gesture Recognizers.

If you want to do two-finger panning instead of the default one-finger panning, you can use the following code:

for (UIGestureRecognizer *gestureRecognizer in scrollView.gestureRecognizers) {          if ([gestureRecognizer  isKindOfClass:[UIPanGestureRecognizer class]]) {         UIPanGestureRecognizer *panGR = (UIPanGestureRecognizer *) gestureRecognizer;         panGR.minimumNumberOfTouches = 2;                    } } 

Answer 2

For iOS 5+, setting this property has the same effect as the answer by Mike Laurence:

self.scrollView.panGestureRecognizer.minimumNumberOfTouches = 2; 

One finger dragging is ignored by panGestureRecognizer and so the one finger drag event gets passed to the content view.