iOS Tap Gesture in a UIScrollview

Question

I have a RootViewController & it's associated nib or xib file. This nib is loaded as the app starts. This nib file contains a UIScrollView in this scrollview I put another custom generated nib - newNib.xib file.

In this newNib.xib I have made changes in interface builder to respond to RootViewController i.e. Custom Class - RootViewController. Then I linked some UIView objects that I created in RootViewController. All fine so far...

I have defined some tapGestureRecognisers in RootViewController on the UIViews defined in newNib.xib but they are not responding to the tap events. Tap Events i defined in RootViewController like this -

UITapGestureRecognizer *messagesTap = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(messagesBucketTap:)];
[messagesTap setNumberOfTapsRequired:1];
[messagesTap setNumberOfTouchesRequired:2];
[self.messagesSnippet addGestureRecognizer:messagesTap];
[messagesTap release];

here self.messagesSnippet is present in newNib.xib Also I load the xib in RootViewController like so -

[[NSBundle mainBundle] loadNibNamed:@"newNib" owner:self options:nil];

But still I dont get the tapGesture to the selector (messagesBucketTap). What am i doing wrong?

Answer 1

The most likely cause is that you forgot to set the delegate of the tap gesture recognizer e.g. [messagesTap setDelegate:self].

Assuming -messagesBucketTap: is declared in the same class, Change your code to:

    UITapGestureRecognizer *messagesTap = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(messagesBucketTap:)];
    [messagesTap setDelegate:self];
    [messagesTap setNumberOfTapsRequired:1];
    [messagesTap setNumberOfTouchesRequired:2];
    [self.messagesSnippet addGestureRecognizer:messagesTap];
    [messagesTap release];

If this doesn't work, check what Jamie said, and make sure you are declaring:

- (void)messagesBucketTap:(UITapGestureRecognizer *)gestureRecognizer;

and not

- (void)messagesBucketTap;

Also, are you tapping once with two fingers? Lastly, ensure that that userInteractionEnabled is YES on the UIView's and that exclusiveTouch is NO on the UIScrollView