Gesture recogniser in different class?

Question

I was wondering if this was possible. To have a class which adds new imageViews to the main view and assigns a gesture recogniser to it.

So in my view builder class, I have the following:

UIImageView *headerPlusIcon = [[UIImageView alloc] initWithImage:[UIImage imageNamed:@"plusIcon.png"]];
headerPlusIcon.frame = CGRectMake(header.frame.size.width - 2.5*(logoSize - 8), yPosition*1.6, logoSize*0.9, logoSize*0.9);
headerPlusIcon.userInteractionEnabled = YES;

UIGestureRecognizer *headerTapGesture = [[UIGestureRecognizer alloc] initWithTarget:mainView action:@selector(testTapGesture:)];
[headerPlusIcon addGestureRecognizer:headerTapGesture];

The tap gesture method goes like this:

-(void)testTapGesture:(UITapGestureRecognizer *)gesture
{
    dispatch_async(dispatch_get_main_queue(), ^{
        mainView.backgroundColor = [UIColor redColor];
    });
}

mainView is passed into this class via the constructor and is simply the main view.

This is called like this:

mainViewbuilder = [[MainViewBuilder alloc] initWithBaseView:self.view];
[mainViewbuilder buildHeader];

Unfortunately the tap gesture method never gets called... how would this be done properly? Thanks!

Answer 1

Try UITapGestureRecognizer

Apple Docs on UITapGestureRecognizer

Answer 2

The code you posted never adds your headerPlusIcon to the view hierarchy. You say in your answer to Adam that you got it working, but I don't see how if you don't add the headerPlusIcon to your view controller's content view hierarchy somewhere.

Note that mucking around in a view controller's view hierarchy from outside is not good object-oriented design.

It would be better to have the view controller ask another object for a view (probably through a protocol) and then add that view itself.