How can I disable the touch events on two UIImageViews after i drag them into each other? - objective-c

Question

I have two draggable UIImageViews within a UIView. When i drag one UIImageView over the other, i would like to disable touch events to those two UIImageViews and create another UIImageView which does respond to my touch events. Ive tried using setUserInteractionEnabled: but it isnt really doing anything at all. Forgive me if this is a no brainer but i am new to programming, here is what i have so far. Please give me some feedback on my code and give me some constructive criticism because i feel as though i am setting this up all wrong.
-(void)swapImageViews
{
if ((self.imgView1.center.x == self.imgView2.center.x) &&
(self.imgView1.center.y == self.imgView2.center.y)) {
[self addSubview:self.imgView3];
self.imgView3.center = CGPointMake(self.imgView1.center.x, self.imgView1.center.y);
[self.imgView1 removeFromSuperView];
[self.imgView2 removeFromSuperView];
[self.imgView1 setUserInteractionEnabled:NO];
[self.imgView2 setUserInteractionEnabled:NO];
}
}
So once again, the goal is to swap out two image views with a fresh one that i can also drag around.
The problem i am running into is that my touch events are still moving the first two image views around behind the third one.

Answer 1

You say that the third image appeared, but the the other two are still in the view and they still receive touch events. There are two two scenarios for this:
You've already added the third image view somewhere else, and your method is never called, or the condition is never met.
self.imgView1 and self.imgView2 are not set to the actual objects in your view stack. They're probably just nil. you can debug that by NSLog(#"%# %#", self.imgView1, self.imgView2); in that method, before the condition, or in viewWillAppear or viewDidLoad.
The reasons that support my opinion:
In that method, you call removeFromSuperview to the two image views you want to disable, yet they are still visible and receiving touch events. That means that this method is not executed. Which means they're nil or some other objects, that are different than the visible ones.
The condition in the start of the method is a bit strict. It's hard to be easily met. Yet the method is executed as the third image view is added to the view. This can happen when the object is nil, so the values returned by methods are the default values.
Check this link "the 10th item" and this one too.

Answer 2

Well this is not the best way to do that, but with the code that you provide to us, we have not a lot of options, you can do something like that, to remove the gestures:
-(void)swapImageViews{
if ((self.imgView1.center.x == self.imgView2.center.x) &&
(self.imgView1.center.y == self.imgView2.center.y)) {
[self addSubview:self.imgView3];
self.imgView3.center = CGPointMake(self.imgView1.center.x, self.imgView1.center.y);
[self.imgView1 removeFromSuperView];
[self.imgView2 removeFromSuperView];
NSArray* gestures1 = [self.imgView1.gestureRecognizers copy];
for(UIGestureRecognizer *gesture in gestures1){
[self.imgView1 removeGestureRecognizer:gesture];
}
NSArray* gestures2 = [self.imgView2.gestureRecognizers copy];
for(UIGestureRecognizer *gesture in gestures2){
[self.imgView2 removeGestureRecognizer:gesture];
}
}
}