Question

I’m going to be using the same code that I have in my view controller in several views and I don’t want to have to paste the code into each.

Can someone show me a few lines of code showing me how to do this ?

I’m guessing i’m going to have to declare an instance of the class in the interface and put a hand back method for each of touch functions I’ll be sub classing ?

Answer 1

If I understand the question correctly you want the same bit of code executed for touchesBegan, touchesMoved… from each of your views.

The way I would do this would be using the delegate pattern.

@protocol ViewTouchDelegate
- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
@end

@interface ViewA : UIView {
    id <ViewTouchDelegate> touchDelegate;
}

@implementation ViewA
- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
    [self->touchDelegate touchesBegan:touches withEvent:event];
}
@end // End View A

@interface ViewB : UIView {
    id <ViewTouchDelegate> touchDelegate;
}

@implementation ViewB
- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
    [self->touchDelegate touchesBegan:touches withEvent:event];
}
@end // End View B

This will let you put all your touch handling code in one place (in a class that conforms to the ViewTouchDelegate protocol), and give that delegate to each of your views.

In my example I have made the signature of touchesBegan the same as UIResponder’s touchesBegan, but you can tailor it to your needs.

Edit: Example ViewTouchDelegate

@interface MyViewTouchDelegate : NSObject <ViewTouchDelegate>
@end

@implementation MyViewTouchDelegate
- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
    //put all your common touch handling code in here
}
@end

Define any additional methods you need in the ViewTouchDelegate protocol for your purposes, for example touchesMoved, touchesEnded, yourOwnCustomEvent.