Question

Im trying to write a simple program that takes 5 images and allows you to drag them from the bottom of the screen and snap them on to 5 other images on the top in any order you like. I have subclassed the UIImageView with a new class and added the touches began, touches moved and touches ended. Then on my main viewcontroller I place the images and set their class to be the new subclass I created. The movement works great in fact I am NSLogging the coordinates in the custom class.

Problem is I’m trying to figure out how to get that CGpoint info from the touches end out of the custom class and get it to call a function in my main view controller that has the image objects so i can test whether or not the image is over another image. and move it to be centered on the image its over (snap onto it).

here is the code in my custom class m file. MY view controller is basically empty with a xib file with 10 image views 5 of which are set to this class and 5 are normal image views..

#import "MoveImage.h"


CGPoint EndPoint;

@implementation MoveImage


- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
    startPoint = [[touches anyObject] locationInView:self];
    }

- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event {
    CGPoint newPoint = [[touches anyObject] locationInView:self.superview];

    newPoint.x -= startPoint.x; 
    newPoint.y -= startPoint.y;
    CGRect frm = [self frame];
    frm.origin = newPoint;
    [self setFrame:frm]; 
}

-(void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event{
    UITouch *end = [[event allTouches] anyObject];
    EndPoint = [end locationInView:self];
    NSLog(@"end ponts x : %f y : %f", EndPoint.x, EndPoint.y);

} 

@end

Answer 1

You could write a MoveImageDelegate protocol which your app controller would then implement. This protocol would have methods that your MoveImage class can call to get its information.

In your header file ( if you don’t know how to write a protocol )

@protocol MoveImageDelegate <TypeOfObjectsThatCanImplementIt> // usually NSObject
// methods
@end

then you can declare an instance variable of type id, but still have the compiler recognize that that variable responds to your delegate selectors ( so you can code without those annoying warnings ).
Something like:

@interface MoveImage : UIImageView
{
 id <MoveImageDelegate> _delegate;
}

@property (assign) id <MoveImageDelegate> delegate;

Lastly:

@implementation MoveImage

@synthesize delegate = _delegate;

And your delegate is complete.