Question

I’m looking for some sample code to track UITouches with a CFDictionary. Unfortunately the apple-docs don’t have a complete example.

http://developer.apple.com/library/IOs/#documentation/EventHandling/Conceptual/EventHandlingiPhoneOS/MultitouchEvents/MultitouchEvents.html#//apple_ref/doc/uid/TP40009541-CH3-SW7

I’m currently using NSMutable array, but I want to store the complete UITouch object, so to get the timestamp as well.

NSMutableArray *touchArray_val;


-(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event{
    touchArray_val = [[NSMutableArray alloc] init];             
}

-(void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event{ 

     for(UITouch *t in touches){
         CGPoint currentPoint = [t locationInView:self];
         [touchArray_val addObject:[NSValue valueWithCGPoint: currentPoint]];    
     }

}

-(void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event{        
    NSLog(@"%i",[touchArray count]);

    for(NSValue *val in touchArray_val){        
        NSLog(@"%@",val);      
    }
}

Answer 1

The pointer of the UITouch will not change over the lifetime of the touch. You can create an NSValue from the pointer.

 // NSMutableDictionary * touchLookup; set up somewhere else...
 NSValue * key = [NSValue valueWithPointer:touch];
 [touchLookup setObject:touch forKey:key];