Creating control pad - objective-c

Question

I am trying to code a controller for an image view to move using buttons.
inside up button code :
-(IBAction)upButton:(id)sender{
mainChac.center = CGPointMake(mainChac.center.x, mainChac.center.y - 5);
}
code is working properly but I have to tap it repeatedly to keep moving up, I wanna know which method to call, to move it, while holding the up button.
edit :
-(void)touchDownRepeat{
mainChac.center = CGPointMake(mainChac.center.x, mainChac.center.y - 5);
}
-(IBAction)upButton:(id)sender{
[upButton addTarget:self action:#selector(touchDownRepeat) forControlEvents:UIControlEventTouchDownRepeat];
}
edit 2: solution
-(void)moveUp{
mainChac.center = CGPointMake(mainChac.center.x, mainChac.center.y - 5);
}
- (void)holdDown
{
NSLog(#"hold Down");
timer = [NSTimer scheduledTimerWithTimeInterval:0.1 target:self selector:#selector(moveUp) userInfo:nil repeats:YES];
}
- (void)holdRelease
{
NSLog(#"hold release");
[timer invalidate];
}
-(IBAction)upButton:(id)sender{
[upButton addTarget:self action:#selector(holdDown) forControlEvents:UIControlEventTouchDown];
[upButton addTarget:self action:#selector(holdRelease) forControlEvents:UIControlEventTouchUpInside];
}

Answer 1

EDIT:
What you need to to have 2 events, one for while the button is pressed down and another for when the button is released like so:
[aButton addTarget:self action:#selector(holdDown) forControlEvents:UIControlEventTouchDown];
[aButton addTarget:self action:#selector(holdRelease) forControlEvents:UIControlEventTouchUpInside];
- (void)holdDown
{
NSLog(#"hold Down");
}
- (void)holdRelease
{
NSLog(#"hold release");
}
Have your hold down function start a loop, and your holdRelease stop the loop.
EDIT-2:
An easy way (but perhaps not the best way) to achieve this loop would be to use NSTImer scheduledTimerWithTimeInterval inside the hold down and invalidate it in the release method.
all of this stuff has been done before, please try googling this stuff. Here is a stackoverlfow question with an example: ios scheduledTimerWithTimeInterval for amount of time