iphone - stop and restore method

i'm using this function to create movement, how do i stop the movement? i want it to restore to the start point. thanks.

[NSTimer scheduledTimerWithTimeInterval:0.02 target:self selector:@selector(shuffleOnTimer) userInfo:nil repeats:YES];

-(void) shuffleOnTimer {

    jb.center = CGPointMake(jb.center开发者_开发知识库.x+pos1.x,jb.center.y+pos1.y);

    if(jb.center.x > 60 || jb.center.x < 0)
    pos1.x = -pos1.x;
    if(jb.center.y > 240 || jb.center.y < 100)
    pos1.y = -pos1.y;}

At some point you should invalidate the timer. You'll need to store a reference to it in order to do this:

In your header file:

@class myClass : NSObject {
    ....
    NSTimer      *timer;
    CGPoint      originalPoint;
    ...
}
@property (nonatomic, readwrite, assign) NSTimer *timer;
@property (nonatomic, readwrite) CGPoint originalPoint;

In your implementation file:

self.originalPoint = jb.position;
self.timer = [NSTimer scheduledTimerWithTimeInterval…

as some later point:

[self.timer invalidate];
self.timer = nil;         //very important, to avoid dangling pointers
jb.position = self.originalPoint;