Question

I’ve made a UIPanRecognizer like this.

- (void)pan:(UIPanGestureRecognizer *)gesture
{
    if ((gesture.state == UIGestureRecognizerStateChanged) ||
        (gesture.state == UIGestureRecognizerStateEnded)) {
        CGPoint translation = [gesture translationInView:self];
        self.origin = CGPointMake(
        self.origin.x+translation.x,self.origin.y+translation.y);
        [gesture setTranslation:CGPointZero inView:self];
}

}

But my view never gets redrawn, that means… my drawRect wont be called again. Anybody ever tried this?

In my viewController I have this

UIGestureRecognizer *pan = [[UIPanGestureRecognizer alloc] initWithTarget:self.graphView action:@selector(pan:)];
[self.graphView addGestureRecognizer:pan]; 
[self updateUI];

My updateUI is

- (void)updateUI { [self.graphView setNeedsDisplay]; } 

Answer 1

You are calling your updateUI method when you attach the gesture recognizer to the view. You should be doing it in your callback method pan:.

Also, you are leaking memory. After allocating and adding the UIGestureRecognizer to the view you should release it.