Question

I am trying to animate a label across the screen however I cannot seem to get it work properly. Currently it animates off the view into the other views.

Also I cannot “stop” the animation when needed. I am using it in a music player to scroll the track name across the UIView and when I tap Next or Prev it must stop mid-animation and start again.

- (void)startAnimation {

    [UIView beginAnimations:nil context:nil];
    [UIView setAnimationDuration:10];   
    [UIView setAnimationDelegate:self]; 
    [UIView setAnimationDidStopSelector:@selector(animationDidStop:)];

    CGRect frame = trackName.frame;
    frame.origin.x = -50;
    trackName.frame = frame;

    [UIView commitAnimations];
}

- (void)animationDidStop:(id)sender {
    NSLog(@"animationDidStop");

    CGRect frame = trackName.frame;
    frame.origin.x = 194;
    trackName.frame = frame;

    [self startAnimation];
}

Answer 1

I assume what you are trying to do is animate the label so that it moves 50 pixels to the left. If so, you need to change the line:

frame.origin.x = -50

to

frame.origin.x -= 50;

The problem is that you are setting the new origin of the frame to -50, which is 50 pixels off the left side of the view. Instead you need to just subtract 50 pixels from it’s current position so that it moves 50 pixels relative to where it was.