Smoother UIView

Question

Hi all, i'm looking for a way to make the menu system of my (very first) app scroll more smoothly. Currently I've got a panorma type view built in IB that's ~1900px wide by 480 tall image. On top of this are 8 buttons in various places along the view/image, when one of the buttons is selected i update 'xPoint' and call the below to update what's on screen (between 400-600px movement each time a button gets clicked in 1-2 seconds duration):

-(void)moveView:(NSNumber *)duration{
    [UIView beginAnimations:nil context:NULL];{
     [UIView setAnimationCurve:UIViewAnimationCurveEaseInOut];
     [UIView setAnimationDuration:[duration floatValue]];
     [UIView setAnimationDelegate:self];  
     viewRect = self.view.frame;
     viewRect.origin.x = xPoint;
     self.view.frame = viewRect;  
    } [UIView commitAnimations]; 
}

I've set everything in IB to be opaque and have unselected 'Clear context before drawing' for every button/image. On a 3GS this seems smoother than a 3G device but still non-perfect - still getting stuttering on the animation.

Is there a better way to do this? If not is there any way i can optimize/smooth out the movement animation?

Answer 1

You should definitely use instruments to debug this issue (unless somebody has the answer right away). you can easily debug framerate + see what layers are opaque/transparent (with the 'blended layers' option in the Core Animation instrument..

Also, at the same time, measure other device activity (that might be the problem).

As a very last resort, you could also use an image to display the buttons. Create a 'screenshot' of the menu, and make THAT slide (that's only one item, a UIImageView). After (or just before) your animation is done, you could quickly replace the UIImageView with the real UIView, including the buttons.

I believe Apple also uses (a form) of this trick when quitting the app; you see the app become smaller and smaller until it disappears.