Question

I’ve thought that a great addition to an iphone app would be the ability to have the OS X Dock implemented in the iphone. My idea is to have like 5 regular menu that can be chosen in my app and when you swipe your finger across the menu the individual icons would magnify and when you chose an option the icon would bounce while you waited.

I personally would love this in my apps, but I’m wondering if it could be done. Be it be too cpu intensive? Any idea if this could be done in Core Graphics or would you need OpenGL ES?

Thanks to all that respond.

Answer 1

The Core Animation framework should work fine for the sorts of animations you’re discussing (bouncing, scaling). I think it’ll be a lot easier than OpenGL.

Here is a code snippet which should animate moving an icon to the y coordinate 148 over a 0.2 second duration:

[UIView beginAnimations: @"iconBounce" context: NULL];
[UIView setAnimationDelegate:self];
[UIView setAnimationDidStopSelector:@selector(iconBounceAnimationDidStop:finished:context:)];

CGRect iconPosition = iconImageView.frame;
iconPosition.origin.y = 148; //bounce up
iconImageView.frame = iconPosition;

[UIView setAnimationDuration: 0.2];
[UIView commitAnimations];

The selector iconBounceAnimationDidStop:finished:context: represents a method which will be called when the animation completes. You can write that method so that it will move the icon back down to a starting position to complete the bounce.