iOS小效果（2）按钮控制图片的放大缩小

- (IBAction)bigger:(id)sender
{
[UIView beginAnimations:nil context:nil];
[UIView setAnimationDuration:1.0];
_btn.transform=CGAffineTransformScale(_btn.transform, 1.2, 1.2);
[UIView commitAnimations];
}

- (IBAction)smaller:(id)sender
{
[UIView beginAnimations:nil context:nil];
[UIView setAnimationDuration:1.0];
_btn.transform=CGAffineTransformScale(_btn.transform, 0.8, 0.8);
[UIView commitAnimations];
}