ShakeAnimation.m

// this code will cause a UIView to shake--good for "login error"

CAKeyframeAnimation * anim = [ CAKeyframeAnimation animationWithKeyPath:@"transform" ] ;
anim.values = [ NSArray arrayWithObjects:
                   [ NSValue valueWithCATransform3D:CATransform3DMakeTranslation(-5.0f, 0.0f, 0.0f) ],
                   [ NSValue valueWithCATransform3D:CATransform3DMakeTranslation(5.0f, 0.0f, 0.0f) ], 
                   nil ] ;
anim.autoreverses = YES ;
anim.repeatCount = 2.0f ;
anim.duration = 0.07f ;
    
[ viewToShake.layer addAnimation:anim forKey:nil ] ;

#import <QuartzCore/QuartzCore.h>
CABasicAnimation *animation = 
                         [CABasicAnimation animationWithKeyPath:@"position"];
[animation setDuration:0.05];
[animation setRepeatCount:8];
[animation setAutoreverses:YES];
[animation setFromValue:[NSValue valueWithCGPoint:
               CGPointMake([lockView center].x - 20.0f, [lockView center].y)]];
[animation setToValue:[NSValue valueWithCGPoint:
               CGPointMake([lockView center].x + 20.0f, [lockView center].y)]];
[[lockView layer] addAnimation:animation forKey:@"position"];