Shake visual effect on iPhone (NOT shaking the device)

Question

On login failure, I\'d prefer to avoid showing an alert, it\'s too fleeting. Showing the alert and then showing the text somewhere on the login screen seems like duplication

Answer 1

I know the question is already answered, but since I have already implemented something like this previously, I feel it can't hurt to add it:

CAKeyframeAnimation *shakeAnimation = [CAKeyframeAnimation animationWithKeyPath:@"transform.rotation.z"];
NSArray *transformValues = [NSArray arrayWithObjects:
                        [NSNumber numberWithFloat:((M_PI)/64)],
                        [NSNumber numberWithFloat:(-((M_PI)/64))],
                        [NSNumber numberWithFloat:((M_PI)/64)],
                        [NSNumber numberWithFloat:(-((M_PI)/64))],
                        [NSNumber numberWithFloat:((M_PI)/64)],
                        [NSNumber numberWithFloat:(-((M_PI)/64))],
                        [NSNumber numberWithFloat:0],                                
                        nil];

[shakeAnimation setValues:transformValues];

NSArray *times = [NSArray arrayWithObjects:
                  [NSNumber numberWithFloat:0.14f],
                  [NSNumber numberWithFloat:0.28f],
                  [NSNumber numberWithFloat:0.42f],
                  [NSNumber numberWithFloat:0.57f],
                  [NSNumber numberWithFloat:0.71f],
                  [NSNumber numberWithFloat:0.85f],
                  [NSNumber numberWithFloat:1.0f], 
                  nil];

[shakeAnimation setKeyTimes:times];

shakeAnimation.fillMode = kCAFillModeForwards;
shakeAnimation.removedOnCompletion = NO;
shakeAnimation.duration = 0.6f;

[self.viewToShake.layer addAnimation:shakeAnimation forKey:@"anim"];

Also, since you want the shaking to indicate that the user failed to log in, you might also consider adding this animation that tints the screen red while the screen shakes:

//Put this in the header (.h)
@property (nonatomic, strong) UIView *redView;

//Put this in the implementation (.m)
@synthesize redView;

//Put this in viewDidLoad
self.redView = [[UIView alloc] initWithFrame:self.view.frame];
self.redView.layer.opacity = 0.0f;
self.redView.layer.backgroundColor = [[UIColor redColor] CGColor];

//Put this wherever you check if the login failed
CAKeyframeAnimation *redTint = [CAKeyframeAnimation animationWithKeyPath:@"opacity"];
NSArray *transformValues = [NSArray arrayWithObjects:
                           [NSNumber numberWithFloat:0.2f],
                           [NSNumber numberWithFloat:0.0f],                                
                           nil];

[redTint setValues:transformValues];

NSArray *times = [NSArray arrayWithObjects:
                  [NSNumber numberWithFloat:0.5f],
                  [NSNumber numberWithFloat:1.0f], 
                  nil];

[redTint setKeyTimes:times];

redTint.fillMode = kCAFillModeForwards;
redTint.removedOnCompletion = NO;
redTint.duration = 0.6f;

[self.redView.layer addAnimation:shakeAnimation forKey:@"anim"];

Hope this helps!

Answer 2

Here's a tutorial that details how to do it in Cocoa. Should be the same for the iPhone (or at least quite similar).

http://www.cimgf.com/2008/02/27/core-animation-tutorial-window-shake-effect/

Answer 3

very easy shake categorie for UIVoew

https://github.com/jonasschnelli/UIView-I7ShakeAnimation

Answer 4

This UIView category snippet worked for me. It's using 3 CABasingAnimations applied to view's layer.

#import <UIKit/UIKit.h>
#import <QuartzCore/QuartzCore.h>

#define Y_OFFSET 2.0f
#define X_OFFSET 2.0f
#define ANGLE_OFFSET (M_PI_4*0.1f)

@interface UIView (shakeAnimation)

-(BOOL)isShakeAnimationRunning;
-(void)startShakeAnimation;
-(void)stopShakeAnimation;

@end



@implementation UIView (shakeAnimation)

-(BOOL)isShakeAnimationRunning{
     return [self.layer animationForKey:@"shake_rotation"] != nil;
}

-(void)startShakeAnimation{
    CFTimeInterval offset=(double)arc4random()/(double)RAND_MAX;
    self.transform=CGAffineTransformRotate(self.transform, -ANGLE_OFFSET*0.5);
    self.transform=CGAffineTransformTranslate(self.transform, -X_OFFSET*0.5f, -Y_OFFSET*0.5f);

    CABasicAnimation *tAnim=[CABasicAnimation animationWithKeyPath:@"position.x"];
    tAnim.repeatCount=HUGE_VALF;
    tAnim.byValue=[NSNumber numberWithFloat:X_OFFSET];
    tAnim.duration=0.07f;
    tAnim.autoreverses=YES;
    tAnim.timeOffset=offset;
    [self.layer addAnimation:tAnim forKey:@"shake_translation_x"];

    CABasicAnimation *tyAnim=[CABasicAnimation animationWithKeyPath:@"position.y"];
    tyAnim.repeatCount=HUGE_VALF;
    tyAnim.byValue=[NSNumber numberWithFloat:Y_OFFSET];
    tyAnim.duration=0.06f;
    tyAnim.autoreverses=YES;
    tyAnim.timeOffset=offset;
    [self.layer addAnimation:tyAnim forKey:@"shake_translation_y"];

    CABasicAnimation *rAnim=[CABasicAnimation animationWithKeyPath:@"transform.rotation"];
    rAnim.repeatCount=HUGE_VALF;
    rAnim.byValue=[NSNumber numberWithFloat:ANGLE_OFFSET];
    rAnim.duration=0.15f;
    rAnim.autoreverses=YES;
    rAnim.timeOffset=offset;
    [self.layer addAnimation:rAnim forKey:@"shake_rotation"];
}
-(void)stopShakeAnimation{
    [self.layer removeAnimationForKey:@"shake_translation_x"];
    [self.layer removeAnimationForKey:@"shake_translation_y"];
    [self.layer removeAnimationForKey:@"shake_rotation"];
    [UIView animateWithDuration:0.2f animations:^{
        self.transform=CGAffineTransformRotate(self.transform, ANGLE_OFFSET*0.5);
        self.transform=CGAffineTransformTranslate(self.transform, X_OFFSET*0.5, Y_OFFSET*0.5f);
    }];
}

@end

Hope it helpes someone :)

Answer 5

I had seen some wobble animation and changed it to shake a view t pixels upright and downleft:

- (void)earthquake:(UIView*)itemView
{
    CGFloat t = 2.0;

    CGAffineTransform leftQuake  = CGAffineTransformTranslate(CGAffineTransformIdentity, t, -t);
    CGAffineTransform rightQuake = CGAffineTransformTranslate(CGAffineTransformIdentity, -t, t);

    itemView.transform = leftQuake;  // starting point

    [UIView beginAnimations:@"earthquake" context:itemView];
    [UIView setAnimationRepeatAutoreverses:YES]; // important
    [UIView setAnimationRepeatCount:5];
    [UIView setAnimationDuration:0.07];
    [UIView setAnimationDelegate:self];
    [UIView setAnimationDidStopSelector:@selector(earthquakeEnded:finished:context:)];

    itemView.transform = rightQuake; // end here & auto-reverse

    [UIView commitAnimations];
}

- (void)earthquakeEnded:(NSString *)animationID finished:(NSNumber *)finished context:(void *)context 
{
    if ([finished boolValue]) 
    {
        UIView* item = (UIView *)context;
        item.transform = CGAffineTransformIdentity;
    }
}