animating UITextField to indicate a wrong password

Question

how can I add an animation to a UITextField to indicate wrong password exactly like the one in facebook app (at login screen) or the Mac OS X login box ?

thank you in advance.

Answer 1

Since the question was about Objective-C, and since I am using Objective-C in my project, I think this Objective-C translation of this previous Swift answer could be useful to someone else:

- (void)shakeView:(UIView*)view
{
    CABasicAnimation *shake = [CABasicAnimation animationWithKeyPath:@"position"];
    CGFloat xDelta = 5.0;
    shake.duration = 0.15;
    shake.repeatCount = 2;
    shake.autoreverses = YES;

    CGPoint fromPoint = CGPointMake(view.center.x - xDelta, view.center.y);
    CGPoint toPoint = CGPointMake(view.center.x + xDelta, view.center.y);

    shake.fromValue = [NSValue valueWithCGPoint:fromPoint];
    shake.toValue = [NSValue valueWithCGPoint:toPoint];
    shake.timingFunction = [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseInEaseOut];
    [view.layer addAnimation:shake forKey:@"position"];
}

Answer 2

If you came here looking for a MonoTouch answer, here is a rough translation of Dickey's code:

public static void /*Harlem*/Shake (this UIView view, int shakes = 6, int translation = 5)
{
    UIView.Animate (0.03 + (shakes * 0.01), 0.01, UIViewAnimationOptions.CurveEaseInOut, () => {
        view.Transform = CGAffineTransform.MakeTranslation (translation, 0);
    }, () => {
       if (shakes == 0) {
            view.Transform = CGAffineTransform.MakeIdentity ();
            return;
        }

        if (translation > 0)
            translation --;

        translation *= -1;
        shakes --;

        Shake (view, shakes, translation);
    });
}

Put it with the rest of your extensions methods and call like that:

password.Shake ();

Answer 3

(Jan 16 2015) Update: (enum UIViewAnimationOptions) cast is fine and UIViewAnimationOptionCurveEaseOut is 2 << 16 per UIView.h under typedef NS_OPTIONS(NSUInteger, UIViewAnimationOptions)

(Jan 31 2013) Further modified Kai's answer to include:

1. edge delay of 0.01s
2. easeInOut
3. reduce duration of shakes every shake from 0.09 to 0.04
4. throttle down movement by a pt every 1 complete loop (right-left-right)

Note: if you plan on shaking two controls (email and password) together you might want to avoid using class or static variables for shakes and translate. Instead, initialize and pass shake and translate as parameters. I used statics so no class variables needed.

-(void)shakeAnimation:(UIView*) view {
    const int reset = 5;
    const int maxShakes = 6;

    //pass these as variables instead of statics or class variables if shaking two controls simultaneously
    static int shakes = 0;
    static int translate = reset;

    [UIView animateWithDuration:0.09-(shakes*.01) // reduce duration every shake from .09 to .04 
                          delay:0.01f//edge wait delay
                        options:(enum UIViewAnimationOptions) UIViewAnimationCurveEaseInOut
                     animations:^{view.transform = CGAffineTransformMakeTranslation(translate, 0);}
                     completion:^(BOOL finished){
                         if(shakes < maxShakes){
                             shakes++;

                             //throttle down movement
                             if (translate>0)
                                 translate--;

                             //change direction
                             translate*=-1;
                             [self shakeAnimation:view];
                         } else {
                             view.transform = CGAffineTransformIdentity;
                             shakes = 0;//ready for next time
                             translate = reset;//ready for next time
                             return;
                         }
                     }];
}

Answer 4

Something like that

-(void)shake:(UIView *)theOneYouWannaShake
{
  [UIView animateWithDuration:0.03 animations:^
                                  {
                                    theOneYouWannaShake.transform = CGAffineTransformMakeTranslation(5*direction, 0);
                                  } 
                                  completion:^(BOOL finished) 
                                  {
                                    if(shakes >= 10)
                                    {
                                      theOneYouWannaShake.transform = CGAffineTransformIdentity;
                                      return;
                                    }
                                    shakes++;
                                    direction = direction * -1;
                                    [self shake:theOneYouWannaShake];
                                  }];
}

So you need three more things: An int direction which is set to 1 before the shake is called an int shakes, which is set to 0 before the shake is called and a constant MAX_SHAKES which is as large as you like. Hope that helps.

EDIT:

call it like this:

  direction = 1;
  shakes = 0;
  [self shake:aUIView];

inside header file add

int direction;
int shakes;

Answer 5

Swift 3 and stack_view instaed textField

func shakeTextField (stack_view : UIStackView, numberOfShakes : Int, direction: CGFloat, maxShakes : Int) {
        let interval : TimeInterval = 0.05

        UIView.animate(withDuration: interval, animations: { () -> Void in
            stack_view.transform = CGAffineTransform(translationX: 5 * direction, y: 0)

        }, completion: { (aBool :Bool) -> Void in

            if (numberOfShakes >= maxShakes) {
                stack_view.becomeFirstResponder()
                return
            }
            self.shakeTextField(stack_view: stack_view, numberOfShakes: numberOfShakes + 1, direction: direction * -1, maxShakes: maxShakes )
        })
    }

Answer 6

I created a category method for UIView that can be used to shake any element - e.g. a UITextField - with the ability to get notified after the shaking has ended. Here is how to use it:

[myPasswordField shake];

// Or with a callback after the shake 
[myPasswordField shakeWithCallback:^{
   NSLog(@"Shaking has ended");
}];

Here is the code.

UIView+Shake.h

#import <UIKit/UIKit.h>

@interface UIView (UIView_Shake)

-(void)shake;
-(void)shakeWithCallback:(void (^)(void))completeBlock;

@end

UIView+Shake.m

#import "UIView+Shake.h"
#import <objc/runtime.h>

@implementation UIView (UIView_Shake)

static void *NumCurrentShakesKey;
static void *NumTotalShakesKey;
static void *ShakeDirectionKey;

- (int)numCurrentShakes {
    return [objc_getAssociatedObject(self, &NumCurrentShakesKey) intValue];
}

- (void)setNumCurrentShakes:(int)value {
    objc_setAssociatedObject(self, &NumCurrentShakesKey, [NSNumber numberWithInt:value], OBJC_ASSOCIATION_RETAIN_NONATOMIC);
}

- (int)numTotalShakes {
    return [objc_getAssociatedObject(self, &NumTotalShakesKey) intValue];
}

- (void)setNumTotalShakes:(int)value {
    objc_setAssociatedObject(self, &NumTotalShakesKey, [NSNumber numberWithInt:value], OBJC_ASSOCIATION_RETAIN_NONATOMIC);
}

- (int)shakeDirection {
    return [objc_getAssociatedObject(self, &ShakeDirectionKey)  intValue];
}

- (void)setShakeDirection:(int)value {
    objc_setAssociatedObject(self, &ShakeDirectionKey, [NSNumber numberWithInt:value], OBJC_ASSOCIATION_RETAIN_NONATOMIC);
}

-(void)shake {
    [self shakeNextWithCompleteBlock:nil];
}

-(void)shakeWithCallback:(void (^)(void))completeBlock {
    self.numCurrentShakes = 0;
    self.numTotalShakes = 6;
    self.shakeDirection = 8;
    [self shakeNextWithCompleteBlock:completeBlock];
}

-(void)shakeNextWithCompleteBlock:(void (^)(void))completeBlock
{
    UIView* viewToShake = self;
    [UIView animateWithDuration:0.08
                     animations:^
     {
         viewToShake.transform = CGAffineTransformMakeTranslation(self.shakeDirection, 0);
     }
                     completion:^(BOOL finished)
     {
         if(self.numCurrentShakes >= self.numTotalShakes)
         {
             viewToShake.transform = CGAffineTransformIdentity;
             if(completeBlock != nil) {
                 completeBlock();
             }
             return;
         }
         self.numCurrentShakes++;
         self.shakeDirection = self.shakeDirection * -1;
         [self shakeNextWithCompleteBlock:completeBlock];
     }];
}

@end