震动效果

//
//  UIView+Shake.h
//  Animations
//
//  Created by YouXianMing on 16/2/25.
//  Copyright © 2016年 YouXianMing. All rights reserved.
//

#import <UIKit/UIKit.h>

// https://github.com/rFlex/SCViewShaker

#define kDefaultShakeOptions  (SCShakeOptionsDirectionHorizontal | SCShakeOptionsForceInterpolationExpDown | SCShakeOptionsAtEndComplete)
#define kDefaultShakeForce    (0.075)
#define kDefaultShakeDuration (0.5)
#define kDefaultShakeIterationDuration (0.03)

typedef enum : NSUInteger {
    
    SCShakeOptionsDirectionRotate                = 0,
    SCShakeOptionsDirectionHorizontal            = 1,
    SCShakeOptionsDirectionVertical              = 2,
    SCShakeOptionsDirectionHorizontalAndVertical = 3,
    SCShakeOptionsForceInterpolationNone         = 4,
    SCShakeOptionsForceInterpolationLinearUp     = 8,
    SCShakeOptionsForceInterpolationLinearDown   = 16,
    SCShakeOptionsForceInterpolationExpUp        = 32,
    SCShakeOptionsForceInterpolationExpDown      = 64,
    SCShakeOptionsForceInterpolationRandom       = 128,
    SCShakeOptionsAtEndRestart                   = 256,
    SCShakeOptionsAtEndComplete                  = 512,
    SCShakeOptionsAtEndContinue                  = 1024,
    SCShakeOptionsAutoreverse                    = 2048
    
} SCShakeOptions;

typedef void(^ShakeCompletionHandler)();

@interface UIView (Shake)

/**
 *  Returns whether the view is currently shaking or not.
 */
@property (readonly, nonatomic) BOOL isShaking;

/**
 *  Shake the view using the default options. The view will be shaken for a short amount of time.
 */
- (void)shake;

/*
 Shake the view using the specified options.
 |shakeOptions| is an enum of options that can be activated by using the OR operator (like SCShakeOptionsDirectionRotate | SCShakeOptionsForceInterpolationNone).
 
 |force| is the coefficient of force to apply on each shake iteration (typically between 0 and 1 even though nothing prevents you for setting a higher value if you want).
 
 |duration| is the total duration of the shaking motion. This may be ignored depending of the options you set.
 iterationDuration is how long each shake iteration will last. You may want to set a very low value (like 0.02) if you want a proper shake effect.
 
 |completionHandler|, if not null, is the block that will be invoked when the shake finishes.
 */
- (void)shakeWithOptions:(SCShakeOptions)shakeOptions
                   force:(CGFloat)force duration:(CGFloat)duration
       iterationDuration:(CGFloat)iterationDuration
       completionHandler:(ShakeCompletionHandler)completionHandler;

/**
 *  End the current shaking action, if any
 */
- (void)endShake;

@end

//
//  UIView+Shake.m
//  Animations
//
//  Created by YouXianMing on 16/2/25.
//  Copyright © 2016年 YouXianMing. All rights reserved.
//

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

#define HAS_OPT(options, option) ((options & option) == option)

@interface SCShakeInfo : NSObject

@property (assign, nonatomic)   CGAffineTransform baseTransform;
@property (assign, nonatomic)   BOOL shaking;
@property (assign, nonatomic)   SCShakeOptions options;
@property (assign, nonatomic)   CGFloat force;
@property (assign, nonatomic)   CGFloat duration;
@property (assign, nonatomic)   CGFloat iterationDuration;
@property (assign, nonatomic)   CFTimeInterval startTime;
@property (strong, nonatomic)   ShakeCompletionHandler completionHandler;
@property (assign, nonatomic)   BOOL reversed;
@property (readonly, nonatomic) CGFloat completionRatio;

@end

@implementation SCShakeInfo

- (CGFloat)completionRatio {
    
    return (CACurrentMediaTime() - self.startTime) / self.duration;
}

@end

@implementation UIView (Shake)

static const char *ShakeInfoKey = "ShakeInfo";

- (void)shake {
    
    [self shakeWithOptions:kDefaultShakeOptions
                     force:kDefaultShakeForce
                  duration:kDefaultShakeDuration
         iterationDuration:kDefaultShakeIterationDuration
         completionHandler:nil];
}

- (void)shakeWithOptions:(SCShakeOptions)shakeOptions
                   force:(CGFloat)force
                duration:(CGFloat)duration
       iterationDuration:(CGFloat)iterationDuration
       completionHandler:(ShakeCompletionHandler)completionHandler {
    
    SCShakeInfo *shakeInfo = [self shakeInfo];
    
    shakeInfo.options           = shakeOptions;
    shakeInfo.force             = force;
    shakeInfo.startTime         = CACurrentMediaTime();
    shakeInfo.duration          = duration;
    shakeInfo.iterationDuration = iterationDuration;
    shakeInfo.completionHandler = completionHandler;
    
    if (!shakeInfo.shaking) {
        
        shakeInfo.baseTransform = self.transform;
        shakeInfo.shaking       = YES;
        
        [self _doAnimation:1];
    }
}

- (CGFloat)_getInterpolationRatio:(CGFloat)completionRatio options:(SCShakeOptions)options {
    
    CGFloat (*interpFunc)(CGFloat) = nil;
    
    if (HAS_OPT(options, SCShakeOptionsForceInterpolationRandom)) {
        
        interpFunc =& InterpolateRandom;
        
    } else if (HAS_OPT(options, SCShakeOptionsForceInterpolationExpDown)) {
        
        interpFunc =& InterpolateExpDown;
        
    } else if (HAS_OPT(options, SCShakeOptionsForceInterpolationExpUp)) {
        
        interpFunc =& InterpolateExpUp;
        
    } else if (HAS_OPT(options, SCShakeOptionsForceInterpolationLinearDown)) {
        
        interpFunc =& InterpolateLinearDown;
        
    } else if (HAS_OPT(options, SCShakeOptionsForceInterpolationLinearUp)) {
        
        interpFunc =& InterpolateLinearUp;
        
    } else {
        
        interpFunc =& InterpolateNone;
    }
    
    return interpFunc(completionRatio);
}

- (void)_animate:(CGFloat)force shakeInfo:(SCShakeInfo *)shakeInfo {
    
    CGAffineTransform baseTransform = shakeInfo.baseTransform;
    SCShakeOptions    options       = shakeInfo.options;
    
    if (HAS_OPT(options, SCShakeOptionsDirectionHorizontalAndVertical)) {
        
        if (arc4random_uniform(2) == 1) {
            
            self.transform = CGAffineTransformTranslate(baseTransform, 0, force * self.bounds.size.height);
            
        } else {
            
            self.transform = CGAffineTransformTranslate(baseTransform, force * self.bounds.size.width, 0);
        }
        
    } else if (HAS_OPT(options, SCShakeOptionsDirectionVertical)) {
        
        self.transform = CGAffineTransformTranslate(baseTransform, 0, force * self.bounds.size.height);
        
    } else if (HAS_OPT(options, SCShakeOptionsDirectionHorizontal)) {
        
        self.transform = CGAffineTransformTranslate(baseTransform, force * self.bounds.size.width, 0);
        
    } else {
        
        self.transform = CGAffineTransformRotate(baseTransform, force * M_PI_2);
    }
}

- (void)_doAnimation:(CGFloat)direction {
    
    SCShakeInfo *shakeInfo  = [self shakeInfo];
    SCShakeOptions options  = shakeInfo.options;
    CGFloat completionRatio = shakeInfo.completionRatio;
    
    if (completionRatio > 1) {
        
        completionRatio = 1;
    }
    
    if (shakeInfo.reversed) {
        
        completionRatio = 1 - completionRatio;
    }
    
    CGFloat interpolationRatio = [self _getInterpolationRatio:completionRatio options:options];
    CGFloat force              = shakeInfo.force * interpolationRatio * direction;
    CGFloat iterationDuration  = shakeInfo.iterationDuration;
    
    [UIView animateWithDuration:iterationDuration animations:^{
        
        [self _animate:force shakeInfo:shakeInfo];
        
    } completion:^(BOOL finished) {
        
        if (shakeInfo.shaking) {
            
            BOOL shouldRecurse = YES;
            if (shakeInfo.completionRatio > 1) {
                
                if (HAS_OPT(shakeInfo.options, SCShakeOptionsAutoreverse)) {
                    
                    shakeInfo.reversed = !shakeInfo.reversed;
                }
                
                if (shakeInfo.reversed || HAS_OPT(shakeInfo.options, SCShakeOptionsAtEndRestart)) {
                    
                    shakeInfo.startTime = CACurrentMediaTime();
                    
                } else if (!HAS_OPT(shakeInfo.options, SCShakeOptionsAtEndContinue)) {
                    
                    shouldRecurse = NO;
                    [self endShake];
                }
            }
            
            if (shouldRecurse) {
                
                [self _doAnimation:direction * -1];
            }
        }
    }];
}

- (void)endShake {
    
    SCShakeInfo *shakeInfo = [self shakeInfo];
    
    if (shakeInfo.shaking) {
        
        shakeInfo.shaking                        = NO;
        self.transform                           = shakeInfo.baseTransform;
        ShakeCompletionHandler completionHandler = shakeInfo.completionHandler;
        shakeInfo.completionHandler              = nil;
        
        if (completionHandler != nil) {
            
            completionHandler();
        }
    }
}

- (BOOL)isShaking {
    
    return [self shakeInfo].shaking;
}

- (SCShakeInfo *)shakeInfo {
    
    SCShakeInfo *shakeInfo = objc_getAssociatedObject(self, ShakeInfoKey);
    
    if (shakeInfo == nil) {
        
        shakeInfo = [SCShakeInfo new];
        objc_setAssociatedObject(self, ShakeInfoKey, shakeInfo, OBJC_ASSOCIATION_RETAIN_NONATOMIC);
    }
    
    return shakeInfo;
}

#pragma Interpolations functions

static CGFloat InterpolateLinearUp(CGFloat input) {
    
    return input;
}

static CGFloat InterpolateLinearDown(CGFloat input) {
    
    return 1 - input;
}

static CGFloat Exp(CGFloat a, int power) {
    
    if (a < 0.5f) {
        
        return (float)pow(a * 2, power) / 2;
        
    } else {
    
        return (float)pow((a - 1) * 2, power) / (power % 2 == 0 ? -2 : 2) + 1;
    }
}

static CGFloat InterpolateExpUp(CGFloat input) {
    
    return Exp(input, 4);
}

static CGFloat InterpolateExpDown(CGFloat input) {
    
    return Exp(1 - input, 4);
}

static CGFloat InterpolateNone(CGFloat input) {
    
    return 1;
}

static CGFloat InterpolateRandom(CGFloat input) {
    
    CGFloat randNb = arc4random_uniform(10000);
    return randNb / 10000.0;
}

@end