吸收效果，像是在Mac上的垃圾桶的效果一样

 #import "AppDelegate.h"
 #import <QuartzCore/QuartzCore.h>

 @interface AppDelegate ()
 @property (nonatomic ,strong)UIImageView *birdImage;
 @end

 @implementation AppDelegate

 - (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
     self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];
     // Override point for customization after application launch.
     self.window.backgroundColor = [UIColor whiteColor];
     // 创建UIImageView
     self.birdImage = [[UIImageView alloc] initWithFrame:[[UIScreen mainScreen] bounds]];
     //设置UIImageView可以操作
     self.birdImage.userInteractionEnabled = YES;
     // 添加图片
     self.birdImage.image = [UIImage imageNamed:@"bird"];
     // 轻拍手势
     UITapGestureRecognizer *tap = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(tapAntion)];
     // 给UIImageView添加手势
     [self.birdImage addGestureRecognizer:tap];
     [self.window addSubview:self.birdImage];

     [self.window makeKeyAndVisible];
     return YES;
 }

 - (void)tapAntion
 {
     // 设置层的背景颜色
     self.window.layer.backgroundColor = [UIColor whiteColor].CGColor;
     // 创建动画
     CATransition *anim = [CATransition animation];
     //设置代理
     anim.delegate = self;
     // 设置动画时间
     anim.duration = 1.5;
     //吸收效果，像是在Mac上的垃圾桶的效果一样（私有API，没有列入官方API）
     anim.type = @"suckEffect";
     [[self.birdImage layer] addAnimation:anim forKey:@"suckEffect"];
     // 隐藏self.birdImage（若不隐藏，图片会保留在窗口）
     self.birdImage.hidden = YES;
 }

 @end