下面是代码  直接一个类就行了

#import "ViewController.h"

@interface ViewController ()

@property (nonatomic,strong) NSTimer *timer;

@property (nonatomic,strong) UIButton *bgBUutton;

@end

@implementation ViewController

- (void)viewDidLoad {

    [super viewDidLoad];

    // Do any additional setup after loading the view, typically from a nib.

    self.bgBUutton = [[UIButton alloc] initWithFrame:UIScreen.mainScreen.bounds];

    [self.bgBUutton addTarget:self action:@selector(btnClick:) forControlEvents:UIControlEventTouchUpInside];

    self.bgBUutton.backgroundColor = [UIColor whiteColor];

    self.bgBUutton.userInteractionEnabled = YES;

    [self.view addSubview:self.bgBUutton];

    [self startRedPackets];

}

-(void)btnClick:(UIButton*)btn{

    NSLog(@"点击了红包");

//    [btn removeFromSuperview];

}

- (void)startRedPackets {

    self.timer = [NSTimer scheduledTimerWithTimeInterval:1 target:self selector:@selector(showRain) userInfo:nil repeats:YES];

    //[self.timer invalidate];

}

- (void)showRain {

    CALayer*moveLayer = [CALayernew];

    moveLayer.bounds=CGRectMake(0,0,80,80);//红包大小

    moveLayer.anchorPoint=CGPointMake(0,0);

    moveLayer.position=CGPointMake(0, -80);//红包起始位置

    moveLayer.contents= (id)[UIImageimageNamed:@"ic_pan_redbag"].CGImage;

    [self.bgBUutton.layeraddSublayer:moveLayer];

    CAKeyframeAnimation *moveAnimation = [CAKeyframeAnimation animationWithKeyPath:@"position"];

//    红包掉落展示的范围

    NSValue *A = [NSValue valueWithCGPoint:CGPointMake(arc4random() % 414, 0)];

    NSValue *B = [NSValue valueWithCGPoint:CGPointMake(arc4random() % 414, 667)];

    moveAnimation.values=@[A,B];

    moveAnimation.duration=arc4random() %200/100.0+5.5;//红包掉落时间

    moveAnimation.repeatCount=1;

    moveAnimation.timingFunction = [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionLinear];

    [moveLayeraddAnimation:moveAnimationforKey:nil];

//    红包掉落时候翻转动画

    CAKeyframeAnimation *transAnimation = [CAKeyframeAnimation animationWithKeyPath:@"transform"];

    CATransform3D r0 = CATransform3DMakeRotation(M_PI/180 * (arc4random() % 360),0,0,-1);

    CATransform3D r1 = CATransform3DMakeRotation(M_PI/180 * (arc4random() % 360),0,0,-1);

    transAnimation.values = @[[NSValue valueWithCATransform3D:r0],[NSValue valueWithCATransform3D:r1]];

    transAnimation.duration=arc4random() %200/100.0+3.5;

    transAnimation.timingFunction = [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseInEaseOut];

    [transAnimationsetFillMode:kCAFillModeForwards];

    [transAnimationsetRemovedOnCompletion:NO];

    [moveLayeraddAnimation:transAnimationforKey:nil];

}

@end