@interface ViewController (){    UIImage *image;}- (IBAction)didAction:(id)sender;@end@implementation ViewController- (void)viewDidLoad {    [super viewDidLoad];    self.view.backgroundColor = [UIColor cyanColor];    //雪花图片    image = [UIImage imageNamed:@"iconfont-xuehua"];    //启动定时器    [NSTimer scheduledTimerWithTimeInterval:0.5 target:self selector:@selector(showTime) userInfo:nil repeats:YES];    // Do any additional setup after loading the view, typically from a nib.}- (void)showTime {    //创建雪花    UIImageView *imageV = [[UIImageView alloc] initWithImage:image];    //添加    [self.view addSubview:imageV];        NSInteger startX = arc4random()%356 + 10;    //雪花开始位置    imageV.frame = CGRectMake(startX, 50, 50, 50);    //动画    [UIView animateWithDuration:2 animations:^{        //雪花下落位置        imageV.frame = CGRectMake(startX, self.view.frame.size.height, 30, 30);    } completion:^(BOOL finished) {        //动画完成移除雪花        [imageV removeFromSuperview];    }];    }- (void)didReceiveMemoryWarning {    [super didReceiveMemoryWarning];    // Dispose of any resources that can be recreated.}- (IBAction)didAction:(id)sender {        WebViewController *web = [[WebViewController alloc] initWithNibName:@"WebViewController" bundle:nil];    [self.navigationController pushViewController:web animated:YES];}@end