雪花飘落效果

- (void)viewDidLoad {
    [super viewDidLoad];
    flakeImage = [UIImage imageNamed:@"flake.png"];
    [NSTimer scheduledTimerWithTimeInterval:(0.05) target:self selector:@selector(play) userInfo:nil repeats:YES];
}

- (BOOL)shouldAutorotateToInte易做图ceOrientation:(UIInte易做图ceOrientation)inte易做图ceOrientation {
    return (inte易做图ceOrientation == UIInte易做图ceOrientationLandscapeLeft);
}

- (void)play {
    UIImageView *flakeView = [[UIImageView alloc] initWithImage:flakeImage];
    int startX = round(random() % 1024);
    int endX = round(random() % 1024);
    double scale = 1 / round(random() % 100) + 1.0;
    double speed = 1 / round(random() % 100) + 1.0;
    flakeView.frame = CGRectMake(startX, -100.0, 25.0 * scale, 25.0 * scale);
    flakeView.alpha = 0.55;
    [self.view addSubview:flakeView];
    [UIView beginAnimations:nil context:flakeView];
    [UIView setAnimationDuration:5 * speed];
    flakeView.frame = CGRectMake(endX, 768.0, 25.0 * scale, 25.0 * scale);
    [UIView setAnimationDidStopSelector:@selector(onAnimationComplete:finished:context:)];
    [UIView setAnimationDelegate:self];
    [UIView commitAnimations];
}

- (void)onAnimationComplete:(NSString *)animationID finished:(NSNumber *)finished context:(void *)context {
    UIImageView *flakeView = context;
    [flakeView removeFromSuperview];
    [flakeView release];
}

- (void)viewDidLoad {
    [super viewDidLoad];
       flakeImage = [UIImage imageNamed:@"flake.png"];
       [NSTimer scheduledTimerWithTimeInterval:(0.05) target:self selector:@selector(play) userInfo:nil repeats:YES];
}

- (BOOL)shouldAutorotateToInte易做图ceOrientation:(UIInte易做图ceOrientation)inte易做图ceOrientation {
       return (inte易做图ceOrientation == UIInte易做图ceOrientationLandscapeLeft);
}

- (void)play {
       UIImageView *flakeView = [[UIImageView alloc] initWithImage:flakeImage];
       int startX = round(random() % 1024);
       int endX = round(random() % 1024);
       double scale = 1 / round(random() % 100) + 1.0;
       double speed = 1 / round(random() % 100) + 1.0;
       flakeView.frame = CGRectMake(startX, -100.0, 25.0 * scale, 25.0 * scale);
       flakeView.alpha = 0.55;
       [self.view addSubview:flakeView];
       [UIView beginAnimations:nil context:flakeView];
       [UIView setAnimationDuration:5 * speed];
       flakeView.frame = CGRectMake(endX, 768.0, 25.0 * scale, 25.0 * scale);
       [UIView setAnimationDidStopSelector:@selector(onAnimationComplete:finished:context:)];
       [UIView setAnimationDelegate:self];
       [UIView commitAnimations];
}

- (void)onAnimationComplete:(NSString *)animationID finished:(NSNumber *)finished context:(void *)context {
       UIImageView *flakeView = context;
       [flakeView removeFromSuperview];
       [flakeView release];
}

示例图：

作者 jsntghf

补充：移动开发 , IOS ,