将VIew移动做成动画效果 这种动画效果没有中间的位移
可以添加动画的View属性center，frame，alpha，transform , backgroundColor
//继续做消失的动画
[UIView animateWithDuration:1 animations:^{
iv.alpha = 0;
} completion:^(BOOL finished) {
//完成动画后执行 可以继续添加
[iv removeFromSuperview];
}];
- (void)viewDidLoad {
[super viewDidLoad];
// Do any
additional setup after loading the view, typically from a nib.
[NSTimer scheduledTimerWithTimeInterval:0.1 target:self selector:@selector(addSnow) userInfo:nil repeats:YES];
}
-(void)addSnow{
int size = arc4random()%10+10;
UIImageView *iv = [[UIImageViewalloc]initWithFrame:CGRectMake(arc4random()%(320-size), -size, size, size)];
iv.image = [UIImageimageNamed:@"snow"];
[self.view addSubview:iv];
int time = arc4random()%4+1;
//添加移动动画
[UIView animateWithDuration:time animations:^{
//移动的终点位置
iv.center = CGPointMake(iv.center.x, 568);
//图形改变终点形状
iv.transform = CGAffineTransformRotate(iv.transform, (arc4random()%360)/180.0*M_PI);
} completion:^(BOOLfinished) {
//继续做雪花消失的动画
[UIView animateWithDuration:1 animations:^{
iv.alpha = 0;
} completion:^(BOOL finished) {
[iv removeFromSuperview];
}];
}];
}