我只使用了一点 UIView 动画和块,基本上是一步动画。我想将几个步骤堆叠成一个序列。下面的代码似乎正在工作,但我想知道这是否是正确的方法和/或在块内放置块是否存在任何问题/限制。
尽管代码格式有点笨拙/不可读,但块似乎很棒。
CGRect newFrame = CGRectMake(0, 0, 500, 500);
UIView *flashView = [[UIView alloc] initWithFrame:newFrame];
flashView.tag = 999;
[flashView setBackgroundColor:[UIColor grayColor]];
[flashView setAlpha:0.f];
[self.view addSubview:flashView];
[UIView animateWithDuration:.2f
animations:^{
// STEP 1: FADE IN
[flashView setAlpha:1.f];
}
completion:^(BOOL finished){
[UIView animateWithDuration:.9f
animations:^{
// STEP 2: FADE OUT
[flashView setAlpha:0.f];
}
completion:^(BOOL finished){
// STEP 3: CLEAN UP
[flashView removeFromSuperview];
}
];
}];