ios - 在 UIView 动画中立即调用完成 block

Question

我试图一个一个地改变 subview 的颜色，但是所有 View 的颜色都会立即改变，即使我已经将动画持续时间设置为 2 秒。

- (void)runAnimation
{
    NSMutableArray *views = [[NSMutableArray alloc]init];

    for (UIView *bubble in self.subviews)
    {
        if(bubble.tag == 2500)
            [views addObject:bubble];
    }

    __weak PKCustomSlider *weak_self = self;
    __block NSInteger currentView = 0;
    self.animationBlock = ^{

        [UIView animateWithDuration:2 animations:^{
             NSLog(@"Animation block called again");
            [views[currentView] setBackgroundColor:[UIColor colorWithRed:1 green:0 blue:0 alpha:1]];
        } completion:^(BOOL finished) {
            currentView += 1;
            if(!finished)
            {
                NSLog(@"Animation hasn't finished");
                return;
            }

            if (currentView == views.count){
                currentView = 0;
                NSLog(@"Animation block ended");
            }
            else
            {
                weak_self.animationBlock();
                NSLog(@"Animation block called again because views still available in the array");
            }
        }];

    self.animationBlock();
}

Answer 1

如果您尝试为一个又一个 View 设置动画，则不必依赖完成 block 。如果动画 block 中没有要完成的动画，可以立即调用完成 block 。

你可以这样做:

- (void)runAnimation
{
    for (int i = 0; i < self.subviews.count; i++) {
        UIView *bubble = self.subviews[i];

        if (bubble.tag != 2500)
            continue;

        [UIView animateWithDuration:2 delay:2*i options:0 animations:^{
            [bubble setBackgroundColor:[UIColor colorWithRed:0 green:1 blue:0 alpha:1]];
        } completion:nil];
    }
}