在UIView动画中调用immediatly的完成块

Question

我试图逐个更改子视图的颜色，但所有视图的颜色都立即更改，即使我已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

如果您尝试为另一个视图设置动画效果，则不必依赖完成块。如果在动画块中没有动画要完成，则可立即调用完成块。

你可以做这样的事情：

- (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]; 
    } 
}