iOS:重复动画 block 直到事件完成

Question

我有以下动画 block ，它旋转一个按钮一次。我想继续旋转按钮，直到 refreshPendingRequests 方法完成。

refreshPendingRequests 方法从我的服务器检索数据，因此我想继续旋转按钮直到检索到数据。

CGFloat direction = 1.0f;  // -1.0f to rotate other way
refreshButton.transform = CGAffineTransformIdentity;
[UIView animateKeyframesWithDuration:1.0 delay:0.0
                             options:UIViewKeyframeAnimationOptionCalculationModePaced | UIViewAnimationOptionCurveEaseInOut
                          animations:^{
                              [UIView addKeyframeWithRelativeStartTime:0.0 relativeDuration:0.0 animations:^{
                                  refreshButton.transform = CGAffineTransformMakeRotation(M_PI * 2.0f / 3.0f * direction);
                              }];
                              [UIView addKeyframeWithRelativeStartTime:0.0 relativeDuration:0.0 animations:^{
                                  refreshButton.transform = CGAffineTransformMakeRotation(M_PI * 4.0f / 3.0f * direction);
                              }];
                              [UIView addKeyframeWithRelativeStartTime:0.0 relativeDuration:0.0 animations:^{
                                  refreshButton.transform = CGAffineTransformIdentity;
                              }];
                          }
                          completion:^(BOOL finished) {
                              [self performSelector:@selector(refreshPendingRequests) withObject:nil afterDelay:0.0];
                          }];

有谁知道我是否可以调用某种类型的repeats 属性，或者我如何执行此动画直到refreshPendingRequests 事件完成？

Answer 1

确实有一个选项:UIViewKeyframeAnimationOptionRepeat。

传递该选项，并为您的完成 block 传递 nil，因为您不需要它。

[UIView animateKeyframesWithDuration:1.0 delay:0.0
                             options:UIViewKeyframeAnimationOptionCalculationModePaced | UIViewAnimationOptionCurveEaseInOut | UIViewKeyframeAnimationOptionRepeat
                          animations:^{
                              [UIView addKeyframeWithRelativeStartTime:0.0 relativeDuration:0.0 animations:^{
                                  refreshButton.transform = CGAffineTransformMakeRotation(M_PI * 2.0f / 3.0f * direction);
                              }];
                              [UIView addKeyframeWithRelativeStartTime:0.0 relativeDuration:0.0 animations:^{
                                  refreshButton.transform = CGAffineTransformMakeRotation(M_PI * 4.0f / 3.0f * direction);
                              }];
                              [UIView addKeyframeWithRelativeStartTime:0.0 relativeDuration:0.0 animations:^{
                                  refreshButton.transform = CGAffineTransformIdentity;
                              }];
                          }
                          completion:nil];

然后当你的刷新完成时:

[refreshButton.layer removeAllAnimations];