ios - 闪烁动画导致 View 卡住

Question

我正在尝试创建一种方法来使我的应用程序中的某些图标闪烁。但是当我使用这段代码时:

-(void)blinkIcon : (UIButton *)theIcon
{
  for (int i = 0; i < 6 ; i++)
  {
    if (theIcon.hidden)
    {
        theIcon.hidden = NO;
    }
    else
    {
        theIcon.hidden = YES;
    }
    [[NSRunLoop currentRunLoop] runUntilDate:[NSDate dateWithTimeIntervalSinceNow:0.3]];
  }
  theIcon.hidden = NO;
}

效果不是很好，因为图标“卡住了”几秒钟，仅此而已。该过程必须结束于:

theIcon.hidden = NO; 

Answer 1

我刚刚写了这个方法，它需要一个按钮来完成我认为你所说的眨眼的意思。

- (void)blinkButton:(UIButton *)button {
    CGFloat newAlpha = button.alpha == 1.0 ? 0.1 : 1.0;
    [UIView animateWithDuration:0.5 animations:^{
        button.alpha = newAlpha;
    } completion:^(BOOL finished) {
        [self blinkButton:button];
    }];
}

它产生以下结果:

https://www.dropbox.com/s/48vfpgn1cw6mj17/blink2.mov?dl=0

如果您不想在将来某个时候停止它，您可以这样做 - 我设置了一个条形按钮项用于测试调用 stopBlinking 方法:

- (void)blinkButton:(UIButton *)button {
    // if we shouldn't be blinking and the button is currently not
    // totally faded in, fade it all the way in
    if (!_shouldBlink && button.alpha != 1.0) {
        [UIView animateWithDuration:0.5 animations:^{
            button.alpha = 1.0;
        }];
    }

    // otherwise we should continue blinking
    else {
        CGFloat newAlpha = button.alpha == 1.0 ? 0.1 : 1.0;
        [UIView animateWithDuration:0.5 animations:^{
            button.alpha = newAlpha;
        } completion:^(BOOL finished) {
            [self blinkButton:button];
        }];
    }
}

- (void)stopBlinking {
    _shouldBlink = NO;
}

这会产生这样的结果:

https://www.dropbox.com/s/sbwol1ac710t6nw/stop.mov?dl=0