如何使iPhone屏幕变暗 [英] How to make iPhone screen dim

问题描述

我的iPhone屏幕上有一个刷新按钮，刷新当前视图中的表格。

I have a refresh button on my iphone screen that refreshes a table in the current view.

屏幕刷新得很漂亮，但有一种方法，屏幕变暗，然后在表刷新后再次点亮？

The screen refresh beautifully, but is there a way I can make the screen dim and then lighten again after the table has refreshed?

推荐答案

您可以在想要调暗的视图上放置一个黑色背景的不透明视图。这将默认的alpha值为0，因此是透明的。然后，您可以使用UIView动画将黑色视图alpha从0设置为0.5（假设），然后返回。

You could place a non-opaque view with a black background over the view you wish to dim. This would have an alpha value of 0 by default and thus be transparent. You could then use a UIView animation to set the black views alpha from 0 to 0.5 (say) and then back.

注意： 以下代码尚未经过测试，但我已使用类似的代码实现相同的效果。

Note: The code below has not been tested but I have used similar to achieve the same effect.

    ...
    dimView.alpha = 0.0f;
    [UIView beginAnimations@"fade" context:nil];
    [UIView setAnimationDuration:0.5f];
    [UIView setAnimationDelegate:self];
    [UIView setAnimationDidStopSelector:@selector(animationDidStop:finished:context:)];
    [UIView setAnimationRepeatAutoreverses:YES];
    dimView.alpha = 0.5f;
    [UIView commitAnimations];
    ...
}

- (void) animationDidStop:(NSString *)animationID finished:(NSNumber *)finished context:(void *)context {
    dimView.alpha = 0.0f;
}

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