在iPhone OS中让文本闪烁的最佳方法是什么？ [英] Best method to get text to blink in iPhone OS?

问题描述

我希望我的文本框闪烁（就像旧的LCD时钟一样）。

I want my text box to blink (like the old LCD clocks).

现在，我正在呼叫无数的NSTimers和选择器等待，改变阿尔法，等待，然后改回来。即便如此，它看起来非常糟糕，而且我认为我必须使用NSTimer来逐渐改变alpha，但是从我听到它们并不意味着那些精确的东西。

Right now, I'm calling a myriad of NSTimers and selectors that wait, change the alpha, wait, then change it back. Even with this, it looks really bad, and I'm thinking I have to put an NSTimer to gradually change the alpha, but from what I hear they are not meant for things of that precision.

我的想法是，必须有一种方法比我目前正在实施的方法做得更好。感觉就像黑客一样。

My thoughts are there must be a way to do this a lot better than how I am currently implementing it. It feels like hack.

推荐答案

使用动画委托可能会减少hacky：

Using an animation delegate might make it less "hacky":

[UIView beginAnimations:nil context:NULL];
[UIView setAnimationDelegate:self];
[UIView setAnimationDidStopSelector:@selector(animationDidStop:finished:context:)];
[myLabel setAlpha:0.0];
[UIView commitAnimations];

然后你可以让你的didStopSelector重新启动动画：

And then you can have your didStopSelector restart the animation:

- (void)animationDidStop:(NSString *)animationID finished:(NSNumber *)finished context:(void *)context {
    [self displayLabel];
}

根据animationID，您可以采取不同的操作，等等。使用UIView的setAnimationDelay也可以派上用场。

Depending on the animationID, you could take different actions, etc. Using UIView's setAnimationDelay might come in handy as well.

UIView还有动画的setDuration调用：

UIView also has a setDuration call for animations:

[UIView setAnimationDuration:0.1];

如果您正在为iOS4构建，请检查文档，因为您应该使用基于块的动画调用比这些基于代表的那些。

If you are building for iOS4, check the documentation since you should be using block-based animation calls rather than these delegate based ones.

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