iphone - 如何使用 MonoTouch 为 UIButton Alpha 属性设置动画

Question

我有一个带有 Alpha 属性的简单 UIButton，我想将其从 1.0f 动画到 0.0f，然后再回到 1.0f。这基本上是对 TouchDown 的响应。

另外，如果我调用的例程不在主线程上（在 ThreadPool 上调用异步委托），我需要做些什么特别的事情吗？

我应该使用 CAAnimation 吗？

谢谢！

Answer 1

除非有人用单声道方法来做，否则我说使用：

- (void) pulseButton {
    button.alpha = 0.0;
    [UIView beginAnimations:nil context:button]; {
        [UIView setAnimationDelegate:self];
        [UIView setAnimationDidStopSelector:@selector(makeVisibleAgain:finished:context:)];
        [UIView setAnimationCurve:UIViewAnimationCurveEaseOut];
        [UIView setAnimationDuration:0.50];
        button.alpha = 0.0;
    } [UIView commitAnimations];
}
- (void)makeVisibleAgain:(NSString *)animationID finished:(NSNumber *)finished context:(void *)context
{
    UIButton *button = ((UIButton *) context);
    [UIView beginAnimations:nil context:nil]; {
        [UIView setAnimationDelegate:nil];
        [UIView setAnimationCurve:UIViewAnimationCurveEaseIn];
        [UIView setAnimationDuration:0.5];
        button.alpha = 1.0;
    } [UIView commitAnimations];

}

Answer 2

感谢您发布 iPhone 代码。

第二个答案是使用全局变量并跳过回调的参数。这是我今天根据第一个答案得出的结论。

private void BeginPulse (Button button)
{
    UIView.BeginAnimations (button+"fadeIn", button.Handle);
    UIView.SetAnimationDelegate (this);
    UIView.SetAnimationDidStopSelector (new MonoTouch.ObjCRuntime.Selector ("makeVisibleAgain:finished:context:"));
    UIView.SetAnimationCurve(UIViewAnimationCurve.EaseOut);
    UIView.SetAnimationDuration (0.5);
     button.Alpha = 0.25f;
    UIView.CommitAnimations ();
}

[Export ("makeVisibleAgain:finished:context:")]
private void EndPulse (NSString animationId, NSNumber finished, UIButton button)
{
    UIView.BeginAnimations (null, System.IntPtr.Zero);
    UIView.SetAnimationDelegate (this);
    UIView.SetAnimationCurve (UIViewAnimationCurve.EaseIn);
    UIView.SetAnimationDuration (0.5);
    button.Alpha = 1;
    UIView.CommitAnimations();
}

Answer 3

这很简单：

UIView button;

public void fadeButtonInAndOut()
{
    UIView.BeginAnimations("fadeOut");
    UIView.SetAnimationDelegate(this);
    UIView.SetAnimationDidStopSelector(new Selector("fadeOutDidFinish"));
    UIView.SetAnimationDuration(0.5f);
    button.Alpha = 0.0f;
    UIView.CommitAnimations();
}

[Export("fadeOutDidFinish")]
public void FadeOutDidFinish()
{
    UIView.BeginAnimations("fadeIn");
    UIView.SetAnimationDuration(0.5f);
    button.Alpha = 1.0f;
    UIView.CommitAnimations();
}