如何逐渐降低 UIButton 的不透明度？

Question

在我的项目中，我有一个 UIButton，单击它会缩放。到这里为止一切都很好，但我要求按钮的不透明度从 1 逐渐降低到 0。我的意思是它应该按 1,0.9,0.8,0.7,0.6,0.5,0.4,0.3,0.2,0.1,0.0 顺序降低。我当前的代码是

    -(void)roundButtonAnimation
{
    self.buttonZoom = [CAKeyframeAnimation animationWithKeyPath:@"transform"];
    self.buttonZoom.duration = 0.8f;
    self.buttonZoom.values = @[[NSValue valueWithCATransform3D:CATransform3DMakeScale(1, 1, 1)],[NSValue valueWithCATransform3D:CATransform3DMakeScale(2,2,2)],[NSValue valueWithCATransform3D:CATransform3DMakeScale(3,3,3)],[NSValue valueWithCATransform3D:CATransform3DMakeScale(5,5,5)],[NSValue valueWithCATransform3D:CATransform3DMakeScale(6,6,6)],[NSValue valueWithCATransform3D:CATransform3DMakeScale(7,7,7)],[NSValue valueWithCATransform3D:CATransform3DMakeScale(9,9,9)],[NSValue valueWithCATransform3D:CATransform3DMakeScale(10,10,10)],[NSValue valueWithCATransform3D:CATransform3DMakeScale(11,11,11)],[NSValue valueWithCATransform3D:CATransform3DMakeScale(12,12,12)],[NSValue valueWithCATransform3D:CATransform3DMakeScale(13,13,13)],[NSValue valueWithCATransform3D:CATransform3DMakeScale(14,14,14)],[NSValue valueWithCATransform3D:CATransform3DMakeScale(15,15,15)],[NSValue valueWithCATransform3D:CATransform3DMakeScale(16,16,16)],[NSValue valueWithCATransform3D:CATransform3DMakeScale(17,17,17)],[NSValue valueWithCATransform3D:CATransform3DMakeScale(18,18,18)],[NSValue valueWithCATransform3D:CATransform3DMakeScale(50,50,50)]];
    self.buttonZoom.timingFunction = [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseOut];
    self.roundButton.transform = CGAffineTransformMakeScale(0,0);
    self.roundButton.alpha = 0.3;
    [self.roundButton.layer addAnimation:self.buttonZoom forKey:@"buttonScale"];

[self.CLSpinnerView1 stopAnimating];
    //[self performSelector:@selector(secondView) withObject:self afterDelay:0.3];

    [self performSelector:@selector(postNotification) withObject:self afterDelay:0.6];
}

Answer 1

UIView animateWithDuration:animations: 应该能满足您的需求。

[UIView animateWithDuration:1.0 animations:^{
    button.alpha = 0.0;
}];

将在一秒内逐渐将按钮的 alpha 更改为 0 (...WithDuration:1.0...)。

有关详细信息，请参阅 The UIView Class Reference。

希望这对您有所帮助。

Answer 2

试试这个

[button.layer removeAnimationForKey:@"opacity"];

Answer 3

[UIView animateWithDuration:1.0
                          delay:0.0
                        options: UIViewAnimationCurveLinear
                     animations:^{
                         self.roundButton.transform = CGAffineTransformMakeScale(50.0f, 50.0f);
                         self.roundButton.alpha = 0.0;
                     } 
                     completion:^(BOOL finished){
                         NSLog(@"Done!");
                     }];
}

让我们稍微解释一下，在这个动画块中你说动画应该在一秒钟内发生，在这一秒钟内基于线性曲线（因此总是等于 increment/decrement）按钮应该缩放 50 倍并且 alpha 应该动画为 0。
我不明白你为什么要在那个简单的动画块上使用更复杂的 CAKeyframeAnimation。
当您想要更强大的计时功能和一组值的动画时，关键帧动画很有用。

如何逐渐降低 UIButton 的不透明度？

How to reduce the opacity of an UIButton gradually?

ios

objective-c

iphone

uibutton

uianimation