如何在禁用状态下更改UIButton图像alpha？ [英] How do you change UIButton image alpha on disabled state?

问题描述

我有一个带有图像的UIButton并且处于禁用状态，此图像应该具有.3 alpha。

I have a UIButton with an image and on its disabled state, this image should have .3 alpha.

UIButton *button = [UIButton buttonWithType:UIButtonTypeCustom];
UIImage *arrowImage = [UIImage imageNamed:@"arrow.png"];
[button setImage:arrowImage forState:UIControlStateNormal];

// The arrow should be half transparent here
[button setImage:arrowImage forState:UIControlStateDisabled];

我如何做到这一点？

UPDATE ：我注意到，默认情况下，UIButton会在禁用状态下降低图像的alpha值（可能是.5？）。但是我想知道如何微调这个值。

UPDATE: I noticed, by default UIButton does reduce the alpha of the image on disabled state (probably at .5?). But I'd like to know how to fine-tune this value.

推荐答案

如果在按钮被禁用时设置alpha则不会工作，然后只需要你想要的阿尔法值的残疾人图像。

If setting alpha while the button is disabled doesn't work, then just make your disabled image at the alpha value you desire.

刚试过这个，你可以在UIButton上设置alpha，无论状态如何，它都有效很好。

Just tested this, you can set the alpha on the UIButton, regardless of state and it works just fine.

self.yourButton.alpha = 0.25;

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