Opacity of a custom UIButton

By d开发者_运维技巧efault, we get the opacity of UIButton set to NO. Can we set it to YES?

Um... opacity is not a boolean value. It is a float in the range from 0.0 (fully transparent) to 1.0 (fully opaque). The property is actually called the alpha, so you'd do:

[myButton setAlpha:0.42];

setAlpha doesn't work in In swift:

photoButton.alpha = 0.3