如何以编程方式设置UIView背景

Question

in the interface builder,i can find the background tag,and select the color and the opacity.

if I create the UIView programmatically,if I want to change color,I can set the backgroundColor property

the question is if I want to change the opactiy,What is the property should I change?

Thanks a lot.

Answer 1

使用视图的alpha属性，或者，如果您不希望视图的内容具有相同的不透明度更改，请更改背景颜色的alpha分量（如使用+colorWithRed:green:blue:alpha: ， +colorWithHue:saturation:brightness:alpha:或+colorWithWhite:alpha:以外的其他值。

Answer 2

You can just use

self.alpha = someFloat;

in your view class.

If you want to change it from viewcontroller, use

self.view.alpha = someFloat;