Question

I want to overlay an image over a button. the button has a background image. If i want to overlay a semi transparent image over the button, suppose i overlay a red color image, which is semi transparent. Can any one suggest how to do that? Suggest some documentation.

Answer 1

UIImageView *overlay = [[UIImageView alloc] initWithImage:...];
[overlay setAlpha:0.5];

UIButton *button = [[UIButton alloc] initWithType:UIButtonTypeRoundedRect];
[button setBackgroundImage:...];

[button addSubview:overlay];
[overlay release];

UIButton also has an image property as well as a backgroundImage property, although I’m unsure how transparency would work with it.

http://developer.apple.com/iphone/library/documentation/uikit/reference/UIButton_Class/UIButton/UIButton.html