UIButton and Appearance API - supported or not?
问题 According to the UIAppearance protocol reference a class need to conform to the UIAppearanceContainer and have supported methods marked with UI_APPEARANCE_SELECTOR in order for the appearance proxy to work properly. In Apples own instruction video from WWDC 2011, "Customizing the appearance of UIControls", they provide examples where they use, and discuss, both UIButton and UILabel. Both of these classes conform (via inheritance from UIView) to the UIAppearance and UIAppaeranceContainer