When subclassing an UIView and you need to create a method for initialization, then you must choose at least one of the following.
- initWithFrame. This is the default initializator. Implement it when your class is created from code.
- initWithCoder. Implement this method when your UIView subclass will be created by the Interface Builder.
- layerClass. Implement this when the view will be draw by an alternative method like OpenGL ES.