Difference between enabled and userInteractionEnabled properties

I read through the documentation, and here are my findings.

UIButton inherits from UIControl the boolean property enabled

A Boolean value that determines whether the receiver is enabled.

Specify YES to make the control enabled; otherwise, specify NO to make it disabled. The default value is YES. If the enabled state is NO, the control ignores touch events and subclasses may draw differently.

UIControl inherits from UIView the boolean property userInteractionEnabled:

A Boolean value that determines whether user events are ignored and removed from the event queue.

When set to NO, user events—such as touch and keyboard—intended for the view are ignored and removed from the event queue. When set to YES, events are delivered to the view normally. The default value is YES.

From this I conclude

• button.userInteractionEnabled = NO means the button looks normal but doesn't respond to touches (from the UIView inheritance).

• button.enabled = NO means the button is grayed out and doesn't respond to touches (from the UIControl inheritance). 

总的来说, userInteractionEnabled = NO,view看起来还是正常的，但是不能响应点击事件。

enabled = NO， view会变灰，如果有文字，文字也会变灰色。view也不能响应点击事件。