In the application to call SystemProperties.set

You great God, I want to ask why I call SystemProperties.set at the application layer () or get () interface function did not respond, I was through the layoulib.jar package into the project, and then import after android.os.SystemProperties, found This call does not respond, you to the point! ! Jia! ! Thank you!<-! Main posts under Banner (D4) -><-! Posts under the main text (D5) ->
Reply:
Their top, beg you guide! !