After reading [http://www.cocos2d-x.org/boards/20/topics/34224] ,
I try to rename the call back function to backClicked(why is it different from the definition of “virtual CCLayer::keyBackClicked”),
and it works with “this.setKeypadEnabled(true);” in layer.onEnter.
Three problems here:
# backClicked is not a function of cc.Layer, so this._super() cann’t be used here.
# obfuscating the code will obfuscate “this.setKeypadEnabled(true);” to “this.Si(1)” lead to the error “this.Si is undefined”.
# backClicked will be obfuscated too.
By the way, cc.RemoveSelf is not exported for jsb yet(it works for html5).