Well..Thanks Atanu Image may be NSFW.
Clik here to view.
I just figured Out another way. As the createContent(oController) of the view gets called first, we can have this.controller = oController inside createContent(oController)
onBeforeShow(evt) {
alert(this.controller); //Here we can access this
}
createContent(oController) {
this.controller = oController;
}