is it ok in an activity's procedure to force the onResume event by calling this.OnResume() ? Or should I implement another procedure that's called by both OnResume and by the first member ?
Implement another procedure that's called in your override of onResume(). The latter is not intended to be called by you, it's a convenience method that tidies up or readies the activity when its state changes to resume. A lot like onCreate() through to onDestroy().
What @SK9 said, but also especially because you must call super.onResume() when you override the onResume method, so you're not in control what happens in the background (views getting refreshed, etc).
来源：https://stackoverflow.com/questions/6012171/calling-onresume-in-androids-activity