Ask : Android how to make the next part of the Activity Activity for drawing without taking up another part of the whole display other controls

Usually we use when drawing View or SurfaceView is doing, in the onCreate () method where :
setContentView (new MySurfaceView (this));
and inner classes defined in the Activity
MySurfaceView extends SurfaceView implements SurfaceHolder.Callback {
...
}
but this will be used to draw the entire Activity , part of how to make Activity drawing, another part of the usual display additional Widget ( such as Button, TextView , etc. ) ?
passing prawn help answer , thank you !

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setContentView () set the layout of this place
layout which contains a ViewGroup graphics devoted to painting , the painting good graphics as subview join.
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MySurfaceView extends SurfaceView implements SurfaceHolder.Callback {

}

setContentView (R.layout.main);
ViewGroup view1 = (ViewGroup) findViewById (R.id.myview);
view1.add (new MySurfaceView ());
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can also use it
------ eference ------------- Fragment --------------------------
Thank you !
ViewGroup view1 = (ViewGroup) findViewById (R.id.myview); here myview is activity_main.xml inside a defined node do ? How activity_main.xml this layout file to define this myview?
------ Eference -------------------------- -------------
Oh, I see, here is the entire layout file activity_main.xml myview the id name . Thank you for it !