Android bitmap.getwidth returns null?

I want to get the width of a bitmap after loading it and i am using this code where mybackground is an int that is equal to R.drawable.background.

background=BitmapFactory.decodeResource(开发者_JAVA技巧context.getResources(),mybackground );

scalefactorbackx=WindowInfo.Width/background.getWidth();
scalefactorbacky=WindowInfo.Height/background.getHeight();

So far it returns a null pointer exception on this line. I have to be doing something fundamentally wrong for this to fail. Tutorials online that I read appeared to just call the .getWidth() function and it was suppose to work.

Thanks

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Your bitmap may be incorrect. Otherwise try to simplify your code to see where's the error. Or just check out some web pages.