get bitmap information from bitmap stored in drawable folder

I wanna read in a bitmap that I have in my drawable folder and store it as a Bitmap variable so that I can set it as a background. Would the best way to do this be using a "file reader"? like

  Bitmap decodeFile (String pathName)开发者_JAVA技巧 method

Or is there a way to just set it like this:

  Bitmap bmp = R.drawable."bitmapFileName"; 

(I have tried this but returns an int, just wondering if I was on the right track)

Any help would be great :)

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The R.drawable."bitmapFileName" is, indeed, just an integer, for it is an index (static integer) at your project's R class (see more here). You can load your bitmap from the resources's folder like this:

Bitmap image = BitmapFactory.decodeResource(getResources(), R.drawable.yourBitmap);

I found this code at the Android Development Community.

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I usually use the assets folder

InputStream is = parentActivity.getResources().getAssets().open(iconFile);
Bitmap bmp = BitmapFactory.decodeStream(is);
BitmapDrawable bitmapDrawable = new BitmapDrawable(is);

then just yourView.setBackgroundDrawable(bitmapDrawable);

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It is possible to load a drawable or bitmap by name. Here is an example:

public Drawable getImageByName(String nameOfTheDrawable, Activity a){
    Drawable drawFromPath;
    int path = a.getResources().getIdentifier(nameOfTheDrawable, 
                                    "drawable", "com.mycompany.myapp"); 

    Options options = new BitmapFactory.Options();
    options.inScaled = false;
    Bitmap source = BitmapFactory.decodeResource(a.getResources(), path, options);

    drawFromPath = new BitmapDrawable(source);  

    return drawFromPath;
}

You can of course return Bitmap instead a drawable.

Drawbale d = getImageByName("mageFileName", this);

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/*
 * You can get Bitmap from drawable resource id in the following way
 */
BitmapDrawable drawable = (BitmapDrawable)context.getResources()
        .getDrawable(drawableId);
bitmap = drawable.getBitmap();