Convert layer-list to bitmap not working probably

Question

I try to convert layer-list to bitmap, then set this bitmap as a background for an ImageView but it not working

This is a test project. I know I can set drawable directly to ImageView, but I want to know why when I convert LayerDrawable to Bitmap then convert Bitmap to BitmapDrawable then set it as background of ImageView, it will look different
Here is my layer-list (ic_circle.xml)

<?xml version="1.0" encoding="utf-8"?>
<layer-list xmlns:android="http://schemas.android.com/apk/res/android"
    >
    <item>
        <shape
            android:shape="oval">
            <solid android:color="#f00"></solid>

        </shape>
    </item>
    <item
        android:bottom="3dp" android:left="3dp" android:right="3dp" android:top="3dp">
        <shape
            android:shape="oval">
            <solid android:color="#ff0"></solid>

        </shape>
    </item>
    <item
        android:bottom="6dp" android:left="6dp" android:right="6dp" android:top="6dp">
        <shape
            android:shape="oval">
            <solid android:color="#0ff"></solid>
        </shape>
    </item>
</layer-list>

Activity code

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        ImageView img = (ImageView) findViewById(R.id.img);
        Bitmap bm = drawableToBitmap(ContextCompat.getDrawable(this, R.drawable.ic_circle));
        img.setBackground(new BitmapDrawable(bm));
    }

    public Bitmap drawableToBitmap (Drawable drawable) {
        int width = drawable.getIntrinsicWidth();
        width = width > 0 ? width : 1;
        int height = drawable.getIntrinsicHeight();
        height = height > 0 ? height : 1;

        Bitmap bitmap = Bitmap.createBitmap(width, height, Bitmap.Config.ARGB_8888);
        Canvas canvas = new Canvas(bitmap);
        drawable.setBounds(0, 0, canvas.getWidth(), canvas.getHeight());
        drawable.draw(canvas);

        return bitmap;
    }
}

Xml code

<LinearLayout
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    >

    <ImageView
        android:layout_width="80dp"
        android:layout_height="80dp"
        android:background="@drawable/ic_circle"
        />


    <ImageView
        android:id="@+id/img"
        android:layout_marginTop="40dp"
        android:layout_width="80dp"
        android:layout_height="80dp"
        />

</LinearLayout>

In the emulator, you will see the second image is different to first image

Answer 1

In your drawable you have you have defined only boundaries of 2 outer small circles (yellow and red), and the blue one should take all the rest space. But since it has no defined size, once you draw it on the canvas, it's size will be 0.

You have to define it's size as well if you want to draw it directly on the bitmap.