How to put text in a drawable?

Here is a brief example of a TextDrawable which works like a normal drawable but lets you specify text as the only constructor variable:

public class TextDrawable extends Drawable {

    private final String text;
    private final Paint paint;

    public TextDrawable(String text) {

        this.text = text;

        this.paint = new Paint();
        paint.setColor(Color.WHITE);
        paint.setTextSize(22f);
        paint.setAntiAlias(true);
        paint.setFakeBoldText(true);
        paint.setShadowLayer(6f, 0, 0, Color.BLACK);
        paint.setStyle(Paint.Style.FILL);
        paint.setTextAlign(Paint.Align.LEFT);
    }

    @Override
    public void draw(Canvas canvas) {
        canvas.drawText(text, 0, 0, paint);
    }

    @Override
    public void setAlpha(int alpha) {
        paint.setAlpha(alpha);
    }

    @Override
    public void setColorFilter(ColorFilter cf) {
        paint.setColorFilter(cf);
    }

    @Override
    public int getOpacity() {
        return PixelFormat.TRANSLUCENT;
    }
}

I've read the book "Professional Android 2 Application Development" (by Reto Meier). Amongst others, it contains an example project where you create a simple compass application where you "draw" text, markers etc.

The brief explanation is that you create a class that extends the android.view.View class and overrides the onDraw(Canvas) method.

All the source code form the book is available for download here: http://www.wrox.com/WileyCDA/WroxTitle/Professional-Android-2-Application-Development.productCd-0470565527,descCd-DOWNLOAD.html. If you download the code and look inside the project named "Chapter 4 Compass", I believe you would find what you're looking for :)

Looking at Plowman's answer and trying to adjust it to my needs I stumpled upon a Class that is used for Camera in this link

Here is the code from the TextDrawable Class. Looks pretty simillar with Plowmans but for me works better:

import android.content.res.Resources;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.ColorFilter;
import android.graphics.Paint;
import android.graphics.Paint.Align;
import android.graphics.Rect;
import android.graphics.drawable.Drawable;
import android.util.TypedValue;

public class TextDrawable extends Drawable {
    private static final int DEFAULT_COLOR = Color.WHITE;
    private static final int DEFAULT_TEXTSIZE = 15;
    private Paint mPaint;
    private CharSequence mText;
    private int mIntrinsicWidth;
    private int mIntrinsicHeight;

    public TextDrawable(Resources res, CharSequence text) {
        mText = text;
        mPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
        mPaint.setColor(DEFAULT_COLOR);
        mPaint.setTextAlign(Align.CENTER);
        float textSize = TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_SP,
                DEFAULT_TEXTSIZE, res.getDisplayMetrics());
        mPaint.setTextSize(textSize);
        mIntrinsicWidth = (int) (mPaint.measureText(mText, 0, mText.length()) + .5);
        mIntrinsicHeight = mPaint.getFontMetricsInt(null);
    }
    @Override
    public void draw(Canvas canvas) {
        Rect bounds = getBounds();
        canvas.drawText(mText, 0, mText.length(),
                bounds.centerX(), bounds.centerY(), mPaint);
    }
    @Override
    public int getOpacity() {
        return mPaint.getAlpha();
    }
    @Override
    public int getIntrinsicWidth() {
        return mIntrinsicWidth;
    }
    @Override
    public int getIntrinsicHeight() {
        return mIntrinsicHeight;
    }
    @Override
    public void setAlpha(int alpha) {
        mPaint.setAlpha(alpha);
    }
    @Override
    public void setColorFilter(ColorFilter filter) {
        mPaint.setColorFilter(filter);
    }
}