Add Images on Canvas with Android

I'm new to android java and I don't really knows how to make the button appear on my VIEW after a long time researching online. I can see my button in the layout but not on my view when I debug it.I'm not sure how to put more than one images in after the button was clicked.Please do correct me if I had done wrong in my code. Any help will be greatly appreciated.THANKS!

My Code in the following:

package com.example.oncanvas;

import android.app.Activity;

public class Main extends Activity {

    @Override
        public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        DrawView DrawView = new DrawView(this);
        DrawView.setBackgroundColor(Color.WHITE);
        setContentView(DrawView);
        DrawView.requestFocus();

}

    public class DrawView extends View {

        private Bitmap  mBitmap;
        private Canvas  mCanvas;
        private Path    mPath;
        private Paint   mBitmapPaint;
        private Paint   mPaint;

        public DrawView(Context c) {
            super(c);

            mPath = new Path();
            mBitmapPaint = new Paint(Paint.DITHER_FLAG);


            mPaint = new Paint();
            mPaint.setAntiAlias(true);
            mPaint.setDither(true);
            mPaint.setColor(0xFF000000);
            mPaint.setStyle(Paint.Style.STROKE);
            mPaint.setStrokeJoin(Paint.Join.ROUND);
            mPaint.setStrokeCap(Paint.Cap.ROUND);
                mPaint.setStrokeWidth(3);
        }  

    protected void onSizeChanged(int w, int h, int oldw, int oldh) {
        super.onSizeChanged(w, h, oldw, oldh);
        mBitmap = Bitmap.createBitmap(w, h, Bitmap.Config.ARGB_8888);
        mCanvas = new Canvas(mBitmap);
    }

    @Override
    protected void onDraw(Canvas canvas) {
        canvas.drawBitmap(mBitmap, 0, 0, mBitmapPaint);

        canvas.drawPath(mPath, mPaint);
    }

    private float mX, mY;
    private static final float TOUCH_TOLERANCE = 4;