Android: SurfaceView/Canvas showing a black screen instead of drawing my Bitmap

Question

I've been trying to create a simple game where a Bitmap (called hunter) moves in the direction of a tap on the screen. I've been following along with this tutorial: https://www.youtube.com/watch?v=oLf32M6lUKo. It advised using a SurfaceView to draw the Bitmap and an OnTouchListener to help move the character.

Unfortunately, the emulator simply shows a black screen when I try to run the code.

Here's my code.

public class MoveTwo extends Activity implements View.OnTouchListener {

    Bitmap hunter;
    OurView v;
    float x, y;
    float newX, newY;
    Paint p;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        v = new OurView(this);
        v.setOnTouchListener(this);
        hunter = BitmapFactory.decodeResource(getResources(), R.drawable.hunter);
        x = y = 0;
        setContentView(v);
        this.p = new Paint();
        p.setColor(Color.WHITE);
    }

    public boolean onTouch(View v, MotionEvent me) {
        newX = me.getX();
        newY = me.getY();
        return true;
    }

    public class OurView extends SurfaceView implements Runnable {
        Thread t = null;
        boolean ok = false;
        SurfaceHolder holder;

        public OurView(Context context) {
            super(context);
            holder = getHolder();
        }

        public void run() {
            while (ok == true) {
                if (!holder.getSurface().isValid()) {
                    continue;
                }
                if (newY > y) {
                    y += 5;
                }
                if (newY < y) {
                    y -= 5;
                }
                if (newX > x) {
                    x +=5;
                }
                if (newX < x) {
                    x -= 5;
                }
                Canvas c = holder.lockCanvas();
                c.drawARGB(255, 150, 150, 10);
                c.drawBitmap(hunter, x, y, p);
                holder.unlockCanvasAndPost(c);
            }
        }

        public void pause() {
            ok = false;
            while (true) {
                try {
                    t.join();
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
                break;
            }
            t = null;
        }

        public void resume() {
            ok = true;
            t = new Thread(this);
            t.start();
        }
    }
}

Do you have any recommendations for me? I'm unfamiliar with SurfaceView, so I've been having trouble trying to figure out the API and find a solution on my own.

Thanks!

Answer 1

Try adding this code right before your onTouch method

  @Override
    protected void onPause() {
    super.onPause();
    v.pause();
}

@Override
protected void onResume() {
super.onResume();
v.resume();
}