How to put the Accelerometer method in my app

Question

I’m creating a Java app with my friend, and I wanted to put an image with an accelerometer that moves around the screen avoiding obstacles, but I’m having a problem the video I saw (only one I found) that makes it leaves a function in a strange way and then I don’t know what to do more.

That’s the code I’m in trouble with:

package softs.gustavo.game;

import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.graphics.Color;
import android.hardware.Sensor;
import android.hardware.SensorEvent;
import android.hardware.SensorEventListener;
import android.hardware.SensorManager;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.view.SurfaceHolder;
import android.view.SurfaceView;

/**
 * Created by Gustavo on 02/03/2016.
 */
public class MoveMago extends AppCompatActivity implements SensorEventListener{
    Bitmap magao = BitmapFactory.decodeResource(getResource(), R.drawable.magao);
    SensorManager sm;
    Mago ourView;
    Float x,y,sensorX,sensorY;
    private Bundle savedInstanceState;

    @Override
    public void onSensorChanged(SensorEvent event) {
      try{
          Thread.sleep(20);
      }catch (InterruptedException e){
          e.printStackTrace();
      }

        sensorX = event.values[0];
        sensorY = event.values[1];

    }

    @Override
    public void onAccuracyChanged(Sensor sensor, int accuracy) {

    }
    public class Mago extends SurfaceView implements Runnable{
        SurfaceHolder ourHolder;
        Thread ourThread =null;
        boolean isRunning = true;

        public Mago(Context context){
            super(context);
            ourHolder = getHolder();

        }

        public void pause(){
            isRunning = false;
            while (true){
                try {
                    ourThread.join();
                } catch (InterruptedException e){
                    e.printStackTrace();
                }
                break;
            }
            ourThread = null;
        }
        public void resume(){
            isRunning = true;
            ourThread = new Thread(this);
            ourThread.start();
        }

        @Override
        public void run() {
            while (isRunning){
                if(!ourHolder.getSurface().isValid())
                    continue;

                Canvas canvas = ourHolder.lockCanvas();
                canvas.drawColor(Color.WHITE);
                canvas.drawBitmap(magao, sensorX*10, sensorY, null);
                ourHolder.unlockCanvasAndPost(canvas);
            }

        }
    }
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        sm = (SensorManager) getSystemService(Context.SENSOR_SERVICE);
        if (sm.getSensorList(Sensor.TYPE_ACCELEROMETER).size() != 0) ;
        //setup a sensor
        Sensor s = sm.getSensorList(Sensor.TYPE_ACCELEROMETER).get(0);
        sm.registerListener(this, s, SensorManager.SENSOR_DELAY_NORMAL);


    }


    magao = BitmapFactory.decodeResource(getResource(),R.drawable.magao);
    x = y = sensorX = sensorY = 0;
    ourView = new MoveMago(this);
    ourView.resume();
    setContentView(ourView);
}