Accelerometer for Android

Question

I developed a sample application using tutorials posted on the Internet. my goal is to access the accelerometer and move the ball in accordance with the orientation of the phone. I have succeeded. But I have two outcomes

• the ball goes beyond the screen
• the ball’s movement is not smooth (it looks like it disappears and a symbol appears on the screen)

here is my code. Are there any changes that I need to make in order to get a smooth and accurate ball movement, as we see in many games.

public class Accelerometer extends Activity implements SensorEventListener{
    /** Called when the activity is first created. */
    CustomDrawableView mCustomDrawableView = null;
    ShapeDrawable mDrawable = new ShapeDrawable();
    public static int x;
    public static int y;
       private Bitmap mBitmap;
       private Bitmap mWood;
    private SensorManager sensorManager = null;

    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState)
    {

        super.onCreate(savedInstanceState);
        // Get a reference to a SensorManager
        sensorManager = (SensorManager) getSystemService(SENSOR_SERVICE);
        mCustomDrawableView = new CustomDrawableView(this);
        setContentView(mCustomDrawableView);
        // setContentView(R.layout.main);

    }

    // This method will update the UI on new sensor events
    public void onSensorChanged(SensorEvent sensorEvent)
    {
        {
           /* if (sensorEvent.sensor.getType() == Sensor.TYPE_ACCELEROMETER) {
                // the values you were calculating originally here were over 10000!
                x = (int) Math.pow(sensorEvent.values[0], 2); 
                y = (int) Math.pow(sensorEvent.values[1], 2);

            }*/

            if (sensorEvent.sensor.getType() == Sensor.TYPE_ORIENTATION) {
                  Display display = getWindowManager().getDefaultDisplay(); 
                  int xmax = display.getWidth();
                  int ymax = display.getHeight();
                  x = (int) Math.pow(sensorEvent.values[1], 2); 
                  y = (int) Math.pow(sensorEvent.values[2], 2);
                  if (x > xmax) {
                      x = xmax;
                  } else if (x < -xmax) {
                      x = -xmax;
                  }
                  if (y > ymax) { 
                      y = ymax;
                  } else if (y < -ymax) {
                      y = -ymax;
                  }

            }
        }
    }

    // I've chosen to not implement this method
    public void onAccuracyChanged(Sensor arg0, int arg1)
    {
        // TODO Auto-generated method stub

    }

    @Override
    protected void onResume()
    {
        super.onResume();
        // Register this class as a listener for the accelerometer sensor
        sensorManager.registerListener(this, sensorManager.getDefaultSensor(Sensor.TYPE_ACCELEROMETER),
                SensorManager.SENSOR_DELAY_GAME);
        // ...and the orientation sensor
        sensorManager.registerListener(this, sensorManager.getDefaultSensor(Sensor.TYPE_ORIENTATION),
                SensorManager.SENSOR_DELAY_NORMAL); 
    }

    @Override
    protected void onStop()
    {
        // Unregister the listener
        sensorManager.unregisterListener(this);
        super.onStop();
    }

    public class CustomDrawableView extends View
    {


        public CustomDrawableView(Context context)
        {
            super(context);

          Bitmap ball = BitmapFactory.decodeResource(getResources(), R.drawable.ball);
          final int dstWidth = 50; 
          final int dstHeight = 50; 
          mBitmap = Bitmap.createScaledBitmap(ball, dstWidth, dstHeight, true);
          mWood = BitmapFactory.decodeResource(getResources(), R.drawable.wood);

        }

        protected void onDraw(Canvas canvas)
        {

            final Bitmap bitmap = mBitmap;

            canvas.drawBitmap(mWood, 0, 0, null);
            canvas.drawBitmap(bitmap, x, y, null);

            invalidate();
        }
    }
}

Answer 1

, ?! / , !

, , , x/y, . , , , , .

:

newspeed = oldSpeed + (acceleration * time)
distance = (original speed*time) + (0.5 * acceleration * time^2).

, .

---

EDIT - .

, -! , . , Open GL , !

public class test2 extends Activity implements SensorEventListener{

CustomDrawableView mCustomDrawableView = null;
ShapeDrawable mDrawable = new ShapeDrawable();
public float xPosition, xAcceleration,xVelocity = 0.0f;
public float yPosition, yAcceleration,yVelocity = 0.0f;
public float xmax,ymax;
private Bitmap mBitmap;
private Bitmap mWood;
private SensorManager sensorManager = null;
public float frameTime = 0.666f;

/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState)
{

    super.onCreate(savedInstanceState);

    //Set FullScreen & portrait
    requestWindowFeature(Window.FEATURE_NO_TITLE);
    getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN, WindowManager.LayoutParams.FLAG_FULLSCREEN);
    setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_PORTRAIT);

    // Get a reference to a SensorManager
    sensorManager = (SensorManager) getSystemService(SENSOR_SERVICE);
    sensorManager.registerListener(this, sensorManager.getDefaultSensor(Sensor.TYPE_ORIENTATION),
            SensorManager.SENSOR_DELAY_GAME);

    mCustomDrawableView = new CustomDrawableView(this);
    setContentView(mCustomDrawableView);
    // setContentView(R.layout.main);

    //Calculate Boundry
    Display display = getWindowManager().getDefaultDisplay();
    xmax = (float)display.getWidth() - 50;
    ymax = (float)display.getHeight() - 50;
}

// This method will update the UI on new sensor events
public void onSensorChanged(SensorEvent sensorEvent)
{
    {
        if (sensorEvent.sensor.getType() == Sensor.TYPE_ORIENTATION) {
            //Set sensor values as acceleration
            yAcceleration = sensorEvent.values[1]; 
            xAcceleration = sensorEvent.values[2];
            updateBall();
        }
    }
}

private void updateBall() {


    //Calculate new speed
    xVelocity += (xAcceleration * frameTime);
    yVelocity += (yAcceleration * frameTime);

    //Calc distance travelled in that time
    float xS = (xVelocity/2)*frameTime;
    float yS = (yVelocity/2)*frameTime;

    //Add to position negative due to sensor 
    //readings being opposite to what we want!
    xPosition -= xS; 
    yPosition -= yS;

    if (xPosition > xmax) {
        xPosition = xmax;
    } else if (xPosition < 0) {
        xPosition = 0;
    }
    if (yPosition > ymax) { 
        yPosition = ymax;
    } else if (yPosition < 0) {
        yPosition = 0;
    }
}

// I've chosen to not implement this method
public void onAccuracyChanged(Sensor arg0, int arg1)
{
    // TODO Auto-generated method stub
}

@Override
protected void onResume()
{
    super.onResume();
    sensorManager.registerListener(this, sensorManager.getDefaultSensor(Sensor.TYPE_ORIENTATION),
            SensorManager.SENSOR_DELAY_GAME); 
}

@Override
protected void onStop()
{
    // Unregister the listener
    sensorManager.unregisterListener(this);
    super.onStop();
}

public class CustomDrawableView extends View
{
    public CustomDrawableView(Context context)
    {
        super(context);
        Bitmap ball = BitmapFactory.decodeResource(getResources(), R.drawable.ball);
        final int dstWidth = 50; 
        final int dstHeight = 50; 
        mBitmap = Bitmap.createScaledBitmap(ball, dstWidth, dstHeight, true);
        mWood = BitmapFactory.decodeResource(getResources(), R.drawable.wood);

    }

    protected void onDraw(Canvas canvas)
    {
        final Bitmap bitmap = mBitmap;
        canvas.drawBitmap(mWood, 0, 0, null);
        canvas.drawBitmap(bitmap, xPosition, yPosition, null);
        invalidate();
    }
}

@Override
public void onConfigurationChanged(Configuration newConfig) {
    // TODO Auto-generated method stub
    super.onConfigurationChanged(newConfig);
    setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_PORTRAIT);
}
}

Answer 2

SENSOR_DELAY

SENSOR_DELAY_FASTEST 

, . . , , xmax ymax display.getWidth/getHeight , BitMap xmax ymax.