How can I receive response from the sensors

Question

I am developing a compass app from this tutorial but with some things different to the tutorial, for example i don´t want to draw the compass, just put the values in a EditText, the thing is that is not working or really I don´t know what is happening... I try to debug the application but the sensors do not respond and the log don´t show any errors... this is what i try:

public class MainActivity extends Activity implements SensorEventListener {

float azimut;
private SensorManager mSensorManager;
Sensor accelerometer;
Sensor magnetometer;
float[] mGravity;
float[] mGeomagnetic;
private EditText edTLatitud;
private EditText edTLongitud;
private EditText edTCompass;
private EditText edTDirecc;


@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    edTCompass = (EditText)this.findViewById(R.id.edTxtBrujula);
    edTDirecc = (EditText)this.findViewById(R.id.edTxtBrujdireccion);

    mSensorManager = (SensorManager)getSystemService(SENSOR_SERVICE);
    accelerometer = mSensorManager.getDefaultSensor(Sensor.TYPE_ACCELEROMETER);
    magnetometer = mSensorManager.getDefaultSensor(Sensor.TYPE_MAGNETIC_FIELD);
}

@Override
public void onSensorChanged(SensorEvent event) {
    if(event.sensor.getType() == Sensor.TYPE_ACCELEROMETER)
        mGravity = event.values;
    if(event.sensor.getType() == Sensor.TYPE_MAGNETIC_FIELD)
        mGeomagnetic = event.values;
    if(mGravity != null && mGeomagnetic != null){
        float R[] = new float[9];
        float I[] = new float[9];
        boolean success = SensorManager.getRotationMatrix(R,I, mGravity, mGeomagnetic);
        if(success){
            float orientation[] = new float[3];
            SensorManager.getOrientation(R, orientation);
            azimut = orientation[0];
            UpdateCompassOnScreen(azimut);
            edTCompass.setText((int)azimut);
        }
    }
}
@Override
public void onAccuracyChanged(Sensor sensor, int accuracy) {
}

// Show the value on the application of the compass with the direction
public void UpdateCompassOnScreen(float value)
{
    if (value >= 338 && value <= 22.9999)
    {
        edTDirecc.setText("° N");
    }
    else if(value >= 23 && value <= 67.9999)
    {
        edTDirecc.setText("° NE");
    }
    else if (value >= 68 && value <= 112.9999)
    {
        edTDirecc.setText("° E");
    }
    else if(value >= 113 && value <= 157.9999)
    {
        edTDirecc.setText("° SE");
    }
    else if(value >= 158 && value <= 202.9999)
    {
        edTDirecc.setText("° S");
    }
    else if(value >= 203 && value <= 247.9999)
    {
        edTDirecc.setText("° SW");
    }
    else if(value >= 248 && value <= 292.9999)
    {
        edTDirecc.setText("° W");
    }
    else if (value >= 293 && value <= 337.9999)
    {
        edTDirecc.setText("° NW");
    }
    edTCompass.setText(String.valueOf(value));
}

thanks in advice.

Answer 1

I think getRotationMatrix returns a Matrix.

Here. There's stuff in API demos. Pro Android 2 has stuff also.

public void onSensorChanged(SensorEvent event) {

        float[] mIdentityMatrix = new float[16];
        mIdentityMatrix[0] = 1;
        mIdentityMatrix[4] = 1;
        mIdentityMatrix[8] = 1;
        mIdentityMatrix[12] = 1;

        if (event.sensor.getType() == Sensor.TYPE_ACCELEROMETER) {
            if (counter++ % 10 == 0) {
                gravityMatrix = event.values.clone();
                sensorReady = true;
            }
        }
        if (event.sensor.getType() == Sensor.TYPE_MAGNETIC_FIELD)
            geomagneticMatrix = event.values.clone();

        if (sensorReady)
            SensorManager.getRotationMatrix(mRotationMatrix,
                    mIdentityMatrix, gravityMatrix, geomagneticMatrix);
    }