Android Open Source - QuestCompass Compass Sensor Listener

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License

The source code is released under:

Apache License

Java Source Code

package de.renard.radar;
/*from ww  w .  j av a2s . com*/
import android.hardware.Sensor;
import android.hardware.SensorEvent;
import android.hardware.SensorEventListener;
import android.hardware.SensorManager;

/**
 * accumulates and averages Magnetic and Acceleration SensorEvents and reports
 * back the device heading.
 * 
 * @author renard
 * 
 */
public class CompassSensorListener implements SensorEventListener {

  /**
   * receives azimuth values
   * 
   * @author renard
   * 
   */
  public interface DirectionListener {
    void onDirectionChanged(final double bearing);

    void onRollChanged(final float roll);

    void onPitchChanged(final float pitch);
    
    void onAccuracyChanged(Sensor sensor, int accuracy);
  }

  // number of values which are averaged
  private final int STACK_SIZE = 15;
  // arrays to keep track of the last Sensor Events
  private final float[][] mAccelerationValues = new float[STACK_SIZE][3];
  private final float[][] mMagneticValues = new float[STACK_SIZE][3];
  // current indexes into the arrays
  private int mAccelerationIndex = 0;
  private int mMagneticIndex = 0;
  // holder for temporary values
  private final float[] mMagnetic = new float[3];
  private final float[] mAcceleration = new float[3];
  float[] mMappedValues = new float[3];
  float[] mR = new float[9];
  float[] mMappedRotationMatrix = new float[9];

  private final DirectionListener mListener;

  // private int mScreenOrientation;

  /**
   * @param Listener
   *            receives direction updates
   * @param windowManager
   *            Needed for device screen rotation
   */
  public CompassSensorListener(final DirectionListener listener) {
    mListener = listener;
  }

  @Override
  public void onSensorChanged(SensorEvent event) {
    switch (event.sensor.getType()) {
    case Sensor.TYPE_ACCELEROMETER:
      System.arraycopy(event.values, 0, mAccelerationValues[mAccelerationIndex++], 0, 3);
      if (mAccelerationIndex >= STACK_SIZE) {
        mAccelerationIndex = 0;
      }
      break;
    case Sensor.TYPE_MAGNETIC_FIELD:
      System.arraycopy(event.values, 0, mMagneticValues[mMagneticIndex++], 0, 3);
      if (mMagneticIndex >= STACK_SIZE) {
        mMagneticIndex = 0;
      }
      break;
    }

    average(mMagneticValues, mMagnetic);
    average(mAccelerationValues, mAcceleration);
    // final int rotation =
    // mWindowManager.getDefaultDisplay().getOrientation();
    // double azimuth = CompassHelper.CalculateHeading(mMagnetic,
    // mAcceleration, mScreenOrientation);
    float[] values = calculateOrientation();
    // mListener.onDirectionChanged(Math.toDegrees(azimuth));
    mListener.onDirectionChanged(values[0]);
    mListener.onPitchChanged(values[1]);
    mListener.onRollChanged(values[2]);
  }

  private float[] calculateOrientation() {

    if (SensorManager.getRotationMatrix(mR, null, mAcceleration, mMagnetic)) {

      // switch (mScreenOrientation) {
      // // portrait - normal
      // case Surface.ROTATION_0:
      // SensorManager.remapCoordinateSystem(mRotationMatrix,
      // SensorManager.AXIS_X, SensorManager.AXIS_Z,
      // mMappedRotationMatrix);
      // break;
      // // rotated left (landscape - keys to bottom)
      // case Surface.ROTATION_90:
      // SensorManager.remapCoordinateSystem(mRotationMatrix,
      // SensorManager.AXIS_Z, SensorManager.AXIS_MINUS_X,
      // mMappedRotationMatrix);
      // break;
      // // upside down
      // case Surface.ROTATION_180:
      // SensorManager.remapCoordinateSystem(mRotationMatrix,
      // SensorManager.AXIS_X, SensorManager.AXIS_Z,
      // mMappedRotationMatrix);
      // break;
      // // rotated right
      // case Surface.ROTATION_270:
      // SensorManager.remapCoordinateSystem(mRotationMatrix,
      // SensorManager.AXIS_MINUS_Z, SensorManager.AXIS_X,
      // mMappedRotationMatrix);
      // break;
      //
      // default:
      // break;
      // }

      // SensorManager.remapCoordinateSystem(mRotationMatrix,
      // SensorManager.AXIS_X, SensorManager.AXIS_Z,
      // mMappedRotationMatrix);

      SensorManager.getOrientation(mR, mMappedValues);

      // float degrees0to360 =
      // (float)(Math.toDegrees(mMappedValues[0])+180);
      // degrees0to360 = CompassFilter.filterSensorValue(degrees0to360);

      // Convert from Radians to Degrees.
      mMappedValues[0] = (float) Math.toDegrees(mMappedValues[0]);
      mMappedValues[1] = (float) Math.toDegrees(mMappedValues[1]);
      mMappedValues[2] = (float) Math.toDegrees(mMappedValues[2]);
    }
    return mMappedValues;
  }

  public void setScreenOrientation(final int orientation) {
    // mScreenOrientation = orientation;
  }

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

  }

  public void average(float[][] values, float[] outAverage) {
    outAverage[0] = 0;
    outAverage[1] = 0;
    outAverage[2] = 0;
    for (int i = 0; i < values.length; i++) {
      for (int j = 0; j < 3; j++) {
        outAverage[j] += values[i][j];
      }
    }
    outAverage[0] /= values.length;
    outAverage[1] /= values.length;
    outAverage[2] /= values.length;
  }
}

Java Source Code List

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