//main.xml
android:layout_width="fill_parent"
android:layout_height="fill_parent">
android:id="@+id/direction"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerInParent="true"
android:textSize="64dip"
android:textStyle="bold"
/>
android:id="@+id/values"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true"
/>
package app.test;
import android.app.Activity;
import android.hardware.Sensor;
import android.hardware.SensorEvent;
import android.hardware.SensorEventListener;
import android.hardware.SensorManager;
import android.os.Bundle;
import android.widget.TextView;
public class Test extends Activity implements SensorEventListener {
private SensorManager mSensorManager;
private Sensor mAccelerometer, mField;
private TextView valueView, directionView;
private float[] mGravity;
private float[] mMagnetic;
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
mSensorManager = (SensorManager)getSystemService(SENSOR_SERVICE);
mAccelerometer = mSensorManager.getDefaultSensor(Sensor.TYPE_ACCELEROMETER);
mField = mSensorManager.getDefaultSensor(Sensor.TYPE_MAGNETIC_FIELD);
valueView = (TextView)findViewById(R.id.values);
directionView = (TextView)findViewById(R.id.direction);
}
protected void onResume() {
super.onResume();
mSensorManager.registerListener(this, mAccelerometer, SensorManager.SENSOR_DELAY_UI);
mSensorManager.registerListener(this, mField, SensorManager.SENSOR_DELAY_UI);
}
protected void onPause() {
super.onPause();
mSensorManager.unregisterListener(this);
}
private void updateDirection() {
float[] temp = new float[9];
float[] R = new float[9];
//Load rotation matrix into R
SensorManager.getRotationMatrix(temp, null, mGravity, mMagnetic);
//Remap to camera's point-of-view
SensorManager.remapCoordinateSystem(temp, SensorManager.AXIS_X, SensorManager.AXIS_Z, R);
//Return the orientation values
float[] values = new float[3];
SensorManager.getOrientation(R, values);
//Convert to degrees
for (int i=0; i < values.length; i++) {
Double degrees = (values[i] * 180) / Math.PI;
values[i] = degrees.floatValue();
}
//Display the compass direction
directionView.setText( getDirectionFromDegrees(values[0]) );
//Display the raw values
valueView.setText(String.format("Azimuth: %1$1.2f, Pitch: %2$1.2f, Roll: %3$1.2f",
values[0], values[1], values[2]));
}
private String getDirectionFromDegrees(float degrees) {
if(degrees >= -22.5 && degrees < 22.5) { return "N"; }
if(degrees >= 22.5 && degrees < 67.5) { return "NE"; }
if(degrees >= 67.5 && degrees < 112.5) { return "E"; }
if(degrees >= 112.5 && degrees < 157.5) { return "SE"; }
if(degrees >= 157.5 || degrees < -157.5) { return "S"; }
if(degrees >= -157.5 && degrees < -112.5) { return "SW"; }
if(degrees >= -112.5 && degrees < -67.5) { return "W"; }
if(degrees >= -67.5 && degrees < -22.5) { return "NW"; }
return null;
}
public void onAccuracyChanged(Sensor sensor, int accuracy) { }
public void onSensorChanged(SensorEvent event) {
switch(event.sensor.getType()) {
case Sensor.TYPE_ACCELEROMETER:
mGravity = event.values.clone();
break;
case Sensor.TYPE_MAGNETIC_FIELD:
mMagnetic = event.values.clone();
break;
default:
return;
}
if(mGravity != null && mMagnetic != null) {
updateDirection();
}
}
}