The document provides a tutorial on using the gyroscope sensor in Android development, detailing necessary code implementation for sensor management. It explains how to use SensorManager to access the gyroscope sensor and handle sensor events through an implemented SensorEventListener. Additionally, it covers registering and unregistering the sensor listener during activity lifecycle events.

1. Develop on Android
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Lesson : The gyroscope sensor

2. The gyroscope sensor
• In this lesson, you will learn to use the gyroscope sensor.
• For this, you will use the SensorManager and the sensor
type TYPE_GYROSCOPE.

3. The gyroscope sensor
• To use the gyroscope sensor, you have to get the sensor manager with the
method getSystemService() then get the sensor by default of type
TYPE_GYROSCOPE.
SensorManager sensorManager = (SensorManager)this.getSystemService (SENSOR_SERVICE);
Sensor sensorGyroscope = sensorManager.getDefaultSensor (Sensor.TYPE_GYROSCOPE);

4. The gyroscope sensor
• To get the values ofthe gyroscope, you have to implement
SensorEventListener and the methods onAccuracyChanged() and
onSensorChanged(). With this method, you can get the values of the
sensor :
extends Activity implements SensorEventListener {
public void onAccuracyChanged (Sensor sensor, int accuracy) {
}
public void onSensorChanged (SensorEvent event) {
// Values : event.values [0], event.values [1], event.values [2]
}

5. The gyroscope sensor
• When the application is paused (onPause() called) and when
it’s resumed (onResume() called), you have to respectively
unregister the listener and register it :
protected void onResume() {
sensorManager.registerListener (this, sensorGyroscope,
SensorManager.SENSOR_DELAY_GAME);
super.onResume();
}
protected void onPause() {
sensorManager.unregisterListener (this, sensorGyroscope);
super.onPause();
}

6. Layout main.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="fill_parent"
android:layout_height="fill_parent" >
<TextView
android:id="@+id/tv_output"
android:layout_width="fill_parent"
android:layout_height="match_parent" />
</LinearLayout>

7. File Main.java
public class Main extends Activity implements SensorEventListener {
private SensorManager sensorManager;
private Sensor sensorGyroscope;
private TextView tv_output;
public void onCreate (Bundle savedInstanceState) {
super.onCreate (savedInstanceState);
setContentView (R.layout.main);
tv_output = (TextView)findViewById (R.id.tv_output);
sensorManager = (SensorManager)this.getSystemService (SENSOR_SERVICE);
sensorGyroscope = sensorManager.getDefaultSensor (Sensor.TYPE_GYROSCOPE);
}
public void onSensorChanged (SensorEvent event) {
tv_output.setText ("0: " + event.values [0] + "n" + "1: " + event.values [1] + "n"
+ "2: " + event.values [2] + "n");
}

8. File Main.java
public void onAccuracyChanged (Sensor sensor, int accuracy) {
}
protected void onResume() {
sensorManager.registerListener (this, sensorGyroscope, SensorManager.SENSOR_DELAY_GAME);
super.onResume();
}
protected void onPause() {
sensorManager.unregisterListener (this, sensorGyroscope);
super.onPause();
}
}

9. Test on your mobile
Sensor_Gyroscope

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