Detect phone flipping

By checking Android's build-in accelerometer sensor status, we can detect the phone flipping (face-up/face-down).

package com.exercise.AndroidDetectFlipping;

import java.util.List;

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 AndroidDetectFlipping extends Activity {
 
 SensorManager sensorManager;
  Sensor accelerometerSensor;
  boolean accelerometerPresent;

  TextView face;
 
  /** Called when the activity is first created. */
  @Override
  public void onCreate(Bundle savedInstanceState) {
      super.onCreate(savedInstanceState);
      setContentView(R.layout.main);
    
      face = (TextView)findViewById(R.id.face);
    
      sensorManager = (SensorManager)getSystemService(SENSOR_SERVICE);
      List<Sensor> sensorList = sensorManager.getSensorList(Sensor.TYPE_ACCELEROMETER);
      if(sensorList.size() > 0){
       accelerometerPresent = true;
       accelerometerSensor = sensorList.get(0);  
      }
      else{
       accelerometerPresent = false;  
       face.setText("No accelerometer present!");
      }
  }

  @Override
 protected void onResume() {
  // TODO Auto-generated method stub
  super.onResume();
  if(accelerometerPresent){
   sensorManager.registerListener(accelerometerListener, accelerometerSensor, SensorManager.SENSOR_DELAY_NORMAL);  
  }
 }

 @Override
 protected void onStop() {
  // TODO Auto-generated method stub
  super.onStop();
  if(accelerometerPresent){
   sensorManager.unregisterListener(accelerometerListener);  
  }
 }
 
 private SensorEventListener accelerometerListener = new SensorEventListener(){

  @Override
  public void onAccuracyChanged(Sensor arg0, int arg1) {
   // TODO Auto-generated method stub
   
  }

  @Override
  public void onSensorChanged(SensorEvent arg0) {
   // TODO Auto-generated method stub
   float z_value = arg0.values[2];
   if (z_value >= 0){
    face.setText("Face UP");
   }
   else{
    face.setText("Face DOWN");
   }
  }};

}

<?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:layout_width="fill_parent"
  android:layout_height="wrap_content"
  android:text="@string/hello"
  />
<TextView
  android:id="@+id/face"
  android:layout_width="fill_parent"
  android:layout_height="wrap_content"
  android:text="@string/hello"
  />
</LinearLayout>

Download the files.

Related articles:
- Get the list of available sensors, SensorManager.getSensorList()
- Detect Android Accelerometer sensor changed
- Detect Shaking