Android Proximity Sensor Example


Every android mobile is shipped with sensors to measure various environmental conditions. In this example we will see how to use the proximity sensors in an android application. Proximity sensors would be useful to reveal the nearness of an object to the phone. We might often experience that our phone screen would turn off when we bring the phone to our ears when we are in a call and the screen will turn on when we take it back. This is because the proximity sensor recognizes the object near the phone.

In this example we will change the image in the ImageView w.r.t the nearness of any object to the phone. Check the sensor functionality by covering the sensor region (mostly the top left of the phone) with your hand .
So lets start

1.Create a new project File ->New -> Project ->Android ->Android Application Project. While creating the new project, name the activity as SensorActivity(SensorActivity.java) and layout as sensor_screen.xml.

2.Now let us design the UI for the SensorActivity i.e sensor_screen.xml with an ImageView.Have two images in drawable folder to differentiate near and far activity.

sensor_screen.xml:


<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
tools:context=".SensorActivity" >

<ImageView
android:id="@+id/imageView1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:src="@drawable/far" />

</RelativeLayout>

3.Now in the SensorActivity we access the device sensor using SensorManager, an instance of this class is got by calling getSystemService(SENSOR_SERVICE) . We implement the class with the SensorEventListener interface to override its methods to do actions on sensor value change.

SensorActivity.java:

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.ImageView;

public class SensorActivity extends Activity implements SensorEventListener {
 private SensorManager mSensorManager;
 private Sensor mSensor;
 ImageView iv;

 @Override
 protected void onCreate(Bundle savedInstanceState) {
  // TODO Auto-generated method stub
  super.onCreate(savedInstanceState);
  setContentView(R.layout.sensor_screen);
  mSensorManager = (SensorManager) getSystemService(SENSOR_SERVICE);
  mSensor = mSensorManager.getDefaultSensor(Sensor.TYPE_PROXIMITY);
  iv = (ImageView) findViewById(R.id.imageView1);
 }

 protected void onResume() {
  super.onResume();
  mSensorManager.registerListener(this, mSensor,
    SensorManager.SENSOR_DELAY_NORMAL);
 }

 protected void onPause() {
  super.onPause();
  mSensorManager.unregisterListener(this);
 }

 public void onAccuracyChanged(Sensor sensor, int accuracy) {
 }

 public void onSensorChanged(SensorEvent event) {
  if (event.values[0] == 0) {
   iv.setImageResource(R.drawable.near);
  } else {
   iv.setImageResource(R.drawable.far);
  }
 }
}

4.Run the project by rightclicking project Run as → android project.

Output:

The output of this example would be similar to the one as follows:

 


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