Using Android device build-in light sensor

It's a simple light meter Using Android device build-in light sensor. A ProgressBar is defined in main.xml as a indicator of the light sensor. The default value of 100 defined in android:max is a dummy value, it will be updated after lightSensor.getMaximumRange(). The updated reading will be be read in lightSensorEventListener, and update the ProgressBar accordingly.

package com.AndroidLightSensor;

import android.app.Activity;
import android.content.Context;
import android.hardware.Sensor;
import android.hardware.SensorEvent;
import android.hardware.SensorEventListener;
import android.hardware.SensorManager;
import android.os.Bundle;
import android.widget.ProgressBar;
import android.widget.TextView;
import android.widget.Toast;

public class AndroidLightSensorActivity extends Activity {
 
 ProgressBar lightMeter;
 TextView textMax, textReading;
 
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        lightMeter = (ProgressBar)findViewById(R.id.lightmeter);
        textMax = (TextView)findViewById(R.id.max);
        textReading = (TextView)findViewById(R.id.reading);
        
        SensorManager sensorManager 
        = (SensorManager)getSystemService(Context.SENSOR_SERVICE);
        Sensor lightSensor 
        = sensorManager.getDefaultSensor(Sensor.TYPE_LIGHT);
     
        if (lightSensor == null){
         Toast.makeText(AndroidLightSensorActivity.this, 
           "No Light Sensor! quit-", 
           Toast.LENGTH_LONG).show();
        }else{
         float max =  lightSensor.getMaximumRange();
         lightMeter.setMax((int)max);
         textMax.setText("Max Reading: " + String.valueOf(max));
         
         sensorManager.registerListener(lightSensorEventListener, 
           lightSensor, 
           SensorManager.SENSOR_DELAY_NORMAL);
         
        }
    }
    
    SensorEventListener lightSensorEventListener
    = new SensorEventListener(){

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

  @Override
  public void onSensorChanged(SensorEvent event) {
   // TODO Auto-generated method stub
   if(event.sensor.getType()==Sensor.TYPE_LIGHT){
    float currentReading = event.values[0];
    lightMeter.setProgress((int)currentReading);
    textReading.setText("Current Reading: " + String.valueOf(currentReading));
   }
  }
     
    };
}

<?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"
    />
<ProgressBar
    android:id="@+id/lightmeter"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:padding="20dp"
    style="?android:attr/progressBarStyleHorizontal"
    android:max="100"
    android:progress="0"
    />
<TextView  
    android:id="@+id/max"
    android:layout_width="fill_parent" 
    android:layout_height="wrap_content" 
    />
<TextView  
    android:id="@+id/reading"
    android:layout_width="fill_parent" 
    android:layout_height="wrap_content" 
    />
</LinearLayout>