How To Turn On/Off Camera LED / Flashlight In Android


           Your LED flash can be turned into a Flashlight using the Android camera parameter 'FLASH_MODE_TORCH'
This camera parameter initiates constant emission of light from the flash.
To access the device camera from the code we need to add below two permissions in AndroidManifest.xml

<uses-permission android:name="android.permission.CAMERA" />
<uses-feature android:name="android.hardware.camera" />

These are the steps followed in this example:
1. Check if the device supports camera
2. If the device supports camera, check if the camera supports flash
3. If the camera supports flash, add 'FLASH_MODE_TORCH' parameter and initiate camera preview.

I have added a toggle button to turn the camera on and off.
Tip:To know more about Android ToggleButton, go to this tutorial.

If the device does not have the camera[or] camera flash support, alert will be displayed to the user.
Tip: To know more about Android Alert dialogs, go to this tutorial.

AndroidManifest.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.example.flashlight"
    android:versionCode="1"
    android:versionName="1.0" >

    <uses-sdk
        android:minSdkVersion="8"
        android:targetSdkVersion="16" />

    <uses-permission android:name="android.permission.CAMERA" />

    <uses-feature android:name="android.hardware.camera" />

    <application
        android:allowBackup="true"
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name"
        android:theme="@style/AppTheme" >
        <activity
            android:name="com.example.flashlight.FlashlightActivity"
            android:label="@string/app_name" >
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>

</manifest>


Layout file:
flashlight.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/relativeLayout1"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent" >


    <ToggleButton
        android:id="@+id/togglebutton"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginLeft="20dp"
        android:layout_marginTop="20dp"
        android:onClick="onToggleClicked"
        android:textOff="Turn Flashlight on"
        android:textOn="Turn Flashlight off"/>

</RelativeLayout>

Activity class:
FlashlightActivity.java

package com.example.flashlight;

import android.app.Activity;
import android.app.AlertDialog;
import android.content.Context;
import android.content.DialogInterface;
import android.content.pm.PackageManager;
import android.hardware.Camera;
import android.hardware.Camera.Parameters;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.ToggleButton;

/**
 * @author Prabu 
 * July 30 2013
 * @version 1.0
 * 
 */
public class FlashlightActivity extends Activity {
 private Camera camera;
 private ToggleButton button;
 private final Context context = this;
 /**
  * @see android.app.Activity#onStop()
  */
 @Override
 protected void onStop() {
  super.onStop();
  if (camera != null) {
   camera.release();
  }
 }

 /**
  * @see android.app.Activity#onCreate(android.os.Bundle)
  */
 @Override
 public void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  setContentView(R.layout.flashlight);
  button = (ToggleButton) findViewById(R.id.togglebutton);
  
  final PackageManager pm = context.getPackageManager();
  if(!isCameraSupported(pm)){
   AlertDialog alertDialog = new AlertDialog.Builder(context).create();
   alertDialog.setTitle("No Camera");
      alertDialog.setMessage("The device's doesn't support camera.");
      alertDialog.setButton(RESULT_OK, "OK", new DialogInterface.OnClickListener() {
          public void onClick(final DialogInterface dialog, final int which) { 
           Log.e("err", "The device's doesn't support camera.");
          }
       });
   alertDialog.show();
  }
  camera = Camera.open();
 }
 public void onToggleClicked(View view) {
  PackageManager pm=context.getPackageManager();
  final Parameters p = camera.getParameters();
  if(isFlashSupported(pm)){
   boolean on = ((ToggleButton) view).isChecked();
   if (on) {
    Log.i("info", "torch is turn on!");
    p.setFlashMode(Parameters.FLASH_MODE_TORCH);
    camera.setParameters(p);
    camera.startPreview();
   } else {
    Log.i("info", "torch is turn off!");
    p.setFlashMode(Parameters.FLASH_MODE_OFF);
    camera.setParameters(p);
    camera.stopPreview();
   }
  }else{
   button.setChecked(false);
   AlertDialog alertDialog = new AlertDialog.Builder(context).create();
   alertDialog.setTitle("No Camera Flash");
      alertDialog.setMessage("The device's camera doesn't support flash.");
      alertDialog.setButton(RESULT_OK, "OK", new DialogInterface.OnClickListener() {
          public void onClick(final DialogInterface dialog, final int which) { 
           Log.e("err", "The device's camera doesn't support flash.");
          }
       });
   alertDialog.show();
  }
 }
 /**
  * @param packageManager
  * @return true <b>if the device support camera flash</b><br/>
  * false <b>if the device doesn't support camera flash</b>
  */
 private boolean isFlashSupported(PackageManager packageManager){ 
  // if device support camera flash?
  if (packageManager.hasSystemFeature(PackageManager.FEATURE_CAMERA_FLASH)) {
   return true;
  } 
  return false;
 }

 /**
  * @param packageManager
  * @return true <b>if the device support camera</b><br/>
  * false <b>if the device doesn't support camera</b>
  */
 private boolean isCameraSupported(PackageManager packageManager){
  // if device support camera?
  if (packageManager.hasSystemFeature(PackageManager.FEATURE_CAMERA)) {
   return true;
  } 
  return false;
 }
}


Output:
Flashlight off
Flashlight OFF

Flashlight on
Flashlight ON

No camera error



Source code of this example:
FlashLight.zip






Reactions:

2 comments :

  1. Thanks!!! you're great!

    ReplyDelete
  2. Hi,
    would you please tell me how to test if the camera is on or off.
    Thanks

    ReplyDelete

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