Android FlashLight Torch Application Development Tutorial

by proxyadmin · Published December 5, 2016 · Updated July 6, 2021

With help of android Camera and Camera.Parameters, we will develop Android Flashlight Torch Application.

FlashLight Application

1. Preparing Application Manifest File

For accessing Camera, we need to declare uses-permission to use it along with uses-feature.

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.androidsrc.flashlightsample"
    android:versionCode="1"
    android:versionName="1.0" >
 
    <uses-sdk
        android:minSdkVersion="14"
        android:targetSdkVersion="19" />
 
    <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=".MainActivity"
            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>

<?xml version="1.0" encoding="utf-8"?>

<manifest xmlns:android="http://schemas.android.com/apk/res/android"

package="com.androidsrc.flashlightsample"

android:versionCode="1"

android:versionName="1.0" >

<uses-sdk

android:minSdkVersion="14"

android:targetSdkVersion="19" />

<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=".MainActivity"

android:label="@string/app_name" >

<intent-filter>

</intent-filter>

</activity>

</application>

</manifest>

2. Preparing UI Components

Our applications main activity layout will have ImageButton for switching on/off of flashlight. Modify your /res/layout/activity_main.xml as below.

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context="com.androidsrc.flashlightsample.MainActivity" >
 
    <ImageButton
        android:id="@+id/flashlight_button"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_centerInParent="true"
        android:background="@null"
        android:contentDescription="@null"
        android:src="@drawable/flashlight_off" />
 
    <TextView
        android:id="@+id/info"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentBottom="true"
        android:layout_centerHorizontal="true"
        android:layout_marginBottom="20dp"
        android:text="http://cs2guru.com"
        android:textColor="@android:color/holo_blue_dark" />
 
</RelativeLayout>

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"

xmlns:tools="http://schemas.android.com/tools"

android:layout_width="match_parent"

android:layout_height="match_parent"

tools:context="com.androidsrc.flashlightsample.MainActivity" >

<ImageButton

android:id="@+id/flashlight_button"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:layout_centerInParent="true"

android:background="@null"

android:contentDescription="@null"

android:src="@drawable/flashlight_off" />

<TextView

android:id="@+id/info"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:layout_alignParentBottom="true"

android:layout_centerHorizontal="true"

android:layout_marginBottom="20dp"

android:text="http://cs2guru.com"

android:textColor="@android:color/holo_blue_dark" />

</RelativeLayout>

For designing ImageButton image resource with 3D effect, I have opted layer-list drawable from this stackoverflow by savanto.

We will two create drawable for on and off torch state.

/res/drawable/flashlight_off.xml

<?xml version="1.0" encoding="utf-8"?>
<layer-list xmlns:android="http://schemas.android.com/apk/res/android">
 
  <!-- Outside border/shadow -->
  <item>
    <shape android:shape="oval">
      <size android:width="200dp" android:height="200dp" />
      <gradient android:angle="90" android:startColor="#f4f4f4" android:endColor="#b9b9b9" />
    </shape>
  </item>
 
  <!-- Inset -->
  <item android:top="1dp" android:left="1dp" android:right="1dp" android:bottom="1dp">
      <shape android:shape="oval">
        <gradient android:angle="90" android:startColor="#dcdcdc" android:endColor="#c9c9c9" />
      </shape>
  </item>
 
  <!-- Inside border/shadow -->
  <item android:top="15dp" android:left="15dp" android:right="15dp" android:bottom="15dp">
    <shape android:shape="oval">
      <gradient android:angle="90" android:startColor="#8c8c8c" android:endColor="#cbcbcb" />
    </shape>
  </item>
 
  <!-- Main button -->
  <item android:top="16dp" android:left="16dp" android:right="16dp" android:bottom="16dp">
    <shape android:shape="oval">
      <solid android:color="#ffffff" />
    </shape>
  </item>
 
  <!-- Button image -->
  <item android:top="70dp" android:left="70dp" android:right="70dp" android:bottom="70dp">
    <shape android:shape="rectangle">
      <solid android:color="#FF3333" />
      <corners android:radius="20dp" />
    </shape>
  </item>
 
  <item android:top="75dp" android:left="75dp" android:right="75dp" android:bottom="75dp">
    <shape android:shape="rectangle">
      <solid android:color="#ffffff" />
      <corners android:radius="20dp" />
    </shape>
  </item>
 
  <item android:top="80dp" android:left="80dp" android:right="80dp" android:bottom="80dp">
    <shape android:shape="rectangle">
      <solid android:color="#FF3333" />
      <corners android:radius="20dp" />
    </shape>
  </item>
 
</layer-list>

<?xml version="1.0" encoding="utf-8"?>

<layer-list xmlns:android="http://schemas.android.com/apk/res/android">

<item>

</shape>

</item>

</shape>

</item>

</shape>

</item>

</shape>

</item>

</shape>

</item>

</shape>

</item>

</shape>

</item>

</layer-list>

/res/drawable/flashlight_on.xml

<?xml version="1.0" encoding="utf-8"?>
<layer-list xmlns:android="http://schemas.android.com/apk/res/android">
 
  <!-- Outside border/shadow -->
  <item>
    <shape android:shape="oval">
      <size android:width="200dp" android:height="200dp" />
      <gradient android:angle="90" android:startColor="#f4f4f4" android:endColor="#b9b9b9" />
    </shape>
  </item>
 
  <!-- Inset -->
  <item android:top="1dp" android:left="1dp" android:right="1dp" android:bottom="1dp">
      <shape android:shape="oval">
        <gradient android:angle="90" android:startColor="#dcdcdc" android:endColor="#c9c9c9" />
      </shape>
  </item>
 
  <!-- Inside border/shadow -->
  <item android:top="15dp" android:left="15dp" android:right="15dp" android:bottom="15dp">
    <shape android:shape="oval">
      <gradient android:angle="90" android:startColor="#8c8c8c" android:endColor="#cbcbcb" />
    </shape>
  </item>
 
  <!-- Main button -->
  <item android:top="16dp" android:left="16dp" android:right="16dp" android:bottom="16dp">
    <shape android:shape="oval">
      <solid android:color="#ffffff" />
    </shape>
  </item>
 
  <!-- Button image -->
  <item android:top="70dp" android:left="70dp" android:right="70dp" android:bottom="70dp">
    <shape android:shape="rectangle">
      <solid android:color="#00CC66" />
      <corners android:radius="20dp" />
    </shape>
  </item>
 
  <item android:top="75dp" android:left="75dp" android:right="75dp" android:bottom="75dp">
    <shape android:shape="rectangle">
      <solid android:color="#ffffff" />
      <corners android:radius="20dp" />
    </shape>
  </item>
 
  <item android:top="80dp" android:left="80dp" android:right="80dp" android:bottom="80dp">
    <shape android:shape="rectangle">
      <solid android:color="#00CC66" />
      <corners android:radius="20dp" />
    </shape>
  </item>
 
</layer-list>

<?xml version="1.0" encoding="utf-8"?>

<layer-list xmlns:android="http://schemas.android.com/apk/res/android">

<item>

</shape>

</item>

</shape>

</item>

</shape>

</item>

</shape>

</item>

</shape>

</item>

</shape>

</item>

</shape>

</item>

</layer-list>

3. Preparing Source Files

In our application launcher activity MainActivity.java, we will use a boolean variable to toggle between Camera flash state. We need to check first if flash feature PackageManager.FEATURE_CAMERA_FLASH is supported by your device hardware. Make sure to set View.OnClickListener for your ImageButton. On Clicking of ImageButton, if flash light is OFF we will turn it on by setting paramters Parameters.FLASH_MODE_TORCH and calling startPreview(). If flash light is ON, we will turn it off setting Parameters.FLASH_MODE_OFF and call stopPreview(). We need to make sure to release camera if held while exiting activity.

package com.androidsrc.flashlightsample;
 
import android.app.Activity;
import android.app.AlertDialog;
import android.content.DialogInterface;
import android.content.DialogInterface.OnClickListener;
import android.content.pm.PackageManager;
import android.hardware.Camera;
import android.hardware.Camera.Parameters;
import android.os.Bundle;
import android.view.View;
import android.widget.ImageButton;
 
public class MainActivity extends Activity {
 
    private Camera camera;
    private Camera.Parameters parameters;
    private ImageButton flashLightButton;
    boolean isFlashLightOn = false;
 
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
 
        flashLightButton = (ImageButton) findViewById(R.id.flashlight_button);
        flashLightButton.setOnClickListener(new FlashOnOffListener());
 
        if (isFlashSupported()) {
            camera = Camera.open();
            parameters = camera.getParameters();
        } else {
            showNoFlashAlert();
        }
    }
 
    private class FlashOnOffListener implements View.OnClickListener {
 
        @Override
        public void onClick(View v) {
            if (isFlashLightOn) {
                flashLightButton.setImageResource(R.drawable.flashlight_off);
                parameters.setFlashMode(Parameters.FLASH_MODE_OFF);
                camera.setParameters(parameters);
                camera.stopPreview();
                isFlashLightOn = false;
            } else {
                flashLightButton.setImageResource(R.drawable.flashlight_on);
                parameters.setFlashMode(Parameters.FLASH_MODE_TORCH);
                camera.setParameters(parameters);
                camera.startPreview();
                isFlashLightOn = true;
            }
 
        }
 
    }
 
    private void showNoFlashAlert() {
        new AlertDialog.Builder(this)
                .setMessage("Your device hardware does not support flashlight!")
                .setIcon(android.R.drawable.ic_dialog_alert).setTitle("Error")
                .setPositiveButton("Ok", new OnClickListener() {
 
                    @Override
                    public void onClick(DialogInterface dialog, int which) {
                        dialog.dismiss();
                        finish();
                    }
                }).show();
    }
 
    private boolean isFlashSupported() {
        PackageManager pm = getPackageManager();
        return pm.hasSystemFeature(PackageManager.FEATURE_CAMERA_FLASH);
    }
 
    @Override
    protected void onDestroy() {
        if (camera != null) {
            camera.stopPreview();
            camera.release();
            camera = null;
        }
        super.onDestroy();
    }
}

package com.androidsrc.flashlightsample;

import android.app.Activity;

import android.app.AlertDialog;

import android.content.DialogInterface;

import android.content.DialogInterface.OnClickListener;

import android.content.pm.PackageManager;

import android.hardware.Camera;

import android.hardware.Camera.Parameters;

import android.os.Bundle;

import android.view.View;

import android.widget.ImageButton;

public class MainActivity extends Activity {

private Camera camera;

private Camera.Parameters parameters;

private ImageButton flashLightButton;

boolean isFlashLightOn = false;

@Override

protected void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.activity_main);

flashLightButton = (ImageButton) findViewById(R.id.flashlight_button);

flashLightButton.setOnClickListener(new FlashOnOffListener());

if (isFlashSupported()) {

camera = Camera.open();

parameters = camera.getParameters();

} else {

showNoFlashAlert();

}

private class FlashOnOffListener implements View.OnClickListener {

@Override

public void onClick(View v) {

if (isFlashLightOn) {

flashLightButton.setImageResource(R.drawable.flashlight_off);

parameters.setFlashMode(Parameters.FLASH_MODE_OFF);

camera.setParameters(parameters);

camera.stopPreview();

isFlashLightOn = false;

} else {

flashLightButton.setImageResource(R.drawable.flashlight_on);

parameters.setFlashMode(Parameters.FLASH_MODE_TORCH);

camera.setParameters(parameters);

camera.startPreview();

isFlashLightOn = true;

}

private void showNoFlashAlert() {

new AlertDialog.Builder(this)

.setMessage("Your device hardware does not support flashlight!")

.setIcon(android.R.drawable.ic_dialog_alert).setTitle("Error")

.setPositiveButton("Ok", new OnClickListener() {

@Override

public void onClick(DialogInterface dialog, int which) {

dialog.dismiss();

finish();

}

}).show();

}

private boolean isFlashSupported() {

PackageManager pm = getPackageManager();

return pm.hasSystemFeature(PackageManager.FEATURE_CAMERA_FLASH);

}

@Override

protected void onDestroy() {

if (camera != null) {

camera.stopPreview();

camera.release();

camera = null;

}

super.onDestroy();

}

4. Building and Running Application

Now build and run your applications, you are done with Android FlashLight Torch Application using Camera and Camera.Parameters.

Android FlashLight Torch Application Development Tutorial

FlashLight Application

1. Preparing Application Manifest File

2. Preparing UI Components

3. Preparing Source Files

4. Building and Running Application

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Android FlashLight Torch Application Development Tutorial

FlashLight Application

1. Preparing Application Manifest File

2. Preparing UI Components

3. Preparing Source Files

4. Building and Running Application

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