Change Brightness of a Screen Using SeekBar in Android Studio

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This article explains how to use a seek bar to change the screen brightness in Android Studio. First, you need to use a SeekBar in an XML file and create its id in a Java class file. Now get the content resolver object by calling getContentResolver() and the current window by calling the getWindow() methods. To get the brightness of a screen use the getint() method that returns the current brightness of a system. You will the brightness to the setProgress() method as an argument. Now set the seekbar on setOnSeekBarChangeListener() to change the brightness of a screen. In the onProgress() method set the progress of the seek bar in percentage. Step 1 Now create an XML file and write this:

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

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

android:layout_width = "fill_parent"

android:layout_height = "fill_parent"

android:background = "#475d5d"

android:orientation = "vertical" >

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

android:layout_margin = "5dp"

android:layout_width = "fill_parent"

android:layout_height = "wrap_content"

android:background = "#354d5d"

android:orientation = "vertical" >

< TextView

android:layout_height = "wrap_content"

android:layout_width = "wrap_content"

android:text = "BrighnessControl"

android:layout_marginLeft = "5dp"

android:layout_marginTop = "10dp"

android:textColor = "#ffffff"

android:textStyle = "bold" >

</ TextView >

< SeekBar

android:layout_width = "300dp"

android:layout_height = "wrap_content"

android:id = "@+id/seekBar"

android:progress = "0"

android:max = "100"

android:layout_marginTop = "20dp"

android:indeterminate = "false"

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

android:layout_width = "fill_parent"

android:layout_height = "25dp"

android:background = "#354d5d"

android:orientation = "horizontal"

android:layout_marginTop = "20dp" >

< TextView

android:layout_height = "wrap_content"

android:layout_width = "wrap_content"

android:text = "0"

android:textStyle = "bold"

android:textSize = "12dp"

android:textColor = "#ffffff"

android:layout_marginLeft = "25dp" />

< TextView

android:layout_height = "wrap_content"

android:layout_width = "wrap_content"

android:textSize = "12dp"

android:text = "20"

android:textColor = "#ffffff"

android:layout_marginLeft = "30dp" />

< TextView

android:layout_height = "wrap_content"

android:textSize = "12dp"

android:layout_width = "wrap_content"

android:text = "40"

android:textColor = "#ffffff"

android:layout_marginLeft = "32dp" />

< TextView

android:layout_height = "wrap_content"

android:textSize = "12dp"

android:layout_width = "wrap_content"

android:text = "60"

android:textColor = "#ffffff"

android:layout_marginLeft = "36dp" />

< TextView

android:textSize = "12dp"

android:layout_height = "wrap_content"

android:layout_width = "wrap_content"

android:text = "80"

android:textColor = "#ffffff"

android:layout_marginLeft = "38dp" />

< TextView

android:textSize = "12dp"

android:layout_height = "wrap_content"

android:layout_width = "wrap_content"

android:text = "100"

android:textColor = "#ffffff"

android:layout_marginLeft = "42dp" />

</ LinearLayout >

< TextView

android:layout_width = "fill_parent"

android:layout_height = "wrap_content"

android:text = ""

android:id = "@+id/txtPercentage" />

</ LinearLayout >

First, you need to use the SeekBar in the XML file and create its id in the Java class file. Now get the content resolver object by calling getContentResolver() and the current window by calling the getWindow() methods. To get the brightness of a screen use the getint() method that returns the current brightness of a system. You will the brightness to the setProgress() method as an argument. Now set the seekbar on setOnSeekBarChangeListener() to change the brightness of a screen. In the onProgress() method set the progress of the seek bar in percentage.

import android.app.Activity;

import android.content.ContentResolver;

import android.os.Bundle;

import android.provider.Settings.SettingNotFoundException;

import android.provider.Settings.System;

import android.util.Log;

import android.view.Window;

import android.view.WindowManager.LayoutParams;

import android.widget.SeekBar;

import android.widget.SeekBar.OnSeekBarChangeListener;

import android.widget.TextView;

public class MainActivity extends Activity { //UI objects//

//Seek bar object

private SeekBar seekBar;

//Variable to store brightness value

private int brightness;

//Content resolver used as a handle to the system's settings

private ContentResolver cResolver;

//Window object, that will store a reference to the current window

private Window window;

TextView txtPerc;

/** Called when the activity is first created. */

@Override

public void onCreate(Bundle savedInstanceState)

super .onCreate(savedInstanceState);

setContentView(R.layout.activity_main);

//Instantiate seekbar object

seekBar = (SeekBar) findViewById(R.id.seekBar);

txtPerc = (TextView) findViewById(R.id.txtPercentage);

//Get the content resolver

cResolver = getContentResolver();

//Get the current window

window = getWindow();

//Set the seekbar range between 0 and 255

//seek bar settings//

//sets the range between 0 and 255

seekBar.setMax( 255 );

//set the seek bar progress to 1

seekBar.setKeyProgressIncrement( 1 );

//Get the current system brightness

brightness = System.getInt(cResolver, System.SCREEN_BRIGHTNESS);

catch (SettingNotFoundException e)

//Throw an error case it couldn't be retrieved

Log.e( "Error" , "Cannot access system brightness" );

e.printStackTrace();

//Set the progress of the seek bar based on the system's brightness

seekBar.setProgress(brightness);

//Register OnSeekBarChangeListener, so it can actually change values

seekBar.setOnSeekBarChangeListener( new OnSeekBarChangeListener()

public void onStopTrackingTouch(SeekBar seekBar)

//Set the system brightness using the brightness variable value

System.putInt(cResolver, System.SCREEN_BRIGHTNESS, brightness);

//Get the current window attributes

LayoutParams layoutpars = window.getAttributes();

//Set the brightness of this window

layoutpars.screenBrightness = brightness / ( float ) 255 ;

//Apply attribute changes to this window

window.setAttributes(layoutpars);

public void onStartTrackingTouch(SeekBar seekBar)

//Nothing handled here

public void onProgressChanged(SeekBar seekBar, int progress, boolean fromUser)

//Set the minimal brightness level

//if seek bar is 20 or any value below

if (progress<= 20 )

//Set the brightness to 20

brightness= 20 ;

else //brightness is greater than 20

//Set brightness variable based on the progress bar

brightness = progress;

//Calculate the brightness percentage

float perc = (brightness /( float ) 255 )* 100 ;

//Set the brightness percentage

txtPerc.setText(( int )perc + " %" );

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

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

package = "com.androidseekbarexample"

android:versionCode = "1"

android:versionName = "1.0" >

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

< uses-sdk

android:minSdkVersion = "7"

android:targetSdkVersion = "16" />

< application

android:allowBackup = "true"

android:icon = "@drawable/ic_launcher"

android:label = "@string/app_name"

android:theme = "@style/AppTheme" >

< activity

android:name = "com.androidseekbarexample.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 >

Step 4 When you run your project: