Android Change Screen Brightness Use Seekbar Example Windows Tricks

This example will tell you how to use the android Seekbar to adjust the screen brightness. This example only takes effect on real physical android device, it will not take effect in the android emulator.

If you can not watch the above video, you can see it on the youtube URL https://youtu.be/bxEwuZJdG5Y.

When you drag the Seekbar, the android device screen brightness will be changed. And the current screen brightness value will be shown in the text view above the seekbar.

Table of Contents

1. Layout XML File.

activity_change_screen_brightness_use_seekbar.xml

<LinearLayout
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:orientation="vertical">

    <TextView
        android:id="@+id/change_screen_brightness_value_text_view"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:gravity="center"
        android:layout_gravity="center_vertical"
        android:layout_marginTop="100dp"/>

    <SeekBar
        android:id="@+id/change_screen_brightness_seekbar"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginTop="20dp"/>

</LinearLayout>

2. Activity Java File.

ChangeScreenBrightnessUseSeekbarActivity.java

package com.dev2qa.example.screen.brightness;

import android.content.Context;
import android.content.Intent;
import android.os.Bundle;
import android.provider.Settings;
import android.support.v7.app.AppCompatActivity;
import android.widget.SeekBar;
import android.widget.TextView;

import com.dev2qa.example.R;

public class ChangeScreenBrightnessUseSeekbarActivity extends AppCompatActivity {

    private static final String SCREEN_BRIGHTNESS_VALUE_PREFIX = "Current device screen brightness value is ";

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_change_screen_brightness_use_seekbar);

        setTitle("dev2qa.com - Seekbar Change Screen Brightness Example.");

        // Get display screen brightness value text view object.
        final TextView screenBrightnessValueTextView = (TextView)findViewById(R.id.change_screen_brightness_value_text_view);

        // Get the seekbar instance.
        SeekBar seekBar = (SeekBar)findViewById(R.id.change_screen_brightness_seekbar);
        seekBar.setOnSeekBarChangeListener(new SeekBar.OnSeekBarChangeListener() {
            @Override
            public void onProgressChanged(SeekBar seekBar, int i, boolean b) {

                Context context = getApplicationContext();

                boolean canWriteSettings = Settings.System.canWrite(context);

                if(canWriteSettings) {

                    // Because max screen brightness value is 255
                    // But max seekbar value is 100, so need to convert.
                    int screenBrightnessValue = i*255/100;

                    // Set seekbar adjust screen brightness value in the text view.
                    screenBrightnessValueTextView.setText(SCREEN_BRIGHTNESS_VALUE_PREFIX + screenBrightnessValue);

                    // Change the screen brightness change mode to manual.
                    Settings.System.putInt(context.getContentResolver(), Settings.System.SCREEN_BRIGHTNESS_MODE, Settings.System.SCREEN_BRIGHTNESS_MODE_MANUAL);
                    // Apply the screen brightness value to the system, this will change the value in Settings ---> Display ---> Brightness level.
                    // It will also change the screen brightness for the device.
                    Settings.System.putInt(context.getContentResolver(), Settings.System.SCREEN_BRIGHTNESS, screenBrightnessValue);
                }else
                {
                    // Show Can modify system settings panel to let user add WRITE_SETTINGS permission for this app.
                    Intent intent = new Intent(Settings.ACTION_MANAGE_WRITE_SETTINGS);
                    context.startActivity(intent);
                }
            }

            @Override
            public void onStartTrackingTouch(SeekBar seekBar) {

            }

            @Override
            public void onStopTrackingTouch(SeekBar seekBar) {

            }
        });

        //Getting Current screen brightness.
        int currBrightness = Settings.System.getInt(getContentResolver(),Settings.System.SCREEN_BRIGHTNESS,0);
        // Set current screen brightness value in the text view.
        screenBrightnessValueTextView.setText( SCREEN_BRIGHTNESS_VALUE_PREFIX + currBrightness);
        // Set current screen brightness value to seekbar progress.
        seekBar.setProgress(currBrightness);
    }
}

3. AndroidManifest.xml File.

AndroidManifest.xml

<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.dev2qa.example">

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

    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:roundIcon="@mipmap/ic_launcher_round"
        android:supportsRtl="true"
        android:theme="@style/AppTheme">
        
        <activity android:name=".screen.brightness.ChangeScreenBrightnessUseSeekbarActivity">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

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

</manifest>

References:

How To Grant Write Settings Permission In Android

1. Layout XML File.

2. Activity Java File.

3. AndroidManifest.xml File.

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