Change the System Brightness Programmatically

Question

I want to change the system brightness programmatically. For that purpose I am using this code:

WindowManager.LayoutParams lp = window.getAttributes();
lp.screenBrightness = (255);
window.setAttributes(lp);

because I heard that max value is 255.

but it does nothing. Please suggest any thing that can change the brightness. Thanks

Answer 1

You can use following :

//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;

In your onCreate write:

//Get the content resolver
cResolver = getContentResolver();

//Get the current window
window = getWindow();

    try
            {
               // To handle the auto
                Settings.System.putInt(cResolver,
                Settings.System.SCREEN_BRIGHTNESS_MODE, Settings.System.SCREEN_BRIGHTNESS_MODE_MANUAL);
 //Get the current system brightness
                brightness = Settings.System.getInt(cResolver, Settings.System.SCREEN_BRIGHTNESS);
            } 
            catch (SettingNotFoundException e) 
            {
                //Throw an error case it couldn't be retrieved
                Log.e("Error", "Cannot access system brightness");
                e.printStackTrace();
            }

Write the code to monitor the change in brightness.

then you can set the updated brightness as follows:

           //Set the system brightness using the brightness variable value
            Settings.System.putInt(cResolver, Settings.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);

Permission in manifest:

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

For API >= 23, you need to request the permission through Settings Activity, described here: Can't get WRITE_SETTINGS permission