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

I had the same problem.

Two solutions:

here, brightness =(int) 0 to 100 range as i am using progressbar

1 SOLUTION

float brightness = brightness / (float)255; WindowManager.LayoutParams lp = getWindow().getAttributes();         lp.screenBrightness = brightness;         getWindow().setAttributes(lp); 

2 SOLUTION

I just used dummy activity to call when my progress bar stop seeking.

 Intent intent = new Intent(getBaseContext(), DummyBrightnessActivity.class);                     Log.d("brightend", String.valueOf(brightness / (float)255));                     intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK); //this is important                     //in the next line 'brightness' should be a float number between 0.0 and 1.0                     intent.putExtra("brightness value", brightness / (float)255);                      getApplication().startActivity(intent); 

Now coming to the DummyBrightnessActivity.class

 public class DummyBrightnessActivity extends Activity{  private static final int DELAYED_MESSAGE = 1;  private Handler handler;  @Override protected void onCreate(Bundle savedInstanceState) {     super.onCreate(savedInstanceState);                 handler = new Handler() {         @Override         public void handleMessage(Message msg) {             if(msg.what == DELAYED_MESSAGE) {                 DummyBrightnessActivity.this.finish();             }             super.handleMessage(msg);         }     };     Intent brightnessIntent = this.getIntent();     float brightness = brightnessIntent.getFloatExtra("brightness value", 0);     WindowManager.LayoutParams lp = getWindow().getAttributes();     lp.screenBrightness = brightness;     getWindow().setAttributes(lp);      Message message = handler.obtainMessage(DELAYED_MESSAGE);     //this next line is very important, you need to finish your activity with slight delay     handler.sendMessageDelayed(message,200);  }  } 

don't forget to register DummyBrightnessActivity to manifest.

hope it helps!!

Answer 2

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 / 255f; // 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