Question

I have a problem that I want to decrease the brightness of the screen on the button click but failed to do that. I don’t know why? I have written the code of few lines but it doesn’t work for me. Please suggest me the right solution regarding the same.

Code:

private void setBrightness() {  

        try {
            int curBrightnessValue = android.provider.Settings.System.getInt(getContentResolver(), android.provider.Settings.System.SCREEN_BRIGHTNESS);
            WindowManager.LayoutParams layoutParams = getWindow().getAttributes();
            layoutParams.screenBrightness = curBrightnessValue/100.0f;
            getWindow().setAttributes(layoutParams);
        } catch (SettingNotFoundException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
      }  

Answer 1

Your code seems to good, but I think for taking effect of brightness your activity has to wait for 500ms, Just use given below code,

 try {
      ContentResolver cr = getContentResolver();
      int brightness = Settings.System.getInt(cr,Settings.System.SCREEN_BRIGHTNESS);            
      Settings.System.putInt(cr, Settings.System.SCREEN_BRIGHTNESS, brightness);
      WindowManager.LayoutParams lp = getWindow().getAttributes();
      lp.screenBrightness = brightness / 255.0f;
      getWindow().setAttributes(lp);
      } catch (Exception e) {
         Log.d("Bright", "toggleBrightness: " + e);
      }

      final Activity activity = this;
      Thread t = new Thread(){
        public void run()
         {
          try {
               sleep(500);
              } catch (InterruptedException e) {}
              activity.finish();
            }
        };
        t.start();

UPDATE:

The main code is just,

WindowManager.LayoutParams layout = getWindow().getAttributes();
layout.screenBrightness = 1F;
getWindow().setAttributes(layout);

Also try this..
Try this and let me know what happen,