I would like to increase the brightness of the screen using a seek bar within my Android application, but I'm not sure how to do this. How can I add this functionality?
Using this you can set the screen brightness:
WindowManager.LayoutParams lp = getWindow().getAttributes();
lp.screenBrightness = 100 / 100.0f;
getWindow().setAttributes(lp);
Now, as you want to implement progress bar like control, i would suggest you to implement SeekBar, so using this you can easily increase/decrease based on tracking value of seekbar.
Here is the full example implemented using the SeekBar.