Question: I want a dialog that adjusts brightness of the screen using `SeekBar`.

How to display custom dialog with `SeekBar` that adjusts brightness of screen?

Answer: 
This [code snippet](http://androidcodesnips.blogspot.com/2011/07/reducing-dimness-while-running-progress.html) should help you

```
pdlg = ProgressDialog.show(getParent(), "Loading...", ""); 
WindowManager.LayoutParams lp = pdlg.getWindow().getAttributes();
p.dimAmount=0.0f;        //Dim Amount
pdlg.getWindow().setAttributes(lp);  //Applying properties to progress dialog
pdlg.dismiss(); //Dismiss the dialog

```
Hey you can set the system brightness like this:

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

```

Or you may refer on this complete [tutorial](http://programondaspot.blogspot.com/2015/09/change-screen-brightness.html)