How to detect if screen brightness has changed in Android?

Question

I have searched extensively and couldn't find a similar question.

I would like to know if there is any way to detect when the screen brightness of a mobile device has been changed.

I have already tried to store the old value when the app starts and repeatedly check usingSettings.System.getInt(getContentResolver(),Settings.System.SCREEN_BRIGHTNESS); to compare the initial and final value of screen brightness , which is not a good way of doing so.

Thanks

EDIT: This question states that I have already tried the solution of using Settings.System.SCREEN_BRIGHTNESS to get current screen values and periodically check for screen brightness changes. I am looking for a more efficient way of doing such an operation.

Possible duplicate of [Get preferred screen brightness in Android](https://stackoverflow.com/questions/4544967/get-preferred-screen-brightness-in-android) — Michael, Sep 08 '17 at 15:03
There doesn't seem to be any system level broadcast about the screen brightness so you cannot know when the user changed it unless you keep polling, which I agree is not the best practice. Add to it the issue that @Michael just linked and you got a pretty hard problem in your hands. — Edson Menegatti, Sep 08 '17 at 15:04
@Michael the problem being discussed there suggests the same method I have already tried, I was looking for an alternative solution :D — Irfan S, Sep 08 '17 at 15:28

Eric · Accepted Answer · 2021-01-30T08:12:25.483

yes, there is a way by using ContentObserver:

code:

  // listen to the brightness system settings
  val contentObserver = object:ContentObserver(Handler())
  {
      override fun onChange(selfChange:Boolean)
      {
          // get system brightness level
          val brightnessAmount = Settings.System.getInt(
                  contentResolver,Settings.System.SCREEN_BRIGHTNESS,0)

          // do something...
      }
  }

  // register the brightness listener upon starting
  contentResolver.registerContentObserver(
          Settings.System.getUriFor(Settings.System.SCREEN_BRIGHTNESS),
          false,contentObserver)

  // .....

  // unregister the listener when we're done (e.g. activity destroyed)
  contentResolver.unregisterContentObserver(contentObserver)

other useful links:

Thank you for your method, but permission is not required, because we get the system settings, not set them — MagicUnderHood, Jun 22 '20 at 10:20

score 5 · Answer 2 · answered Sep 08 '17 at 15:22

5

There are no receivers provided to detect brightness change.

You have to run a Service or Thread to check the brightness change by yourself.

Settings.System.getInt(getContext().getContentResolver(), 
             Settings.System.SCREEN_BRIGHTNESS);

The above code will give you current system brightness level. Periodically detect the brightness and compare with the old one.

Note: If the system is in Auto Brightness mode, you can't get current brightness level. See this answer.

answered Sep 08 '17 at 15:22

Bhuvanesh BS

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I have already tried out this method (already stated in question) , was looking for a more efficient way to do so. – Irfan S Sep 08 '17 at 15:29
1

The answer is no. There is no method to do it efficiently. See the link I have shared in the answer. – Bhuvanesh BS Sep 08 '17 at 15:31

How to detect if screen brightness has changed in Android?

2 Answers2

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