Update Display Brightness on Android after changing it programmatically
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09-10-2019 - |
문제
I'm trying to update the display brightness from a widget but i have some problems.
To change brightness level, i use:
Settings.System.putInt(context.getContentResolver(),android.provider.Settings.System.SCREEN_BRIGHTNESS, 200);
This modifies the display setting (in fact in Display->Brightness the level is correct) but the effective brightness of display is not changed. If i lock the screen and unlock, the brightness finally changes to the value i set.
I assume this is a Settings Update issue, so how can the display settings be immediatly updated after settings change?
I read that WindowManager.LayoutParams lp = getWindow().getAttributes();
should be used but I am working in a App Widget so getWindow() cannot be called.
해결책
I had a similar issue and just created an Activity with no UI to do the brightness change, used an intent to run it from the App Widget.
다른 팁
First, the value to modify in LayoutParams is screenBrightness. You'll then have to do a window.setAttributes to apply it. As GeekYouUp said, you can make a dummy activity to get your Window object.
Can you use this code in your RemoteView,
Settings.System.putInt(context.getContentResolver(), Settings.System.SCREEN_BRIGHTNESS, brightness);
// This makes the new screen brightness effective
WindowManager.LayoutParams layoutParams = ((Activity)context).getWindow().getAttributes();
float b = brightness/255.0f;
if(b == 0.0)
b = 0.01f;
layoutParams.screenBrightness = b;
((Activity)context).getWindow().setAttributes(layoutParams);
This code fine works when you are setting phone screen brightness from inside a User-defined class which is not extending an Activity but you only need the context.