问题
How can I change the adaptive brightness level programmatically, on Android Lollipop?
I know how to change the manual brightness level, and to toggle on or off the adaptive brightness. It is done like that:
Settings.System.putInt(cr, Settings.System.SCREEN_BRIGHTNESS, newLevel);
However, with adaptive brightness is enabled, the OS combines it with another brightness level which is different than the manual one.
Is there a way to do this?
Target/min/max SDK is 21.
回答1:
Don't know why but there is a hidden constant SCREEN_AUTO_BRIGHTNESS_ADJ in Android API to adjust adaptive brightness. But you can pass "screen_auto_brightness_adj" string value instead like I did.
Adaptive brightness adjustment is stored as float value in range [-1;1]. If you use brightness value in range [0;255], you can convert it to proper value as shown below.
float value = (((float)brightness*2)/255) - 1.0f;
Settings.System.putFloat(contentResolver, "screen_auto_brightness_adj", value);
回答2:
If your app targetSdkVersion is 23+, Settings.System.putFloat(contentResolver, "screen_auto_brightness_adj", value) won't work as Android disables you to modify any "hidden" settings.
Read frameworks\base\packages\SettingsProvider\src\com\android\providers\settings\SettingsProvider.java warnOrThrowForUndesiredSecureSettingsMutationForTargetSdk() for details.
来源：https://stackoverflow.com/questions/29349153/change-adaptive-brightness-level-programmatically