Question about dark / light mode on RP1 Pie

The system-wide theme setting isn't a standard Android feature until Android 10/Q. Google has been steadily rolling out dark mode support on an app-by-app basis for Android 9/Pie and older, though. However, there are also light/dark mode settings in Nova Launcher, too. I don't think that'll affect other apps, just the launcher's appearance and the Google Discover integration.

If you enable your developer settings (tap build number repeatedly) you'll find an option to enable night mode all the time which will keep all the Google apps locked Into dark mode.

BPMOmega
The system-wide theme setting isn't a standard Android feature until Android 10/Q. Google has been steadily rolling out dark mode support on an app-by-app basis for Android 9/Pie and older, though. However, there are also light/dark mode settings in Nova Launcher, too. I don't think that'll affect other apps, just the launcher's appearance and the Google Discover integration.

The issue is the setting just randomly changes from time to time. I want consistently experience.

Rox598
If you enable your developer settings (tap build number repeatedly) you'll find an option to enable night mode all the time which will keep all the Google apps locked Into dark mode.

Thanks. This helps. It's weird that when I check the options, it's already "Always off". I will check this options again if my system changed to dark mode by itself in the future.

Just follow up this issue. Today the system went to dark mode by itself again and I checked the setting. It's indeed changed to "Always on" by itself, and I could revert back to light mode by changing it back. Now the question is who did that. I would suspect it's one of the apps that has the permission to change system setting, but there are several of them. It would take time to figure out considering that each test iteration would take days or weeks as it just happens randomly.

If you're still using the default launcher (Nova Launcher) check the night mode settings there. There's a pull down with various selections and also a check box for location base changes. Mine is just set to on only.

MrRaptor63
If you're still using the default launcher (Nova Launcher) check the night mode settings there. There's a pull down with various selections and also a check box for location base changes. Mine is just set to on only.

I still have that installed but it's not my default launcher and I seldom use it. The setting of that is "Default", not sure if that means on, off or auto, but based on it's behavior, it's more likely be off. However, even turn it on, it doesn't change system setting (apps other than Nova) so I doubt that could be the reason.

Okay, for me I am just using Nova and it is set to allow for modifying system settings. Any 3rd party apps initially downloaded from the play store are set to not allow for me.

Update: I have change the Modify system settings to Not allowed for all apps except Google, Google Play Music, Google Play services and Google Play Store. However, it happened again. I doubt it's due to any Google own app but I will continue testing by set everything as not allowed. I'm wondering if it's possible that this setting doesn't really work, or there's really a bug with new system update that could change the night mode setting.

OK, now I finally solved this mystery. It's due to Android feature that turn system into night mode if battery saver is on. https://9to5google.com/2018/11/13/android-night-mode-battery-saver-update/ The feature is that the system turns on night mode when the battery saver is on, and turns off night mode when the battery saver is off. The feature can't be disabled. However, there's a bug in this feature that If the phone run out of battery, next time when the phone turned on with battery saver disabled due to the phone already charged or is charging, the night mode is not turned off. I don't know if the above bug exists for all Android phones, or just RP1 (or maybe RP2?). So what happened to me is that whenever my phone run out of battery, next time I turned on the phone it's night mode. However, when the phone is in night mode, if it's drops battery below threshold again that turned on the battery saver, and I charged it before battery runs out, the night mode would turn off. Since my battery is dying that the scenario of run out of battery sometimes happens, and dark mode is not visible unless I uses certain apps, the overall behavior looks random to me.