If your device is rooted, you can use this app directly.
If your device runs a custom ROM with signature spoofing like LineageOs, AOSP, ResurrectionRemix, etc. you can use this app without root.
Otherwise (or if you don't know what i'm talking about) you can use this app just to see app permissions and manage them manually, through system settings.
Pause the app before uninstalling or deleting its data, so it will grant permissions back to all apps needed.
Regain your privacy, rule your permissions!
Do you want to stop your apps using dangerous permissions when the screen is off? Did you ever asked yourself if an app can spy on you through your microphone when the device lays on your table? (the answer is no: apps cannot spy on you that easily, unless they are real malwares, but they can access your files, or get your location, etc.)
Then you want Permission Ruler, a powerful and automatic permission manager!
Every time you turn off the screen, Permission Ruler will automatically revoke all permissions from all your apps for you, so you don't have to worry about your privacy or wasting your battery.
Permission Ruler will give you:
Increased privacy (when the screen is off no app can do dangerous things)
Increased battery life (since the apps can't do whatever they want, they will run less time, consuming less battery life)
Simple usage: click on the only button in the main page when you install it, and forget it
Lock permissions, revoking but not granting them back automatically
Ignore specific apps
Manually manage permissions through the app (will send to system settings)
Don't grant permissions back automatically to apps not used recently
Special features (donate version)
Ignore specific permissions of specific apps
Lock specific apps/permissions
Manage system apps
Grant permissions back takes almost half time compared to normal version, using even less battery
Who can use it?
Anyone can use the app, but there are some limits.
To allows the app to automatically grant and revoke permissions you need Root permissions. An experimental support has been developed for custom ROMs with signature spoofing (https://forum.xda-developers.com/android/general/index-list-custom-roms-offering-t3557047), like LineageOs, AOSP, ResurrectionRemix, etc.
How does it work?
When you turn off your screen, Permission Ruler will revoke all permissions from all apps (unless they are ignored). When you turn on the screen, it will grant all permissions back (unless they are locked).
Why should I use it?
Usually a phone lays for more than 70% time with the screen off. This means that if you grant a permission to an app to use a feature, that app will get that permission forever, even if you use that feature for less than 30% of the time.
Also, It's highly probable you granted permissions to an app you use a few times a year (like traveling/hotel booking apps). By default Permission Ruler will not grant permissions back to apps not used recently.