most android apps that need any kind of auth go straight to biometrics or firebase. fine — but what if you just need a simple PIN lockscreen? no backend, no cloud calls, just "enter your code to continue". that's what AndroidAppLockscreen does. i built it after copy-pasting the same lockscreen implementation across three different projects. the design is inspired by Diary — clean, minimal, nothing fancy. what it handles set password check password on launch change password disable password forgot password flow customisable background color setup add the JitPack repo and one dependency: implementation 'com.github.p32929:AndroidAppLockscreen:1.2' extend your activities with LockscreenHandler , then in MainActivity 's onCreate : EasyLock . checkPassword ( this ); first launch, no password set → does nothing. password set → blocks app until correct code is entered. managing passwords after that: EasyLock . setPassword ( activity ); EasyLock . changePassword ( activity ); EasyLock . disablePassword ( activity ); the non-obvious part the tricky bit wasn't the UI. it was activity lifecycle. you don't want the lockscreen triggering on screen rotation or when the user returns from a camera/file picker intent. LockscreenHandler handles all of that — it knows the difference between "user left the app" and "activity was recreated internally". 64 stars, 21 forks, MIT licensed. repo: https://github.com/p32929/AndroidAppLockscreen would love feedback, PRs, or stars if it saves you time. open to building with sharp teams and solo founders — dms open.