Auto finish secure activities when the screen goes off

(and the user is inactive for a certain short duration)

app/src/main/java/app/grapheneos/camera/AutoFinishOnSleep.kt

@@ -0,0 +1,53 @@
+package app.grapheneos.camera
+
+import android.app.Activity
+import android.content.BroadcastReceiver
+import android.content.Context
+import android.content.Intent
+import android.content.IntentFilter
+import android.os.Handler
+import android.os.Looper
+import androidx.core.app.ActivityCompat
+
+// Finishes the passed [activity] and the ones present below it in the stack if the screen
+// turns off and the user is inactive for [WAITING_TIME_IN_MS] milliseconds
+class AutoFinishOnSleep(val activity: Activity) {
+
+    companion object {
+        private const val TAG = "AutoFinishOnSleep"
+        private const val WAITING_TIME_IN_MS = 1500L
+
+        private val intentFilter = IntentFilter().apply {
+            addAction(Intent.ACTION_SCREEN_ON)
+            addAction(Intent.ACTION_SCREEN_OFF)
+        }
+    }
+
+    private val handler = Handler(Looper.getMainLooper())
+
+    private val runnable = Runnable {
+        ActivityCompat.finishAffinity(activity)
+    }
+
+    private val receiver = object: BroadcastReceiver() {
+        override fun onReceive(context: Context?, intent: Intent?) {
+            when (intent?.action) {
+                Intent.ACTION_SCREEN_OFF -> {
+                    handler.postDelayed(runnable, WAITING_TIME_IN_MS)
+                }
+
+                Intent.ACTION_SCREEN_ON -> {
+                    handler.removeCallbacks(runnable)
+                }
+            }
+        }
+    }
+
+    fun start() {
+        activity.registerReceiver(receiver, intentFilter)
+    }
+
+    fun stop() {
+        activity.unregisterReceiver(receiver)
+    }
+}

app/src/main/java/app/grapheneos/camera/ui/activities/InAppGallery.kt

@@ -34,6 +34,7 @@ import androidx.core.view.WindowInsetsCompat
 import androidx.core.view.WindowInsetsControllerCompat
 import androidx.viewpager2.widget.ViewPager2
 import androidxc.exifinterface.media.ExifInterface
+import app.grapheneos.camera.AutoFinishOnSleep
 import app.grapheneos.camera.CapturedItem
 import app.grapheneos.camera.CapturedItems
 import app.grapheneos.camera.GSlideTransformer
@@ -70,6 +71,8 @@ class InAppGallery : AppCompatActivity() {
 
     private lateinit var rootView: View
 
+    private val autoFinisher = AutoFinishOnSleep(this)
+
     private var lastViewedMediaItem : CapturedItem? = null
 
     private lateinit var windowInsetsController: WindowInsetsControllerCompat
@@ -446,6 +449,7 @@ class InAppGallery : AppCompatActivity() {
         if (isSecureMode) {
             setShowWhenLocked(true)
             setTurnScreenOn(true)
+            autoFinisher.start()
         }
 
         ogColor = ContextCompat.getColor(this, R.color.system_neutral1_900)
@@ -637,6 +641,9 @@ class InAppGallery : AppCompatActivity() {
         super.onDestroy()
         asyncLoaderOfCapturedItems.shutdownNow()
         asyncImageLoader.shutdownNow()
+        if (isSecureMode) {
+            autoFinisher.stop()
+        }
     }
 
     fun vibrateDevice() {

app/src/main/java/app/grapheneos/camera/ui/activities/MoreSettingsSecure.kt

@@ -1,3 +1,19 @@
 package app.grapheneos.camera.ui.activities
 
-class MoreSettingsSecure : MoreSettings()
+import android.os.Bundle
+import app.grapheneos.camera.AutoFinishOnSleep
+
+class MoreSettingsSecure : MoreSettings() {
+
+    private val autoFinisher = AutoFinishOnSleep(this)
+
+    override fun onCreate(savedInstanceState: Bundle?) {
+        super.onCreate(savedInstanceState)
+        autoFinisher.start()
+    }
+
+    override fun onDestroy() {
+        super.onDestroy()
+        autoFinisher.stop()
+    }
+}

app/src/main/java/app/grapheneos/camera/ui/activities/SecureMainActivity.kt

@@ -1,6 +1,8 @@
 package app.grapheneos.camera.ui.activities
 
 import android.content.SharedPreferences
+import android.os.Bundle
+import app.grapheneos.camera.AutoFinishOnSleep
 import app.grapheneos.camera.CapturedItem
 import app.grapheneos.camera.util.EphemeralSharedPrefsNamespace
 import app.grapheneos.camera.util.getPrefs
@@ -9,6 +11,18 @@ open class SecureMainActivity : MainActivity(), SecureActivity {
     val capturedItems = ArrayList<CapturedItem>()
     val ephemeralPrefsNamespace = EphemeralSharedPrefsNamespace()
 
+    private val autoFinisher = AutoFinishOnSleep(this)
+
+    override fun onCreate(savedInstanceState: Bundle?) {
+        super.onCreate(savedInstanceState)
+        autoFinisher.start()
+    }
+
+    override fun onDestroy() {
+        super.onDestroy()
+        autoFinisher.stop()
+    }
+
     override fun getSharedPreferences(name: String, mode: Int): SharedPreferences {
         return ephemeralPrefsNamespace.getPrefs(this, name, mode, cloneOriginal = true)
     }

app/src/main/java/app/grapheneos/camera/ui/activities/VideoPlayer.kt

@@ -16,6 +16,7 @@ import androidx.core.view.ViewCompat
 import androidx.core.view.WindowCompat
 import androidx.core.view.WindowInsetsCompat
 import androidx.lifecycle.Lifecycle
+import app.grapheneos.camera.AutoFinishOnSleep
 import app.grapheneos.camera.R
 import app.grapheneos.camera.databinding.VideoPlayerBinding
 import app.grapheneos.camera.util.getParcelableExtra
@@ -32,6 +33,10 @@ class VideoPlayer : AppCompatActivity() {
 
     private lateinit var binding: VideoPlayerBinding
 
+    private val autoFinisher = AutoFinishOnSleep(this)
+
+    private var isSecureMode = false
+
     override fun onCreate(savedInstanceState: Bundle?) {
         super.onCreate(savedInstanceState)
         enableEdgeToEdge()
@@ -42,10 +47,15 @@ class VideoPlayer : AppCompatActivity() {
         windowInsetsController.show(WindowInsetsCompat.Type.systemBars())
 
         val intent = this.intent
-        if (intent.getBooleanExtra(IN_SECURE_MODE, false)) {
+
+        isSecureMode = intent.getBooleanExtra(IN_SECURE_MODE, false)
+
+        if (isSecureMode) {
             setShowWhenLocked(true)
             setTurnScreenOn(true)
+            autoFinisher.start()
         }
+
         binding = VideoPlayerBinding.inflate(layoutInflater)
         setContentView(binding.root)
 
@@ -165,4 +175,11 @@ class VideoPlayer : AppCompatActivity() {
             alpha(1f)
         }
     }
+
+    override fun onDestroy() {
+        super.onDestroy()
+        if (isSecureMode) {
+            this.autoFinisher.stop()
+        }
+    }
 }