reintroduce AccessibilityService from 9bc8d6bb6d (cf. #65)

app/src/main/AndroidManifest.xml

@@ -65,5 +65,17 @@
                 <action android:name="android.app.action.DEVICE_ADMIN_ENABLED" />
             </intent-filter>
         </receiver>
+
+        <service android:name=".actions.LauncherAccessibilityService"
+            android:exported="true"
+            android:permission="android.permission.BIND_ACCESSIBILITY_SERVICE"
+            android:label="@string/accessibility_service_name">
+            <intent-filter>
+                <action android:name="android.accessibilityservice.AccessibilityService" />
+            </intent-filter>
+            <meta-data
+                android:name="android.accessibilityservice"
+                android:resource="@xml/accessibility_service_config" />
+        </service>
     </application>
 </manifest>

app/src/main/java/de/jrpie/android/launcher/actions/LauncherAccessibilityService.kt

@@ -0,0 +1,74 @@
+package de.jrpie.android.launcher.actions
+
+import android.accessibilityservice.AccessibilityService
+import android.accessibilityservice.AccessibilityServiceInfo
+import android.content.Context
+import android.content.Intent
+import android.os.Build
+import android.util.Log
+import android.view.accessibility.AccessibilityEvent
+import android.view.accessibility.AccessibilityManager
+import android.widget.Toast
+import androidx.core.content.getSystemService
+import de.jrpie.android.launcher.R
+
+class LauncherAccessibilityService : AccessibilityService() {
+    override fun onInterrupt() { }
+
+    override fun onAccessibilityEvent(event: AccessibilityEvent?) {
+        // Intentionally left blank, we are not interested in any AccessibilityEvents.
+        // DO NOT ADD ANY CODE HERE!
+    }
+
+    companion object {
+        const val ACTION_LOCK_SCREEN = "ACTION_LOCK_SCREEN"
+
+        private fun lockScreen(context: Context){
+            try {
+                context.startService(Intent(context, LauncherAccessibilityService::class.java).apply {
+                    action = ACTION_LOCK_SCREEN
+                })
+            } catch (e: Exception) {
+                Toast.makeText(
+                    context,
+                    context.getString(R.string.alert_lock_screen_failed),
+                    Toast.LENGTH_LONG
+                ).show()
+            }
+        }
+    }
+
+    private fun isServiceEnabled(): Boolean {
+        val accessibilityManager = getSystemService<AccessibilityManager>() ?: return false
+        val enabledServices = accessibilityManager.getEnabledAccessibilityServiceList(AccessibilityServiceInfo.FEEDBACK_ALL_MASK)
+        return enabledServices.any { it.id.contains(packageName) }
+    }
+
+    override fun onStartCommand(intent: Intent?, flags: Int, startId: Int): Int {
+        intent?.action?.let { action ->
+            if (!isServiceEnabled()) {
+                Toast.makeText(this, getString(R.string.toast_accessibility_service_not_enabled), Toast.LENGTH_LONG).show()
+                startActivity(Intent(android.provider.Settings.ACTION_ACCESSIBILITY_SETTINGS).addFlags(Intent.FLAG_ACTIVITY_NEW_TASK))
+                return START_NOT_STICKY
+            }
+
+            when (action) {
+                ACTION_LOCK_SCREEN -> handleLockScreen()
+            }
+        }
+        return super.onStartCommand(intent, flags, startId)
+    }
+
+    private fun handleLockScreen(){
+        if (Build.VERSION.SDK_INT < Build.VERSION_CODES.P) {
+            Toast.makeText(
+                this,
+                getText(R.string.toast_lock_screen_not_supported),
+                Toast.LENGTH_SHORT
+            ).show()
+            return
+        }
+
+        performGlobalAction(GLOBAL_ACTION_LOCK_SCREEN)
+    }
+}

app/src/main/java/de/jrpie/android/launcher/actions/LauncherAction.kt

@@ -12,6 +12,7 @@ import android.view.KeyEvent
 import android.widget.Toast
 import de.jrpie.android.launcher.Application
 import de.jrpie.android.launcher.R
+import de.jrpie.android.launcher.actions.LauncherAccessibilityService.Companion.ACTION_LOCK_SCREEN
 import de.jrpie.android.launcher.apps.AppFilter
 import de.jrpie.android.launcher.apps.AppInfo.Companion.INVALID_USER
 import de.jrpie.android.launcher.ui.list.ListActivity
@@ -251,9 +252,4 @@ fun openAppsList(context: Context, favorite: Boolean = false, hidden: Boolean =
     )
 
     context.startActivity(intent)
-}
-
-
-
-
-
+}

app/src/main/res/values/strings.xml

@@ -243,4 +243,10 @@
     <string name="device_admin_description">Enable the lock screen action</string>
     <string name="alert_no_torch_found">No camera with torch detected.</string>
     <string name="alert_torch_access_exception">Error: Can\'t access torch.</string>
+    <string name="alert_lock_screen_failed">Error: Failed to lock screen.</string>
+    <string name="toast_accessibility_service_not_enabled">μLauncher\'s accessibility service is not enabled. Please enable it in settings</string>
+    <string name="toast_lock_screen_not_supported">Error: Locking the screen using accessibility is not supported on this device. Please use device admin instead.</string>
+    <string name="accessibility_service_name">µLauncher - lock screen</string>
+    <string name="accessibility_service_description">Setting µLauncher as an accessibility service allows it to lock the screen. Note that excessive permissions are required, you should never grant such permissions lightly to any app. µLauncher will use the accessibility service only for locking the screen. You should check the source code to make sure. Note that locking the screen can also be accomplished by granting µLauncher device administrator permissions. Those are more fine grained. However that method doesn\'t work with fingerprint and facial recognition.</string>
+
 </resources>

app/src/main/res/xml/accessibility_service_config.xml

@@ -0,0 +1,19 @@
+<?xml version="1.0" encoding="utf-8"?>
+
+<!--
+    The accessibility service is only used for locking the screen.
+
+    * android:accessibilityEventTypes is unspecified intentionally, as we don't want to listen to any
+    events.
+    * android:packageNames is set to an empty list, as we don't want to interact or read data from
+    any app.
+-->
+<accessibility-service xmlns:android="http://schemas.android.com/apk/res/android"
+    android:accessibilityFlags="flagDefault"
+    android:canRequestEnhancedWebAccessibility="false"
+    android:canRequestFilterKeyEvents="false"
+    android:canRequestTouchExplorationMode="false"
+    android:canRetrieveWindowContent="false"
+    android:description="@string/accessibility_service_description"
+    android:packageNames=""
+    android:settingsActivity="de.jrpie.android.launcher.ui.settings.SettingsActivity" />