lock screen: use device admin instead of accessibility service

app/src/main/AndroidManifest.xml

@@ -52,17 +52,18 @@
                 <category android:name="android.intent.category.DEFAULT"/>
             </intent-filter>
         </activity>
-        <service android:name=".actions.LauncherAccessibilityService"
-            android:exported="true"
-            android:permission="android.permission.BIND_ACCESSIBILITY_SERVICE"
-            android:label="@string/app_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>
 
+        <receiver android:name=".actions.LauncherDeviceAdmin"
+            android:exported="true"
+            android:label="@string/app_name"
+            android:description="@string/device_admin_description"
+            android:permission="android.permission.BIND_DEVICE_ADMIN">
+
+            <meta-data android:name="android.app.device_admin"
+                android:resource="@xml/device_admin_config" />
+            <intent-filter>
+                <action android:name="android.app.action.DEVICE_ADMIN_ENABLED" />
+            </intent-filter>
+        </receiver>
+    </application>
 </manifest>

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

@@ -1,51 +0,0 @@
-package de.jrpie.android.launcher.actions
-
-import android.accessibilityservice.AccessibilityService
-import android.accessibilityservice.AccessibilityServiceInfo
-import android.content.Intent
-import android.os.Build
-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?) {
-    }
-
-    companion object {
-        const val ACTION_LOCK_SCREEN = "ACTION_LOCK_SCREEN"
-    }
-
-    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) {
-            performGlobalAction(GLOBAL_ACTION_LOCK_SCREEN)
-        } else {
-            Toast.makeText(this, getText(R.string.toast_lock_screen_not_supported), Toast.LENGTH_SHORT).show()
-        }
-    }
-}

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

@@ -10,7 +10,6 @@ import android.os.SystemClock
 import android.view.KeyEvent
 import android.widget.Toast
 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
@@ -76,7 +75,7 @@ enum class LauncherAction(
         "launcher:lockScreen",
         R.string.list_other_lock_screen,
         R.drawable.baseline_lock_24px,
-        ::lockScreen
+        LauncherDeviceAdmin::lockScreen
     ),
     NOP("launcher:nop", R.string.list_other_nop, R.drawable.baseline_not_interested_24, {});
 
@@ -206,20 +205,6 @@ private fun expandSettingsPanel(context: Context) {
     }
 }
 
-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 openSettings(context: Context) {
     context.startActivity(Intent(context, SettingsActivity::class.java))
 }

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

@@ -0,0 +1,53 @@
+package de.jrpie.android.launcher.actions
+
+import android.app.Activity
+import android.app.admin.DeviceAdminReceiver
+import android.app.admin.DevicePolicyManager
+import android.content.ComponentName
+import android.content.Context
+import android.content.Intent
+import android.widget.Toast
+import de.jrpie.android.launcher.R
+
+class LauncherDeviceAdmin : DeviceAdminReceiver() {
+    companion object {
+        private fun getComponentName(context: Context): ComponentName {
+            return ComponentName(context, LauncherDeviceAdmin::class.java)
+        }
+
+        private fun requestDeviceAdmin(context: Context) {
+
+            val intent = Intent(DevicePolicyManager.ACTION_ADD_DEVICE_ADMIN).apply {
+                putExtra(DevicePolicyManager.EXTRA_DEVICE_ADMIN, getComponentName(context))
+                putExtra(DevicePolicyManager.EXTRA_ADD_EXPLANATION,
+                    context.getString(R.string.device_admin_explanation))
+            }
+            context.startActivity(intent)
+
+        }
+
+        private fun assertDeviceAdmin(context: Context): Boolean {
+            val dpm = context.getSystemService(Context.DEVICE_POLICY_SERVICE) as DevicePolicyManager
+            if (!dpm.isAdminActive(getComponentName(context))) {
+                Toast.makeText(
+                    context,
+                    context.getString(R.string.toast_device_admin_not_enabled),
+                    Toast.LENGTH_LONG
+                ).show()
+                requestDeviceAdmin(context)
+                return false
+            }
+
+            return true
+        }
+
+        fun lockScreen(context: Context) {
+            assertDeviceAdmin(context) || return
+
+            val dpm = context.getSystemService(Context.DEVICE_POLICY_SERVICE) as DevicePolicyManager
+            dpm.lockNow()
+        }
+    }
+
+
+}

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

@@ -1,5 +1,4 @@
 <resources>
-    <string name="accessibility_service_description">Enable lock screen action</string>
     <!--
       -
       - Home
@@ -7,12 +6,8 @@
       -->
     <string name="alert_cant_open_title">Can\'t open app</string>
     <string name="alert_cant_open_message">Want to change its settings?</string>
-    <string name="alert_lock_screen_failed">Failed to lock screen</string>
-
 
     <string name="toast_cant_open_message">Open settings to choose an action for this gesture</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">Sorry, lock screen is available on Android 9+</string>
 
     <!--
       -
@@ -207,11 +202,13 @@
     <string name="tutorial_finish_button">Start</string>
 
 
-
     <string name="settings">Settings</string>
     <string name="ic_menu_alt">More options</string>
     <string name="alert_cant_expand_status_bar_panel">Error: Can\'t expand status bar.\nThis action is using functionality that is not part of the published Android API. Unfortunately, it does not seem to work on your device.</string>
     <string name="snackbar_app_hidden">App hidden. You can make it visible again in settings.</string>
     <string name="undo">Undo</string>
     <string name="list_other_expand_settings_panel">Quick Settings</string>
+    <string name="toast_device_admin_not_enabled">µLauncher needs to be a device admin in order to lock the screen.</string>
+    <string name="device_admin_explanation">This is required for the lock screen action.</string>
+    <string name="device_admin_description">Enable the lock screen action</string>
 </resources>

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

@@ -1,7 +0,0 @@
-<?xml version="1.0" encoding="utf-8"?>
-<accessibility-service xmlns:android="http://schemas.android.com/apk/res/android"
-    android:accessibilityEventTypes="typeAllMask"
-    android:accessibilityFeedbackType="feedbackAllMask"
-    android:accessibilityFlags="flagDefault"
-    android:description="@string/accessibility_service_description"
-    />

app/src/main/res/xml/device_admin_config.xml

@@ -0,0 +1,6 @@
+<?xml version="1.0" encoding="utf-8"?>
+<device-admin xmlns:android="http://schemas.android.com/apk/res/android">
+    <uses-policies>
+        <force-lock />
+    </uses-policies>
+</device-admin>