ui: root: rewrite in kotlin

Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>

7 files changed, 352 insertions, 398 deletions

diff --git a/ui/src/main/java/com/wireguard/android/Application.java b/ui/src/main/java/com/wireguard/android/Application.java
deleted file mode 100644
index 62cf25a1..00000000
--- a/ui/src/main/java/com/wireguard/android/Application.java
+++ /dev/null
@@ -1,180 +0,0 @@
-/*
- * Copyright © 2017-2019 WireGuard LLC. All Rights Reserved.
- * SPDX-License-Identifier: Apache-2.0
- */
-
-package com.wireguard.android;
-
-import android.content.Context;
-import android.content.Intent;
-import android.content.SharedPreferences;
-import android.os.AsyncTask;
-import android.os.Build;
-import android.os.Handler;
-import android.os.Looper;
-import android.os.StrictMode;
-import android.util.Log;
-
-import com.wireguard.android.backend.Backend;
-import com.wireguard.android.backend.GoBackend;
-import com.wireguard.android.backend.WgQuickBackend;
-import com.wireguard.android.configStore.FileConfigStore;
-import com.wireguard.android.model.TunnelManager;
-import com.wireguard.android.util.AsyncWorker;
-import com.wireguard.android.util.ExceptionLoggers;
-import com.wireguard.android.util.ModuleLoader;
-import com.wireguard.android.util.RootShell;
-import com.wireguard.android.util.ToolsInstaller;
-import com.wireguard.util.NonNullForAll;
-
-import java.lang.ref.WeakReference;
-import java.util.Locale;
-
-import androidx.annotation.Nullable;
-import androidx.appcompat.app.AppCompatDelegate;
-import androidx.preference.PreferenceManager;
-import java9.util.concurrent.CompletableFuture;
-
-@NonNullForAll
-public class Application extends android.app.Application implements SharedPreferences.OnSharedPreferenceChangeListener {
-    public static final String USER_AGENT = String.format(Locale.ENGLISH, "WireGuard/%s (Android %d; %s; %s; %s %s; %s)", BuildConfig.VERSION_NAME, Build.VERSION.SDK_INT, Build.SUPPORTED_ABIS.length > 0 ? Build.SUPPORTED_ABIS[0] : "unknown ABI", Build.BOARD, Build.MANUFACTURER, Build.MODEL, Build.FINGERPRINT);
-    private static final String TAG = "WireGuard/" + Application.class.getSimpleName();
-    @SuppressWarnings("NullableProblems") private static WeakReference<Application> weakSelf;
-    private final CompletableFuture<Backend> futureBackend = new CompletableFuture<>();
-    @SuppressWarnings("NullableProblems") private AsyncWorker asyncWorker;
-    @Nullable private Backend backend;
-    @SuppressWarnings("NullableProblems") private ModuleLoader moduleLoader;
-    @SuppressWarnings("NullableProblems") private RootShell rootShell;
-    @SuppressWarnings("NullableProblems") private SharedPreferences sharedPreferences;
-    @SuppressWarnings("NullableProblems") private ToolsInstaller toolsInstaller;
-    @SuppressWarnings("NullableProblems") private TunnelManager tunnelManager;
-
-    public Application() {
-        weakSelf = new WeakReference<>(this);
-    }
-
-    public static Application get() {
-        return weakSelf.get();
-    }
-
-    public static AsyncWorker getAsyncWorker() {
-        return get().asyncWorker;
-    }
-
-    public static Backend getBackend() {
-        final Application app = get();
-        synchronized (app.futureBackend) {
-            if (app.backend == null) {
-                Backend backend = null;
-                boolean didStartRootShell = false;
-                if (!ModuleLoader.isModuleLoaded() && app.moduleLoader.moduleMightExist()) {
-                    try {
-                        app.rootShell.start();
-                        didStartRootShell = true;
-                        app.moduleLoader.loadModule();
-                    } catch (final Exception ignored) {
-                    }
-                }
-                if (!app.sharedPreferences.getBoolean("disable_kernel_module", false) && ModuleLoader.isModuleLoaded()) {
-                    try {
-                        if (!didStartRootShell)
-                            app.rootShell.start();
-                        final WgQuickBackend wgQuickBackend = new WgQuickBackend(app.getApplicationContext(), app.rootShell, app.toolsInstaller);
-                        wgQuickBackend.setMultipleTunnels(app.sharedPreferences.getBoolean("multiple_tunnels", false));
-                        backend = wgQuickBackend;
-                    } catch (final Exception ignored) {
-                    }
-                }
-                if (backend == null) {
-                    backend = new GoBackend(app.getApplicationContext());
-                    GoBackend.setAlwaysOnCallback(() -> {
-                        get().tunnelManager.restoreState(true).whenComplete(ExceptionLoggers.D);
-                    });
-                }
-                app.backend = backend;
-            }
-            return app.backend;
-        }
-    }
-
-    public static CompletableFuture<Backend> getBackendAsync() {
-        return get().futureBackend;
-    }
-
-    public static ModuleLoader getModuleLoader() {
-        return get().moduleLoader;
-    }
-
-    public static RootShell getRootShell() {
-        return get().rootShell;
-    }
-
-    public static SharedPreferences getSharedPreferences() {
-        return get().sharedPreferences;
-    }
-
-    public static ToolsInstaller getToolsInstaller() {
-        return get().toolsInstaller;
-    }
-
-    public static TunnelManager getTunnelManager() {
-        return get().tunnelManager;
-    }
-
-    @Override
-    protected void attachBaseContext(final Context context) {
-        super.attachBaseContext(context);
-
-        if (BuildConfig.MIN_SDK_VERSION > Build.VERSION.SDK_INT) {
-            final Intent intent = new Intent(Intent.ACTION_MAIN);
-            intent.addCategory(Intent.CATEGORY_HOME);
-            intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TASK);
-            intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
-            startActivity(intent);
-            System.exit(0);
-        }
-
-        if (BuildConfig.DEBUG) {
-            StrictMode.setVmPolicy(new StrictMode.VmPolicy.Builder().detectAll().penaltyLog().build());
-        }
-    }
-
-    @Override
-    public void onCreate() {
-        Log.i(TAG, USER_AGENT);
-        super.onCreate();
-
-        asyncWorker = new AsyncWorker(AsyncTask.SERIAL_EXECUTOR, new Handler(Looper.getMainLooper()));
-        rootShell = new RootShell(getApplicationContext());
-        toolsInstaller = new ToolsInstaller(getApplicationContext(), rootShell);
-        moduleLoader = new ModuleLoader(getApplicationContext(), rootShell, USER_AGENT);
-
-        sharedPreferences = PreferenceManager.getDefaultSharedPreferences(getApplicationContext());
-        if (Build.VERSION.SDK_INT < Build.VERSION_CODES.Q) {
-            AppCompatDelegate.setDefaultNightMode(
-                    sharedPreferences.getBoolean("dark_theme", false) ?
-                            AppCompatDelegate.MODE_NIGHT_YES : AppCompatDelegate.MODE_NIGHT_NO);
-        } else {
-            AppCompatDelegate.setDefaultNightMode(AppCompatDelegate.MODE_NIGHT_FOLLOW_SYSTEM);
-        }
-
-        tunnelManager = new TunnelManager(new FileConfigStore(getApplicationContext()));
-        tunnelManager.onCreate();
-
-        asyncWorker.supplyAsync(Application::getBackend).thenAccept(futureBackend::complete);
-
-        sharedPreferences.registerOnSharedPreferenceChangeListener(this);
-    }
-
-    @Override
-    public void onSharedPreferenceChanged(final SharedPreferences sharedPreferences, final String key) {
-        if ("multiple_tunnels".equals(key) && backend != null && backend instanceof WgQuickBackend)
-            ((WgQuickBackend) backend).setMultipleTunnels(sharedPreferences.getBoolean(key, false));
-    }
-
-    @Override
-    public void onTerminate() {
-        sharedPreferences.unregisterOnSharedPreferenceChangeListener(this);
-        super.onTerminate();
-    }
-}
diff --git a/ui/src/main/java/com/wireguard/android/Application.kt b/ui/src/main/java/com/wireguard/android/Application.kt
new file mode 100644
index 00000000..0e522abf
--- /dev/null
+++ b/ui/src/main/java/com/wireguard/android/Application.kt
@@ -0,0 +1,159 @@
+/*
+ * Copyright © 2017-2019 WireGuard LLC. All Rights Reserved.
+ * SPDX-License-Identifier: Apache-2.0
+ */
+package com.wireguard.android
+
+import android.content.Context
+import android.content.Intent
+import android.content.SharedPreferences
+import android.content.SharedPreferences.OnSharedPreferenceChangeListener
+import android.os.AsyncTask
+import android.os.Build
+import android.os.Handler
+import android.os.Looper
+import android.os.StrictMode
+import android.os.StrictMode.VmPolicy
+import android.util.Log
+import androidx.appcompat.app.AppCompatDelegate
+import androidx.preference.PreferenceManager
+import com.wireguard.android.backend.Backend
+import com.wireguard.android.backend.GoBackend
+import com.wireguard.android.backend.WgQuickBackend
+import com.wireguard.android.configStore.FileConfigStore
+import com.wireguard.android.model.TunnelManager
+import com.wireguard.android.util.AsyncWorker
+import com.wireguard.android.util.ExceptionLoggers
+import com.wireguard.android.util.ModuleLoader
+import com.wireguard.android.util.RootShell
+import com.wireguard.android.util.ToolsInstaller
+import java9.util.concurrent.CompletableFuture
+import java.lang.ref.WeakReference
+import java.util.Locale
+
+class Application : android.app.Application(), OnSharedPreferenceChangeListener {
+    private val futureBackend = CompletableFuture<Backend>()
+    private lateinit var asyncWorker: AsyncWorker
+    private var backend: Backend? = null
+    private lateinit var moduleLoader: ModuleLoader
+    private lateinit var rootShell: RootShell
+    private lateinit var sharedPreferences: SharedPreferences
+    private lateinit var toolsInstaller: ToolsInstaller
+    private lateinit var tunnelManager: TunnelManager
+
+    override fun attachBaseContext(context: Context) {
+        super.attachBaseContext(context)
+        if (BuildConfig.MIN_SDK_VERSION > Build.VERSION.SDK_INT) {
+            val intent = Intent(Intent.ACTION_MAIN)
+            intent.addCategory(Intent.CATEGORY_HOME)
+            intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TASK)
+            intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK)
+            startActivity(intent)
+            System.exit(0)
+        }
+        if (BuildConfig.DEBUG) {
+            StrictMode.setVmPolicy(VmPolicy.Builder().detectAll().penaltyLog().build())
+        }
+    }
+
+    override fun onCreate() {
+        Log.i(TAG, USER_AGENT)
+        super.onCreate()
+        asyncWorker = AsyncWorker(AsyncTask.SERIAL_EXECUTOR, Handler(Looper.getMainLooper()))
+        rootShell = RootShell(applicationContext)
+        toolsInstaller = ToolsInstaller(applicationContext, rootShell)
+        moduleLoader = ModuleLoader(applicationContext, rootShell, USER_AGENT)
+        sharedPreferences = PreferenceManager.getDefaultSharedPreferences(applicationContext)
+        if (Build.VERSION.SDK_INT < Build.VERSION_CODES.Q) {
+            AppCompatDelegate.setDefaultNightMode(
+                    if (sharedPreferences.getBoolean("dark_theme", false)) AppCompatDelegate.MODE_NIGHT_YES else AppCompatDelegate.MODE_NIGHT_NO)
+        } else {
+            AppCompatDelegate.setDefaultNightMode(AppCompatDelegate.MODE_NIGHT_FOLLOW_SYSTEM)
+        }
+        tunnelManager = TunnelManager(FileConfigStore(applicationContext))
+        tunnelManager.onCreate()
+        asyncWorker.supplyAsync { getBackend() }.thenAccept { futureBackend.complete(it) }
+        sharedPreferences.registerOnSharedPreferenceChangeListener(this)
+    }
+
+    override fun onSharedPreferenceChanged(sharedPreferences: SharedPreferences, key: String) {
+        if ("multiple_tunnels" == key && backend != null && backend is WgQuickBackend)
+            (backend as WgQuickBackend).setMultipleTunnels(sharedPreferences.getBoolean(key, false))
+    }
+
+    override fun onTerminate() {
+        sharedPreferences.unregisterOnSharedPreferenceChangeListener(this)
+        super.onTerminate()
+    }
+
+    companion object {
+        val USER_AGENT = String.format(Locale.ENGLISH, "WireGuard/%s (Android %d; %s; %s; %s %s; %s)", BuildConfig.VERSION_NAME, Build.VERSION.SDK_INT, if (Build.SUPPORTED_ABIS.isNotEmpty()) Build.SUPPORTED_ABIS[0] else "unknown ABI", Build.BOARD, Build.MANUFACTURER, Build.MODEL, Build.FINGERPRINT)
+        private val TAG = "WireGuard/" + Application::class.java.simpleName
+        private lateinit var weakSelf: WeakReference<Application>
+
+        @JvmStatic
+        fun get(): Application {
+            return weakSelf.get()!!
+        }
+
+        @JvmStatic
+        fun getAsyncWorker() = get().asyncWorker
+
+        @JvmStatic
+        fun getBackend(): Backend {
+            val app = get()
+            synchronized(app.futureBackend) {
+                if (app.backend == null) {
+                    var backend: Backend? = null
+                    var didStartRootShell = false
+                    if (!ModuleLoader.isModuleLoaded() && app.moduleLoader.moduleMightExist()) {
+                        try {
+                            app.rootShell.start()
+                            didStartRootShell = true
+                            app.moduleLoader.loadModule()
+                        } catch (ignored: Exception) {
+                        }
+                    }
+                    if (!app.sharedPreferences.getBoolean("disable_kernel_module", false) && ModuleLoader.isModuleLoaded()) {
+                        try {
+                            if (!didStartRootShell)
+                                app.rootShell.start()
+                            val wgQuickBackend = WgQuickBackend(app.applicationContext, app.rootShell, app.toolsInstaller)
+                            wgQuickBackend.setMultipleTunnels(app.sharedPreferences.getBoolean("multiple_tunnels", false))
+                            backend = wgQuickBackend
+                        } catch (ignored: Exception) {
+                        }
+                    }
+                    if (backend == null) {
+                        backend = GoBackend(app.applicationContext)
+                        GoBackend.setAlwaysOnCallback { get().tunnelManager.restoreState(true).whenComplete(ExceptionLoggers.D) }
+                    }
+                    app.backend = backend
+                }
+                return app.backend!!
+            }
+        }
+
+        @JvmStatic
+        fun getBackendAsync() = get().futureBackend
+
+        @JvmStatic
+        fun getModuleLoader() = get().moduleLoader
+
+        @JvmStatic
+        fun getRootShell() = get().rootShell
+
+        @JvmStatic
+        fun getSharedPreferences() = get().sharedPreferences
+
+        @JvmStatic
+        fun getToolsInstaller() = get().toolsInstaller
+
+        @JvmStatic
+        fun getTunnelManager() = get().tunnelManager
+    }
+
+    init {
+        weakSelf = WeakReference(this)
+    }
+}
diff --git a/ui/src/main/java/com/wireguard/android/BootShutdownReceiver.java b/ui/src/main/java/com/wireguard/android/BootShutdownReceiver.java
deleted file mode 100644
index 3f4bcd83..00000000
--- a/ui/src/main/java/com/wireguard/android/BootShutdownReceiver.java
+++ /dev/null
@@ -1,40 +0,0 @@
-/*
- * Copyright © 2017-2019 WireGuard LLC. All Rights Reserved.
- * SPDX-License-Identifier: Apache-2.0
- */
-
-package com.wireguard.android;
-
-import android.content.BroadcastReceiver;
-import android.content.Context;
-import android.content.Intent;
-import android.util.Log;
-
-import com.wireguard.android.backend.WgQuickBackend;
-import com.wireguard.android.model.TunnelManager;
-import com.wireguard.android.util.ExceptionLoggers;
-import com.wireguard.util.NonNullForAll;
-
-@NonNullForAll
-public class BootShutdownReceiver extends BroadcastReceiver {
-    private static final String TAG = "WireGuard/" + BootShutdownReceiver.class.getSimpleName();
-
-    @Override
-    public void onReceive(final Context context, final Intent intent) {
-        Application.getBackendAsync().thenAccept(backend -> {
-            if (!(backend instanceof WgQuickBackend))
-                return;
-            final String action = intent.getAction();
-            if (action == null)
-                return;
-            final TunnelManager tunnelManager = Application.getTunnelManager();
-            if (Intent.ACTION_BOOT_COMPLETED.equals(action)) {
-                Log.i(TAG, "Broadcast receiver restoring state (boot)");
-                tunnelManager.restoreState(false).whenComplete(ExceptionLoggers.D);
-            } else if (Intent.ACTION_SHUTDOWN.equals(action)) {
-                Log.i(TAG, "Broadcast receiver saving state (shutdown)");
-                tunnelManager.saveState();
-            }
-        });
-    }
-}
diff --git a/ui/src/main/java/com/wireguard/android/BootShutdownReceiver.kt b/ui/src/main/java/com/wireguard/android/BootShutdownReceiver.kt
new file mode 100644
index 00000000..e9759143
--- /dev/null
+++ b/ui/src/main/java/com/wireguard/android/BootShutdownReceiver.kt
@@ -0,0 +1,34 @@
+/*
+ * Copyright © 2017-2019 WireGuard LLC. All Rights Reserved.
+ * SPDX-License-Identifier: Apache-2.0
+ */
+package com.wireguard.android
+
+import android.content.BroadcastReceiver
+import android.content.Context
+import android.content.Intent
+import android.util.Log
+import com.wireguard.android.backend.Backend
+import com.wireguard.android.backend.WgQuickBackend
+import com.wireguard.android.util.ExceptionLoggers
+
+class BootShutdownReceiver : BroadcastReceiver() {
+    override fun onReceive(context: Context, intent: Intent) {
+        Application.getBackendAsync().thenAccept { backend: Backend? ->
+            if (backend !is WgQuickBackend) return@thenAccept
+            val action = intent.action ?: return@thenAccept
+            val tunnelManager = Application.getTunnelManager()
+            if (Intent.ACTION_BOOT_COMPLETED == action) {
+                Log.i(TAG, "Broadcast receiver restoring state (boot)")
+                tunnelManager.restoreState(false).whenComplete(ExceptionLoggers.D)
+            } else if (Intent.ACTION_SHUTDOWN == action) {
+                Log.i(TAG, "Broadcast receiver saving state (shutdown)")
+                tunnelManager.saveState()
+            }
+        }
+    }
+
+    companion object {
+        private val TAG = "WireGuard/" + BootShutdownReceiver::class.java.simpleName
+    }
+}
diff --git a/ui/src/main/java/com/wireguard/android/QuickTileService.java b/ui/src/main/java/com/wireguard/android/QuickTileService.java
deleted file mode 100644
index a485ae1e..00000000
--- a/ui/src/main/java/com/wireguard/android/QuickTileService.java
+++ /dev/null
@@ -1,177 +0,0 @@
-/*
- * Copyright © 2017-2019 WireGuard LLC. All Rights Reserved.
- * SPDX-License-Identifier: Apache-2.0
- */
-
-package com.wireguard.android;
-
-import android.content.Intent;
-import android.graphics.Bitmap;
-import android.graphics.Canvas;
-import android.graphics.drawable.Icon;
-import android.os.Build;
-import android.os.IBinder;
-import android.service.quicksettings.Tile;
-import android.service.quicksettings.TileService;
-import android.util.Log;
-
-import com.wireguard.android.activity.MainActivity;
-import com.wireguard.android.activity.TunnelToggleActivity;
-import com.wireguard.android.backend.Tunnel.State;
-import com.wireguard.android.model.ObservableTunnel;
-import com.wireguard.android.widget.SlashDrawable;
-import com.wireguard.util.NonNullForAll;
-
-import java.util.Objects;
-
-import androidx.annotation.Nullable;
-import androidx.annotation.RequiresApi;
-import androidx.databinding.Observable;
-import androidx.databinding.Observable.OnPropertyChangedCallback;
-
-/**
- * Service that maintains the application's custom Quick Settings tile. This service is bound by the
- * system framework as necessary to update the appearance of the tile in the system UI, and to
- * forward click events to the application.
- */
-
-@RequiresApi(Build.VERSION_CODES.N)
-@NonNullForAll
-public class QuickTileService extends TileService {
-    private static final String TAG = "WireGuard/" + QuickTileService.class.getSimpleName();
-
-    private final OnStateChangedCallback onStateChangedCallback = new OnStateChangedCallback();
-    private final OnTunnelChangedCallback onTunnelChangedCallback = new OnTunnelChangedCallback();
-    @Nullable private Icon iconOff;
-    @Nullable private Icon iconOn;
-    @Nullable private ObservableTunnel tunnel;
-
-    /* This works around an annoying unsolved frameworks bug some people are hitting. */
-    @Override
-    @Nullable
-    public IBinder onBind(final Intent intent) {
-        IBinder ret = null;
-        try {
-            ret = super.onBind(intent);
-        } catch (final Exception e) {
-            Log.d(TAG, "Failed to bind to TileService", e);
-        }
-        return ret;
-    }
-
-    @Override
-    public void onClick() {
-        if (tunnel != null) {
-            unlockAndRun(() -> {
-                final Tile tile = getQsTile();
-                if (tile != null) {
-                    tile.setIcon(tile.getIcon() == iconOn ? iconOff : iconOn);
-                    tile.updateTile();
-                }
-                tunnel.setState(State.TOGGLE).whenComplete((v, t) -> {
-                    if (t == null) {
-                        updateTile();
-                    } else {
-                        final Intent toggleIntent = new Intent(this, TunnelToggleActivity.class);
-                        toggleIntent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
-                        startActivity(toggleIntent);
-                    }
-                });
-            });
-        } else {
-            final Intent intent = new Intent(this, MainActivity.class);
-            intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
-            startActivityAndCollapse(intent);
-        }
-    }
-
-    @Override
-    public void onCreate() {
-        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.P) {
-            iconOff = iconOn = Icon.createWithResource(this, R.drawable.ic_tile);
-            return;
-        }
-        final SlashDrawable icon = new SlashDrawable(getResources().getDrawable(R.drawable.ic_tile, Application.get().getTheme()));
-        icon.setAnimationEnabled(false); /* Unfortunately we can't have animations, since Icons are marshaled. */
-        icon.setSlashed(false);
-        Bitmap b = Bitmap.createBitmap(icon.getIntrinsicWidth(), icon.getIntrinsicHeight(), Bitmap.Config.ARGB_8888);
-        Canvas c = new Canvas(b);
-        icon.setBounds(0, 0, c.getWidth(), c.getHeight());
-        icon.draw(c);
-        iconOn = Icon.createWithBitmap(b);
-        icon.setSlashed(true);
-        b = Bitmap.createBitmap(icon.getIntrinsicWidth(), icon.getIntrinsicHeight(), Bitmap.Config.ARGB_8888);
-        c = new Canvas(b);
-        icon.setBounds(0, 0, c.getWidth(), c.getHeight());
-        icon.draw(c);
-        iconOff = Icon.createWithBitmap(b);
-    }
-
-    @Override
-    public void onStartListening() {
-        Application.getTunnelManager().addOnPropertyChangedCallback(onTunnelChangedCallback);
-        if (tunnel != null)
-            tunnel.addOnPropertyChangedCallback(onStateChangedCallback);
-        updateTile();
-    }
-
-    @Override
-    public void onStopListening() {
-        if (tunnel != null)
-            tunnel.removeOnPropertyChangedCallback(onStateChangedCallback);
-        Application.getTunnelManager().removeOnPropertyChangedCallback(onTunnelChangedCallback);
-    }
-
-    private void updateTile() {
-        // Update the tunnel.
-        final ObservableTunnel newTunnel = Application.getTunnelManager().getLastUsedTunnel();
-        if (newTunnel != tunnel) {
-            if (tunnel != null)
-                tunnel.removeOnPropertyChangedCallback(onStateChangedCallback);
-            tunnel = newTunnel;
-            if (tunnel != null)
-                tunnel.addOnPropertyChangedCallback(onStateChangedCallback);
-        }
-        // Update the tile contents.
-        final String label;
-        final int state;
-        final Tile tile = getQsTile();
-        if (tunnel != null) {
-            label = tunnel.getName();
-            state = tunnel.getState() == State.UP ? Tile.STATE_ACTIVE : Tile.STATE_INACTIVE;
-        } else {
-            label = getString(R.string.app_name);
-            state = Tile.STATE_INACTIVE;
-        }
-        if (tile == null)
-            return;
-        tile.setLabel(label);
-        if (tile.getState() != state) {
-            tile.setIcon(state == Tile.STATE_ACTIVE ? iconOn : iconOff);
-            tile.setState(state);
-        }
-        tile.updateTile();
-    }
-
-    private final class OnStateChangedCallback extends OnPropertyChangedCallback {
-        @Override
-        public void onPropertyChanged(final Observable sender, final int propertyId) {
-            if (!Objects.equals(sender, tunnel)) {
-                sender.removeOnPropertyChangedCallback(this);
-                return;
-            }
-            if (propertyId != 0 && propertyId != BR.state)
-                return;
-            updateTile();
-        }
-    }
-
-    private final class OnTunnelChangedCallback extends OnPropertyChangedCallback {
-        @Override
-        public void onPropertyChanged(final Observable sender, final int propertyId) {
-            if (propertyId != 0 && propertyId != BR.lastUsedTunnel)
-                return;
-            updateTile();
-        }
-    }
-}
diff --git a/ui/src/main/java/com/wireguard/android/QuickTileService.kt b/ui/src/main/java/com/wireguard/android/QuickTileService.kt
new file mode 100644
index 00000000..cd95f12d
--- /dev/null
+++ b/ui/src/main/java/com/wireguard/android/QuickTileService.kt
@@ -0,0 +1,158 @@
+/*
+ * Copyright © 2017-2019 WireGuard LLC. All Rights Reserved.
+ * SPDX-License-Identifier: Apache-2.0
+ */
+package com.wireguard.android
+
+import android.content.Intent
+import android.graphics.Bitmap
+import android.graphics.Canvas
+import android.graphics.drawable.Icon
+import android.os.Build
+import android.os.IBinder
+import android.service.quicksettings.Tile
+import android.service.quicksettings.TileService
+import android.util.Log
+import androidx.annotation.RequiresApi
+import androidx.databinding.Observable
+import androidx.databinding.Observable.OnPropertyChangedCallback
+import com.wireguard.android.activity.MainActivity
+import com.wireguard.android.activity.TunnelToggleActivity
+import com.wireguard.android.backend.Tunnel
+import com.wireguard.android.model.ObservableTunnel
+import com.wireguard.android.widget.SlashDrawable
+
+/**
+ * Service that maintains the application's custom Quick Settings tile. This service is bound by the
+ * system framework as necessary to update the appearance of the tile in the system UI, and to
+ * forward click events to the application.
+ */
+@RequiresApi(Build.VERSION_CODES.N)
+class QuickTileService : TileService() {
+    private val onStateChangedCallback = OnStateChangedCallback()
+    private val onTunnelChangedCallback = OnTunnelChangedCallback()
+    private var iconOff: Icon? = null
+    private var iconOn: Icon? = null
+    private var tunnel: ObservableTunnel? = null
+
+    /* This works around an annoying unsolved frameworks bug some people are hitting. */
+    override fun onBind(intent: Intent): IBinder? {
+        var ret: IBinder? = null
+        try {
+            ret = super.onBind(intent)
+        } catch (e: Exception) {
+            Log.d(TAG, "Failed to bind to TileService", e)
+        }
+        return ret
+    }
+
+    override fun onClick() {
+        if (tunnel != null) {
+            unlockAndRun {
+                val tile = qsTile
+                if (tile != null) {
+                    tile.icon = if (tile.icon == iconOn) iconOff else iconOn
+                    tile.updateTile()
+                }
+                tunnel!!.setState(Tunnel.State.TOGGLE).whenComplete { _, t ->
+                    if (t == null) {
+                        updateTile()
+                    } else {
+                        val toggleIntent = Intent(this, TunnelToggleActivity::class.java)
+                        toggleIntent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK)
+                        startActivity(toggleIntent)
+                    }
+                }
+            }
+        } else {
+            val intent = Intent(this, MainActivity::class.java)
+            intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK)
+            startActivityAndCollapse(intent)
+        }
+    }
+
+    override fun onCreate() {
+        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.P) {
+            iconOn = Icon.createWithResource(this, R.drawable.ic_tile)
+            iconOff = iconOn
+            return
+        }
+        val icon = SlashDrawable(resources.getDrawable(R.drawable.ic_tile, Application.get().theme))
+        icon.setAnimationEnabled(false) /* Unfortunately we can't have animations, since Icons are marshaled. */
+        icon.setSlashed(false)
+        var b = Bitmap.createBitmap(icon.intrinsicWidth, icon.intrinsicHeight, Bitmap.Config.ARGB_8888)
+                ?: return
+        var c = Canvas(b)
+        icon.setBounds(0, 0, c.width, c.height)
+        icon.draw(c)
+        iconOn = Icon.createWithBitmap(b)
+        icon.setSlashed(true)
+        b = Bitmap.createBitmap(icon.intrinsicWidth, icon.intrinsicHeight, Bitmap.Config.ARGB_8888)
+                ?: return
+        c = Canvas(b)
+        icon.setBounds(0, 0, c.width, c.height)
+        icon.draw(c)
+        iconOff = Icon.createWithBitmap(b)
+    }
+
+    override fun onStartListening() {
+        Application.getTunnelManager().addOnPropertyChangedCallback(onTunnelChangedCallback)
+        if (tunnel != null) tunnel!!.addOnPropertyChangedCallback(onStateChangedCallback)
+        updateTile()
+    }
+
+    override fun onStopListening() {
+        if (tunnel != null) tunnel!!.removeOnPropertyChangedCallback(onStateChangedCallback)
+        Application.getTunnelManager().removeOnPropertyChangedCallback(onTunnelChangedCallback)
+    }
+
+    private fun updateTile() {
+        // Update the tunnel.
+        val newTunnel = Application.getTunnelManager().lastUsedTunnel
+        if (newTunnel != tunnel) {
+            if (tunnel != null) tunnel!!.removeOnPropertyChangedCallback(onStateChangedCallback)
+            tunnel = newTunnel
+            if (tunnel != null) tunnel!!.addOnPropertyChangedCallback(onStateChangedCallback)
+        }
+        // Update the tile contents.
+        val label: String
+        val state: Int
+        val tile = qsTile
+        if (tunnel != null) {
+            label = tunnel!!.name
+            state = if (tunnel!!.state == Tunnel.State.UP) Tile.STATE_ACTIVE else Tile.STATE_INACTIVE
+        } else {
+            label = getString(R.string.app_name)
+            state = Tile.STATE_INACTIVE
+        }
+        if (tile == null) return
+        tile.label = label
+        if (tile.state != state) {
+            tile.icon = if (state == Tile.STATE_ACTIVE) iconOn else iconOff
+            tile.state = state
+        }
+        tile.updateTile()
+    }
+
+    private inner class OnStateChangedCallback : OnPropertyChangedCallback() {
+        override fun onPropertyChanged(sender: Observable, propertyId: Int) {
+            if (sender != tunnel) {
+                sender.removeOnPropertyChangedCallback(this)
+                return
+            }
+            if (propertyId != 0 && propertyId != BR.state) return
+            updateTile()
+        }
+    }
+
+    private inner class OnTunnelChangedCallback : OnPropertyChangedCallback() {
+        override fun onPropertyChanged(sender: Observable, propertyId: Int) {
+            if (propertyId != 0 && propertyId != BR.lastUsedTunnel) return
+            updateTile()
+        }
+    }
+
+    companion object {
+        private val TAG = "WireGuard/" + QuickTileService::class.java.simpleName
+    }
+}
diff --git a/ui/src/main/java/com/wireguard/android/preference/VersionPreference.kt b/ui/src/main/java/com/wireguard/android/preference/VersionPreference.kt
index 6c5284ec..0734df45 100644
--- a/ui/src/main/java/com/wireguard/android/preference/VersionPreference.kt
+++ b/ui/src/main/java/com/wireguard/android/preference/VersionPreference.kt
@@ -43,7 +43,7 @@ class VersionPreference(context: Context, attrs: AttributeSet?) : Preference(con
     }
 
     init {
-        Application.getBackendAsync().thenAccept { backend: Backend ->
+        Application.getBackendAsync().thenAccept { backend ->
             versionSummary = getContext().getString(R.string.version_summary_checking, getBackendPrettyName(context, backend).toLowerCase(Locale.ENGLISH))
             Application.getAsyncWorker().supplyAsync(backend::getVersion).whenComplete { version, exception ->
                 versionSummary = if (exception == null)