theme: add dark theme with toggle

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

app/src/main/java/com/wireguard/android/Application.java

@@ -12,6 +12,7 @@ import android.os.AsyncTask;
 import android.os.Handler;
 import android.os.Looper;
 import android.preference.PreferenceManager;
+import android.support.v7.app.AppCompatDelegate;
 
 import com.wireguard.android.backend.Backend;
 import com.wireguard.android.backend.GoBackend;
@@ -22,6 +23,7 @@ import com.wireguard.android.model.TunnelManager;
 import com.wireguard.android.util.AsyncWorker;
 import com.wireguard.android.util.RootShell;
 import com.wireguard.android.util.ToolsInstaller;
+import com.wireguard.android.util.Topic;
 
 import java.io.File;
 import java.util.concurrent.Executor;
@@ -66,6 +68,8 @@ public class Application extends android.app.Application {
         ToolsInstaller getToolsInstaller();
 
         TunnelManager getTunnelManager();
+
+        Topic getThemeChangeTopic();
     }
 
     @Qualifier
@@ -86,6 +90,10 @@ public class Application extends android.app.Application {
 
         private ApplicationModule(final Application application) {
             context = application.getApplicationContext();
+
+            AppCompatDelegate.setDefaultNightMode(
+                    getPreferences(context).getBoolean("dark_theme", false) ?
+                          AppCompatDelegate.MODE_NIGHT_YES : AppCompatDelegate.MODE_NIGHT_NO);
         }
 
         @ApplicationScope
@@ -111,6 +119,12 @@ public class Application extends android.app.Application {
             return new FileConfigStore(context);
         }
 
+        @ApplicationScope
+        @Provides
+        public static Topic getThemeChangeTopic() {
+            return new Topic();
+        }
+
 
         @ApplicationScope
         @Provides

app/src/main/java/com/wireguard/android/activity/BaseActivity.java

@@ -16,6 +16,7 @@ import com.wireguard.android.Application;
 import com.wireguard.android.backend.GoBackend;
 import com.wireguard.android.model.Tunnel;
 import com.wireguard.android.model.TunnelManager;
+import com.wireguard.android.util.Topic;
 
 import java.util.Objects;
 
@@ -23,7 +24,7 @@ import java.util.Objects;
  * Base class for activities that need to remember the currently-selected tunnel.
  */
 
-public abstract class BaseActivity extends AppCompatActivity {
+public abstract class BaseActivity extends AppCompatActivity implements Topic.Subscriber {
     private static final String KEY_SELECTED_TUNNEL = "selected_tunnel";
 
     private final SelectionChangeRegistry selectionChangeRegistry = new SelectionChangeRegistry();
@@ -40,6 +41,8 @@ public abstract class BaseActivity extends AppCompatActivity {
 
     @Override
     protected void onCreate(final Bundle savedInstanceState) {
+        subscribeTopics();
+
         // Restore the saved tunnel if there is one; otherwise grab it from the arguments.
         String savedTunnelName = null;
         if (savedInstanceState != null)
@@ -62,6 +65,12 @@ public abstract class BaseActivity extends AppCompatActivity {
         }
     }
 
+    @Override
+    protected void onDestroy() {
+        unsubscribeTopics();
+        super.onDestroy();
+    }
+
     @Override
     protected void onSaveInstanceState(final Bundle outState) {
         if (selectedTunnel != null)
@@ -105,4 +114,14 @@ public abstract class BaseActivity extends AppCompatActivity {
             super(new SelectionChangeNotifier());
         }
     }
+
+    @Override
+    public void onTopicPublished(Topic topic) {
+        recreate();
+    }
+
+    @Override
+    public Topic[] getSubscription() {
+        return new Topic[] { Application.getComponent().getThemeChangeTopic() };
+    }
 }

app/src/main/java/com/wireguard/android/activity/SettingsActivity.java

@@ -6,12 +6,14 @@
 
 package com.wireguard.android.activity;
 
+import android.content.SharedPreferences;
 import android.content.pm.PackageManager;
 import android.os.Bundle;
 import android.support.annotation.NonNull;
 import android.support.v4.app.ActivityCompat;
 import android.support.v4.content.ContextCompat;
 import android.support.v7.app.AppCompatActivity;
+import android.support.v7.app.AppCompatDelegate;
 import android.support.v7.preference.Preference;
 import android.support.v7.preference.PreferenceFragmentCompat;
 import android.view.MenuItem;
@@ -19,6 +21,7 @@ import android.view.MenuItem;
 import com.wireguard.android.Application;
 import com.wireguard.android.R;
 import com.wireguard.android.backend.WgQuickBackend;
+import com.wireguard.android.util.Topic;
 
 import java.util.ArrayList;
 import java.util.Arrays;
@@ -30,7 +33,7 @@ import java.util.Map;
  * Interface for changing application-global persistent settings.
  */
 
-public class SettingsActivity extends AppCompatActivity {
+public class SettingsActivity extends AppCompatActivity implements Topic.Subscriber {
     private final Map<Integer, PermissionRequestCallback> permissionRequestCallbacks = new HashMap<>();
     private int permissionRequestCounter;
 
@@ -56,6 +59,7 @@ public class SettingsActivity extends AppCompatActivity {
     @Override
     protected void onCreate(final Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
+        subscribeTopics();
         if (getSupportFragmentManager().findFragmentById(android.R.id.content) == null) {
             getSupportFragmentManager().beginTransaction()
                     .add(android.R.id.content, new SettingsFragment())
@@ -63,6 +67,12 @@ public class SettingsActivity extends AppCompatActivity {
         }
     }
 
+    @Override
+    protected void onDestroy() {
+        unsubscribeTopics();
+        super.onDestroy();
+    }
+
     @Override
     public boolean onOptionsItemSelected(final MenuItem item) {
         switch (item.getItemId()) {
@@ -89,7 +99,17 @@ public class SettingsActivity extends AppCompatActivity {
         void done(String[] permissions, int[] grantResults);
     }
 
-    public static class SettingsFragment extends PreferenceFragmentCompat {
+    @Override
+    public void onTopicPublished(Topic topic) {
+        recreate();
+    }
+
+    @Override
+    public Topic[] getSubscription() {
+        return new Topic[] { Application.getComponent().getThemeChangeTopic() };
+    }
+
+    public static class SettingsFragment extends PreferenceFragmentCompat implements SharedPreferences.OnSharedPreferenceChangeListener {
         @Override
         public void onCreatePreferences(final Bundle savedInstanceState, final String key) {
             addPreferencesFromResource(R.xml.preferences);
@@ -100,5 +120,26 @@ public class SettingsActivity extends AppCompatActivity {
                 getPreferenceScreen().removePreference(pref);
             }
         }
+
+        @Override
+        public void onResume() {
+            super.onResume();
+            getPreferenceManager().getSharedPreferences().registerOnSharedPreferenceChangeListener(this);
+        }
+
+        @Override
+        public void onPause() {
+            getPreferenceManager().getSharedPreferences().unregisterOnSharedPreferenceChangeListener(this);
+            super.onPause();
+        }
+
+        @Override
+        public void onSharedPreferenceChanged(SharedPreferences sharedPreferences, String key) {
+            if ("dark_theme".equals(key)) {
+                AppCompatDelegate.setDefaultNightMode(
+                        sharedPreferences.getBoolean(key, false) ? AppCompatDelegate.MODE_NIGHT_YES : AppCompatDelegate.MODE_NIGHT_NO);
+                Application.getComponent().getThemeChangeTopic().publish(false);
+            }
+        }
     }
 }

app/src/main/java/com/wireguard/android/util/Topic.java

@@ -0,0 +1,97 @@
+/*
+ * Copyright © 2017 John Wu <topjohnwu@gmail.com>
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+
+package com.wireguard.android.util;
+
+import java.lang.ref.WeakReference;
+import java.util.Iterator;
+import java.util.LinkedList;
+import java.util.List;
+
+public class Topic {
+
+    private static final int NON_INIT = 0;
+    private static final int PENDING = 1;
+    private static final int PUBLISHED = 2;
+
+    private int state = NON_INIT;
+    private List<WeakReference<Subscriber>> subscribers;
+    private Object[] results;
+
+    public void subscribe(Subscriber sub) {
+        if (subscribers == null) {
+            subscribers = new LinkedList<>();
+        }
+        subscribers.add(new WeakReference<>(sub));
+    }
+
+    public void unsubscribe() {
+        subscribers = null;
+    }
+
+    public void unsubscribe(Subscriber sub) {
+        for (Iterator<WeakReference<Subscriber>> i = subscribers.iterator(); i.hasNext();) {
+            WeakReference<Subscriber> subscriber = i.next();
+            if (subscriber.get() == null || subscriber.get() == sub) {
+                i.remove();
+            }
+        }
+    }
+
+    public void reset() {
+        state = NON_INIT;
+        results = null;
+    }
+
+    public boolean isPublished() {
+        return state == PUBLISHED;
+    }
+
+    public void publish() {
+        publish(true);
+    }
+
+    public void publish(boolean record, Object... results) {
+        if (record)
+            state = PUBLISHED;
+        this.results = results;
+        if (subscribers != null) {
+            for (WeakReference<Subscriber> subscriber : subscribers) {
+                if (subscriber.get() != null)
+                    subscriber.get().onTopicPublished(this);
+            }
+        }
+    }
+
+    public Object[] getResults() {
+        return results;
+    }
+
+    public boolean isPending() {
+        return state == PENDING;
+    }
+
+    public void setPending() {
+        state = PENDING;
+    }
+
+    public interface Subscriber {
+        default void subscribeTopics() {
+            for (Topic topic : getSubscription()) {
+                if (topic.isPublished()) {
+                    onTopicPublished(topic);
+                }
+                topic.subscribe(this);
+            }
+        }
+        default void unsubscribeTopics() {
+            for (Topic event : getSubscription()) {
+                event.unsubscribe(this);
+            }
+        }
+        void onTopicPublished(Topic topic);
+        Topic[] getSubscription();
+    }
+}

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

@@ -29,6 +29,9 @@
     <string name="create_activity_title">Create WireGuard Tunnel</string>
     <string name="create_empty">Create from scratch</string>
     <string name="create_from_file">Create from file or archive</string>
+    <string name="dark_theme_title">Use dark theme</string>
+    <string name="dark_theme_summary_on">Currently using dark night theme</string>
+    <string name="dark_theme_summary_off">Currently using light day theme</string>
     <string name="delete">Delete</string>
     <string name="dns_servers">DNS servers</string>
     <string name="edit">Edit</string>

app/src/main/res/xml/preferences.xml

@@ -7,4 +7,10 @@
         android:title="@string/restore_on_boot_title" />
     <com.wireguard.android.preference.ToolsInstallerPreference android:key="tools_installer" />
     <com.wireguard.android.preference.ZipExporterPreference android:key="zip_exporter" />
+    <CheckBoxPreference
+        android:defaultValue="false"
+        android:key="dark_theme"
+        android:summaryOn="@string/dark_theme_summary_on"
+        android:summaryOff="@string/dark_theme_summary_off"
+        android:title="@string/dark_theme_title" />
 </PreferenceScreen>