Issue 4399 - Add WebView inheritor with ad blocking

libadblockplus-android-settings/src/org/adblockplus/libadblockplus/android/settings/BaseSettingsFragment.java

Index: libadblockplus-android-settings/src/org/adblockplus/libadblockplus/android/settings/BaseSettingsFragment.java
diff --git a/libadblockplus-android-settings/src/org/adblockplus/libadblockplus/android/settings/BaseSettingsFragment.java b/libadblockplus-android-settings/src/org/adblockplus/libadblockplus/android/settings/BaseSettingsFragment.java
new file mode 100644
index 0000000000000000000000000000000000000000..443e1ce93361592d5385f7ffe48287cf927ad377
--- /dev/null
+++ b/libadblockplus-android-settings/src/org/adblockplus/libadblockplus/android/settings/BaseSettingsFragment.java
@@ -0,0 +1,122 @@
+/*
+ * This file is part of Adblock Plus <https://adblockplus.org/>,
+ * Copyright (C) 2006-2016 Eyeo GmbH
+ *
+ * Adblock Plus is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 3 as
+ * published by the Free Software Foundation.
+ *
+ * Adblock Plus is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with Adblock Plus.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+package org.adblockplus.libadblockplus.android.settings;
+
+import android.app.Activity;
+import android.os.Bundle;
+import android.preference.PreferenceFragment;
+import android.util.Log;
+
+import org.adblockplus.libadblockplus.android.AdblockEngine;
+import org.adblockplus.libadblockplus.android.Utils;
+
+public abstract class BaseSettingsFragment
+  <ListenerClass extends BaseSettingsFragment.Listener>
+  extends PreferenceFragment
+{
+  protected final String TAG = Utils.getTag(this.getClass());
+  protected AdblockSettings settings;
+  protected Provider provider;
+  protected ListenerClass listener;
+
+  /**
+   * Provides AdblockEngine and SharedPreferences to store settings
+   * (activity holding BaseSettingsFragment fragment should implement this interface)
+   */
+  public interface Provider
+  {
+    AdblockEngine getAdblockEngine();
+    AdblockSettingsStorage getAdblockSettingsStorage();
+  }
+
+  /**
+   * Listens for Adblock settings events
+   */
+  public interface Listener
+  {
+    /**
+     * `Settings were changed` callback
+     * Note: settings are available using BaseSettingsFragment.getSettings()
+     *
+     * @param fragment fragment
+     */
+    void onAdblockSettingsChanged(BaseSettingsFragment fragment);
+  }
+
+  protected <T> T castOrThrow(Activity activity, Class<T> clazz)
+  {
+    if (!(activity instanceof Provider))
+    {
+      String message = activity.getClass().getSimpleName()
+        + " should implement "
+        + clazz.getSimpleName()
+        + " interface";
+
+      Log.e(TAG, message);
+      throw new RuntimeException(message);
+    }
+
+    return (T) activity;
+  }
+
+  public void loadSettings()
+  {
+    settings = provider.getAdblockSettingsStorage().load();
+    if (settings == null)
+    {
+      Log.w(TAG, "No adblock settings, yet. Using defdault ones from adblock engine");
+
+      // null because it was not saved yet
+      settings = AdblockSettingsStorage.getDefaultSettings(provider.getAdblockEngine());
+    }
+  }
+
+  @Override
+  public void onCreate(Bundle savedInstanceState)
+  {
+    super.onCreate(savedInstanceState);
+    loadSettings();
+  }
+
+  @Override
+  public void onAttach(Activity activity)
+  {
+    super.onAttach(activity);
+    provider = castOrThrow(activity, Provider.class);
+  }
+
+  @Override
+  public void onResume()
+  {
+    super.onResume();
+    loadSettings();
+  }
+
+  public AdblockSettings getSettings()
+  {
+    return settings;
+  }
+
+  @Override
+  public void onDetach()
+  {
+    super.onDetach();
+    provider = null;
+    listener = null;
+  }
+}