Bug 1494026 - Part 1: Add link to OS app notification settings. r=VladBaicu

Starting from Android O, more fine-grained control over which notifications
should be displayed is available through Android's notification channel system.
To aid discoverability, we add a link to the corresponding settings screen from
inside our own settings menu.

Differential Revision: https://phabricator.services.mozilla.com/D29973

--HG--
extra : moz-landing-system : lando

mobile/android/app/src/main/res/xml/preferences_notifications.xml

@@ -1,5 +1,8 @@
 <?xml version="1.0" encoding="utf-8"?>
 <PreferenceScreen xmlns:android="http://schemas.android.com/apk/res/android">
+    <org.mozilla.gecko.preferences.NotificationSettingsLinkPreference
+        android:key="android.not_a_preference.notifications.settings_link"
+        android:title="@string/pref_notification_settings_link" />
     <SwitchPreference android:key="android.not_a_preference.notifications.whats_new"
         android:title="@string/pref_whats_new_notification"
         android:summary="@string/pref_whats_new_notification_summary"

mobile/android/base/java/org/mozilla/gecko/preferences/GeckoPreferences.java

@@ -155,6 +155,7 @@ public class GeckoPreferences
     private static final String PREFS_FAQ_LINK = NON_PREF_PREFIX + "faq.link";
     private static final String PREFS_FEEDBACK_LINK = NON_PREF_PREFIX + "feedback.link";
     private static final String PREFS_SCREEN_NOTIFICATIONS = NON_PREF_PREFIX + "notifications_screen";
+    private static final String PREFS_NOTIFICATIONS_SETTINGS_LINK = NON_PREF_PREFIX + "notifications.settings_link";
     public static final String PREFS_NOTIFICATIONS_WHATS_NEW = NON_PREF_PREFIX + "notifications.whats_new";
     public static final String PREFS_NOTIFICATIONS_FEATURES_TIPS = NON_PREF_PREFIX + "notifications.features.tips";
     public static final String PREFS_APP_UPDATE_LAST_BUILD_ID = "app.update.last_build_id";
@@ -849,6 +850,12 @@ public class GeckoPreferences
                         i--;
                         continue;
                     }
+                } else if (PREFS_NOTIFICATIONS_SETTINGS_LINK.equals(key)) {
+                    if (!showNotificationSettingsLink()) {
+                        preferences.removePreference(pref);
+                        i--;
+                        continue;
+                    }
                 } else if (PREFS_NOTIFICATIONS_WHATS_NEW.equals(key)) {
                     if (!SwitchBoard.isInExperiment(this, Experiments.WHATSNEW_NOTIFICATION)) {
                         preferences.removePreference(pref);
@@ -1533,8 +1540,14 @@ public class GeckoPreferences
         return GeckoPreferences.getBooleanPref(context, PREFS_HEALTHREPORT_UPLOAD_ENABLED, true);
     }
 
+    private static boolean showNotificationSettingsLink() {
+        // Notification channels are available starting from Oreo.
+        return AppConstants.Versions.feature26Plus;
+    }
+
     private static boolean haveNotificationsPreferences(@NonNull Context context) {
-        return SwitchBoard.isInExperiment(context, Experiments.WHATSNEW_NOTIFICATION) ||
+        return showNotificationSettingsLink() ||
+                SwitchBoard.isInExperiment(context, Experiments.WHATSNEW_NOTIFICATION) ||
                 MmaDelegate.isMmaExperimentEnabled(context);
     }
 }

mobile/android/base/java/org/mozilla/gecko/preferences/NotificationSettingsLinkPreference.java

@@ -0,0 +1,38 @@
+/* -*- Mode: Java; c-basic-offset: 4; tab-width: 4; indent-tabs-mode: nil; -*-
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.preferences;
+
+import android.annotation.TargetApi;
+import android.content.Context;
+import android.content.Intent;
+import android.preference.Preference;
+import android.provider.Settings;
+import android.util.AttributeSet;
+
+/**
+ * On Android O and following, this will open the app's OS notification settings when clicked on.
+ */
+public class NotificationSettingsLinkPreference extends Preference {
+    public NotificationSettingsLinkPreference(Context context, AttributeSet attrs) {
+        super(context, attrs);
+    }
+    public NotificationSettingsLinkPreference(Context context, AttributeSet attrs, int defStyle) {
+        super(context, attrs, defStyle);
+    }
+
+    @Override
+    protected void onClick() {
+        final Context context = getContext();
+        final Intent intent = getLinkIntent(context);
+        context.startActivity(intent);
+    }
+
+    @TargetApi(26)
+    private Intent getLinkIntent(final Context context) {
+        return new Intent(Settings.ACTION_APP_NOTIFICATION_SETTINGS)
+                .putExtra(Settings.EXTRA_APP_PACKAGE, context.getPackageName());
+    }
+}

mobile/android/base/locales/en-US/android_strings.dtd

@@ -919,6 +919,7 @@ Picture-in-picture mini window -->
 <!ENTITY pip_pause_button_title "Pause">
 <!ENTITY pip_pause_button_description "Pause playing">
 
+<!ENTITY pref_notification_settings_link "Manage notification settings">
 <!-- Notification channels names -->
 <!ENTITY default_notification_channel2 "Browser">
 <!ENTITY mls_notification_channel "&vendorShortName; Location Service">

mobile/android/base/strings.xml.in

@@ -659,6 +659,7 @@
   <string name="pip_pause_button_title">&pip_pause_button_title;</string>
   <string name="pip_pause_button_description">&pip_pause_button_description;</string>
 
+  <string name="pref_notification_settings_link">&pref_notification_settings_link;</string>
   <string name="default_notification_channel2">&default_notification_channel2;</string>
   <string name="mls_notification_channel">&mls_notification_channel;</string>
   <string name="media_notification_channel2">&media_notification_channel2;</string>