Refactor help menu stuff into a controller

This is a clean up to action bar menu item pattern, we will use the same
pattern to build search icon on all pages in a later change.

Bug: 68814716
Test: robotests
Change-Id: Iedd3ec263e8ccb63ed75ec7a95b28c00878b1de4

src/com/android/settings/support/actionbar/HelpMenuController.java

@@ -0,0 +1,67 @@
+/*
+ * Copyright (C) 2017 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.settings.support.actionbar;
+
+import static com.android.settings.support.actionbar.HelpResourceProvider.HELP_URI_RESOURCE_KEY;
+
+import android.annotation.NonNull;
+import android.app.Activity;
+import android.app.Fragment;
+import android.os.Bundle;
+import android.view.Menu;
+import android.view.MenuInflater;
+
+import com.android.settingslib.HelpUtils;
+import com.android.settingslib.core.lifecycle.LifecycleObserver;
+import com.android.settingslib.core.lifecycle.ObservablePreferenceFragment;
+import com.android.settingslib.core.lifecycle.events.OnCreateOptionsMenu;
+
+/**
+ * A controller that adds help menu to any Settings page.
+ */
+public class HelpMenuController implements LifecycleObserver, OnCreateOptionsMenu {
+
+    private final Fragment mHost;
+
+    public static void init(@NonNull ObservablePreferenceFragment host) {
+        host.getLifecycle().addObserver(new HelpMenuController(host));
+    }
+
+    private HelpMenuController(@NonNull Fragment host) {
+        mHost = host;
+    }
+
+    @Override
+    public void onCreateOptionsMenu(Menu menu, MenuInflater inflater) {
+        final Bundle arguments = mHost.getArguments();
+        int helpResourceId = 0;
+        if (arguments != null && arguments.containsKey(HELP_URI_RESOURCE_KEY)) {
+            helpResourceId = arguments.getInt(HELP_URI_RESOURCE_KEY);
+        } else if (mHost instanceof HelpResourceProvider) {
+            helpResourceId = ((HelpResourceProvider) mHost).getHelpResource();
+        }
+
+        String helpUri = null;
+        if (helpResourceId != 0) {
+            helpUri = mHost.getContext().getString(helpResourceId);
+        }
+        final Activity activity = mHost.getActivity();
+        if (helpUri != null && activity != null) {
+            HelpUtils.prepareHelpMenuItem(activity, menu, helpUri, mHost.getClass().getName());
+        }
+    }
+}

src/com/android/settings/support/actionbar/HelpResourceProvider.java

@@ -0,0 +1,36 @@
+/*
+ * Copyright (C) 2017 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.settings.support.actionbar;
+
+import com.android.settings.R;
+
+public interface HelpResourceProvider {
+    /**
+     * The Help Uri Resource key. This can be passed as an extra argument when creating the
+     * Fragment.
+     **/
+    String HELP_URI_RESOURCE_KEY = "help_uri_resource";
+
+    /**
+     * Override this if you want to show a help item in the menu, by returning the resource id.
+     *
+     * @return the resource id for the help url
+     */
+    default int getHelpResource() {
+        return R.string.help_uri_default;
+    }
+}