Upstreaming AppMenu.

chrome/android/java/src/org/chromium/chrome/browser/appmenu/AppMenuHandler.java

+// Copyright 2013 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+package org.chromium.chrome.browser.appmenu;
+
+import android.app.Activity;
+import android.view.ContextThemeWrapper;
+import android.view.Menu;
+import android.view.View;
+import android.widget.PopupMenu;
+
+import org.chromium.chrome.R;
+import org.chromium.chrome.browser.UmaBridge;
+
+import java.util.ArrayList;
+
+/**
+ * Object responsible for handling the creation, showing, hiding of the AppMenu and notifying the
+ * AppMenuObservers about these actions.
+ */
+public class AppMenuHandler {
+    private AppMenu mAppMenu;
+    private Menu mMenu;
+    private final ArrayList<AppMenuObserver> mObservers;
+
+    private final AppMenuPropertiesDelegate mDelegate;
+    private final Activity mActivity;
+
+    /**
+     * Constructs an AppMenuHandler object.
+     * @param activity Activity that is using the AppMenu.
+     * @param delegate Delegate used to check the desired AppMenu properties on show.
+     */
+    public AppMenuHandler(Activity activity, AppMenuPropertiesDelegate delegate) {
+        mActivity = activity;
+        mDelegate = delegate;
+        mObservers = new ArrayList<AppMenuObserver>();
+    }
+
+    /**
+     * Show the app menu.
+     * @param anchorView         Anchor view (usually a menu button) to be used for the popup.
+     * @param isByHardwareButton True if hardware button triggered it. (oppose to software
+     *                           button)
+     * @param startDragging      Whether dragging is started. For example, if the app menu is
+     *                           showed by tapping on a button, this should be false. If it is
+     *                           showed by start dragging down on the menu button, this should
+     *                           be true. Note that if isByHardwareButton is true, this is
+     *                           ignored.
+     * @return True, if the menu is shown, false, if menu is not shown, example reasons:
+     *         the menu is not yet available to be shown, or the menu is already showing.
+     */
+    public boolean showAppMenu(View anchorView, boolean isByHardwareButton, boolean startDragging) {
+        if (!mDelegate.shouldShowAppMenu()) return false;
+
+        if (mMenu == null) {
+            // Use a PopupMenu to create the Menu object. Note this is not the same as the
+            // AppMenu (mAppMenu) created below.
+            PopupMenu tempMenu = new PopupMenu(mActivity, anchorView);
+            tempMenu.inflate(R.menu.main_menu);
+            mMenu = tempMenu.getMenu();
+        }
+        mDelegate.prepareMenu(mMenu);
+
+        if (mAppMenu == null) {
+            mAppMenu = new AppMenu(mActivity, mMenu, mDelegate.getItemRowHeight(), this);
+        }
+
+        ContextThemeWrapper wrapper = new ContextThemeWrapper(mActivity,
+                mDelegate.getMenuThemeResourceId());
+        boolean showIcons = mDelegate.shouldShowIconRow();
+        mAppMenu.show(wrapper, anchorView, showIcons, isByHardwareButton, startDragging);
+        UmaBridge.menuShow();
+        return true;
+    }
+
+    /**
+     * @return Whether the App Menu is currently showing.
+     */
+    public boolean isAppMenuShowing() {
+        return mAppMenu != null && mAppMenu.isShowing();
+    }
+
+    /**
+     * @return The App Menu that the menu handler is interacting with.
+     */
+    AppMenu getAppMenu() {
+        return mAppMenu;
+    }
+
+    /**
+     * Requests to hide the App Menu.
+     */
+    public void hideAppMenu() {
+        if (mAppMenu != null && mAppMenu.isShowing()) mAppMenu.dismiss();
+    }
+
+    /**
+     * @return The number of items in the AppMenu.
+     */
+    public int getItemCount() {
+        if (mAppMenu == null) return -1;
+        return mAppMenu.getCount();
+    }
+
+    /**
+     * Adds the observer to App Menu.
+     * @param observer Observer that should be notified about App Menu changes.
+     */
+    public void addObserver(AppMenuObserver observer) {
+        mObservers.add(observer);
+    }
+
+    /**
+     * Removes the observer from the App Menu.
+     * @param observer Observer that should no longer be notified about App Menu changes.
+     */
+    public void removeObserver(AppMenuObserver observer) {
+        mObservers.remove(observer);
+    }
+
+    /**
+     * Called by AppMenu to report that the App Menu visibility has changed.
+     * @param newState Whether the App Menu is showing.
+     * @param focusedPosition The current focused position.
+     */
+    void onMenuVisibilityChanged(boolean newState, int focusedPosition) {
+        for (int i = 0; i < mObservers.size(); ++i) {
+            mObservers.get(i).onMenuVisibilityChanged(newState, focusedPosition);
+        }
+    }
+
+    /**
+     * Called by AppMenu to report that the keyboard focus has changed.
+     * @param focusedPosition The new focused position.
+     */
+    void onKeyboardFocusChanged(int focusedPosition) {
+        for (int i = 0; i < mObservers.size(); ++i) {
+            mObservers.get(i).onKeyboardFocusChanged(focusedPosition);
+        }
+    }
+
+    /**
+     * Called by AppMenu to report that the keyboard has activated an item.
+     * @param focusedPosition The activated item.
+     */
+    void onKeyboardActivatedItem(int focusedPosition) {
+        for (int i = 0; i < mObservers.size(); ++i) {
+            mObservers.get(i).onKeyboardActivatedItem(focusedPosition);
+        }
+    }
+
+    /**
+     * TODO(kkimlabs) remove this call.
+     */
+    public void hardwareMenuButtonUp() {
+        if (mAppMenu != null) mAppMenu.hardwareMenuButtonUp();
+    }
+}