src/com/android/mail/ui/MailActionBarView.java

/*
 * Copyright (C) 2012 Google Inc.
 * Licensed to 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.mail.ui;

import android.app.ActionBar;
import android.app.SearchManager;
import android.app.SearchableInfo;
import android.content.ContentResolver;
import android.content.Context;
import android.content.res.Resources;
import android.database.Cursor;
import android.net.Uri;
import android.os.AsyncTask;
import android.os.Build;
import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
import android.text.TextUtils;
import android.util.AttributeSet;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewConfiguration;
import android.widget.LinearLayout;
import android.widget.SearchView;
import android.widget.SearchView.OnQueryTextListener;
import android.widget.SearchView.OnSuggestionListener;
import android.widget.TextView;

import com.android.mail.ConversationListContext;
import com.android.mail.R;
import com.android.mail.preferences.MailPrefs;
import com.android.mail.providers.Account;
import com.android.mail.providers.AccountObserver;
import com.android.mail.providers.Conversation;
import com.android.mail.providers.Folder;
import com.android.mail.providers.FolderObserver;
import com.android.mail.providers.SearchRecentSuggestionsProvider;
import com.android.mail.providers.UIProvider;
import com.android.mail.providers.UIProvider.AccountCapabilities;
import com.android.mail.providers.UIProvider.FolderCapabilities;
import com.android.mail.providers.UIProvider.FolderType;
import com.android.mail.utils.LogTag;
import com.android.mail.utils.LogUtils;
import com.android.mail.utils.Utils;

/**
 * View to manage the various states of the Mail Action Bar.
 * <p>
 * This also happens to be the custom view we supply to ActionBar.
 *
 */
public class MailActionBarView extends LinearLayout implements ViewMode.ModeChangeListener,
        OnQueryTextListener, OnSuggestionListener, MenuItem.OnActionExpandListener,
        View.OnClickListener {

    protected ActionBar mActionBar;
    protected ControllableActivity mActivity;
    protected ActivityController mController;
    /**
     * The current mode of the ActionBar and Activity
     */
    private ViewMode mViewModeController;

    private MenuItem mSearch;
    /**
     * The account currently being shown
     */
    private Account mAccount;
    /**
     * The folder currently being shown
     */
    private Folder mFolder;

    private SearchView mSearchWidget;
    private MenuItem mHelpItem;
    private MenuItem mSendFeedbackItem;
    private MenuItem mFolderSettingsItem;
    private MenuItem mEmptyTrashItem;
    private MenuItem mEmptySpamItem;
    private boolean mUseLegacyTitle;
    private View mLegacyTitleContainer;
    private TextView mLegacyTitle;
    private TextView mLegacySubTitle;

    /** True if the current device is a tablet, false otherwise. */
    protected final boolean mIsOnTablet;
    private Conversation mCurrentConversation;

    public static final String LOG_TAG = LogTag.getLogTag();

    private FolderObserver mFolderObserver;

    /** A handler that changes the subtitle when it receives a message. */
    private final class SubtitleHandler extends Handler {
        /** Message sent to display the account email address in the subtitle. */
        private static final int EMAIL = 0;

        @Override
        public void handleMessage(Message message) {
            assert (message.what == EMAIL);
            final String subtitleText;
            if (mAccount != null) {
                // Display the account name (email address).
                subtitleText = mAccount.name;
            } else {
                subtitleText = null;
                LogUtils.wtf(LOG_TAG, "MABV.handleMessage() has a null account!");
            }
            setSubtitle(subtitleText);
            super.handleMessage(message);
        }
    }

    /** Changes the subtitle to display the account name */
    private final SubtitleHandler mHandler = new SubtitleHandler();
    /** Unread count for the current folder. */
    private int mUnreadCount = 0;
    /** We show the email address after this delay: 5 seconds currently */
    private static final int ACCOUNT_DELAY_MS = 5 * 1000;
    /** At what point do we stop showing the unread count: 999+ currently */
    private final int UNREAD_LIMIT;

    /** Updates the resolver and tells it the most recent account. */
    private final class UpdateProvider extends AsyncTask<Bundle, Void, Void> {
        final Uri mAccount;
        final ContentResolver mResolver;
        public UpdateProvider(Uri account, ContentResolver resolver) {
            mAccount = account;
            mResolver = resolver;
        }

        @Override
        protected Void doInBackground(Bundle... params) {
            mResolver.call(mAccount, UIProvider.AccountCallMethods.SET_CURRENT_ACCOUNT,
                    mAccount.toString(), params[0]);
            return null;
        }
    }

    private final AccountObserver mAccountObserver = new AccountObserver() {
        @Override
        public void onChanged(Account newAccount) {
            updateAccount(newAccount);
        }
    };

    public MailActionBarView(Context context) {
        this(context, null);
    }

    public MailActionBarView(Context context, AttributeSet attrs) {
        this(context, attrs, 0);
    }

    public MailActionBarView(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);
        final Resources r = getResources();
        mIsOnTablet = Utils.useTabletUI(r);
        UNREAD_LIMIT = r.getInteger(R.integer.maxUnreadCount);
    }

    private void initializeTitleViews() {
        mLegacyTitleContainer = findViewById(R.id.legacy_title_container);
        if (mLegacyTitleContainer != null) {
            // Determine if this device is running on MR1.1 or later
            final boolean runningMR11OrLater = actionBarSupportsNewMethods(mActionBar);
            if (runningMR11OrLater || !mController.isDrawerEnabled()) {
                // We don't need the legacy view, just hide it
                mLegacyTitleContainer.setVisibility(View.GONE);
                mUseLegacyTitle = false;
            } else {
                mUseLegacyTitle = true;
                // We need to show the legacy title/subtitle.  Set the click listener
                mLegacyTitleContainer.setOnClickListener(this);

                mLegacyTitle = (TextView)mLegacyTitleContainer.findViewById(R.id.legacy_title);
                mLegacySubTitle =
                        (TextView)mLegacyTitleContainer.findViewById(R.id.legacy_subtitle);
            }
        }
    }

    public void expandSearch() {
        if (mSearch != null) {
            mSearch.expandActionView();
        }
    }

    /**
     * Close the search view if it is expanded.
     */
    public void collapseSearch() {
        if (mSearch != null) {
            mSearch.collapseActionView();
        }
    }

    /**
     * Get the search menu item.
     */
    protected MenuItem getSearch() {
        return mSearch;
    }

    public boolean onCreateOptionsMenu(Menu menu) {
        // If the mode is valid, then set the initial menu
        if (getMode() == ViewMode.UNKNOWN) {
            return false;
        }
        mSearch = menu.findItem(R.id.search);
        if (mSearch != null) {
            mSearchWidget = (SearchView) mSearch.getActionView();
            mSearch.setOnActionExpandListener(this);
            SearchManager searchManager = (SearchManager) mActivity.getActivityContext()
                    .getSystemService(Context.SEARCH_SERVICE);
            if (searchManager != null && mSearchWidget != null) {
                SearchableInfo info = searchManager.getSearchableInfo(mActivity.getComponentName());
                mSearchWidget.setSearchableInfo(info);
                mSearchWidget.setOnQueryTextListener(this);
                mSearchWidget.setOnSuggestionListener(this);
                mSearchWidget.setIconifiedByDefault(true);
            }
        }
        mHelpItem = menu.findItem(R.id.help_info_menu_item);
        mSendFeedbackItem = menu.findItem(R.id.feedback_menu_item);
        mFolderSettingsItem = menu.findItem(R.id.folder_options);
        mEmptyTrashItem = menu.findItem(R.id.empty_trash);
        mEmptySpamItem = menu.findItem(R.id.empty_spam);
        return true;
    }

    public int getOptionsMenuId() {
        switch (getMode()) {
            case ViewMode.UNKNOWN:
                return R.menu.conversation_list_menu;
            case ViewMode.CONVERSATION:
                return R.menu.conversation_actions;
            case ViewMode.CONVERSATION_LIST:
                return R.menu.conversation_list_menu;
            case ViewMode.SEARCH_RESULTS_LIST:
                return R.menu.conversation_list_search_results_actions;
            case ViewMode.SEARCH_RESULTS_CONVERSATION:
                return R.menu.conversation_actions;
            case ViewMode.WAITING_FOR_ACCOUNT_INITIALIZATION:
                return R.menu.wait_mode_actions;
        }
        LogUtils.wtf(LOG_TAG, "Menu requested for unknown view mode");
        return R.menu.conversation_list_menu;
    }

    public void initialize(ControllableActivity activity, ActivityController callback,
            ActionBar actionBar) {
        mActionBar = actionBar;
        mController = callback;
        mActivity = activity;
        initializeTitleViews();

        mFolderObserver = new FolderObserver() {
            @Override
            public void onChanged(Folder newFolder) {
                onFolderUpdated(newFolder);
            }
        };
        // Return values are purposely discarded. Initialization happens quite early, and we don't
        // have a valid folder, or a valid list of accounts.
        mFolderObserver.initialize(mController);
        updateAccount(mAccountObserver.initialize(activity.getAccountController()));
    }

    private void updateAccount(Account account) {
        final boolean accountChanged = mAccount == null || !mAccount.uri.equals(account.uri);
        mAccount = account;
        if (mAccount != null && accountChanged) {
            final ContentResolver resolver = mActivity.getActivityContext().getContentResolver();
            final Bundle bundle = new Bundle(1);
            bundle.putParcelable(UIProvider.SetCurrentAccountColumns.ACCOUNT, account);
            final UpdateProvider updater = new UpdateProvider(mAccount.uri, resolver);
            updater.execute(bundle);
            setFolderAndAccount(false /* folderChanged */);
        }
    }

    /**
     * Called by the owner of the ActionBar to change the current folder.
     */
    public void setFolder(Folder folder) {
        mFolder = folder;
        setFolderAndAccount(true);
    }

    public void onDestroy() {
        if (mFolderObserver != null) {
            mFolderObserver.unregisterAndDestroy();
            mFolderObserver = null;
        }
        mAccountObserver.unregisterAndDestroy();
        mHandler.removeMessages(SubtitleHandler.EMAIL);
    }

    @Override
    public void onViewModeChanged(int newMode) {
        mActivity.invalidateOptionsMenu();
        mHandler.removeMessages(SubtitleHandler.EMAIL);
        // Check if we are either on a phone, or in Conversation mode on tablet. For these, the
        // recent folders is enabled.
        switch (getMode()) {
            case ViewMode.UNKNOWN:
                break;
            case ViewMode.CONVERSATION_LIST:
                showNavList();
                break;
            case ViewMode.SEARCH_RESULTS_CONVERSATION:
                mActionBar.setDisplayHomeAsUpEnabled(true);
                setEmptyMode();
                break;
            case ViewMode.CONVERSATION:
            case ViewMode.AD:
                closeSearchField();
                mActionBar.setDisplayHomeAsUpEnabled(true);
                setEmptyMode();
                break;
            case ViewMode.WAITING_FOR_ACCOUNT_INITIALIZATION:
                // We want the user to be able to switch accounts while waiting for an account
                // to sync.
                showNavList();
                break;
        }
    }

    /**
     * Close the search query entry field to avoid keyboard events, and to restore the actionbar
     * to non-search mode.
     */
    private void closeSearchField() {
        if (mSearch == null) {
            return;
        }
        mSearch.collapseActionView();
    }

    protected int getMode() {
        if (mViewModeController != null) {
            return mViewModeController.getMode();
        } else {
            return ViewMode.UNKNOWN;
        }
    }

    public boolean onPrepareOptionsMenu(Menu menu) {
        // We start out with every option enabled. Based on the current view, we disable actions
        // that are possible.
        LogUtils.d(LOG_TAG, "ActionBarView.onPrepareOptionsMenu().");

        if (mHelpItem != null) {
            mHelpItem.setVisible(mAccount != null
                    && mAccount.supportsCapability(AccountCapabilities.HELP_CONTENT));
        }
        if (mSendFeedbackItem != null) {
            mSendFeedbackItem.setVisible(mAccount != null
                    && mAccount.supportsCapability(AccountCapabilities.SEND_FEEDBACK));
        }
        if (mController.shouldHideMenuItems()) {
            // Shortcut: hide all remaining menu items if the drawer is shown
            final int size = menu.size();

            for (int i = 0; i < size; i++) {
                final MenuItem item = menu.getItem(i);
                final int id = item.getItemId();
                if (id != R.id.settings
                        && id != R.id.feedback_menu_item
                        && id != R.id.help_info_menu_item) {
                    item.setVisible(false);
                }
            }
            return false;
        }
        if (mFolderSettingsItem != null) {
            mFolderSettingsItem.setVisible(mFolder != null
                    && mFolder.supportsCapability(FolderCapabilities.SUPPORTS_SETTINGS));
        }
        if (mEmptyTrashItem != null) {
            mEmptyTrashItem.setVisible(mAccount != null && mFolder != null
                    && mAccount.supportsCapability(AccountCapabilities.EMPTY_TRASH)
                    && mFolder.isTrash() && mFolder.totalCount > 0);
        }
        if (mEmptySpamItem != null) {
            mEmptySpamItem.setVisible(mAccount != null && mFolder != null
                    && mAccount.supportsCapability(AccountCapabilities.EMPTY_SPAM)
                    && mFolder.isType(FolderType.SPAM) && mFolder.totalCount > 0);
        }

        switch (getMode()) {
            case ViewMode.CONVERSATION:
            case ViewMode.SEARCH_RESULTS_CONVERSATION:
                // We update the ActionBar options when we are entering conversation view because
                // waiting for the AbstractConversationViewFragment to do it causes duplicate icons
                // to show up during the time between the conversation is selected and the fragment
                // is added.
                setConversationModeOptions(menu);
                // We want to use the user's preferred menu items here
                final Resources resources = getResources();
                final int maxItems = resources.getInteger(R.integer.actionbar_max_items);
                final int hiddenItems = resources.getInteger(
                        R.integer.actionbar_hidden_non_cab_items_no_physical_button);
                final int totalItems = maxItems
                        - (ViewConfiguration.get(getContext()).hasPermanentMenuKey()
                                ? 0 : hiddenItems);
                reorderMenu(getContext(), mAccount, menu, totalItems);
                break;
            case ViewMode.CONVERSATION_LIST:
                // Show compose and search based on the account
                // The only option that needs to be disabled is search
                Utils.setMenuItemVisibility(menu, R.id.search,
                        mAccount.supportsCapability(AccountCapabilities.FOLDER_SERVER_SEARCH));
                break;
            case ViewMode.SEARCH_RESULTS_LIST:
                // Hide compose and search
                Utils.setMenuItemVisibility(menu, R.id.compose, false);
                Utils.setMenuItemVisibility(menu, R.id.search, false);
                break;
        }

        return false;
    }

    /**
     * Reorders the specified {@link Menu}, taking into account the user's Archive/Delete
     * preference.
     */
    public static void reorderMenu(final Context context, final Account account, final Menu menu,
            final int maxItems) {
        final String removalAction = MailPrefs.get(context).getRemovalAction(
                account.supportsCapability(AccountCapabilities.ARCHIVE));
        final boolean showArchive = MailPrefs.RemovalActions.ARCHIVE.equals(removalAction) ||
                MailPrefs.RemovalActions.ARCHIVE_AND_DELETE.equals(removalAction);
        final boolean showDelete = MailPrefs.RemovalActions.DELETE.equals(removalAction) ||
                MailPrefs.RemovalActions.ARCHIVE_AND_DELETE.equals(removalAction);

        // Do a first pass to extract necessary information on what is safe to display
        boolean archiveVisibleEnabled = false;
        boolean deleteVisibleEnabled = false;
        for (int i = 0; i < menu.size(); i++) {
            final MenuItem menuItem = menu.getItem(i);
            final int itemId = menuItem.getItemId();
            final boolean visible = menuItem.isVisible();
            final boolean enabled = menuItem.isEnabled();

            if (itemId == R.id.archive || itemId == R.id.remove_folder) {
                archiveVisibleEnabled |= (visible & enabled);
            } else if (itemId == R.id.delete || itemId == R.id.discard_drafts) {
                deleteVisibleEnabled |= (visible & enabled);
            }
        }

        int actionItems = 0;

        for (int i = 0; i < menu.size(); i++) {
            final MenuItem menuItem = menu.getItem(i);
            final int itemId = menuItem.getItemId();

            // We only want to promote it if it's visible and has an icon
            if (menuItem.isVisible() && menuItem.getIcon() != null) {
                if (itemId == R.id.archive || itemId == R.id.remove_folder) {
                    /*
                     * If this is disabled, and we want to show both archive and delete, we will
                     * hide archive (rather than showing it disabled), and take up one of our
                     * spaces. If we only want to show archive, we'll hide it, but not take up
                     * a space.
                     */
                    if (!menuItem.isEnabled() && showArchive) {
                        menuItem.setVisible(false);

                        if (showDelete) {
                            actionItems++;
                        }
                    } else {
                        /*
                         * We show this if the following are all true:
                         * 1. The user wants to display archive, or delete is not visible
                         * 2. We have room for it
                         */
                        if ((showArchive || !deleteVisibleEnabled) && actionItems < maxItems) {
                            menuItem.setShowAsAction(MenuItem.SHOW_AS_ACTION_ALWAYS);
                            actionItems++;
                        }
                    }
                } else if (itemId == R.id.delete || itemId == R.id.discard_drafts) {
                    /*
                     * We show this if the following are all true:
                     * 1. The user wants to display delete, or archive is not visible
                     * 2. We have room for it
                     */
                    if ((showDelete || !archiveVisibleEnabled) && actionItems < maxItems) {
                        menuItem.setShowAsAction(MenuItem.SHOW_AS_ACTION_ALWAYS);
                        actionItems++;
                    }
                } else if (itemId == R.id.change_folders) {
                    final boolean showChangeFolder = account
                            .supportsCapability(AccountCapabilities.MULTIPLE_FOLDERS_PER_CONV);
                    menuItem.setVisible(showChangeFolder);

                    if (showChangeFolder && actionItems < maxItems) {
                        menuItem.setShowAsAction(MenuItem.SHOW_AS_ACTION_ALWAYS);
                        actionItems++;
                    }
                } else if (itemId == R.id.search) {
                    menuItem.setShowAsAction(MenuItem.SHOW_AS_ACTION_ALWAYS
                            | MenuItem.SHOW_AS_ACTION_COLLAPSE_ACTION_VIEW);
                    actionItems++;
                } else {
                    if (actionItems < maxItems) {
                        menuItem.setShowAsAction(MenuItem.SHOW_AS_ACTION_ALWAYS);
                        actionItems++;
                    }
                }
            }
        }
    }

    /**
     * Put the ActionBar in List navigation mode.
     */
    private void showNavList() {
        setTitleModeFlags(getActionBarTitleModeFlag());
        setFolderAndAccount(false);
    }

    private void setSubtitle(CharSequence subtitle) {
        if (!TextUtils.equals(subtitle, mActionBar.getSubtitle())) {
            mActionBar.setSubtitle(subtitle);
        }
        if (mLegacySubTitle != null) {
            mLegacySubTitle.setText(subtitle);
        }
    }

    private void setTitle(CharSequence title) {
        if (!TextUtils.equals(title, mActionBar.getTitle())) {
            mActionBar.setTitle(title);
        }
        if (mLegacyTitle != null) {
            mLegacyTitle.setText(title);
        }
    }

    private int getActionBarTitleModeFlag() {
        return mUseLegacyTitle ? ActionBar.DISPLAY_SHOW_CUSTOM : ActionBar.DISPLAY_SHOW_TITLE;
    }

    /**
     * Set the actionbar mode to empty: no title, no subtitle, no custom view.
     */
    protected void setEmptyMode() {
        // Disable title/subtitle and the custom view by setting the bitmask to all off.
        setTitleModeFlags(0);
    }

    /**
     * Removes the back button from being shown
     */
    public void removeBackButton() {
        if (mActionBar == null) {
            return;
        }
        // Remove the back button but continue showing an icon.
        final int mask = ActionBar.DISPLAY_HOME_AS_UP | ActionBar.DISPLAY_SHOW_HOME;
        mActionBar.setDisplayOptions(ActionBar.DISPLAY_SHOW_HOME, mask);
        mActivity.getActionBar().setHomeButtonEnabled(false);
    }

    public void setBackButton() {
        if (mActionBar == null) {
            return;
        }
        // Show home as up, and show an icon.
        final int mask = ActionBar.DISPLAY_HOME_AS_UP | ActionBar.DISPLAY_SHOW_HOME;
        mActionBar.setDisplayOptions(mask, mask);
        mActivity.getActionBar().setHomeButtonEnabled(true);
    }

    @Override
    public boolean onQueryTextSubmit(String query) {
        if (mSearch != null) {
            mSearch.collapseActionView();
            mSearchWidget.setQuery("", false);
        }
        mController.executeSearch(query.trim());
        return true;
    }

    @Override
    public boolean onQueryTextChange(String newText) {
        return false;
    }

    // Next two methods are called when search suggestions are clicked.
    @Override
    public boolean onSuggestionSelect(int position) {
        return onSuggestionClick(position);
    }

    @Override
    public boolean onSuggestionClick(int position) {
        final Cursor c = mSearchWidget.getSuggestionsAdapter().getCursor();
        final boolean haveValidQuery = (c != null) && c.moveToPosition(position);
        if (!haveValidQuery) {
            LogUtils.d(LOG_TAG, "onSuggestionClick: Couldn't get a search query");
            // We haven't handled this query, but the default behavior will
            // leave EXTRA_ACCOUNT un-populated, leading to a crash. So claim
            // that we have handled the event.
            return true;
        }
        collapseSearch();
        // what is in the text field
        String queryText = mSearchWidget.getQuery().toString();
        // What the suggested query is
        String query = c.getString(c.getColumnIndex(SearchManager.SUGGEST_COLUMN_QUERY));
        // If the text the user typed in is a prefix of what is in the search
        // widget suggestion query, just take the search widget suggestion
        // query. Otherwise, it is a suffix and we want to remove matching
        // prefix portions.
        if (!TextUtils.isEmpty(queryText) && query.indexOf(queryText) != 0) {
            final int queryTokenIndex = queryText
                    .lastIndexOf(SearchRecentSuggestionsProvider.QUERY_TOKEN_SEPARATOR);
            if (queryTokenIndex > -1) {
                queryText = queryText.substring(0, queryTokenIndex);
            }
            // Since we auto-complete on each token in a query, if the query the
            // user typed up until the last token is a substring of the
            // suggestion they click, make sure we don't double include the
            // query text. For example:
            // user types john, that matches john palo alto
            // User types john p, that matches john john palo alto
            // Remove the first john
            // Only do this if we have multiple query tokens.
            if (queryTokenIndex > -1 && !TextUtils.isEmpty(query) && query.contains(queryText)
                    && queryText.length() < query.length()) {
                int start = query.indexOf(queryText);
                query = query.substring(0, start) + query.substring(start + queryText.length());
            }
        }
        mController.executeSearch(query.trim());
        return true;
    }

    /**
     * Uses the current state to update the current folder {@link #mFolder} and the current
     * account {@link #mAccount} shown in the actionbar. Also updates the actionbar subtitle to
     * momentarily display the unread count if it has changed.
     * @param folderChanged true if folder changed in terms of URI
     */
    private void setFolderAndAccount(final boolean folderChanged) {
        // Very little can be done if the actionbar or activity is null.
        if (mActionBar == null || mActivity == null) {
            return;
        }
        if (ViewMode.isWaitingForSync(getMode())) {
            // Account is not synced: clear title and update the subtitle.
            setTitle("");
            removeUnreadCount(true);
            return;
        }
        // Check if we should be changing the actionbar at all, and back off if not.
        final boolean isShowingFolder = mIsOnTablet || ViewMode.isListMode(getMode());
        if (!isShowingFolder) {
            // It isn't necessary to set the title in this case, as the title view will
            // be hidden
            return;
        }
        if (mFolder == null) {
            // Clear the action bar title.  We don't want the app name to be shown while
            // waiting for the folder query to finish
            setTitle("");
            return;
        }
        setTitle(mFolder.name);

        final int folderUnreadCount = mFolder.isUnreadCountHidden() ? 0 : mFolder.unreadCount;
        // The user shouldn't see "999+ unread messages", and then a short while later: "999+
        // unread messages". So we set our unread count just past the limit. This way we can
        // change the subtitle the first time around but not for subsequent changes as far as the
        // unread count remains over the limit.
        final int toDisplay = (folderUnreadCount > UNREAD_LIMIT)
                ? (UNREAD_LIMIT + 1) : folderUnreadCount;
        if ((mUnreadCount != toDisplay || folderChanged) && toDisplay != 0) {
            setSubtitle(Utils.getUnreadMessageString(mActivity.getApplicationContext(), toDisplay));
        }
        // Schedule a removal of unread count for the future, if there isn't one already. If the
        // unread count dropped to zero, remove it and show the account name right away.
        removeUnreadCount(toDisplay == 0);
        // Remember the new value for the next run
        mUnreadCount = toDisplay;
    }

    /**
     * Remove the unread count and show the account name, if required.
     * @param now true if you want the change to happen immediately. False if you want to enforce
     *            it happens later.
     */
    private void removeUnreadCount(boolean now) {
        if (now) {
            // Remove all previous messages which might change the subtitle
            mHandler.removeMessages(SubtitleHandler.EMAIL);
            // Update the subtitle: clear it or show account name.
            mHandler.sendEmptyMessage(SubtitleHandler.EMAIL);
        } else {
            if (!mHandler.hasMessages(SubtitleHandler.EMAIL)) {
                // In a short while, show the account name in its place.
                mHandler.sendEmptyMessageDelayed(SubtitleHandler.EMAIL, ACCOUNT_DELAY_MS);
            }
        }
    }

    /**
     * Notify that the folder has changed.
     */
    public void onFolderUpdated(Folder folder) {
        if (folder == null) {
            return;
        }
        /** True if we are changing folders. */
        final boolean changingFolders = (mFolder == null || !mFolder.equals(folder));
        mFolder = folder;
        setFolderAndAccount(changingFolders);
        final ConversationListContext listContext = mController == null ? null :
                mController.getCurrentListContext();
        if (changingFolders && !ConversationListContext.isSearchResult(listContext)) {
            closeSearchField();
        }
    }

    @Override
    public boolean onMenuItemActionExpand(MenuItem item) {
        // Do nothing. Required as part of the interface, we ar only interested in
        // onMenuItemActionCollapse(MenuItem).
        // Have to return true here. Unlike other callbacks, the return value here is whether
        // we want to suppress the action (rather than consume the action). We don't want to
        // suppress the action.
        return true;
    }

    @Override
    public boolean onMenuItemActionCollapse(MenuItem item) {
        // Work around b/6664203 by manually forcing this view to be VISIBLE
        // upon ActionView collapse. DISPLAY_SHOW_CUSTOM will still control its final
        // visibility.
        setVisibility(VISIBLE);
        // Have to return true here. Unlike other callbacks, the return value
        // here is whether we want to suppress the action (rather than consume the action). We
        // don't want to suppress the action.
        return true;
    }

    /**
     * Sets the actionbar mode: Pass it an integer which contains each of these values, perhaps
     * OR'd together: {@link ActionBar#DISPLAY_SHOW_CUSTOM} and
     * {@link ActionBar#DISPLAY_SHOW_TITLE}. To disable all, pass a zero.
     * @param enabledFlags
     */
    private void setTitleModeFlags(int enabledFlags) {
        final int mask = ActionBar.DISPLAY_SHOW_TITLE | ActionBar.DISPLAY_SHOW_CUSTOM;
        mActionBar.setDisplayOptions(enabledFlags, mask);
    }

    public void setCurrentConversation(Conversation conversation) {
        mCurrentConversation = conversation;
    }

    //We need to do this here instead of in the fragment
    public void setConversationModeOptions(Menu menu) {
        if (mCurrentConversation == null) {
            return;
        }
        final boolean showMarkImportant = !mCurrentConversation.isImportant();
        Utils.setMenuItemVisibility(menu, R.id.mark_important, showMarkImportant
                && mAccount.supportsCapability(UIProvider.AccountCapabilities.MARK_IMPORTANT));
        Utils.setMenuItemVisibility(menu, R.id.mark_not_important, !showMarkImportant
                && mAccount.supportsCapability(UIProvider.AccountCapabilities.MARK_IMPORTANT));
        final boolean showDelete = mFolder != null &&
                mFolder.supportsCapability(UIProvider.FolderCapabilities.DELETE);
        Utils.setMenuItemVisibility(menu, R.id.delete, showDelete);
        // We only want to show the discard drafts menu item if we are not showing the delete menu
        // item, and the current folder is a draft folder and the account supports discarding
        // drafts for a conversation
        final boolean showDiscardDrafts = !showDelete && mFolder != null && mFolder.isDraft() &&
                mAccount.supportsCapability(AccountCapabilities.DISCARD_CONVERSATION_DRAFTS);
        Utils.setMenuItemVisibility(menu, R.id.discard_drafts, showDiscardDrafts);
        final boolean archiveVisible = mAccount.supportsCapability(AccountCapabilities.ARCHIVE)
                && mFolder != null && mFolder.supportsCapability(FolderCapabilities.ARCHIVE)
                && !mFolder.isTrash();
        Utils.setMenuItemVisibility(menu, R.id.archive, archiveVisible);
        Utils.setMenuItemVisibility(menu, R.id.remove_folder, !archiveVisible && mFolder != null
                && mFolder.supportsCapability(FolderCapabilities.CAN_ACCEPT_MOVED_MESSAGES)
                && !mFolder.isProviderFolder()
                && mAccount.supportsCapability(AccountCapabilities.ARCHIVE));
        Utils.setMenuItemVisibility(menu, R.id.move_to, mFolder != null
                && mFolder.supportsCapability(FolderCapabilities.ALLOWS_REMOVE_CONVERSATION));
        Utils.setMenuItemVisibility(menu, R.id.move_to_inbox, mFolder != null
                && mFolder.supportsCapability(FolderCapabilities.ALLOWS_MOVE_TO_INBOX));

        final MenuItem removeFolder = menu.findItem(R.id.remove_folder);
        if (mFolder != null && removeFolder != null) {
            removeFolder.setTitle(mActivity.getApplicationContext().getString(
                    R.string.remove_folder, mFolder.name));
        }
        Utils.setMenuItemVisibility(menu, R.id.report_spam,
                mAccount.supportsCapability(AccountCapabilities.REPORT_SPAM) && mFolder != null
                        && mFolder.supportsCapability(FolderCapabilities.REPORT_SPAM)
                        && !mCurrentConversation.spam);
        Utils.setMenuItemVisibility(menu, R.id.mark_not_spam,
                mAccount.supportsCapability(AccountCapabilities.REPORT_SPAM) && mFolder != null
                        && mFolder.supportsCapability(FolderCapabilities.MARK_NOT_SPAM)
                        && mCurrentConversation.spam);
        Utils.setMenuItemVisibility(menu, R.id.report_phishing,
                mAccount.supportsCapability(AccountCapabilities.REPORT_PHISHING) && mFolder != null
                        && mFolder.supportsCapability(FolderCapabilities.REPORT_PHISHING)
                        && !mCurrentConversation.phishing);
        Utils.setMenuItemVisibility(menu, R.id.mute,
                        mAccount.supportsCapability(AccountCapabilities.MUTE) && mFolder != null
                        && mFolder.supportsCapability(FolderCapabilities.DESTRUCTIVE_MUTE)
                        && !mCurrentConversation.muted);
    }

    private static boolean actionBarSupportsNewMethods(ActionBar bar) {
        // TODO(pwestbro) switch this to
        // (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN_MR2) when we switch to the
        // latest SDK
        if (Build.VERSION.SDK_INT > 17) {
            return true;
        }
        if (Build.VERSION.SDK_INT <= Build.VERSION_CODES.JELLY_BEAN) {
            return false;
        }
        boolean supportsNewApi = false;
        try {
            if (bar != null) {
                supportsNewApi = (ActionBar.class.getField("DISPLAY_TITLE_MULTIPLE_LINES") != null);
            }
        } catch (NoSuchFieldException e) {
            // stay false
        }
        return supportsNewApi;
    }

    @Override
    public void onClick (View v) {
        if (v.getId() == R.id.legacy_title_container) {
            mController.onUpPressed();
        }
    }

    public ViewMode getViewModeController() {
        return mViewModeController;
    }

    public void setViewModeController(ViewMode viewModeController) {
        mViewModeController = viewModeController;
        mViewModeController.addListener(this);
    }
}