Android Open Source - android-compat-actionbar Action Bar Helper Base

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License

The source code is released under:

Apache License

Java Source Code

/*
 * Copyright 2011 The Android Open Source Project
 */*from w w w. j  a v  a2s .  co m*/
 * 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 android.support.v4.actionbar;

import java.io.IOException;
import java.util.HashSet;
import java.util.Set;

import android.app.Activity;
import android.content.Context;
import android.content.res.XmlResourceParser;
import android.os.Bundle;
import android.view.InflateException;
import android.view.Menu;
import android.view.MenuInflater;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;
import android.view.Window;
import android.widget.ImageButton;
import android.widget.ImageView;
import android.widget.LinearLayout;
import android.widget.ProgressBar;
import android.widget.TextView;

import org.xmlpull.v1.XmlPullParser;
import org.xmlpull.v1.XmlPullParserException;

/**
 * A class that implements the action bar pattern for pre-Honeycomb devices.
 */
public class ActionBarHelperBase extends ActionBarHelper
{
        private static final String MENU_RES_NAMESPACE = "http://schemas.android.com/apk/res/android";
        private static final String MENU_ATTR_ID = "id";
        private static final String MENU_ATTR_SHOW_AS_ACTION = "showAsAction";

        protected Set < Integer > mActionItemIds = new HashSet < Integer > ();

        protected ActionBarHelperBase ( Activity activity )
        {
                super ( activity );
        }

        /** {@inheritDoc} */
        @Override
        public void onCreate ( Bundle savedInstanceState )
        {
                mActivity.requestWindowFeature ( Window.FEATURE_CUSTOM_TITLE );
        }

        /** {@inheritDoc} */
        @Override
        public void onPostCreate ( Bundle savedInstanceState )
        {
                mActivity.getWindow ().setFeatureInt ( Window.FEATURE_CUSTOM_TITLE, R.layout.actionbar_compat );
                setupActionBar ();

                SimpleMenu menu = new SimpleMenu ( mActivity );
                mActivity.onCreatePanelMenu ( Window.FEATURE_OPTIONS_PANEL, menu );
                mActivity.onPrepareOptionsMenu ( menu );
                for ( int i = 0; i < menu.size (); i++ )
                {
                        MenuItem item = menu.getItem ( i );
                        if ( mActionItemIds.contains ( item.getItemId () ) )
                        {
                                addActionItemCompatFromMenuItem ( item );
                        }
                }
        }

        /**
         * Sets up the compatibility action bar with the given title.
         */
        private void setupActionBar ()
        {
                final ViewGroup actionBarCompat = getActionBarCompat ();
                if ( actionBarCompat == null )
                {
                        return;
                }

                LinearLayout.LayoutParams springLayoutParams = new LinearLayout.LayoutParams ( 0,
                        ViewGroup.LayoutParams.FILL_PARENT );
                springLayoutParams.weight = 1;

                // Add Home button
                SimpleMenu tempMenu = new SimpleMenu ( mActivity );
                SimpleMenuItem homeItem = new SimpleMenuItem ( tempMenu, android.R.id.home, 0,
                        mActivity.getString ( R.string.app_name ) );
                homeItem.setIcon ( R.drawable.ic_home );
                addActionItemCompatFromMenuItem ( homeItem );

                // Add title text
                TextView titleText = new TextView ( mActivity, null, R.attr.actionbarCompatTitleStyle );
                titleText.setLayoutParams ( springLayoutParams );
                titleText.setText ( mActivity.getTitle () );
                actionBarCompat.addView ( titleText );
        }

        /** {@inheritDoc} */
        @Override
        public void setRefreshActionItemState ( boolean refreshing )
        {
                View refreshButton = mActivity.findViewById ( R.id.actionbar_compat_item_refresh );
                View refreshIndicator = mActivity.findViewById ( R.id.actionbar_compat_item_refresh_progress );

                if ( refreshButton != null )
                {
                        refreshButton.setVisibility ( refreshing ? View.GONE : View.VISIBLE );
                }
                if ( refreshIndicator != null )
                {
                        refreshIndicator.setVisibility ( refreshing ? View.VISIBLE : View.GONE );
                }
        }

        /**
         * Action bar helper code to be run in {@link Activity#onCreateOptionsMenu(android.view.Menu)}. NOTE: This code
         * will mark on-screen menu items as invisible.
         */
        @Override
        public boolean onCreateOptionsMenu ( Menu menu )
        {
                // Hides on-screen action items from the options menu.
                for ( Integer id : mActionItemIds )
                {
                        menu.findItem ( id ).setVisible ( false );
                }
                return true;
        }

        /** {@inheritDoc} */
        @Override
        public void onTitleChanged ( CharSequence title, int color )
        {
                TextView titleView = ( TextView ) mActivity.findViewById ( R.id.actionbar_compat_title );
                if ( titleView != null )
                {
                        titleView.setText ( title );
                }
        }

        /**
         * Returns a {@link android.view.MenuInflater} that can read action bar metadata on pre-Honeycomb devices.
         */
        public MenuInflater getMenuInflater ( MenuInflater superMenuInflater )
        {
                return new WrappedMenuInflater ( mActivity, superMenuInflater );
        }

        /**
         * Returns the {@link android.view.ViewGroup} for the action bar on phones (compatibility action bar). Can
         * return null, and will return null on Honeycomb.
         */
        private ViewGroup getActionBarCompat ()
        {
                return ( ViewGroup ) mActivity.findViewById ( R.id.actionbar_compat );
        }

        /**
         * Adds an action button to the compatibility action bar, using menu information from a
         * {@link android.view.MenuItem}. If the menu item ID is <code>menu_refresh</code>, the menu item's state can be
         * changed to show a loading spinner using
         * {@link android.support.v4.actionbar.ActionBarHelperBase#setRefreshActionItemState(boolean)}.
         */
        private View addActionItemCompatFromMenuItem ( final MenuItem item )
        {
                final int itemId = item.getItemId ();

                final ViewGroup actionBar = getActionBarCompat ();
                if ( actionBar == null )
                {
                        return null;
                }

                // Create the button
                ImageButton actionButton = new ImageButton ( mActivity, null,
                        itemId == android.R.id.home ? R.attr.actionbarCompatItemHomeStyle
                                : R.attr.actionbarCompatItemStyle );
                actionButton
                        .setLayoutParams ( new ViewGroup.LayoutParams ( ( int ) mActivity.getResources ().getDimension (
                                itemId == android.R.id.home ? R.dimen.actionbar_compat_button_home_width
                                        : R.dimen.actionbar_compat_button_width ), ViewGroup.LayoutParams.FILL_PARENT ) );
                if ( itemId == R.id.menu_refresh )
                {
                        actionButton.setId ( R.id.actionbar_compat_item_refresh );
                }
                actionButton.setImageDrawable ( item.getIcon () );
                actionButton.setScaleType ( ImageView.ScaleType.CENTER );
                actionButton.setContentDescription ( item.getTitle () );
                actionButton.setOnClickListener ( new View.OnClickListener ()
                {
                        public void onClick ( View view )
                        {
                                mActivity.onMenuItemSelected ( Window.FEATURE_OPTIONS_PANEL, item );
                        }
                } );

                actionBar.addView ( actionButton );

                if ( item.getItemId () == R.id.menu_refresh )
                {
                        // Refresh buttons should be stateful, and allow for indeterminate progress indicators,
                        // so add those.
                        ProgressBar indicator = new ProgressBar ( mActivity, null,
                                R.attr.actionbarCompatProgressIndicatorStyle );

                        final int buttonWidth = mActivity.getResources ().getDimensionPixelSize (
                                R.dimen.actionbar_compat_button_width );
                        final int buttonHeight = mActivity.getResources ().getDimensionPixelSize (
                                R.dimen.actionbar_compat_height );
                        final int progressIndicatorWidth = buttonWidth / 2;

                        LinearLayout.LayoutParams indicatorLayoutParams = new LinearLayout.LayoutParams (
                                progressIndicatorWidth, progressIndicatorWidth );
                        indicatorLayoutParams.setMargins ( ( buttonWidth - progressIndicatorWidth ) / 2,
                                ( buttonHeight - progressIndicatorWidth ) / 2,
                                ( buttonWidth - progressIndicatorWidth ) / 2, 0 );
                        indicator.setLayoutParams ( indicatorLayoutParams );
                        indicator.setVisibility ( View.GONE );
                        indicator.setId ( R.id.actionbar_compat_item_refresh_progress );
                        actionBar.addView ( indicator );
                }

                return actionButton;
        }

        /**
         * A {@link android.view.MenuInflater} that reads action bar metadata.
         */
        private class WrappedMenuInflater extends MenuInflater
        {
                MenuInflater mInflater;

                public WrappedMenuInflater ( Context context, MenuInflater inflater )
                {
                        super ( context );
                        mInflater = inflater;
                }

                @Override
                public void inflate ( int menuRes, Menu menu )
                {
                        loadActionBarMetadata ( menuRes );
                        mInflater.inflate ( menuRes, menu );
                }

                /**
                 * Loads action bar metadata from a menu resource, storing a list of menu item IDs that should be shown
                 * on-screen (i.e. those with showAsAction set to always or ifRoom).
                 * 
                 * @param menuResId
                 */
                private void loadActionBarMetadata ( int menuResId )
                {
                        XmlResourceParser parser = null;
                        try
                        {
                                parser = mActivity.getResources ().getXml ( menuResId );

                                int eventType = parser.getEventType ();
                                int itemId;
                                int showAsAction;

                                boolean eof = false;
                                while ( !eof )
                                {
                                        switch ( eventType )
                                        {
                                        case XmlPullParser.START_TAG:
                                                if ( !parser.getName ().equals ( "item" ) )
                                                {
                                                        break;
                                                }

                                                itemId = parser.getAttributeResourceValue ( MENU_RES_NAMESPACE,
                                                        MENU_ATTR_ID, 0 );
                                                if ( itemId == 0 )
                                                {
                                                        break;
                                                }

                                                showAsAction = parser.getAttributeIntValue ( MENU_RES_NAMESPACE,
                                                        MENU_ATTR_SHOW_AS_ACTION, -1 );
                                                if ( showAsAction == MenuItem.SHOW_AS_ACTION_ALWAYS
                                                        || showAsAction == MenuItem.SHOW_AS_ACTION_IF_ROOM )
                                                {
                                                        mActionItemIds.add ( itemId );
                                                }
                                                break;

                                        case XmlPullParser.END_DOCUMENT:
                                                eof = true;
                                                break;
                                        }

                                        eventType = parser.next ();
                                }
                        }
                        catch ( XmlPullParserException e )
                        {
                                throw new InflateException ( "Error inflating menu XML", e );
                        }
                        catch ( IOException e )
                        {
                                throw new InflateException ( "Error inflating menu XML", e );
                        }
                        finally
                        {
                                if ( parser != null )
                                {
                                        parser.close ();
                                }
                        }
                }

        }
}

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