Android DrawerLayout抽屉效果

官网guide：http://developer.android.com/training/implementing-navigation/nav-drawer.html

官网示例：NavigationDrawer.zip  

android.support.v4.widget.DrawerLayout 抽屉layout。该widget只能实现从左向右、从右向左

   openDrawer(), closeDrawer(), isDrawerOpen()

示例图：(示例图中增加了左右菜单功能，下面的代码基本还是官方原版的)

下面贴一下示例的主要的布局文件 和 activity实现

activity_main.xml

package com.stone.drawerlayout;
/*
 * Copyright 2013 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.
 */

import java.util.Locale;

import android.app.Activity;
import android.app.Fragment;
import android.app.FragmentManager;
import android.app.SearchManager;
import android.content.Intent;
import android.content.res.Configuration;
import android.os.Bundle;
import android.support.v4.app.ActionBarDrawerToggle;
import android.support.v4.view.GravityCompat;
import android.support.v4.widget.DrawerLayout;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.MenuInflater;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.ImageView;
import android.widget.ListView;
import android.widget.Toast;

/**
 * This example illustrates a common usage of the DrawerLayout widget
 * in the Android support library.
 * 

 * 
When a navigation (left) drawer is present, the host activity should detect presses of
 * the action bar's Up affordance as a signal to open and close the navigation drawer. The
 * ActionBarDrawerToggle facilitates this behavior.
 * Items within the drawer should fall into one of two categories:
 * 

 * 

 * 
View switches. A view switch follows the same basic policies as
 * list or tab navigation in that a view switch does not create navigation history.
 * This pattern should only be used at the root activity of a task, leaving some form
 * of Up navigation active for activities further down the navigation hierarchy.
 * 
Selective Up. The drawer allows the user to choose an alternate
 * parent for Up navigation. This allows a user to jump across an app's navigation
 * hierarchy at will. The application should treat this as it treats Up navigation from
 * a different task, replacing the current task stack using TaskStackBuilder or similar.
 * This is the only form of navigation drawer that should be used outside of the root
 * activity of a task.
 * 
 * 

 * 
Right side drawers should be used for actions, not navigation. This follows the pattern
 * established by the Action Bar that navigation should be to the left and actions to the right.
 * An action should be an operation performed on the current contents of the window,
 * for example enabling or disabling a data overlay on top of the current content.
 */
public class MainActivity extends Activity {
    private DrawerLayout mDrawerLayout;
    private ListView mDrawerList;
    private ActionBarDrawerToggle mDrawerToggle;

    private CharSequence mDrawerTitle;
    private CharSequence mTitle;
    private String[] mPlanetTitles;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        mTitle = mDrawerTitle = getTitle();
        mPlanetTitles = getResources().getStringArray(R.array.planets_array);
        mDrawerLayout = (DrawerLayout) findViewById(R.id.drawer_layout);
        mDrawerList = (ListView) findViewById(R.id.left_drawer);//抽屉里的view

        // set a custom shadow that overlays the main content when the drawer opens
        mDrawerLayout.setDrawerShadow(R.drawable.drawer_shadow, GravityCompat.START);//设置shadow
        // set up the drawer's list view with items and click listener
        mDrawerList.setAdapter(new ArrayAdapter(this,
                R.layout.drawer_list_item, mPlanetTitles));
        mDrawerList.setOnItemClickListener(new DrawerItemClickListener());

        // enable ActionBar app icon to behave as action to toggle nav drawer   需要api level 11
        getActionBar().setDisplayHomeAsUpEnabled(true);//给home icon的左边加上一个返回的图标
        getActionBar().setHomeButtonEnabled(true); //需要api level 14  使用home-icon 可点击

        // ActionBarDrawerToggle ties together the the proper interactions
        // between the sliding drawer and the action bar app icon
        mDrawerToggle = new ActionBarDrawerToggle(//v4控件  actionbar上的抽屉开关
                this,                  /* host Activity */
                mDrawerLayout,         /* DrawerLayout object */
                R.drawable.ic_drawer,  /* nav drawer image to replace 'Up' caret */		//上一级图标 返回图标
                R.string.drawer_open,  /* "open drawer" description for accessibility */
                R.string.drawer_close  /* "close drawer" description for accessibility */
                ) {
            public void onDrawerClosed(View view) {//抽屉关闭后
                getActionBar().setTitle(mDrawerTitle);
                invalidateOptionsMenu(); // creates call to onPrepareOptionsMenu()
            }

            public void onDrawerOpened(View drawerView) {//抽屉打开后
                getActionBar().setTitle(mTitle);
                invalidateOptionsMenu(); // creates call to onPrepareOptionsMenu()
            }
            
            @Override
            public boolean onOptionsItemSelected(MenuItem item) {
            	if (item != null && item.getItemId() == android.R.id.home) {//actionbar上的home icon
            		//END即gravity.right 从右向左显示   START即left  从左向右弹出显示
                    if (mDrawerLayout.isDrawerVisible(GravityCompat.END)) {
                        mDrawerLayout.closeDrawer(GravityCompat.END);//关闭抽屉
                    } else {
                        mDrawerLayout.openDrawer(GravityCompat.END);//打开抽屉
                    }
                    return true;
                }
                return false;
            }
        };
        mDrawerLayout.setDrawerListener(mDrawerToggle);//设置抽屉监听

        if (savedInstanceState == null) {
//            selectItem(0);
        }
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {//加载menu  sdk3.0以后menu包含在actionbar中
        MenuInflater inflater = getMenuInflater();
        inflater.inflate(R.menu.main, menu);
        return super.onCreateOptionsMenu(menu);
    }

    /* Called whenever we call invalidateOptionsMenu() */
    @Override
    public boolean onPrepareOptionsMenu(Menu menu) {
        // If the nav drawer is open, hide action items related to the content view
        boolean drawerOpen = mDrawerLayout.isDrawerOpen(mDrawerList);
        menu.findItem(R.id.action_websearch).setVisible(!drawerOpen);//search的显示与drawer的显示相反
        return super.onPrepareOptionsMenu(menu);
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
         // The action bar home/up action should open or close the drawer.
         // ActionBarDrawerToggle will take care of this.
        if (mDrawerToggle.onOptionsItemSelected(item)) {
            return true;
        }
        // Handle action buttons
        switch(item.getItemId()) {
        case R.id.action_websearch:
            // create intent to perform web search for this planet
            Intent intent = new Intent(Intent.ACTION_WEB_SEARCH);
            intent.putExtra(SearchManager.QUERY, getActionBar().getTitle());
            // catch event that there's no activity to handle intent
            if (intent.resolveActivity(getPackageManager()) != null) {
                startActivity(intent);
            } else {
                Toast.makeText(this, R.string.app_not_available, Toast.LENGTH_LONG).show();
            }
            return true;
        default:
            return super.onOptionsItemSelected(item);
        }
    }

    /* The click listner for ListView in the navigation drawer */
    private class DrawerItemClickListener implements ListView.OnItemClickListener {
        @Override
        public void onItemClick(AdapterView parent, View view, int position, long id) {
            selectItem(position);
        }
    }
    
  //内容区显示PlanetFragment
    private void selectItem(int position) {
        // update the main content by replacing fragments
        Fragment fragment = new PlanetFragment();
        Bundle args = new Bundle();
        args.putInt(PlanetFragment.ARG_PLANET_NUMBER, position);
        fragment.setArguments(args);

        FragmentManager fragmentManager = getFragmentManager();
        fragmentManager.beginTransaction().replace(R.id.content_frame, fragment).commit();

        // update selected item and title, then close the drawer
//        mDrawerList.setItemChecked(position, true);
//        setTitle(mPlanetTitles[position]);
        mDrawerLayout.closeDrawer(mDrawerList);
    }

    @Override
    public void setTitle(CharSequence title) {
    	mDrawerTitle = title;
        getActionBar().setTitle(mDrawerTitle);
    }

    /**
     * When using the ActionBarDrawerToggle, you must call it during
     * onPostCreate() and onConfigurationChanged()...
     */

    @Override
    protected void onPostCreate(Bundle savedInstanceState) {
        super.onPostCreate(savedInstanceState);
        // Sync the toggle state after onRestoreInstanceState has occurred.
        mDrawerToggle.syncState();
    }

    @Override
    public void onConfigurationChanged(Configuration newConfig) {
        super.onConfigurationChanged(newConfig);
        // Pass any configuration change to the drawer toggls
        mDrawerToggle.onConfigurationChanged(newConfig);
    }

    /**
     * Fragment that appears in the "content_frame", shows a planet
     */
    public static class PlanetFragment extends Fragment {
        public static final String ARG_PLANET_NUMBER = "planet_number";

        public PlanetFragment() {
            // Empty constructor required for fragment subclasses
        }

        @Override
        public View onCreateView(LayoutInflater inflater, ViewGroup container,
                Bundle savedInstanceState) {
            View rootView = inflater.inflate(R.layout.fragment_planet, container, false);
            int i = getArguments().getInt(ARG_PLANET_NUMBER);
            String planet = getResources().getStringArray(R.array.planets_array)[i];
            //查找出 res-drawable资源的id
            int imageId = getResources().getIdentifier(planet.toLowerCase(Locale.getDefault()),
                            "drawable", getActivity().getPackageName());
            ((ImageView) rootView.findViewById(R.id.image)).setImageResource(imageId);
            getActivity().setTitle(planet);
            return rootView;
        }
    }
}