Navigation Drawer是从屏幕的左侧滑出，显示应用导航的视图。官方是这样定义的：

    The navigation drawer is a panel that displays the app’s main navigation options on the left edge of the screen. It is hidden most of the time, but is revealed when the user swipes a finger from the left edge of the screen or, while at the top level of the app, the user touches the app icon in the action bar.

如下图指示：

Navigation Drawer不同于SlidingDrawer，它不存在可以拖动的handle；它也不同于SlidingMenu，Navigation Drawer滑出时主屏幕视图不一定。Navigation Drawer是覆盖在主视图上的。

Navigation Drawer是Android团对在2013 google IO大会期间更新的Support库（V13）中新加入的重要的功能。实现现Navigation Drawer需要使用最新支持库（V13）的DrawerLayout。Navigation Drawer的设计指南请参考

Navigation Drawer design guide。

Create a Drawer Layout

创建Navigation Drawer需要用DrawerLayout 作为界面根控件。在DrawerLayout里面第一个View为当前界面主内容；第二个和第三个View为Navigation Drawer内容。如果当前界面只需要一个Navigation Drawer，则第三个View可以省略。

下面的例子中DrawerLayout里面包含两个View，第一个FrameLayout中是当前界面主要内容显示区域；第二个ListView为Navigation Drawer内容。

<android.support.v4.widget.DrawerLayoutxmlns:android="http://schemas.android.com/apk/res/android"android:id="@+id/drawer_layout"android:layout_width="match_parent"android:layout_height="match_parent"><!-- The main content view --><FrameLayoutandroid:id="@+id/content_frame"android:layout_width="match_parent"android:layout_height="match_parent" /><!-- The navigation drawer --><ListView android:id="@+id/left_drawer"android:layout_width="240dp"android:layout_height="match_parent"android:layout_gravity="start"android:choiceMode="singleChoice"android:divider="@android:color/transparent"android:dividerHeight="0dp"android:background="#111"/>
</android.support.v4.widget.DrawerLayout>

上面的代码中有如下几点需要注意：

• 1、显示界面主要内容的View (上面的 FrameLayout ) 必须为DrawerLayout的第一个子View， 原因在于 XML 布局文件中的View顺序为Android系统中的 z-ordering顺序，而Navigation Drawer必须出现在内容之上。
• 2、显示界面内容的View宽度和高度设置为和父View一样，原因在于当Navigation Drawer不可见的时候，界面内容代表整个界面UI。
• 3、Navigation Drawer (上面的 ListView) 必须使用android:layout_gravity属性设置水平的 gravity值 .如果要支持 right-to-left (RTL，从右向左阅读)语言 用 "start" 代替 "left" (当在 RTL语言运行时候，菜单出现在右侧)。
• 4、抽屉菜单的宽度为 dp 单位而高度和父View一样。抽屉菜单的宽度应该不超过320dp，这样用户可以在菜单打开的时候看到部分内容界面。

Initialize the Drawer List

在您的Activity中需要先初始化Navigation Drawer内容，根据您的应用需要Navigation Drawer的内容可能不是ListView，可以使用其他View。

在上面的示例中，我们需要给Navigation Drawer的ListView设置一个Adapter来提供数据。如下所示：

public class MainActivity extends Activity {private String[] mPlanetTitles;private DrawerLayout mDrawerLayout;private ListView mDrawerList;...@Overridepublic void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);mPlanetTitles = getResources().getStringArray(R.array.planets_array);mDrawerLayout = (DrawerLayout) findViewById(R.id.drawer_layout);mDrawerList = (ListView) findViewById(R.id.left_drawer);// Set the adapter for the list viewmDrawerList.setAdapter(new ArrayAdapter<String>(this,R.layout.drawer_list_item, mPlanetTitles));// Set the list's click listenermDrawerList.setOnItemClickListener(new DrawerItemClickListener());...}
}

上面的代码调用了 setOnItemClickListener() 函数来接受Navigation Drawer点击事件。下面会介绍如何通过点击Navigation Drawer显示主界面内容。

Handle Navigation Click Events

当用户选择Navigation Drawer List中的条目时，系统会调用  OnItemClickListener的 onItemClick()函数。

根据您的应用需要，onItemClick函数的实现方式可能不同。下面的示例中，选择Navigation Drawer条目会在程序主界面中插入不同的 Fragment 。

private class DrawerItemClickListener implements ListView.OnItemClickListener {@Overridepublic void onItemClick(AdapterView parent, View view, int position, long id) {selectItem(position);}
}/** Swaps fragments in the main content view */
private void selectItem(int position) {// Create a new fragment and specify the planet to show based on positionFragment fragment = new PlanetFragment();Bundle args = new Bundle();args.putInt(PlanetFragment.ARG_PLANET_NUMBER, position);fragment.setArguments(args);// Insert the fragment by replacing any existing fragmentFragmentManager fragmentManager = getFragmentManager();fragmentManager.beginTransaction().replace(R.id.content_frame, fragment).commit();// Highlight the selected item, update the title, and close the drawermDrawerList.setItemChecked(position, true);setTitle(mPlanetTitles[position]);mDrawerLayout.closeDrawer(mDrawerList);
}@Override
public void setTitle(CharSequence title) {mTitle = title;getActionBar().setTitle(mTitle);
}

Listen for Open and Close Events

如果需要监听菜单打开关闭事件，则需要调用 DrawerLayout类的 setDrawerListener() 函数，参数为 DrawerLayout.DrawerListener接口的实现。该接口提供了菜单打开关闭等事件的回调函数，例如 onDrawerOpened() 和onDrawerClosed().

如果您的Activity使用了 action bar，则您可以使用Support库提供的 ActionBarDrawerToggle 类，该类实现了 DrawerLayout.DrawerListener接口，并且您还可以根据需要重写相关的函数。该类实现了菜单和Action bar相关的操作。

根据在 Navigation Drawer 设计指南中的介绍，当菜单显示的时候您应该根据情况隐藏ActionBar上的功能菜单并且修改ActionBar的标题。下面的代码演示了如何重写 ActionBarDrawerToggle 类的相关函数来实现该功能。

public class MainActivity extends Activity {private DrawerLayout mDrawerLayout;private ActionBarDrawerToggle mDrawerToggle;private CharSequence mDrawerTitle;private CharSequence mTitle;...@Overridepublic void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);...mTitle = mDrawerTitle = getTitle();mDrawerLayout = (DrawerLayout) findViewById(R.id.drawer_layout);mDrawerToggle = new ActionBarDrawerToggle(this, mDrawerLayout,R.drawable.ic_drawer, R.string.drawer_open, R.string.drawer_close) {/** Called when a drawer has settled in a completely closed state. */public void onDrawerClosed(View view) {getActionBar().setTitle(mTitle);invalidateOptionsMenu(); // creates call to onPrepareOptionsMenu()}/** Called when a drawer has settled in a completely open state. */public void onDrawerOpened(View drawerView) {getActionBar().setTitle(mDrawerTitle);invalidateOptionsMenu(); // creates call to onPrepareOptionsMenu()}};// Set the drawer toggle as the DrawerListenermDrawerLayout.setDrawerListener(mDrawerToggle);}/* Called whenever we call invalidateOptionsMenu() */@Overridepublic boolean onPrepareOptionsMenu(Menu menu) {// If the nav drawer is open, hide action items related to the content viewboolean drawerOpen = mDrawerLayout.isDrawerOpen(mDrawerList);menu.findItem(R.id.action_websearch).setVisible(!drawerOpen);return super.onPrepareOptionsMenu(menu);}
}

Open and Close with the App Icon

用户可以从屏幕边缘滑动来打开Navigation Drawer，如果您使用了 action bar，应该让用户通过点击应用图标也可以打开抽屉菜单。并且应用图标也应该使用一个特殊的图标来指示抽屉菜单。您可以使用 ActionBarDrawerToggle 类来实现这些功能。

使用 ActionBarDrawerToggle ，先通过其构造函数来创建该对象，构造函数需要如下参数：

• 1）显示Navigation Drawer的 Activity 对象
• 2） DrawerLayout 对象
• 3）一个用来指示Navigation Drawer的 drawable资源
• 4）一个用来描述打开Navigation Drawer的文本 (用于支持可访问性)。
• 5）一个用来描述关闭Navigation Drawer的文本(用于支持可访问性).

无论你是否继承 ActionBarDrawerToggle 来实现Navigation Drawer监听器，您都需要在Activity的生命周期函数中调用ActionBarDrawerToggle 的一些函数。

如下所示：

public class MainActivity extends Activity {private DrawerLayout mDrawerLayout;private ActionBarDrawerToggle mDrawerToggle;...public void onCreate(Bundle savedInstanceState) {...mDrawerLayout = (DrawerLayout) findViewById(R.id.drawer_layout);mDrawerToggle = new ActionBarDrawerToggle(this,                  /* host Activity */mDrawerLayout,         /* DrawerLayout object */R.drawable.ic_drawer,  /* nav drawer icon to replace 'Up' caret */R.string.drawer_open,  /* "open drawer" description */R.string.drawer_close  /* "close drawer" description */) {/** Called when a drawer has settled in a completely closed state. */public void onDrawerClosed(View view) {getActionBar().setTitle(mTitle);}/** Called when a drawer has settled in a completely open state. */public void onDrawerOpened(View drawerView) {getActionBar().setTitle(mDrawerTitle);}};// Set the drawer toggle as the DrawerListenermDrawerLayout.setDrawerListener(mDrawerToggle);getActionBar().setDisplayHomeAsUpEnabled(true);getActionBar().setHomeButtonEnabled(true);}@Overrideprotected void onPostCreate(Bundle savedInstanceState) {super.onPostCreate(savedInstanceState);// Sync the toggle state after onRestoreInstanceState has occurred.mDrawerToggle.syncState();}@Overridepublic void onConfigurationChanged(Configuration newConfig) {super.onConfigurationChanged(newConfig);mDrawerToggle.onConfigurationChanged(newConfig);}@Overridepublic boolean onOptionsItemSelected(MenuItem item) {// Pass the event to ActionBarDrawerToggle, if it returns// true, then it has handled the app icon touch eventif (mDrawerToggle.onOptionsItemSelected(item)) {return true;}// Handle your other action bar items...return super.onOptionsItemSelected(item);}...
}

代码下载：demo

参考：

https://developer.android.com/reference/android/support/v4/widget/DrawerLayout.html

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

http://developer.android.com/design/patterns/navigation-drawer.html