Android DrawerLayout

在support.v4包中新增的DrawerLayout可以满足基本的导航抽屉视图的需求，但是和网易等客户端相比还是有差距的

效果：

      

点击左边listview的栏目会切换背景，有2种方法调出左边的listview，一种是用手势从左向右滑动，一种是点击左上角的抽屉图片。

下面说下实现，是根据官网training给出的例子简化的。实现这个效果需要一点点Fragment和ActionBar的知识

第一步，.在布局文件中使用DrawerLayout

<android.support.v4.widget.DrawerLayout    xmlns: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 -->    <FrameLayout        android: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>

要注意这几个原则：

1.主view(content view) 必须是drawerlayout的第一个子节点

2.主view宽和高必需match_parent

3.drawer view必须指定android:layout_gravity属性，如果值为“start”，会根据系统的语言顺序自动决定从左滑还是从右滑

4. drawer view宽度不能太宽，最好不要超过320dp

这里主view是一个FrameLayout，用来切换Fragment，也就是显示的背景图片

第二步，初始化选择list

这里用最基本的adapter就可以

        mPlanetTitles = getResources().getStringArray(R.array.planets_array);        mDrawerList = (ListView) findViewById(R.id.left_drawer);        mDrawerList.setAdapter(new ArrayAdapter<String>(this,                R.layout.drawer_list_item, mPlanetTitles));

第三步，处理列表的点击，这里用DrawerItemClickListener，onItemClick方法中处理fragment的切换

    private class DrawerItemClickListener implements ListView.OnItemClickListener {        @Override        public void onItemClick(AdapterView<?> parent, View view, int position, long id) {            selectItem(position);        }    }

mDrawerList.setOnItemClickListener(new DrawerItemClickListener());

第四步，监听抽屉的打开和关闭

如果activitiy中有ActionBar的话，可以用ActionBarDrawerToggle

        mDrawerToggle = new ActionBarDrawerToggle(                this,                  /* host Activity */                mDrawerLayout,         /* DrawerLayout object */                R.drawable.ic_drawer,  /* nav drawer image to replace 'Up' caret */                R.string.drawer_open,  /* "open drawer" description for accessibility */                R.string.drawer_close  /* "close drawer" description for accessibility */                ) {            public void onDrawerClosed(View view) {                getActionBar().setTitle(mTitle);                invalidateOptionsMenu(); // creates call to onPrepareOptionsMenu()            }            public void onDrawerOpened(View drawerView) {                getActionBar().setTitle(mDrawerTitle);                invalidateOptionsMenu(); // creates call to onPrepareOptionsMenu()            }        };        mDrawerLayout.setDrawerListener(mDrawerToggle);

第四步，让左上角的图标可以控制抽屉的打开和关闭

注意一定要设置这2个属性

        getActionBar().setDisplayHomeAsUpEnabled(true);        getActionBar().setHomeButtonEnabled(true);

同时重写onOptionsItemSelected方法

    @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;        }        return false;    }

下面是完整的代码：

工程目录：

、

布局文件：

activity_main.xml

<android.support.v4.widget.DrawerLayout    xmlns:android="http://schemas.android.com/apk/res/android"    android:id="@+id/drawer_layout"    android:layout_width="match_parent"    android:layout_height="match_parent">          <FrameLayout        android:id="@+id/content_frame"        android:layout_width="match_parent"        android:layout_height="match_parent" />             <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>    

drawer_list_item.xml

<?xml version="1.0" encoding="utf-8"?><TextView xmlns:android="http://schemas.android.com/apk/res/android"    android:id="@android:id/text1"    android:layout_width="match_parent"    android:layout_height="wrap_content"    android:textAppearance="?android:attr/textAppearanceListItemSmall"    android:gravity="center_vertical"    android:paddingLeft="16dp"    android:paddingRight="16dp"    android:textColor="#fff"    android:background="?android:attr/activatedBackgroundIndicator"    android:minHeight="?android:attr/listPreferredItemHeightSmall"/>

fragment_planet.xml

<ImageView xmlns:android="http://schemas.android.com/apk/res/android"    android:id="@+id/image"    android:layout_width="match_parent"    android:layout_height="match_parent"    android:background="#000000"    android:gravity="center"    android:padding="32dp" />

资源文件 strings.xml,每个item的值和drawable文件夹下的图片名字一样

<?xml version="1.0" encoding="utf-8"?><resources>    <string name="app_name">Navigation Drawer Example</string>    <string-array name="planets_array">        <item>Mercury</item>        <item>Venus</item>        <item>Earth</item>        <item>Mars</item>        <item>Jupiter</item>        <item>Saturn</item>        <item>Uranus</item>        <item>Neptune</item>    </string-array>        <string name="drawer_open">Open navigation drawer</string>    <string name="drawer_close">Close navigation drawer</string>    <string name="action_websearch">Web search</string>    <string name="app_not_available">Sorry, there\'s no web browser available</string></resources>

MainActivity.java

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);        mDrawerList.setAdapter(new ArrayAdapter<String>(this,                R.layout.drawer_list_item, mPlanetTitles));        mDrawerList.setOnItemClickListener(new DrawerItemClickListener());        //使得左上角的图标可以控制drawerlayout        getActionBar().setDisplayHomeAsUpEnabled(true);        getActionBar().setHomeButtonEnabled(true);        // ActionBarDrawerToggle ties together the the proper interactions        // between the sliding drawer and the action bar app icon        mDrawerToggle = new ActionBarDrawerToggle(                this,                  /* host Activity */                mDrawerLayout,         /* DrawerLayout object */                R.drawable.ic_drawer,  /* nav drawer image to replace 'Up' caret */                R.string.drawer_open,  /* "open drawer" description for accessibility */                R.string.drawer_close  /* "close drawer" description for accessibility */                ) {            public void onDrawerClosed(View view) {                getActionBar().setTitle(mTitle);                invalidateOptionsMenu(); // creates call to onPrepareOptionsMenu()            }            public void onDrawerOpened(View drawerView) {                getActionBar().setTitle(mDrawerTitle);                invalidateOptionsMenu(); // creates call to onPrepareOptionsMenu()            }        };        mDrawerLayout.setDrawerListener(mDrawerToggle);        if (savedInstanceState == null) {            selectItem(0);        }    }    @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;        }        return false;    }    /* 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);        }    }    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) {        mTitle = title;        getActionBar().setTitle(mTitle);    }    /**     * 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];            int imageId = getResources().getIdentifier(planet.toLowerCase(Locale.getDefault()),                            "drawable", getActivity().getPackageName());            ((ImageView) rootView.findViewById(R.id.image)).setImageResource(imageId);            getActivity().setTitle(planet);            return rootView;        }    }}

用到的图片资源官网的training页面都有的。

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