40、DrawerLayout使用详情

1、主内容视图一定要是DrawerLayout的第一个子视图
2、主内容视图宽度和高度匹配父视图，即“match_parent”
3、必须显示指定抽屉视图（如ListView）的 android:layout_gravity 属性
    1）、 android:layout_gravity=“start”时，从左向右滑出菜单
    2）、 android:layout_gravity=“end” 时，从右向左滑出菜单
    3）、不推荐使用 “left”和“right”
4、抽屉视图的宽度以dp为单位，请不要超过320dp（为了总能看到一些主内容视图。

【知识点】

1、mDrawerLayout.setDrawerListener(DrawerLayout.DrawerListener);

2、ActionBarDrawerToggle是DrawerLayout.DrawerListener的具体实现类

1）、改变android.R.id.home图标(构造方法)

2）、Drawer拉出、隐藏，带有android.R.id.home动画效果(syncState())

3）、监听Drawer拉出、隐藏事件

3、覆写ActionBarDrawerToggle的onDrawerOpened()和onDrawerClosed()以监 听抽屉拉出或隐藏事件

4、覆写Activity的onPostCreate()和onConfigurationChanged()方法

【范例】

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" >

     <!-- The main content view -->
     <FrameLayout
         android:id="@+id/content_frame"
         android:layout_width="match_parent"
         android:layout_height="match_parent" />

     <!-- The navigation view -->
     <ListView
         android:id="@+id/left_drawer"
         android:layout_width="240dp"
         android:layout_height="match_parent"
         android:layout_gravity="start"
         android:background="#ffffcc"
         android:choiceMode="singleChoice"
         android:divider="@android:color/transparent"
         android:dividerHeight="0dp" />

 </android.support.v4.widget.DrawerLayout>

MainActivity.java

 public class MainActivity extends Activity implements OnItemClickListener {

     private DrawerLayout mDrawerLayout;
     private ListView mDrawerList;
     private ArrayList<String> menuLists;
     private ArrayAdapter<String> adapter;
     private ActionBarDrawerToggle mDrawerToggle;
     private String mTitle;

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

         mTitle = (String) getTitle();

         mDrawerLayout = (DrawerLayout) findViewById(R.id.drawer_layout);
         mDrawerList = (ListView) findViewById(R.id.left_drawer);
         menuLists = new ArrayList<String>();
         for (int i = 0; i < 5; i++)
             menuLists.add("Android开发0" + i);
         adapter = new ArrayAdapter<String>(this,
                 android.R.layout.simple_list_item_1, menuLists);
         mDrawerList.setAdapter(adapter);
         mDrawerList.setOnItemClickListener(this);

         mDrawerToggle = new ActionBarDrawerToggle(this, mDrawerLayout,
                 R.drawable.ic_drawer, R.string.drawer_open,
                 R.string.drawer_close) {
             @Override
             public void onDrawerOpened(View drawerView) {
                 super.onDrawerOpened(drawerView);
                 getActionBar().setTitle("请选择");
                 invalidateOptionsMenu(); // Call onPrepareOptionsMenu()
             }
             @Override
             public void onDrawerClosed(View drawerView) {
                 super.onDrawerClosed(drawerView);
                 getActionBar().setTitle(mTitle);
                 invalidateOptionsMenu();
             }
         };
         mDrawerLayout.setDrawerListener(mDrawerToggle);

         //开启ActionBar上APP ICON的功能
         getActionBar().setDisplayHomeAsUpEnabled(true);
         getActionBar().setHomeButtonEnabled(true);
     }

     @Override
     public boolean onPrepareOptionsMenu(Menu menu) {
         boolean isDrawerOpen = mDrawerLayout.isDrawerOpen(mDrawerList);
         menu.findItem(R.id.action_websearch).setVisible(!isDrawerOpen);
         return super.onPrepareOptionsMenu(menu);
     }

     @Override
     public boolean onCreateOptionsMenu(Menu menu) {
         // Inflate the menu; this adds items to the action bar if it is present.
         getMenuInflater().inflate(R.menu.main, menu);
         return true;
     }

     @Override
     public boolean onOptionsItemSelected(MenuItem item) {
         //将ActionBar上的图标与Drawer结合起来
         if (mDrawerToggle.onOptionsItemSelected(item)){
             return true;
         }
         switch (item.getItemId()) {
         case R.id.action_websearch:
             Intent intent = new Intent();
             intent.setAction("android.intent.action.VIEW");
             Uri uri = Uri.parse("http://www.cnblogs.com/androidsj");
             intent.setData(uri);
             startActivity(intent);
             break;
         }
         return super.onOptionsItemSelected(item);
     }

     @Override
     protected void onPostCreate(Bundle savedInstanceState) {
         super.onPostCreate(savedInstanceState);
         //需要将ActionDrawerToggle与DrawerLayout的状态同步
         //将ActionBarDrawerToggle中的drawer图标，设置为ActionBar中的Home-Button的Icon
         mDrawerToggle.syncState();
     }

     @Override
     public void onConfigurationChanged(Configuration newConfig) {
         super.onConfigurationChanged(newConfig);
         mDrawerToggle.onConfigurationChanged(newConfig);
     }

     @Override
     public void onItemClick(AdapterView<?> arg0, View arg1, int position,
             long arg3) {
         // 动态插入一个Fragment到FrameLayout当中
         Fragment contentFragment = new ContentFragment();
         Bundle args = new Bundle();
         args.putString("text", menuLists.get(position));
         contentFragment.setArguments(args);

         FragmentManager fm = getFragmentManager();
         fm.beginTransaction().replace(R.id.content_frame, contentFragment)
                 .commit();

         mDrawerLayout.closeDrawer(mDrawerList);
     }

 }

ContentFragment.java

 public class ContentFragment extends Fragment {
     private TextView textView;
     @Override
     public View onCreateView(LayoutInflater inflater, ViewGroup container,
             Bundle savedInstanceState) {
         View view = inflater.inflate(R.layout.fragment_content, container, false);
         textView = (TextView) view.findViewById(R.id.textView);

         String text = getArguments().getString("text");
         textView.setText(text);

         return view;
     }
 }

 <?xml version="1.0" encoding="utf-8"?>
 <LinearLayout
     xmlns:android="http://schemas.android.com/apk/res/android"
     android:layout_width="match_parent"
     android:layout_height="match_parent"
     android:orientation="vertical" >
     <TextView
         android:id="@+id/textView"
         android:layout_width="match_parent"
         android:layout_height="wrap_content"
         android:textSize="25sp" />
 </LinearLayout>