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>