【support包学习】DrawerLayout的使用

为了让开发者能更快更好的进行安卓app开发（或者是为了填坑），谷歌推出了一系列的support package给广大开发者使用。从最早的v4到现在的v21，里面包括了很多好用的UI控件例如ViewPager以及工具类。本系列仅用于记录support包各个常用模块的学习过程。

曾几何时，对于我这种UI生手来说为app实现侧边栏有着相当的工作量，现如今谷人希在v4包里面为我们带来了利器DrawerLayout。侧边栏就是弹指一挥间的事情了，下面直接上demo。

首先，将主Activity的layout改为DrawerLayout，可以看出实际上DrawerLayout由两部分组成，一部分是作为主界面的FrameLayout，一部分是作为侧边栏的ListView。

<?xml version="1.0" encoding="utf-8"?><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="200dp"        android:layout_height="match_parent"        android:layout_gravity="start"        android:background="#111"        android:choiceMode="singleChoice"        android:divider="@android:color/holo_blue_light"        android:dividerHeight="1dp" /></android.support.v4.widget.DrawerLayout>

然后在主Activity的onCreate()中设置侧边栏菜单

    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.drawerlayout);        mNavigationDrawerItemTitles= getResources().getStringArray(R.array.navigation_drawer_items_array);        mDrawerLayout = (DrawerLayout) findViewById(R.id.drawer_layout);        mDrawerList = (ListView) findViewById(R.id.left_drawer);        ObjectDrawerItem[] drawerItem = new ObjectDrawerItem[3];        // 三个菜单选项        drawerItem[0] = new ObjectDrawerItem(R.drawable.reset, "Create");        drawerItem[1] = new ObjectDrawerItem(R.drawable.security, "Read");        drawerItem[2] = new ObjectDrawerItem(R.drawable.touch, "Help");        DrawerItemCustomAdapter adapter = new DrawerItemCustomAdapter(this, R.layout.listview_item_row, drawerItem);        mDrawerList.setAdapter(adapter);        mDrawerList.setOnItemClickListener(new DrawerItemClickListener());        // 初始化状态        selectItem(0);    }

菜单部分很简单，就是普通的ListView，设置好adapter以及listener就完事儿了。至于主界面，可以使用fragment来填充，当用户点击不同的菜单的时候切换不同的fragment即可。

    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) {        CreateFragment fragment = null;        switch (position) {            case 0:                fragment = new CreateFragment();                fragment.setTitle("Create");                fragment.setIcon(R.drawable.reset);                break;            case 1:                fragment = new CreateFragment();                fragment.setTitle("Read");                fragment.setIcon(R.drawable.security);                break;            case 2:                fragment = new CreateFragment();                fragment.setTitle("Help");                fragment.setIcon(R.drawable.touch);                break;            default:                break;        }        if (fragment != null) {            FragmentManager fragmentManager = getFragmentManager();            fragmentManager.beginTransaction().replace(R.id.content_frame, fragment).commit();            mDrawerList.setItemChecked(position, true);            mDrawerList.setSelection(position);            ActionBar ab = getActionBar();            if (ab != null) {                ab.setTitle(mNavigationDrawerItemTitles[position]);            }            mDrawerLayout.closeDrawer(mDrawerList);        } else {            Log.e("MainActivity", "Error in creating fragment");        }    }

可从这里下载demo源码。