【Android开发笔记】底部菜单栏 FragmentTabHost

公司项目，需求本来是按照谷歌官方指南写的，菜单栏设计成在导航栏下方

结果呢，审评时，BOSS为了和iOS统一，改成了底部菜单栏（标准结局），我只能呵呵呵呵呵呵呵

查了查资料发现实现底部菜单栏用的是FragmentTabHost，下面记录下具体如何实现的

首先，假设我有3个菜单栏，对应3个Fragment：FragmentA、FragmentB、FragmentC

这3个Fragment将由一个Activity控制：TabHostActivity

TabHostActivity对应的xml文件：

 <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
               android:orientation="vertical"
               android:layout_width="match_parent"
               android:layout_height="match_parent">

     <FrameLayout
         android:id="@+id/real_tab_content"
         android:layout_width="match_parent"
         android:layout_height="0dp"
         android:layout_weight="1"/>

     <RadioGroup
         android:id="@+id/radio_tab_bottom_menu"
         android:layout_width="match_parent"
         android:layout_height="wrap_content"
         android:background="#111111"
         android:orientation="horizontal">

         <RadioButton
             android:id="@+id/tab_patient_list"
             style="@style/tab_rb_style"
             android:checked="true"
             android:text="@string/tab_patient_list"/>

         <RadioButton
             android:id="@+id/tab_message"
             style="@style/tab_rb_style"
             android:text="@string/tab_message"/>

         <RadioButton
             android:id="@+id/tab_settings"
             style="@style/tab_rb_style"
             android:text="@string/tab_settings"/>

     </RadioGroup>

     <android.support.v4.app.FragmentTabHost
         android:id="@android:id/tabhost"
         android:layout_width="match_parent"
         android:layout_height="wrap_content"
         android:visibility="gone" >

         <FrameLayout
             android:id="@android:id/tabcontent"
             android:layout_width="0dp"
             android:layout_height="0dp"
             android:layout_weight="0"/>
     </android.support.v4.app.FragmentTabHost>

 </LinearLayout>

其中，id为real_tab_content的fragment存放用于显示的Fragment。

TabHostActivity：

 public class TabHostActivity extends FragmentActivity{
     private FragmentTabHost mFragmentTabHost;
     private RadioGroup mTabRg;

     private final Class[] fragments = {
             FragmentA.class,
             FragmentB.class,
             FragmentC.class
     };

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

         initView();
     }

     private void initView() {
         // 构建TabHost
         mFragmentTabHost = (FragmentTabHost) findViewById(android.R.id.tabhost);
         // getSupportFragmentManager()：
         // return the fragmentManager for interacting with fragments associated with this activity.
         // setup(Context context, FragmentManager manager, int containerId)
         mFragmentTabHost.setup(this, getSupportFragmentManager(), R.id.real_tab_content);

         int count = fragments.length;
         for (int i = 0; i < count; i++) {
             // A tab has a tab indicator, content, and a tag that is used to keep track of it.
             // newTabSpec(String tag):
             // Get a new TabHost.TabSpec associated with this tab host.
             TabHost.TabSpec tabSpec = mFragmentTabHost.newTabSpec(i + "").setIndicator(i + "");
             mFragmentTabHost.addTab(tabSpec, fragments[i], null);
         }

         mTabRg = (RadioGroup) findViewById(R.id.radio_tab_bottom_menu);

         mTabRg.setOnCheckedChangeListener(new RadioGroup.OnCheckedChangeListener() {
             @Override
             public void onCheckedChanged(RadioGroup radioGroup, int i) {
                 switch (i) {
                     case R.id.tab_patient_list:
                         mFragmentTabHost.setCurrentTab(0);
                         break;

                     case R.id.tab_message:
                         mFragmentTabHost.setCurrentTab(1);
                         break;

                     case R.id.tab_settings:
                         mFragmentTabHost.setCurrentTab(2);
                         break;

                     default:
                         break;
                 }
             }
         });
     }

 }

FragmentA：

 public class FragmentA extends Fragment {
     private View rootView;

     @Override
     public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
         if (rootView == null) {
             rootView = inflater.inflate(R.layout.fragment_settings, container, false);
         }
 　　　　　
         ViewGroup parent = (ViewGroup) rootView.getParent();
         if (parent != null) {
             parent.removeView(rootView);
         }

         return rootView;
     }
 }

FragmentB、C同理。