Fragment嵌套Fragment实现的Tab导航

要实现的效果就是底部导航，具体到每一个Fragment又在上部设置一个导航条，分成两个Fragment实现。效果图是：

首先给出activity的layout:

<android.support.v4.app.FragmentTabHost xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@android:id/tabhost"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:orientation="vertical">
        <FrameLayout
            android:id="@android:id/tabcontent"
            android:layout_width="fill_parent"
            android:layout_height="0dp"
            android:layout_weight="1" />
        <TabWidget
            android:id="@android:id/tabs"
            android:layout_width="fill_parent"
            android:layout_height="wrap_content"
            android:layout_gravity="bottom" />

    </LinearLayout>

</android.support.v4.app.FragmentTabHost>

然后是main activity的代码：

package com.example.xxx.myapplication;

import android.os.Bundle;
import android.support.v4.app.FragmentActivity;
import android.support.v4.app.FragmentTabHost;
import android.view.Menu;
import android.view.MenuItem;

public class MainActivity extends FragmentActivity {

    private FragmentTabHost mTabHost;

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

        mTabHost = (FragmentTabHost) findViewById(android.R.id.tabhost);
        mTabHost.setup(this, getSupportFragmentManager(), android.R.id.tabcontent);
        mTabHost.addTab(mTabHost.newTabSpec("Tab1").setIndicator("TAB1", null), Fragment1.class, null);
        mTabHost.addTab(mTabHost.newTabSpec("Tab2").setIndicator("TAB2", null), Fragment2.class,
                null);
    }
}

我在Fragment2中嵌套两个fragment,这个layout比较重要，容易出问题的地方就是这里。

<?xml version="1.0" encoding="utf-8"?>
<android.support.v4.app.FragmentTabHost
    android:id="@android:id/tabhost"
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:orientation="vertical">
        <TextView
            android:layout_width="match_parent"
            android:layout_height="50dp"
            android:background="@color/bg_color"
            android:textColor="@android:color/white"
            android:textSize="24sp"
            android:gravity="center_horizontal|center_vertical"
            android:text="hello"/>
        <TabWidget
            android:id="@android:id/tabs"
            android:layout_width="fill_parent"
            android:layout_height="wrap_content"
            android:layout_gravity="bottom"/>
        <FrameLayout
            android:id="@android:id/tabcontent"
            android:layout_width="fill_parent"
            android:layout_height="0dp"
            android:layout_weight="1"/>

    </LinearLayout>

</android.support.v4.app.FragmentTabHost>

fragment2的代码实现

public class Fragment2 extends Fragment {

    private FragmentTabHost tabHost;

    @Nullable
    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        View view  = inflater.inflate(R.layout.fragment_test, null);
        tabHost = (FragmentTabHost) view.findViewById(android.R.id.tabhost);
        tabHost.setup(getActivity(),getChildFragmentManager(), android.R.id.tabcontent);
        tabHost.addTab(tabHost.newTabSpec("friends").setIndicator("friends", null), FriendsFragment
                .class, null);
        tabHost.addTab(tabHost.newTabSpec("groups").setIndicator("groups", null), GroupFragment
                        .class,
                null);
        tabHost.setCurrentTab(0);
        return view;
    }
}