android - fragment 中的 Tablayout 在抽屉导航中不起作用

Question

我正在创建一个选项卡式布局作为抽屉导航 Activity 的主页 fragment ，

所以我在主要 Activity 中将名为“test”的 fragment 称为默认 fragment 。喜欢

        test home_fragment=new test();
        android.support.v4.app.FragmentManager manager=getSupportFragmentManager();
        manager.beginTransaction().replace(R.id.layout, home_fragment,home_fragment.getTag()).commit();

如果我再次调用这个 fragment 。喜欢

if (id == R.id.nav_home) {


        test home_fragment=new test();
        android.support.v4.app.FragmentManager manager=getSupportFragmentManager();
        manager.beginTransaction().replace(R.id.layout, home_fragment,home_fragment.getTag()).commit();


    }

现在结果是tab1和tab2都没有了

更多引用请看截图

这是我的测试类(标签式布局)

 package com.hackerinside.jaisonjoseph.testapp;


 import android.os.Bundle;
 import android.support.annotation.Nullable;
 import android.support.design.widget.TabLayout;
 import android.support.v4.app.Fragment;
 import android.support.v4.app.FragmentManager;
 import android.support.v4.app.FragmentPagerAdapter;
 import android.support.v4.view.ViewPager;
 import android.view.LayoutInflater;
 import android.view.View;
 import android.view.ViewGroup;

 import static android.R.attr.x;


/**
 * A simple {@link Fragment} subclass.
*/
public class test extends Fragment {




public SectionsPagerAdapter mSectionsPagerAdapter;
public ViewPager mViewPager;





public test() {


}



@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
                         Bundle savedInstanceState) {


    View rootView = inflater.inflate(R.layout.fragment_test, container, false);
   // View x =  inflater.inflate(R.layout.fragment_test,null);
    mSectionsPagerAdapter = new  SectionsPagerAdapter (getFragmentManager());
    mViewPager = (ViewPager) rootView.findViewById(R.id.container);
    mViewPager.setAdapter(mSectionsPagerAdapter);
    TabLayout tabLayout = (TabLayout) rootView.findViewById(R.id.tabs);
    //Adding the tabs using addTab() method
    tabLayout.addTab(tabLayout.newTab().setText("Tab Title 1"));
    tabLayout.addTab(tabLayout.newTab().setText("Tab Title 2"));
    tabLayout.setTabGravity(TabLayout.GRAVITY_FILL);
    tabLayout.setupWithViewPager(mViewPager);

    return rootView;

}

public class SectionsPagerAdapter extends FragmentPagerAdapter {

    private SectionsPagerAdapter(FragmentManager fm) {
        super(fm);
    }

    @Override
    public Fragment getItem(int position) {


        switch (position)
        {
            case 0:

                tab1 tab1=new tab1();

                return tab1;
            case 1:

                tab2 tab2=new tab2();

                return tab2;


            default:return null;
        }



    }

    @Override
    public int getCount() {
        // Show 3 total pages.
        return 2;
    }

    @Override
    public CharSequence getPageTitle(int position) {
        switch (position) {
            case 0:
                return "SECTION 1";
            case 1:
                return "SECTION 2";

        }
        return null;
    }
}



}

这是我的标签布局xml代码

   <?xml version="1.0" encoding="utf-8"?>
  <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
  xmlns:app="http://schemas.android.com/apk/res-auto"
  xmlns:tools="http://schemas.android.com/tools"
  android:id="@+id/main_content"
  android:layout_width="match_parent"
  android:layout_height="match_parent"
  android:fitsSystemWindows="true"
  tools:context="com.hackerinside.jaisonjoseph.testapp.MainActivity"
  android:orientation="vertical">

  <android.support.design.widget.AppBarLayout
    android:id="@+id/appbar"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:theme="@style/AppTheme.AppBarOverlay">


      <android.support.design.widget.TabLayout
        android:id="@+id/tabs"
        android:layout_width="match_parent"
        android:layout_height="wrap_content" />

    </android.support.design.widget.AppBarLayout>

    <android.support.v4.view.ViewPager
    android:id="@+id/container"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    app:layout_behavior="@string/appbar_scrolling_view_behavior" />


   </LinearLayout>

Answer 1

尝试这两种解决方案:

解决方案一

代替

public class SectionsPagerAdapter extends FragmentPagerAdapter {

使用

public class SectionsPagerAdapter extends FragmentStatePagerAdapter {

方案二

使用 getChildFragmentManager() 而不是 getFragmentManager()

mSectionsPagerAdapter = new  SectionsPagerAdapter (getChildFragmentManager());