Question

我有一个MainActivIty，它支持两个片段，即Home和Profile.Home有一个TabLayout，而TabLayout又有三个片段Trending，Followed和Nearby。所以问题是当首次加载Home时它会显示Tab片段的内容和标签布局的滑块正确移动但是当我进行配置文件然后回到主页时，标签布局片段不会加载并且从左向右滑动滑块不顺利。这就是代码。

public class MainActivity extends AppCompatActivity {

 ImageButton home_btn,myProfile_btn;
FragmentManager fragmentManager;
FragmentTransaction fragmentTransaction;
TextView txt_action_bar;
Home home;
ProfileFragment profile;
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    home_btn=(ImageButton)findViewById(R.id.home_btn) ;
    discover_btn=(ImageButton)findViewById(R.id.discover_btn) ;
    myProfile_btn=(ImageButton)findViewById(R.id.profile_btn) ;
    notification_btn=(ImageButton)findViewById(R.id.notification_btn) ;
    plus_btn=(ImageButton)findViewById(R.id.btn_plus) ;

    Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
     txt_action_bar = (TextView)findViewById(R.id.toolbar_title);
    displayMetrics = getResources().getDisplayMetrics();
    Typeface custom_font = Typeface.createFromAsset(getAssets(),"fonts/NoteworthyLight.ttf");
    txt_action_bar.setTypeface(custom_font);


    setSupportActionBar(toolbar);
     fragmentManager = getSupportFragmentManager();
    fragmentTransaction = fragmentManager.beginTransaction();
     home = new Home();
     profile = new ProfileFragment();
    fragmentTransaction.add(R.id.main_fragment_container,home,"home");
    fragmentTransaction.commit();


}

public void onClickHome(View view)
{


    fragmentManager = getSupportFragmentManager();
    fragmentTransaction = fragmentManager.beginTransaction();

    fragmentTransaction.replace(R.id.main_fragment_container,home,"home");
    fragmentTransaction.commit();
}

public void onClickMyProfile(View view)
{

    fragmentManager = getSupportFragmentManager();
    fragmentTransaction = fragmentManager.beginTransaction();

    fragmentTransaction.replace(R.id.main_fragment_container,profile,"profile");

   fragmentTransaction.commit();
}

}

Home.java

public class Home extends Fragment {


private SectionsPagerAdapter mSectionsPagerAdapter;
private ViewPager mViewPager;

public Home() {
    // Required empty public constructor
}



@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

}

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
                         Bundle savedInstanceState) {
    View view=inflater.inflate(R.layout.fragment_home, container, false);

    mSectionsPagerAdapter = new SectionsPagerAdapter(getFragmentManager());
    mViewPager = (ViewPager) view.findViewById(R.id.container);
    mViewPager.setAdapter(mSectionsPagerAdapter);
    TabLayout tabLayout = (TabLayout) view.findViewById(R.id.tabs);
    tabLayout.setupWithViewPager(mViewPager);
    return view;
}

FollowedFragment.java

public class FollowedFragment extends Fragment {


public FollowedFragment() {
}

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
                         Bundle savedInstanceState) {
    final View rootView = inflater.inflate(R.layout.feeds_list, container, false);
    new DownloadFollowedFeeds().execute();
    return rootView;
}

fragment_home.xml

<LinearLayout android:layout_below="@+id/header"
android:layout_above="@+id/footer"
android:layout_height="wrap_content"
android:layout_width="match_parent"
android:layout_gravity="center_vertical"
android:orientation="vertical"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:android="http://schemas.android.com/apk/res/android">
<android.support.design.widget.TabLayout
    android:id="@+id/tabs"
    style="@style/TabNameStyle"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:background="@color/medium_turquoise"
    app:tabGravity="fill"
    app:tabMode="fixed" />

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

SectionPagerAdapter.java

public class SectionsPagerAdapter extends FragmentPagerAdapter {

private String tabTitles[] = new String[] { "Trending", "Followed","Nearby" };


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

@Override
public Fragment getItem(int position) {
    // getItem is called to instantiate the fragment for the given page.
    // Return a PlaceholderFragment (defined as a static inner class below).
    Log.i("tag","number"+String.valueOf(position));
    if(position==0)  return  new TrendingFragment();
    else if(position==1)    return new FollowedFragment();
    else return new NearbyFragment();
}

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

@Override
public CharSequence getPageTitle(int position) {
    return tabTitles[position];
}

}

Answer 1

回答here：

在Home.java中创建视图适配器时：

而不是

mSectionsPagerAdapter = new SectionsPagerAdapter(getFragmentManager());

你应该这样做，

mSectionsPagerAdapter = new SectionsPagerAdapter(getChildFragmentManager());

当父片段替换其他片段

1 个答案: