ViewPager具有相同类的多个片段实例

Question

我正在尝试创建一个包含5个片段的ViewPager.5个片段"容器",因此每个片段包含2个片段.4个第一个片段具有相同的布局并属于同一个类.第五个来自另一个班级,那个没有问题.

问题是当活动启动时,只有1个片段似乎正在工作(viewPager中位置0的片段).我试图在我的PagerAdapter中的第0位返回新的Fragment(),但是当我这样做时,它是第二个正在工作的片段.(通过工作我的意思是在左边显示列表,我仍然没有处理右边的细节片段)

这是一些代码

CustomPagerAdapter.java

public class CustomPagerAdapter extends FragmentPagerAdapter{

public CustomPagerAdapter(FragmentManager fm) {
    super(fm);
}
public CustomPagerAdapter(FragmentManager fm, Context context) {
    super(fm);

}

@Override   
public Fragment getItem(int pos) {

    if(pos == 4)
        return new OtherContainerFragment();
    else
        return new ContainerFragment(pos);

}

@Override
public int getCount() {

    return 5;
}

ContainerFragment.java

public class ContainerFragment extends Fragment {
private int CONTAINER_TYPE;

public ContainerFragment(){

}

public ContainerFragment(int type){
    CONTAINER_TYPE = type;
}



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


@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
    return inflater.inflate(R.layout.fragment_container, container, false);
}

@Override
public void onViewCreated(View view, Bundle savedInstanceState) {
    super.onViewCreated(view, savedInstanceState);


    FragmentTransaction ft = getActivity().getSupportFragmentManager().beginTransaction();
    CustomListFragment frag = new CustomListFragment(CONTAINER_TYPE);

    ft.replace(R.id.replaceable_list, frag);

    ft.commit();

CustomListFragment.java

public class CustomListFragment extends SuperCustomListFragment{

private ArrayList<Model> mModels;
private int TYPE;


public CustomListFragment(){

}

public CustomListFragment(int type){
    TYPE = type;
}


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


@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
    return super.onCreateView(inflater, container, savedInstanceState);
}


@Override
public void onViewCreated(View view, Bundle savedInstanceState) {
    super.onViewCreated(view, savedInstanceState);

    mModels = new ArrayList<Model>();


     if(TYPE == AppConstants.FRAGMENT_TYPE_JOURNAL){
        mAdapter = AppUtils.getJournalListAdapter(getActivity(), mModels);
        new syncPapers().execute();
     }else if(TYPE == AppConstants.FRAGMENT_TYPE_MOVIES){
         mAdapter = AppUtils.getMoviesListAdapter(getActivity(), mModels);
         new syncMovies().execute();
     }


    if(mAdapter != null)
        mListView.setAdapter(mAdapter);  //mListView is defined in the superClass 

以下是我使用的常量:

public class AppConstants {


public static final int FRAGMENT_TYPE_AGENDA = 0; //so Fragment at position 0 should be of type agenda
public static final int FRAGMENT_TYPE_NEWS = 1; // position 1 should be of type news
public static final int FRAGMENT_TYPE_MOVIES = 2; // ...
public static final int FRAGMENT_TYPE_JOURNAL = 3; // ...

}

而容器的xml:

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

<LinearLayout
    android:id="@+id/replaceable_list"
    android:layout_width="match_parent"
    android:layout_height="match_parent" >
</LinearLayout>

<LinearLayout
    android:id="@+id/replaceable_details"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:layout_weight="1"
    android:background="@drawable/background" >
</LinearLayout>

</LinearLayout>

因此,此代码不工作,似乎对在片段容器左边的列表被替换在每个片段中,只有0将其显示在片段在位置.(目前它显示带有"JOURNAL"类型的适配器的列表,但它应显示"AGENDA"类型的列表.

-------------------- *但是!...* --------------------

如果我创建不同fragment_container布局文件,并写入IF在onCreateView和onViewCreated在ContainerFragment.java条件下,一切工作正常.所以:

ContainerFragment.java

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle      savedInstanceState) {
if(CONTAINER_TYPE == AppConstants.FRAGMENT_TYPE_JOURNAL)
    return inflater.inflate(R.layout.fragment_container_journal, container, false);
else if(CONTAINER_TYPE == AppConstants.FRAGMENT_TYPE_MOVIES)
    return inflater.inflater(R.layout.fragment_container_movies, container, false);
else
    return super.onCreateView(LayoutInflater inflater, ViewGroup container, Bundle      savedInstanceState);
}


@Override
public void onViewCreated(View view, Bundle savedInstanceState) {
    super.onViewCreated(view, savedInstanceState);


    FragmentTransaction ft = getActivity().getSupportFragmentManager().beginTransaction();
    CustomListFragment frag = new CustomListFragment(CONTAINER_TYPE);

    if(CONTAINER_TYPE == AppConstants.FRAGMENT_TYPE_JOURNAL)
        ft.replace(R.id.replaceable_journal_list, frag);
    else if(CONTAINER_TYPE == AppConstants.FRAGMENT_TYPE_MOVIES)
        ft.replace(R.id.replaceable_movies_list, frag);
    else 
        return;

    ft.commit();

我猜那是因为在每个片段中,我替换了相同ID的LinearLayout？(replaceable_list)我认为这是可以共享相同的布局文件为每个碎片,并没有想创建4个布局文件是相同的.但看起来我必须这样做？或者我在这里遗漏了什么？

感谢您的时间,

Answer 1

虽然是一个非常晚的回应,但我面临同样的问题,我通过使用修复了这个问题

getChildFragmentManager().beginTransaction()

代替

getActivity().getSupportFragmentManager().beginTransaction()

在这种情况下,我们试图从一个片段中进行事务处理(连接到ViewPager的片段列表中的一个,因此持有ViewPager的Activity),所以我们必须在这里使用getChildFragmentManager()来获得所需的结果.

Answer 2

我能够通过将每个片段中膨胀的布局的id设置到其位置来解决这个问题.

您需要做的只是将ContainerFragment类中的onCreateView方法更改为:

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
    View v = inflater.inflate(R.layout.fragment_container, container, false);
    v.setId(CONTAINER_TYPE)
    return v;

这是因为FragmentPagerAdapter实现处理片段标记的方式.