ListFragment 在 ViewPager 中事务后显示空白屏幕

Question

我要做什么
创建一个 ListFragment（将在 ViewPager 中），它将自己替换为一个新的 ListFragment，其中包含基于前一个列表的点击位置的新数据。

我遇到的问题
onListItemClick 后，屏幕不显示任何内容。我考虑只清除 ListAdapter 而不是初始化多个 ListFragments，但我想保留 backStack（我不知道如何在没有 Fragment Transactions 的情况下保留 backStack）

MainActivity.java

import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentActivity;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentPagerAdapter;
import android.support.v4.view.ViewPager;


public class MainActivity extends FragmentActivity {

    private ViewPager mPager;
    private MainPagerAdapter mPagerAdapter;

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

        mPagerAdapter = new MainPagerAdapter(this.getSupportFragmentManager());
        mPager = (ViewPager) this.findViewById(R.id.fragment_container);
        mPager.setAdapter(mPagerAdapter);
    }

    private class MainPagerAdapter extends FragmentPagerAdapter {
        public MainPagerAdapter(FragmentManager fm) {
            super(fm);
        }

        @Override
        public Fragment getItem(int position) {
            return new MyListFragment(); //Simplified for the post
        }

        @Override
        public int getCount() {
            return 1; //Simplified for the post
        }
    }
}

MyListFragment.java

import java.util.ArrayList;

import android.os.Bundle;
import android.support.v4.app.ListFragment;
import android.view.View;
import android.widget.ArrayAdapter;
import android.widget.ListView;

public class MyListFragment extends ListFragment {
    private ArrayList<String> titles;

    public MyListFragment() {
        titles = new ArrayList<String>();
        titles.add("one");titles.add("two");titles.add("three");
    }

    public MyListFragment(ArrayList<String> titles) {
        this.titles = titles;
    }

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        this.setListAdapter(new MyListAdapter());
    }

    @Override
    public void onListItemClick (ListView l, View v, int position, long id) {
        ArrayList<String> list = new ArrayList<String>();
        list.add("1");list.add("2");list.add("3");

        getFragmentManager().beginTransaction()
            .replace(R.id.fragment_container, new MyListFragment(list))
            .addToBackStack(null)
            .commit();
    }

    private class MyListAdapter extends ArrayAdapter<String> {
        public MyListAdapter() {
            super(getActivity(), android.R.layout.simple_list_item_1, titles);
        }
    }
}

activity_main.xml

<RelativeLayout 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" >

    <android.support.v4.view.ViewPager android:id="@+id/fragment_container"
        android:layout_width="match_parent"
        android:layout_height="match_parent" />

</RelativeLayout>

Answer 1

终于明白了。我创建了一个 ListRootFragment，它会扩展其布局并添加到 ListFragment。

ListRootFragment.java

import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;

public class ListRootFragment extends Fragment {
    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
            Bundle savedInstanceState) {
        // Inflate the layout for this fragment
        View view = inflater.inflate(R.layout.fragment, container, false);

        this.getActivity().getSupportFragmentManager().beginTransaction()
            .replace(R.id.fragment, new MyListFragment())
            .commit();

        return view;
    }
}

fragment.xml

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

</LinearLayout>

更新 MainActivity.java

import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentActivity;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentStatePagerAdapter;
import android.support.v4.view.ViewPager;


public class MainActivity extends FragmentActivity {

    ...

    private class MainPagerAdapter extends FragmentStatePagerAdapter {
        ...

        @Override
        public Fragment getItem(int position) {
            return new ListRootFragment();
        }

        ...
    }
}