如何将Cardview放入片段中

Question

美好的一天， 我有一个应用程序，主要活动，碎片和标签碎片。我正在尝试使用Cardview显示我的Allposts片段上的帖子列表。但是，当我运行它时，没有任何显示。

MainActivity.java

package com.example.stephan.regnotifier;

import android.content.Intent;
import android.os.Bundle;
import android.support.design.widget.NavigationView;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentTransaction;
import android.support.v4.widget.DrawerLayout;
import android.support.v7.app.ActionBarDrawerToggle;
import android.support.v7.app.AppCompatActivity;
import android.view.MenuItem;

import com.example.stephan.regnotifier.activity.AboutFragment;
import com.example.stephan.regnotifier.activity.PostsFragment;
import com.example.stephan.regnotifier.activity.SettingsFragment;
import com.example.stephan.regnotifier.activity.TabFragment;
import com.example.stephan.regnotifier.activity.TimetableFragment;

public class MainActivity extends AppCompatActivity{
    DrawerLayout mDrawerLayout;
    NavigationView mNavigationView;
    FragmentManager mFragmentManager;
    FragmentTransaction mFragmentTransaction;

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

        /**
         *Setup the DrawerLayout and NavigationView
         */

        mDrawerLayout = (DrawerLayout) findViewById(R.id.drawerLayout);
        mNavigationView = (NavigationView) findViewById(R.id.shitstuff) ;

        /**
         * Lets inflate the very first fragment
         * Here , we are inflating the TabFragment as the first Fragment
         */

        mFragmentManager = getSupportFragmentManager();
        mFragmentTransaction = mFragmentManager.beginTransaction();
        mFragmentTransaction.replace(R.id.containerView,new TabFragment()).commit();
        /**
         * Setup click events on the Navigation View Items.
         */

        mNavigationView.setNavigationItemSelectedListener(new NavigationView.OnNavigationItemSelectedListener() {
            @Override
            public boolean onNavigationItemSelected(MenuItem menuItem) {
                mDrawerLayout.closeDrawers();



                if (menuItem.getItemId() == R.id.nav_item_timetable) {
                    FragmentTransaction fragmentTransaction = mFragmentManager.beginTransaction();
                    fragmentTransaction.replace(R.id.containerView,new TimetableFragment()).commit();

                }

                if (menuItem.getItemId() == R.id.nav_item_post) {
                    FragmentTransaction xfragmentTransaction = mFragmentManager.beginTransaction();
                    xfragmentTransaction.replace(R.id.containerView,new TabFragment()).commit();
                }

                if (menuItem.getItemId() == R.id.nav_item_profile) {
                    FragmentTransaction xfragmentTransaction = mFragmentManager.beginTransaction();
                    xfragmentTransaction.replace(R.id.containerView,new PostsFragment()).commit();


                }

                if (menuItem.getItemId() == R.id.nav_item_settings) {
                    FragmentTransaction xfragmentTransaction = mFragmentManager.beginTransaction();
                    xfragmentTransaction.replace(R.id.containerView,new SettingsFragment()).commit();
                }

                if (menuItem.getItemId() == R.id.nav_item_about) {
                    FragmentTransaction xfragmentTransaction = mFragmentManager.beginTransaction();
                    xfragmentTransaction.replace(R.id.containerView,new AboutFragment()).commit();
                }

                if (menuItem.getItemId() == R.id.nav_item_logout) {
                    Intent logout = new Intent(MainActivity.this, LoginActivity.class);
                    startActivity(logout);
                }

                return false;
            }

        });

        /**
         * Setup Drawer Toggle of the Toolbar
         */

        android.support.v7.widget.Toolbar toolbar = (android.support.v7.widget.Toolbar) findViewById(R.id.toolbar);
        ActionBarDrawerToggle mDrawerToggle = new ActionBarDrawerToggle(this,mDrawerLayout, toolbar,R.string.app_name,
                R.string.app_name);

        mDrawerLayout.setDrawerListener(mDrawerToggle);

        mDrawerToggle.syncState();

    }
}

AllpostsFragment.java

package com.example.stephan.regnotifier.activity;


import android.content.Context;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.support.v7.widget.CardView;
import android.support.v7.widget.DefaultItemAnimator;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;

import com.example.stephan.regnotifier.R;

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


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


    CardView mCardView;
    RecyclerView mRecyclerView;
    RecyclerView.LayoutManager mLayoutManager;
    RecyclerView.Adapter mAdapter;
    Context context;

    public static AllpostsFragment newInstance() {
        AllpostsFragment fragment = new AllpostsFragment();
        fragment.setRetainInstance(true);
        return fragment;
    }


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

    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        // Inflate the layout for this fragment
        View v = inflater.inflate(R.layout.fragment_allposts, container, false);
        RecyclerView rv = (RecyclerView)v.findViewById(R.id.cardList);
        mLayoutManager = new LinearLayoutManager(context, LinearLayoutManager.HORIZONTAL, false);
        rv.setLayoutManager(mLayoutManager);
        rv.setItemAnimator(new DefaultItemAnimator());
        rv.setHasFixedSize(true);
        return v;
    }

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


    }

}

PostList.java

package com.example.stephan.regnotifier.model;

/**
 * Created by StephAn on 18-Feb-16.
 */
public class Posts_list {
    private String mName;
    private int mThumbnail;

    public String getName() {
        return mName;
    }

    public void setName(String name) {
        this.mName = name;
    }

    public int getThumbnail() {
        return mThumbnail;
    }

    public void setThumbnail(int thumbnail) {
        this.mThumbnail = thumbnail;
    }
}

CardAdapter.java

package com.example.stephan.regnotifier.adapter;

import android.support.v7.widget.RecyclerView;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ImageView;
import android.widget.TextView;

import com.example.stephan.regnotifier.R;
import com.example.stephan.regnotifier.model.Posts_list;

import java.util.ArrayList;
import java.util.List;

/**
 * Created by StephAn on 18-Feb-16.
 */
public class CardAdapter extends RecyclerView.Adapter<CardAdapter.CardViewHolder>{
    List<Posts_list> pItems;

    public CardAdapter() {
        super();
        pItems = new ArrayList<Posts_list>();
        Posts_list posts_list = new Posts_list();
        posts_list.setName("The Amazing Spider-Man 2");
        posts_list.setThumbnail(R.drawable.sample);
        pItems.add(posts_list);

        posts_list = new Posts_list();
        posts_list.setName("X-men: Days of Future Past");
        posts_list.setThumbnail(R.drawable.sample);
        pItems.add(posts_list);

        posts_list = new Posts_list();
        posts_list.setName("The Hunger Game");
        posts_list.setThumbnail(R.drawable.sample);
        pItems.add(posts_list);

        posts_list = new Posts_list();
        posts_list.setName("Guardians of the Galaxy");
        posts_list.setThumbnail(R.drawable.sample);
        pItems.add(posts_list);

        posts_list = new Posts_list();
        posts_list.setName("Maleficent");
        posts_list.setThumbnail(R.drawable.sample);
        pItems.add(posts_list);

        posts_list = new Posts_list();
        posts_list.setName("How to Train Your Dragon 2");
        posts_list.setThumbnail(R.drawable.sample);
        pItems.add(posts_list);

        posts_list = new Posts_list();
        posts_list.setName("What If");
        posts_list.setThumbnail(R.drawable.sample);
        pItems.add(posts_list);
    }

    @Override
    public CardViewHolder onCreateViewHolder(ViewGroup viewGroup, int i) {
        View v = LayoutInflater.from(viewGroup.getContext())
                .inflate(R.layout.card_view_layout, viewGroup, false);
        CardViewHolder viewHolder = new CardViewHolder(v);
        return viewHolder;
    }

    @Override
    public void onBindViewHolder(CardViewHolder cardViewHolder, int i) {
        Posts_list posts_list = pItems.get(i);
        cardViewHolder.tvMovie.setText(posts_list.getName());
        cardViewHolder.imgThumbnail.setImageResource(posts_list.getThumbnail());
    }

    @Override
    public int getItemCount() {
        return pItems.size();
    }

    class CardViewHolder extends RecyclerView.ViewHolder{

        public ImageView imgThumbnail;
        public TextView tvMovie;

        public CardViewHolder(View itemView) {
            super(itemView);
            imgThumbnail = (ImageView)itemView.findViewById(R.id.img_thumbnail);
            tvMovie = (TextView)itemView.findViewById(R.id.tv_movie);
        }
    }
}

fragment_allpost.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:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    android:paddingBottom="@dimen/activity_vertical_margin"
    tools:context=".MyActivity">

    <android.support.v7.widget.RecyclerView
        android:id="@+id/cardList"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        />

</RelativeLayout>

card_view_layout.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:card_view="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical">

    <android.support.v7.widget.CardView
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        card_view:contentPadding="@dimen/activity_horizontal_margin"
        card_view:cardCornerRadius="3dp">

        <ImageView
            android:id="@+id/img_thumbnail"
            android:layout_width="fill_parent"
            android:layout_height="150dp" />

        <TextView
            android:id="@+id/tv_movie"
            android:layout_width="fill_parent"
            android:layout_height="50dp"
            android:paddingLeft="@dimen/activity_horizontal_margin"
            android:paddingRight="@dimen/activity_horizontal_margin"
            android:layout_gravity="bottom"
            android:gravity="center_vertical"
            android:background="#757575"
            android:alpha="0.8"
            android:textSize="@dimen/abc_text_size_headline_material"
            android:text="Test"/>

    </android.support.v7.widget.CardView>

</LinearLayout>