android: 查看下一个选项卡时收到异常

Question

我想在片段中添加 Recyclerview，然后想在 viewpager.So 中添加片段，我按照 youtube.after 上的教程进行编译。显示了 recyclerview，但是当我转到下一个选项卡时，出现异常 appear.Hope你们可以帮我解决这个问题。

错误

D/AndroidRuntime: Shutting down VM
E/AndroidRuntime: FATAL EXCEPTION: main
                  Process: com.example.user.recyclerviewpagerfragment, PID: 3705
                  java.lang.ClassCastException: android.support.v7.widget.LinearLayoutCompat cannot be cast to android.support.v7.widget.RecyclerView
                      at com.example.user.recyclerviewpagerfragment.Fragments.DocumentaryFragment.onCreateView(DocumentaryFragment.java:30)
                      at android.support.v4.app.Fragment.performCreateView(Fragment.java:2080)
                      at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1108)
                      at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1290)
                      at android.support.v4.app.BackStackRecord.run(BackStackRecord.java:801)
                      at android.support.v4.app.FragmentManagerImpl.execSingleAction(FragmentManager.java:1638)
                      at android.support.v4.app.BackStackRecord.commitNowAllowingStateLoss(BackStackRecord.java:679)
                      at android.support.v4.app.FragmentPagerAdapter.finishUpdate(FragmentPagerAdapter.java:143)
                      at android.support.v4.view.ViewPager.populate(ViewPager.java:1240)
                      at android.support.v4.view.ViewPager.populate(ViewPager.java:1088)
                      at android.support.v4.view.ViewPager.run(ViewPager.java:275)
                      at android.view.Choreographer$CallbackRecord.run(Choreographer.java:858)
                      at android.view.Choreographer.doCallbacks(Choreographer.java:670)
                      at android.view.Choreographer.doFrame(Choreographer.java:603)
                      at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:844)
                      at android.os.Handler.handleCallback(Handler.java:739)
                      at android.os.Handler.dispatchMessage(Handler.java:95)
                      at android.os.Looper.loop(Looper.java:148)
                      at android.app.ActivityThread.main(ActivityThread.java:5417)
                      at java.lang.reflect.Method.invoke(Native Method)
                      at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726)
                      at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)
I/Process: Sending signal. PID: 3705 SIG: 9
Application terminated.

MainActivity.java

package com.example.user.recyclerviewpagerfragment;

import android.os.Bundle;
import android.support.design.widget.FloatingActionButton;
import android.support.design.widget.Snackbar;
import android.support.design.widget.TabLayout;
import android.support.v4.view.ViewPager;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import android.view.View;
import android.view.Menu;
import android.view.MenuItem;

import com.example.user.recyclerviewpagerfragment.Fragments.CrimeFragment;
import com.example.user.recyclerviewpagerfragment.Fragments.DocumentaryFragment;
import com.example.user.recyclerviewpagerfragment.Fragments.DramaFragment;

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
        setSupportActionBar(toolbar);

        //initialize view pager.
        ViewPager viewPager = (ViewPager) findViewById(R.id.viewpager_id);
        this.addPages(viewPager);

        TabLayout tabLayout = (TabLayout) findViewById(R.id.tab_id);
        //it gonna occupy the whole screen..
        tabLayout.setTabGravity(TabLayout.GRAVITY_FILL);
        tabLayout.setupWithViewPager(viewPager);
        tabLayout.addOnTabSelectedListener(listener(viewPager));
    }

    // add all pages
    private void addPages(ViewPager pager){
        FragPagerAdapter adapter = new FragPagerAdapter(getSupportFragmentManager());
        adapter.addPage(new CrimeFragment());
        adapter.addPage(new DramaFragment());
        adapter.addPage(new DocumentaryFragment());

        //set adapter to pager
        pager.setAdapter(adapter);
    }

    private TabLayout.OnTabSelectedListener listener(final ViewPager pager){
        return new TabLayout.OnTabSelectedListener() {
            @Override
            public void onTabSelected(TabLayout.Tab tab) {
              pager.setCurrentItem(tab.getPosition());
            }

            @Override
            public void onTabUnselected(TabLayout.Tab tab) {

            }

            @Override
            public void onTabReselected(TabLayout.Tab tab) {

            }
        };

    }

}

FragPagerAdapter.java

package com.example.user.recyclerviewpagerfragment;

import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentPagerAdapter;

import java.util.ArrayList;

/**
 * Created by User on 10/4/2016.
 */

public class FragPagerAdapter extends FragmentPagerAdapter{

    //create arraylist..where its gonna hol fragment.

    ArrayList<Fragment> pages = new ArrayList<>();

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

    @Override
    public Fragment getItem(int position) {
        return pages.get(position);
    }

    @Override
    public int getCount() {
        return pages.size();
    }

    // add a page
    public void addPage(Fragment f){
        pages.add(f);
    }

    //set title for tab

    @Override
    public CharSequence getPageTitle(int position) {
        return pages.get(position).toString();
        //return super.getPageTitle(position);
    }
}

MyRecyclerAdapter.java

package com.example.user.recyclerviewpagerfragment.Recycler;

import android.content.Context;
import android.support.v7.widget.RecyclerView;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Toast;

import com.example.user.recyclerviewpagerfragment.R;

import java.util.ArrayList;

/**
 * Created by User on 10/4/2016.
 */

public class MyRecyclerAdapter extends RecyclerView.Adapter<MyViewHolder> {

    Context context;
    ArrayList<Movie> movies;

    public MyRecyclerAdapter(Context context, ArrayList<Movie> movies) {
        this.context = context;
        this.movies = movies;
    }

    //initialize holder.
    @Override
    public MyViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        View view  = LayoutInflater.from(parent.getContext()).inflate(R.layout.model,null);
        MyViewHolder holder =  new MyViewHolder(view);
        return holder;
        //return null;
    }


    //bind data to views
    @Override
    public void onBindViewHolder(MyViewHolder holder, int position) {
        holder.nameTxt.setText(movies.get(position).getImage());
        holder.img.setImageResource(movies.get(position).getImage());

        //listener
        holder.setItemClickListener(new ItemClickListener() {
            @Override
            public void onItemClick(View view, int position) {
                Toast.makeText(context,movies.get(position).getName(),Toast.LENGTH_SHORT).show();
            }
        });
    }

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

MyViewHolder.java

package com.example.user.recyclerviewpagerfragment.Recycler;

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

import com.example.user.recyclerviewpagerfragment.R;

/**
 * Created by User on 10/4/2016.
 */

public class MyViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener{

    ImageView img;
    TextView nameTxt;
    ItemClickListener itemClickListener;
    public MyViewHolder(View itemView) {
        super(itemView);

        nameTxt = (TextView) itemView.findViewById(R.id.nameTxt);
        img = (ImageView) itemView.findViewById(R.id.movieImage);

        //above...if want to make click on nameTxt,can change itemView to nameTxt
        itemView.setOnClickListener(this);
    }

    public void setItemClickListener(ItemClickListener itemClickListener){
        this.itemClickListener = itemClickListener;
    }

    @Override
    public void onClick(View view) {
        this.itemClickListener.onItemClick(view,getLayoutPosition());
    }
}

DocumentaryFragment.java

package com.example.user.recyclerviewpagerfragment.Fragments;

import android.os.Bundle;
import android.support.annotation.Nullable;
import android.support.v4.app.Fragment;
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.user.recyclerviewpagerfragment.R;
import com.example.user.recyclerviewpagerfragment.Recycler.Movie;
import com.example.user.recyclerviewpagerfragment.Recycler.MyRecyclerAdapter;

import java.util.ArrayList;

/**
 * Created by User on 10/4/2016.
 */

public class DocumentaryFragment extends Fragment {
    @Nullable
    @Override
    public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {

        //call view
        View view = inflater.inflate(R.layout.documentary_fragment,null);
        //recyclerview
        RecyclerView recyclerView = (RecyclerView) view.findViewById(R.id.mRecyclerDocumentary);
        recyclerView.setLayoutManager(new LinearLayoutManager(this.getActivity()));
        //set Adapter
        recyclerView.setAdapter(new MyRecyclerAdapter(this.getActivity(),getDocumentaryMovies()));
        return view;
        //return super.onCreateView(inflater, container, savedInstanceState);
    }

    private ArrayList<Movie> getDocumentaryMovies() {
        //collection of crime movies.
        ArrayList<Movie> movies = new ArrayList<>();
        //single movie
        Movie movie = new Movie("Crime:tank5",R.drawable.e);
        //add to collection..
        movies.add(movie);

        movie = new Movie("Crime:tank6",R.drawable.f);
        movies.add(movie);
        return movies;
        /*
        Movie movie = new Movie("tank1",R.drawable.a);
        movies.add(movie);

        Movie movie = new Movie("tank1",R.drawable.a);
        movies.add(movie);
        */
    }


    //set title for the fragment

    @Override
    public String toString() {
        return "Documentary";
    }
}

activity_main.xml

   <?xml version="1.0" encoding="utf-8"?>
    <android.support.design.widget.CoordinatorLayout 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:layout_width="match_parent"
        android:layout_height="match_parent"
        android:fitsSystemWindows="true"
        tools:context="com.example.user.recyclerviewpagerfragment.MainActivity">

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

            <android.support.v7.widget.Toolbar
                android:id="@+id/toolbar"
                android:layout_width="match_parent"
                android:layout_height="?attr/actionBarSize"
                android:background="?attr/colorPrimary"
                app:popupTheme="@style/AppTheme.PopupOverlay" />

            <!-- add above for adding tablayout -->
            <android.support.design.widget.TabLayout
                android:id="@+id/tab_id"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"/>

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

        <include layout="@layout/content_main" />

        <android.support.design.widget.FloatingActionButton
            android:id="@+id/fab"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_gravity="bottom|end"
            android:layout_margin="@dimen/fab_margin"
            app:srcCompat="@android:drawable/ic_dialog_email" />

        <!-- add above for adding viewpager -->
        <android.support.v4.view.ViewPager
            android:id="@+id/viewpager_id"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            app:layout_behavior="@string/appbar_scrolling_view_behavior" />

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

Documentary_fragment.xml

<android.support.v7.widget.LinearLayoutCompat
    android:id="@+id/mRecyclerDocumentary"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"></android.support.v7.widget.LinearLayoutCompat> </LinearLayout>

Model.xml

<?xml version="1.0" encoding="utf-8"?>
<android.support.v7.widget.CardView
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="horizontal"
    android:layout_width="match_parent"
    xmlns:card_view="http://schemas.android.com/apk/res-auto"
    android:layout_margin="10dp"
    card_view:cardCornerRadius="10dp"
    card_view:cardElevation="10dp"
    android:layout_height="wrap_content">

    <RelativeLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent">

        <ImageView
            android:layout_width="wrap_content"
            android:layout_height="match_parent"
            android:id="@+id/movieImage"
            android:padding="10dp"
            android:src="@drawable/a"/>
        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:textAppearance="?android:attr/textAppearanceLarge"
            android:text="Name"
            android:id="@+id/nameTxt"
            android:padding="10dp"
            android:textColor="@color/colorAccent"
            android:layout_below="@+id/movieImage"
            android:layout_alignParentLeft="true"/>

        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:textAppearance="?android:attr/textAppearanceLarge"
            android:text="this tanks is awsome no need to jurge it."
            android:id="@+id/descTxt"
            android:layout_below="@+id/nameTxt"
            android:layout_alignParentLeft="true"/>

        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:textAppearance="?android:attr/textAppearanceLarge"
            android:text="TV Show"
            android:id="@+id/posTxt"
            android:padding="10dp"
            android:layout_below="@id/movieImage"
            android:layout_alignParentRight="true"/>

        <CheckBox
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:id="@+id/chk"
            android:layout_alignParentRight="true"/>
    </RelativeLayout>
</android.support.v7.widget.CardView>

Answer 1

错误是

java.lang.ClassCastException: android.support.v7.widget.LinearLayoutCompat cannot be cast to android.support.v7.widget.RecyclerView
                  at com.example.user.recyclerviewpagerfragment.Fragments.DocumentaryFragment.onCreateView(DocumentaryFragment.java:30)

正如它所说，问题出在 DocumentaryFragment 中，您正在将 LinearLayout 转换为 ReciclerView，您应该向我们提供该 Fragment。希望对你有帮助，我想发表评论，但我还没有必要条件。

android: 查看下一个选项卡时收到异常

android: receive exception when view next tab

android

fragment

android-viewpager

android-recyclerview

cardview