Android的 - RecyclerView片段内 - NullPointerException异常段内、异常、Android、RecyclerView

由网友(幼儿园老大)分享简介：我试图使用 RecyclerView 内部的片段（把它用在一个 ViewPager ），但我得到了一个 NullPointerException异常当我尝试执行：流程：com.yomansk8.birthdaysoundboard，PID：4448显示java.lang.NullPointerException：尝试...

我试图使用 RecyclerView 内部的片段（把它用在一个 ViewPager ），但我得到了一个 NullPointerException异常当我尝试执行：

 流程：com.yomansk8.birthdaysoundboard，PID：4448
显示java.lang.NullPointerException：尝试调用虚拟方法无效android.support.v7.widget.RecyclerView$LayoutManager.onMeasure(android.support.v7.widget.RecyclerView$Recycler, android.support.v7.widget.RecyclerView $州，在一个空对象引用INT，INT）
        在android.support.v7.widget.RecyclerView.onMeasure（RecyclerView.java:1764）
        在android.view.View.measure（View.java:17430）
        在android.view.ViewGroup.measureChildWithMargins（ViewGroup.java:5463）
        在android.widget.FrameLayout.onMeasure（FrameLayout.java:430）
        在android.view.View.measure（View.java:17430）
        在android.support.v4.view.ViewPager.onMeasure（ViewPager.java:1456）
        在android.view.View.measure（View.java:17430）
        在android.view.ViewGroup.measureChildWithMargins（ViewGroup.java:5463）
        在android.widget.FrameLayout.onMeasure（FrameLayout.java:430）
        在android.view.View.measure（View.java:17430）
        在android.view.ViewGroup.measureChildWithMargins（ViewGroup.java:5463）
        在android.widget.FrameLayout.onMeasure（FrameLayout.java:430）
        在android.view.View.measure（View.java:17430）
        在android.view.ViewGroup.measureChildWithMargins（ViewGroup.java:5463）
        在android.widget.FrameLayout.onMeasure（FrameLayout.java:430）
        在android.view.View.measure（View.java:17430）
        在android.view.ViewGroup.measureChildWithMargins（ViewGroup.java:5463）
        在android.widget.LinearLayout.measureChildBeforeLayout（LinearLayout.java:1436）
        在android.widget.LinearLayout.measureVertical（LinearLayout.java:722）
        在android.widget.LinearLayout.onMeasure（LinearLayout.java:613）
        在android.view.View.measure（View.java:17430）
        在android.view.ViewGroup.measureChildWithMargins（ViewGroup.java:5463）
        在android.widget.FrameLayout.onMeasure（FrameLayout.java:430）
        在android.view.View.measure（View.java:17430）
        在android.view.ViewGroup.measureChildWithMargins（ViewGroup.java:5463）
        在android.widget.LinearLayout.measureChildBeforeLayout（LinearLayout.java:1436）
        在android.widget.LinearLayout.measureVertical（LinearLayout.java:722）
        在android.widget.LinearLayout.onMeasure（LinearLayout.java:613）
        在android.view.View.measure（View.java:17430）
        在android.view.ViewGroup.measureChildWithMargins（ViewGroup.java:5463）
        在android.widget.FrameLayout.onMeasure（FrameLayout.java:430）
        在com.android.internal.policy.impl.PhoneWindow $ DecorView.onMeasure（PhoneWindow.java:2560）
        在android.view.View.measure（View.java:17430）
        在android.view.ViewRootImpl.performMeasure（ViewRootImpl.java:2001）
        在android.view.ViewRootImpl.measureHierarchy（ViewRootImpl.java:1166）
        在android.view.ViewRootImpl.performTraversals（ViewRootImpl.java:1372）
        在android.view.ViewRootImpl.doTraversal（ViewRootImpl.java:1054）
        在android.view.ViewRootImpl $ TraversalRunnable.run（ViewRootImpl.java:5779）
        在android.view.Choreographer $ CallbackRecord.run（Choreographer.java:767）
        在android.view.Choreographer.doCallbacks（Choreographer.java:580）
        在android.view.Choreographer.doFrame（Choreographer.java:550）
        在android.view.Choreographer $ FrameDisplayEventReceiver.run（Choreographer.java:753）
        在android.os.Handler.handleCallback（Handler.java:739）
        在android.os.Handler.dispatchMessage（Handler.java:95）
        在android.os.Looper.loop（Looper.java:135）
        在android.app.ActivityThread.main（ActivityThread.java:5221）
        在java.lang.reflect.Method.invoke（本机方法）
        在java.lang.reflect.Method.invoke（Method.java:372）
        在com.android.internal.os.ZygoteInit $ MethodAndArgsCaller.run（ZygoteInit.java:899）
        在com.android.internal.os.ZygoteInit.main（ZygoteInit.java:694）

首先，这是我的片段的布局，它只是包含 RecyclerView ：

 ＆LT; XML版本=1.0编码=UTF-8＆GT？;
＆LT; android.support.v7.widget.RecyclerView的xmlns：机器人=http://schemas.android.com/apk/res/android
机器人：ID =@ + ID / recyclerDivers
机器人：layout_width =match_parent
机器人：layout_height =match_parent
机器人：ATTR / actionBarSizepaddingTop =
机器人：clipToPadding =FALSE/＆GT;

这是我的片段：

 包com.yomansk8.birthdaysoundboard.Fragments;

进口android.app.Activity;
进口android.media.MediaPlayer;
进口android.os.Bundle;
进口android.support.annotation.Nullable;
进口android.support.v4.app.Fragment;
进口android.support.v7.app.ActionBar;
进口android.support.v7.widget.GridLayoutManager;
进口android.support.v7.widget.LinearLayoutManager;
进口android.support.v7.widget.RecyclerView;
进口android.support.v7.widget.Toolbar;
进口android.util.Log;
进口android.view.LayoutInflater;
进口android.view.View;
进口android.view.ViewGroup;

进口com.yomansk8.birthdaysoundboard.Adapters.RecyclerViewAdapter;
进口com.yomansk8.birthdaysoundboard.GenerateDatas;
进口com.yomansk8.birthdaysoundboard.MainActivity;
进口com.yomansk8.birthdaysoundboard.Models.ViewModel;
进口com.yomansk8.birthdaysoundboard.R;
进口com.yomansk8.birthdaysoundboard.ScrollManager;

进口的java.util.List;

/ **
 *在2015年9月3日的创Yohann。
 * /
公共类DiversFragment扩展片段实现RecyclerViewAdapter.OnItemClickListener {

私人MediaPlayer的MPLAYER = NULL;
私人工具条工具栏;
私人RecyclerView recyclerView;
私人GridLayoutManager mLayoutManager;
私人RecyclerViewAdapter适配器;
私人列表＆LT;视图模型＆GT;项目;

@覆盖
公共查看onCreateView（LayoutInflater充气，@Nullable的ViewGroup容器，@Nullable捆绑savedInstanceState）{
    视图V = inflater.inflate（R.layout.fragment_divers，集装箱，假）;

    工具栏=（（MainActivity）getActivity（））getToolbar（）。

    recyclerView =（RecyclerView）v.findViewById（R.id.recyclerDivers）;
    recyclerView.setHasFixedSize（真正的）;

    项= GenerateDatas.getAmbianceList（）;


    适配器=新RecyclerViewAdapter（项目）;


    /*toolbar.post(new的Runnable（）{
        @覆盖公共无效的run（）{
            ScrollManager经理=新ScrollManager（）;
            manager.attach（recyclerView）;
            manager.addView（工具栏，ScrollManager.Direction.UP）;
            manager.setInitialOffset（toolbar.getHeight（））;
        }
    }）; * /
    Log.v（测试，onCreateView（））;
    返回伏;

}

@覆盖
公共无效onViewCreated（查看视图，捆绑savedInstanceState）{
    super.onViewCreated（查看，savedInstanceState）;
    Log.v（测试，onViewCreated（））;
    mLayoutManager =新GridLayoutManager（getActivity（），3）;
    recyclerView.setLayoutManager（mLayoutManager）;
    adapter.setOnItemClickListener（本）;
    recyclerView.setAdapter（适配器）;

}

@覆盖公共无效onItemClick（查看视图，视图模型视图模型）{
    //里拉勒的儿子ICI
    。整数声音= getResources（）则getIdentifier（viewModel.getSound（），生，getActivity（）getPackageName（））;
    playSound（音）;
}

私人无效playSound（INT渣油）{
    如果（MPLAYER！= NULL）{
        mPlayer.stop（）;
        mPlayer.release（）;
    }
    MPLAYER = MediaPlayer.create（getActivity（），渣油）;
    mPlayer.start（）;
}

@覆盖
公共无效的onPause（）{
    super.onPause（）;
    如果（MPLAYER！= NULL）{
        mPlayer.stop（）;
        mPlayer.release（）;
    }
}

}

我也试图把我的 RecyclerView 初始化的 onCreateView 和 onViewCreated ，但没有成功。

你知道吗？

编辑：

下面是我的适配器的code：

 包com.yomansk8.birthdaysoundboard.Adapters;

进口android.os.Handler;
进口android.support.v7.widget.RecyclerView;
进口android.view.LayoutInflater;
进口android.view.View;
进口android.view.ViewGroup;
进口android.widget.ImageView;
进口android.widget.TextView;

进口com.squareup.picasso.Picasso;
进口com.yomansk8.birthdaysoundboard.R;
进口com.yomansk8.birthdaysoundboard.Models.ViewModel;

进口的java.util.List;

/ **
 *在19/02/2015创建者Yohann。
 * /
公共类RecyclerViewAdapter扩展RecyclerView.Adapter＆LT; RecyclerViewAdapter.ViewHolder＆GT;实现View.OnClickListener {

私人列表＆LT;视图模型＆GT;项目;
私人OnItemClickListener onItemClickListener;

公共RecyclerViewAdapter（名单＆LT;视图模型＆GT;项目）{

    this.items =项目;
}

公共无效setOnItemClickListener（OnItemClickListener onItemClickListener）{
    this.onItemClickListener = onItemClickListener;
}

@覆盖公共ViewHolder onCreateViewHolder（ViewGroup中父，诠释viewType）{
    视图V = LayoutInflater.from（parent.getContext（））膨胀（R.layout.item_recycler，父母，假）。
    v.setOnClickListener（本）;
    返回新ViewHolder（V）;
}

@覆盖公共无效onBindViewHolder（ViewHolder持有人，INT位置）{
    视图模型项目= items.get（位置）;
    holder.text.setText（item.getText（））;
    holder.image.setImageBitmap（空）;
    整数mImage = holder.image.getResources（）则getIdentifier（item.getImage（），可拉伸，holder.image.getContext（）getPackageName（）。）。
    。Picasso.with（holder.image.getContext（））负载（mImage）。走进（holder.image）;
    holder.itemView.setTag（项目）;
}

@覆盖公众诠释getItemCount（）{
    返回items.size（）;
}

@覆盖公共无效的onClick（最终查看V）{
    //给予一定时间的波动来完成的效果
    如果（onItemClickListener！= NULL）{
        新的处理程序（）。postDelayed（新的Runnable（）{
            @覆盖公共无效的run（）{
                onItemClickListener.onItemClick（ⅴ，（视图模型）v.getTag（））;
            }
        }，200）;
    }
}

受保护的静态类ViewHolder扩展RecyclerView.ViewHolder {
    公众ImageView的形象;
    公共TextView的文字;

    公共ViewHolder（查看ItemView控件）{
        超（ItemView控件）;
        图像=（ImageView的）itemView.findViewById（R.id.image）;
        文=（TextView的）itemView.findViewById（R.id.text）;
    }
}

公共接口OnItemClickListener {

    无效onItemClick（查看视图，视图模型视图模型）;

}
}

解决方案

我看你使用的旧版本recyclerview的我一样。我通过了修订 recyclerview-20.0.0 第一个发行版本，当然还有例外发生。所以我升级我的Android SDK，然后复制这个最新版本 22.1.1 （均支持-v4和recyclerview-V7罐）到我的项目的库，然后我的项目工作。

在为prevent我的团队的序列家伙会比较混乱的版本，我命名的两个罐子，包括修订信息：

在我的项目的libs目录罐子：

Android的支持 - v4-22.1.1.jar

Android的支持-V7-recyclerview-22.1.1.jar

在这之前，我也想不出办法的修订的 20.0.0 ，我创建了一个名为 MyRecyclerView 一个部件从RecyclerView延伸，然后新的一个粗略的布局管理的构造。

 公共类MyRecyclerView扩展RecyclerView {
    公共MyRecyclerView（上下文的背景下）{
        这（背景下，NULL）;
    }

    公共MyRecyclerView（上下文的背景下，ATTRS的AttributeSet）{
        这（背景下，ATTRS，0）;
    }

    公共MyRecyclerView（上下文的背景下，ATTRS的AttributeSet，诠释defStyle）{
        超（背景下，ATTRS，defStyle）;
        setLayoutManager（新布局管理（）{
            @覆盖
            公众的LayoutParams generateDefaultLayoutParams（）{
                返回null;
            }
        }）;
    }
}

它可以工作，但不是完美的方法。

顺便说一句，作为@yigit在他的回答说，这是缺少整合与IDE 和在未来，将会有更好的整合

I'm trying to use a RecyclerView inside of a Fragment (to use it in a ViewPager) but I got a NullPointerException when I try to execute:

 Process: com.yomansk8.birthdaysoundboard, PID: 4448
java.lang.NullPointerException: Attempt to invoke virtual method 'void android.support.v7.widget.RecyclerView$LayoutManager.onMeasure(android.support.v7.widget.RecyclerView$Recycler, android.support.v7.widget.RecyclerView$State, int, int)' on a null object reference
        at android.support.v7.widget.RecyclerView.onMeasure(RecyclerView.java:1764)
        at android.view.View.measure(View.java:17430)
        at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5463)
        at android.widget.FrameLayout.onMeasure(FrameLayout.java:430)
        at android.view.View.measure(View.java:17430)
        at android.support.v4.view.ViewPager.onMeasure(ViewPager.java:1456)
        at android.view.View.measure(View.java:17430)
        at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5463)
        at android.widget.FrameLayout.onMeasure(FrameLayout.java:430)
        at android.view.View.measure(View.java:17430)
        at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5463)
        at android.widget.FrameLayout.onMeasure(FrameLayout.java:430)
        at android.view.View.measure(View.java:17430)
        at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5463)
        at android.widget.FrameLayout.onMeasure(FrameLayout.java:430)
        at android.view.View.measure(View.java:17430)
        at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5463)
        at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1436)
        at android.widget.LinearLayout.measureVertical(LinearLayout.java:722)
        at android.widget.LinearLayout.onMeasure(LinearLayout.java:613)
        at android.view.View.measure(View.java:17430)
        at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5463)
        at android.widget.FrameLayout.onMeasure(FrameLayout.java:430)
        at android.view.View.measure(View.java:17430)
        at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5463)
        at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1436)
        at android.widget.LinearLayout.measureVertical(LinearLayout.java:722)
        at android.widget.LinearLayout.onMeasure(LinearLayout.java:613)
        at android.view.View.measure(View.java:17430)
        at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5463)
        at android.widget.FrameLayout.onMeasure(FrameLayout.java:430)
        at com.android.internal.policy.impl.PhoneWindow$DecorView.onMeasure(PhoneWindow.java:2560)
        at android.view.View.measure(View.java:17430)
        at android.view.ViewRootImpl.performMeasure(ViewRootImpl.java:2001)
        at android.view.ViewRootImpl.measureHierarchy(ViewRootImpl.java:1166)
        at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1372)
        at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1054)
        at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:5779)
        at android.view.Choreographer$CallbackRecord.run(Choreographer.java:767)
        at android.view.Choreographer.doCallbacks(Choreographer.java:580)
        at android.view.Choreographer.doFrame(Choreographer.java:550)
        at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:753)
        at android.os.Handler.handleCallback(Handler.java:739)
        at android.os.Handler.dispatchMessage(Handler.java:95)
        at android.os.Looper.loop(Looper.java:135)
        at android.app.ActivityThread.main(ActivityThread.java:5221)
        at java.lang.reflect.Method.invoke(Native Method)
        at java.lang.reflect.Method.invoke(Method.java:372)
        at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:899)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:694)

First, this is the layout of my fragment, it's only containing a RecyclerView:

<?xml version="1.0" encoding="utf-8"?>
<android.support.v7.widget.RecyclerView xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/recyclerDivers"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingTop="?attr/actionBarSize"
android:clipToPadding="false"/>

This is my Fragment:

package com.yomansk8.birthdaysoundboard.Fragments;

import android.app.Activity;
import android.media.MediaPlayer;
import android.os.Bundle;
import android.support.annotation.Nullable;
import android.support.v4.app.Fragment;
import android.support.v7.app.ActionBar;
import android.support.v7.widget.GridLayoutManager;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.support.v7.widget.Toolbar;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;

import com.yomansk8.birthdaysoundboard.Adapters.RecyclerViewAdapter;
import com.yomansk8.birthdaysoundboard.GenerateDatas;
import com.yomansk8.birthdaysoundboard.MainActivity;
import com.yomansk8.birthdaysoundboard.Models.ViewModel;
import com.yomansk8.birthdaysoundboard.R;
import com.yomansk8.birthdaysoundboard.ScrollManager;

import java.util.List;

/**
 * Created by Yohann on 09/03/2015.
 */
public class DiversFragment extends Fragment implements  RecyclerViewAdapter.OnItemClickListener {

private MediaPlayer mPlayer = null;
private Toolbar toolbar;
private RecyclerView recyclerView;
private GridLayoutManager mLayoutManager;
private RecyclerViewAdapter adapter;
private  List<ViewModel> items;

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

    toolbar = ((MainActivity)getActivity()).getToolbar();

    recyclerView = (RecyclerView) v.findViewById(R.id.recyclerDivers);
    recyclerView.setHasFixedSize(true);

    items = GenerateDatas.getAmbianceList();


    adapter = new RecyclerViewAdapter(items);


    /*toolbar.post(new Runnable() {
        @Override public void run() {
            ScrollManager manager = new ScrollManager();
            manager.attach(recyclerView);
            manager.addView(toolbar, ScrollManager.Direction.UP);
            manager.setInitialOffset(toolbar.getHeight());
        }
    });*/
    Log.v("TEST", "onCreateView()");
    return v;

}

@Override
public void onViewCreated(View view , Bundle savedInstanceState) {
    super.onViewCreated(view, savedInstanceState);
    Log.v("TEST", "onViewCreated()");
    mLayoutManager = new GridLayoutManager(getActivity(), 3);
    recyclerView.setLayoutManager(mLayoutManager);
    adapter.setOnItemClickListener(this);
    recyclerView.setAdapter(adapter);

}

@Override public void onItemClick(View view, ViewModel viewModel) {
    // Lire le son ici
    Integer sound = getResources().getIdentifier(viewModel.getSound(), "raw", getActivity().getPackageName());
    playSound(sound);
}

private void playSound(int resId) {
    if(mPlayer != null) {
        mPlayer.stop();
        mPlayer.release();
    }
    mPlayer = MediaPlayer.create(getActivity(), resId);
    mPlayer.start();
}

@Override
public void onPause() {
    super.onPause();
    if(mPlayer != null) {
        mPlayer.stop();
        mPlayer.release();
    }
}

}

I've also tried to put the initialisation of my RecyclerView inside of onCreateView and onViewCreated, with no success.

Any idea?

EDIT :

Here is the code of my Adapter :

package com.yomansk8.birthdaysoundboard.Adapters;

import android.os.Handler;
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.squareup.picasso.Picasso;
import com.yomansk8.birthdaysoundboard.R;
import com.yomansk8.birthdaysoundboard.Models.ViewModel;

import java.util.List;

/**
 * Created by Yohann on 19/02/2015.
 */
public class RecyclerViewAdapter extends RecyclerView.Adapter<RecyclerViewAdapter.ViewHolder> implements View.OnClickListener {

private List<ViewModel> items;
private OnItemClickListener onItemClickListener;

public RecyclerViewAdapter(List<ViewModel> items) {

    this.items = items;
}

public void setOnItemClickListener(OnItemClickListener onItemClickListener) {
    this.onItemClickListener = onItemClickListener;
}

@Override public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
    View v = LayoutInflater.from(parent.getContext()).inflate(R.layout.item_recycler, parent, false);
    v.setOnClickListener(this);
    return new ViewHolder(v);
}

@Override public void onBindViewHolder(ViewHolder holder, int position) {
    ViewModel item = items.get(position);
    holder.text.setText(item.getText());
    holder.image.setImageBitmap(null);
    Integer mImage = holder.image.getResources().getIdentifier(item.getImage(), "drawable", holder.image.getContext().getPackageName());
    Picasso.with(holder.image.getContext()).load(mImage).into(holder.image);
    holder.itemView.setTag(item);
}

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

@Override public void onClick(final View v) {
    // Give some time to the ripple to finish the effect
    if (onItemClickListener != null) {
        new Handler().postDelayed(new Runnable() {
            @Override public void run() {
                onItemClickListener.onItemClick(v, (ViewModel) v.getTag());
            }
        }, 200);
    }
}

protected static class ViewHolder extends RecyclerView.ViewHolder {
    public ImageView image;
    public TextView text;

    public ViewHolder(View itemView) {
        super(itemView);
        image = (ImageView) itemView.findViewById(R.id.image);
        text = (TextView) itemView.findViewById(R.id.text);
    }
}

public interface OnItemClickListener {

    void onItemClick(View view, ViewModel viewModel);

}
}

解决方案

I think you had used an old revision of recyclerview just like me. I adopted revision recyclerview-20.0.0 the first release version, and of course the exception occurring. so I upgrade my android sdk, then copy the lastest version 22.1.1(both support-v4 and recyclerview-v7 jars) into my project's libs, then my project work.

In order to prevent the subsequence guys of my team get confusing of the versions, I naming that two jars to including the revision information :

jars in my project's libs directory :

android-support-v4-22.1.1.jar

android-support-v7-recyclerview-22.1.1.jar

Before that, I also figure out a solution in revision 20.0.0, I create a widget named MyRecyclerView which extended from RecyclerView, then new a rough LayoutManager in constructors.

public class MyRecyclerView extends RecyclerView {
    public MyRecyclerView(Context context) {
        this(context, null);
    }

    public MyRecyclerView(Context context, AttributeSet attrs) {
        this(context, attrs, 0);
    }

    public MyRecyclerView(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);
        setLayoutManager(new LayoutManager() {
            @Override
            public LayoutParams generateDefaultLayoutParams() {
                return null;
            }
        });
    }
}

It can work but wasn't the perfect approach.

BTW, as @yigit said in his answer, this is a lack of integration with the IDE and In the future, there will be better integration.

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相关专题：段内；异常；Android ；RecyclerView ；NullPointerException ；发布时间：2023-09-07 14:23:05