Android 带有RecyclerView的RecyclerView。当超过1项时适配器不更新

我有一个带有RecyclerView适配器的RecyclerView，它只在只有一个孩子的情况下更新，而有两个或更多孩子的情况下不更新信息。要显示正确的信息，我需要关闭然后重新打开应用程序

通过调试器进行检查，发现在更新数据时，正确和完整的信息确实到达onBindViewHolder方法，但即使在调用notifyDataSetChanged时，也不会更新UI，代码如下：

这是适配器和recyclerview初始化的时间：

      LinearLayoutManager layoutManagerForServers = new LinearLayoutManager(getContext());
        recyclerViewServers.setLayoutManager(layoutManagerForServers);
        mainArrayListForServers = new ArrayList<>();
        mAdapterForServers = new ViewServersAdapter(getContext());
        recyclerViewServers.setAdapter(mAdapterForServers);

LinearLayoutManager布局管理器forserver=newlinearlayoutmanager（getContext（））；
setLayoutManager（layoutManagerForServers）；
mainArrayListForServers=新建ArrayList（）；
mAdapterForServers=newviewserversadapter（getContext（））；
setAdapter（mAdapterForServers）；

这是数据更新的时间：

   final ViewModelForServers viewModel = new ViewModelProvider(this).get(ViewModelForServers.class);
    final LiveData<ArrayList<Server>> liveData = viewModel.getServersMediatorLiveData();

    liveData.observe(this, new Observer<ArrayList<Server>>() {
        @Override
        public void onChanged(@Nullable ArrayList<Server> serverArrayList) {
            if (serverArrayList != null) {
                mainArrayListForServers = serverArrayList;
                // update the UI here with values in the snapshot
                mAdapterForServers.setServersArrayList(mainArrayListForServers);
                mAdapterForServers.notifyDataSetChanged();
                setEmptyView();

            }
        }
    });

final ViewModelForServers viewModel=new ViewModelProvider（this.get）（viewmodelforserver.class）；
final LiveData LiveData=viewModel.getserversmeditorlivedata（）；
liveData.observe（这个，新的观察者（）{
@凌驾
更改后的公共void（@Nullable ArrayList serverArrayList）{
如果（serverArrayList！=null）{
mainArrayListForServers=serverArrayList；
//使用快照中的值更新此处的UI
mAdapterForServers.setServersArrayList（mainArrayListForServers）；
mAdapterForServers.notifyDataSetChanged（）；
setEmptyView（）；
}
}
});

最后是回收器适配器：

public class ViewServersAdapter extends RecyclerView.Adapter<ViewServersAdapter.MyViewHolder> {
private ArrayList<Server> serversArrayList = new ArrayList<>();
private ViewServersFragmentItemBinding viewServersFragmentItemBinding;
private Context context;

ViewServersAdapter(Context context){
    this.context = context;
}

static class MyViewHolder extends RecyclerView.ViewHolder{
    Context context;

    MyViewHolder(@NonNull View itemView, Context context) {
        super(itemView);
        this.context = context;
    }

    void bindView(Server server, ViewServersFragmentItemBinding viewQFragmentItemBinding){

        TextView serverNameTxt = viewQFragmentItemBinding.serverName;
        TextView serverStatus = viewQFragmentItemBinding.serverStatus;
        TextView serverNumber = viewQFragmentItemBinding.serverNumber;
        TextView userOnCall = viewQFragmentItemBinding.userOnCall;
        TextView duration = viewQFragmentItemBinding.callDuration;
        ImageView userProfile = viewQFragmentItemBinding.profilePicture;


        serverNameTxt.setText(server.getServerName());
        serverStatus.setText(Utils.getServerStatus(server.getServerStatus(),context));
        serverNumber.setText(String.valueOf(server.getServerNumber()).substring(3));
        if (server.getCallRequest()!= null){
            userOnCall.setText(server.getCallRequest().getUser());
            duration.setText(Utils.getTimeOnMinutes(server.getCallRequest().getTime(),context,false));
            Uri profilePictureUri = Uri.parse(server.getCallRequest().getProfilePicture());
            userProfile.setScaleX(1);
            userProfile.setImageResource(ListOfProfilePictureSmallsInt.get(Utils.getPhotoUrlIndex(profilePictureUri)));
        } else {
            userOnCall.setText("");
            duration.setText("");
            userProfile.setScaleX(-1);
            userProfile.setImageResource(R.drawable.ic_waiting);
        }

    }
}


void setServersArrayList(ArrayList<Server> serverArrayList){
   this.serversArrayList = serverArrayList;
}

@NonNull
@Override
public ViewServersAdapter.MyViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
    LayoutInflater inflater = LayoutInflater.from(parent.getContext());
    viewServersFragmentItemBinding = ViewServersFragmentItemBinding.inflate(inflater,parent,false);
    // create a new view
    ConstraintLayout v = (ConstraintLayout) viewServersFragmentItemBinding.getRoot();
    RecyclerView.LayoutParams lp = new RecyclerView.LayoutParams(
            ViewGroup.LayoutParams.MATCH_PARENT, //width
            ViewGroup.LayoutParams.WRAP_CONTENT);//height
    v.setLayoutParams(lp);//override default layout params

    return new MyViewHolder(v, context);
}

@Override
public void onBindViewHolder(@NonNull ViewServersAdapter.MyViewHolder holder, int position) {
    Server server = serversArrayList.get(position);
    holder.bindView(server, viewServersFragmentItemBinding);
}

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

公共类ViewServersAdapter扩展了RecyclerView.Adapter{
private ArrayList serversArrayList=new ArrayList（）；
私有ViewServersFragmentItemBinding ViewServersFragmentItemBinding；
私人语境；
ViewServersAdapter（上下文）{
this.context=上下文；
}
静态类MyViewHolder扩展了RecyclerView.ViewHolder{
语境；
MyViewHolder（@NonNull视图项视图，上下文）{
超级（项目视图）；
this.context=上下文；
}
void bindView（服务器，ViewServersFragmentItemBinding视图QFragmentItemBinding）{
TextView serverNameTxt=viewQFragmentItemBinding.serverName；
TextView serverStatus=viewQFragmentItemBinding.serverStatus；
TextView serverNumber=viewQFragmentItemBinding.serverNumber；
TextView userOnCall=viewQFragmentItemBinding.userOnCall；
TextView duration=viewQFragmentItemBinding.callDuration；
ImageView userProfile=viewQFragmentItemBinding.profilePicture；
serverNameTxt.setText（server.getServerName（））；
setText（Utils.getServerStatus（server.getServerStatus（），context））；
setText（String.valueOf（server.getServerNumber（））.substring（3））；
if（server.getCallRequest（）！=null）{
userOnCall.setText（server.getCallRequest（）.getUser（））；
duration.setText（Utils.getTimeOnMinutes（server.getCallRequest（）.getTime（），context，false））；
Uri profilePictureUri=Uri.parse（server.getCallRequest（）.getProfilePicture（））；
userProfile.setScaleX（1）；
userProfile.setImageResource（profilePictureSallsint.get（Utils.getPhotoUrlIndex（profilePictureUri））；
}否则{
userOnCall.setText（“”）；
持续时间。setText（“”）；
userProfile.setScaleX（-1）；
setImageResource（R.drawable.ic_waiting）；
}
}
}
void setServersArrayList（ArrayList服务器ArrayList）{
this.serversArrayList=serverArrayList；
}
@非空
@凌驾
public ViewServersAdapter.MyViewHolder onCreateViewHolder（@NonNull ViewGroup父级，int-viewType）{
LayoutInflater充气器=LayoutInflater.from（parent.getContext（））；
viewServersFragmentItemBinding=viewServersFragmentItemBinding.充气（充气器，父项，false）；
//创建新视图
ConstraintLayout v=（ConstraintLayout）viewServersFragmentItemBinding.getRoot（）；
RecyclerView.LayoutParams lp=新的RecyclerView.LayoutParams(
ViewGroup.LayoutParams.MATCH_父项，//宽度
ViewGroup.LayoutParams.WRAP_CONTENT）；//高度
v、 setLayoutParams（lp）；//覆盖默认布局参数
返回新的MyViewHolder（v，上下文）；
}
@凌驾
public void onBindViewHolder（@NonNull ViewServersAdapter.MyViewHolder，int位置）{
Server=serversArrayList.get（位置）；
holder.bindView（服务器、viewServersFragmentItemBinding）；
}
@凌驾
public int getItemCount（）{
返回服务器raylist.size（）；
}

}

---

我真的很感激任何帮助。谢谢

您可以做一件事，在适配器类中添加一个方法，如下所示

public void updateData(ArrayList<Server> serversArrayList)
{
this.serversArrayList = serversArrayList;
notifyDataSetChanged();
}

---

它是否嵌套在另一个

RecyclerView

中？配置更改（屏幕旋转）后是否更新

我多次遇到相同的错误，添加新元素时，recyclerview不会更新UI，尽管所有适配器的事情都完成了。我在这里使用了一种解决方法：

mRecyclerView.scrollBy（0,1）

，请在调用

notifyDataSetChanged（）

之后立即调用它

RecyclerView

实际的行为如何？它显示所有的项目吗？它们是否都更新了相同的信息？还是只是最后一个更新的项目

编辑

问题似乎不是RV没有更新UI，而是数据绑定和如何使用它。它实际上只是正确更新的最后一项吗

问题是您的

viewServersFragmentItemBinding

是在适配器类中声明的，但它应该声明并保存在viewholder类中（也是最终的）。这意味着在调用所有的

onCreateViewHolder

方法之后，只存储最后一个viewholder的数据绑定，并且所有

mAdapterForServers.updateData(serverArrayList);

    public MyViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        LayoutInflater layoutInflater = LayoutInflater.from(parent.getContext());
        ViewDataBinding binding = DataBindingUtil.inflate(layoutInflater, viewType, parent, false);
        return new MyViewHolder(binding);
    }

    public void onBindViewHolder(MyViewHolder holder, int position) {
        Object obj = getObjForPosition(position);
        holder.bind(obj);
    }

public class MyViewHolder extends RecyclerView.ViewHolder {
    private final ViewDataBinding binding;

    public MyViewHolder(ViewDataBinding binding) {
        super(binding.getRoot());
        this.binding = binding;
    }

    public void bind(Object obj) {
        binding.setVariable(BR.obj, obj);
        binding.executePendingBindings();
    }
}

 LinearLayoutManager layoutManagerForServers = new LinearLayoutManager(getContext());
    recyclerViewServers.setLayoutManager(layoutManagerForServers);
    mainArrayListForServers = new ArrayList<>();
    mAdapterForServers = new ViewServersAdapter(getContext(),mainArrayListForServers);
    recyclerViewServers.setAdapter(mAdapterForServers);

public class ViewServersAdapter extends RecyclerView.Adapter<ViewServersAdapter.MyViewHolder> {
private ArrayList<Server> serversArrayList;
private ViewServersFragmentItemBinding viewServersFragmentItemBinding;
private Context context;

ViewServersAdapter(Context context,ArrayList<Server> serversArrayList){
    this.context = context;
    this.serversArrayList = serversArrayList;
}

static class MyViewHolder extends RecyclerView.ViewHolder{
    Context context;

    MyViewHolder(@NonNull View itemView, Context context) {
        super(itemView);
        this.context = context;
    }

    void bindView(Server server, ViewServersFragmentItemBinding viewQFragmentItemBinding){

        TextView serverNameTxt = viewQFragmentItemBinding.serverName;
        TextView serverStatus = viewQFragmentItemBinding.serverStatus;
        TextView serverNumber = viewQFragmentItemBinding.serverNumber;
        TextView userOnCall = viewQFragmentItemBinding.userOnCall;
        TextView duration = viewQFragmentItemBinding.callDuration;
        ImageView userProfile = viewQFragmentItemBinding.profilePicture;


        serverNameTxt.setText(server.getServerName());
        serverStatus.setText(Utils.getServerStatus(server.getServerStatus(),context));
        serverNumber.setText(String.valueOf(server.getServerNumber()).substring(3));
        if (server.getCallRequest()!= null){
            userOnCall.setText(server.getCallRequest().getUser());
            duration.setText(Utils.getTimeOnMinutes(server.getCallRequest().getTime(),context,false));
            Uri profilePictureUri = Uri.parse(server.getCallRequest().getProfilePicture());
            userProfile.setScaleX(1);
            userProfile.setImageResource(ListOfProfilePictureSmallsInt.get(Utils.getPhotoUrlIndex(profilePictureUri)));
        } else {
            userOnCall.setText("");
            duration.setText("");
            userProfile.setScaleX(-1);
            userProfile.setImageResource(R.drawable.ic_waiting);
        }

    }
}


@NonNull
@Override
public ViewServersAdapter.MyViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
    LayoutInflater inflater = LayoutInflater.from(parent.getContext());
    viewServersFragmentItemBinding = ViewServersFragmentItemBinding.inflate(inflater,parent,false);
    // create a new view
    ConstraintLayout v = (ConstraintLayout) viewServersFragmentItemBinding.getRoot();
    RecyclerView.LayoutParams lp = new RecyclerView.LayoutParams(
            ViewGroup.LayoutParams.MATCH_PARENT, //width
            ViewGroup.LayoutParams.WRAP_CONTENT);//height
    v.setLayoutParams(lp);//override default layout params

    return new MyViewHolder(v, context);
}

@Override
public void onBindViewHolder(@NonNull ViewServersAdapter.MyViewHolder holder, int position) {
    Server server = serversArrayList.get(position);
    holder.bindView(server, viewServersFragmentItemBinding);
}

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

final ViewModelForServers viewModel = new ViewModelProvider(this).get(ViewModelForServers.class);
final LiveData<ArrayList<Server>> liveData = viewModel.getServersMediatorLiveData();

liveData.observe(this, new Observer<ArrayList<Server>>() {
    @Override
    public void onChanged(@Nullable ArrayList<Server> serverArrayList) {
        if (serverArrayList != null) {
            mainArrayListForServers.clear();
            mainArrayListForServers.addAll(serverArrayList);
            mAdapterForServers.notifyDataSetChanged();

        }
    }
});