Question

原因：java.lang.NullPointerException：尝试在空对象引用上调用虚拟方法“ void android.support.v7.widget.RecyclerView.setAdapter（android.support.v7.widget.RecyclerView $ Adapter）” 在com.datbrothers.califinder.MainActivity.onStart（MainActivity.java:379）在android.app.Instrumentation.callActivityOnStart（Instrumentation.java:1340）在android.app.Activity.performStart（Activity.java:7200）在android.app.ActivityThread.performLaunchActivity（ActivityThread.java:2920）在android.app.ActivityThread.handleLaunchActivity（ActivityThread.java:3032）在android.app.ActivityThread.-wrap11（未知来源：0）在android.app.ActivityThread $ H.handleMessage（ActivityThread.java:1696）在android.os.Handler.dispatchMessage（Handler.java:105）在android.os.Looper.loop（Looper.java:164）在android.app.ActivityThread.main（ActivityThread.java:6944）在java.lang.reflect.Method.invoke（本机方法）在com.android.internal.os.Zygote $ MethodAndArgsCaller.run（Zygote.java:327） com.android.internal.os.ZygoteInit.main（ZygoteInit.java:1374）

 @Override
protected void onStart() {

    super.onStart();

    FirebaseRecyclerOptions<Comments> options = new FirebaseRecyclerOptions.Builder<Comments>().setQuery(MarkersRef, Comments.class).build();
    FirebaseRecyclerAdapter<Comments, CommentsViewHolder> adapter = new FirebaseRecyclerAdapter<Comments, CommentsViewHolder>(options) {
        @Override
        protected void onBindViewHolder(@NonNull CommentsViewHolder holder, int position, @NonNull Comments model) {

            holder.username.setText(model.getUsername());
            holder.comment.setText(model.getComment());
            holder.date.setText(model.getDate());
            holder.time.setText(model.getTime());


        }

        @NonNull
        @Override
        public CommentsViewHolder onCreateViewHolder(@NonNull ViewGroup viewGroup, int i) {
            View view = LayoutInflater.from(viewGroup.getContext()).inflate(R.layout.comment, viewGroup, false);
            CommentsViewHolder viewHolder = new CommentsViewHolder(view);
            return viewHolder;
        }
    };

    CommentsList.setAdapter(adapter);
    adapter.startListening();
}

public static class CommentsViewHolder extends RecyclerView.ViewHolder {
    TextView comment, date, time, username;


    public CommentsViewHolder(@NonNull View itemView) {


        super(itemView);


        username = itemView.findViewById(R.id.username_comment);
        comment = itemView.findViewById(R.id.comment_text);
        date = itemView.findViewById(R.id.date_comment);
        time = itemView.findViewById(R.id.time_comment);


    }
}

和评论列表

MarkersRef = FirebaseDatabase.getInstance().getReference("Users").child(marker.getTitle().toString()).child("Comments");

        CommentsList = (RecyclerView) myDialog.findViewById(R.id.comments_list);
        CommentsList.setHasFixedSize(true);
        LinearLayoutManager linearLayoutManager = new LinearLayoutManager(this);
        linearLayoutManager.setReverseLayout(true);
        linearLayoutManager.setStackFromEnd(true);
        CommentsList.setLayoutManager(linearLayoutManager);

请问我真的需要您的帮助

空对象引用上的'void android.support.v7.widget.RecyclerView.setAdapter（android.support.v7.widget.RecyclerView $ Adapter）'

0 个答案: