java - 更新 RecycleView 内的 Firestore 字段

Question

我想在 OnClick 发生时更新 Firestore 中的字段。 问题是我不知道如何检索我的实际项目的 id，因为这是自动生成的。 (我想更新assignedTo字段)。 Firestore的结构如下: :

我的 RecyclerView 适配器的代码 fragment 是:

public class AvailableTaskListAdapter extends RecyclerView.Adapter<AvailableTaskListAdapter.ViewHolder> {
public List<Task> taskList;
Activity mActivity;
FirebaseFirestore firestore;

public AvailableTaskListAdapter(List<Task> taskList, Context mContext, FirebaseFirestore firestore) {
    this.taskList = taskList;
    this.mActivity = (Activity) mContext;
    this.firestore = firestore;
}

@NonNull
@Override
public AvailableTaskListAdapter.ViewHolder onCreateViewHolder(@NonNull ViewGroup viewGroup, int i) {
    View view = LayoutInflater.from(viewGroup.getContext()).inflate(R.layout.layout_available_tasks_item, viewGroup, false);
    view.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {


            //HERE I want to be happening the update of my field.


        }
    });
    return new AvailableTaskListAdapter.ViewHolder(view);

}

@Override
public void onBindViewHolder(@NonNull AvailableTaskListAdapter.ViewHolder viewHolder, int i) {
    viewHolder.tvEmail.setText(taskList.get(i).getUser());
    ...
}

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

public class ViewHolder extends RecyclerView.ViewHolder {
    View mView;

    public TextView tvEmail;
    ...

    public ViewHolder(View itemView) {
        super(itemView);
        mView = itemView;

        tvEmail = (TextView) mView.findViewById(R.id.tvEmail);
        ...
    }
}

public void showDialog(final Activity activity) {
    final Dialog dialog = new Dialog(activity);
    dialog.requestWindowFeature(Window.FEATURE_NO_TITLE);
    dialog.setCancelable(false);
    dialog.setContentView(R.layout.dialog_apply_to_task);
    dialog.getWindow().setBackgroundDrawable(new ColorDrawable(android.graphics.Color.TRANSPARENT));

    FrameLayout mDialogNo = dialog.findViewById(R.id.frmNo);
    mDialogNo.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {

            Toast.makeText(activity.getApplicationContext(),"Cancel" ,Toast.LENGTH_SHORT).show();
            dialog.dismiss();
        }
    });

    FrameLayout mDialogOk = dialog.findViewById(R.id.frmOk);
    mDialogOk.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            Toast.makeText(activity.getApplicationContext(),"Okay" ,Toast.LENGTH_SHORT).show();
            dialog.cancel();
        }
    });

    dialog.show();
}}

Answer 1

正如我在您的代码中看到的，您将获得 Task 的列表对象，但您没有获得每个文档的 key 。为了解决这个问题，您需要跟踪适配器中文档的键和值。推荐的方法是保留两个列表，一个包含键，另一个包含值。

所以首先添加 List<String>对于适配器类中的键，如下所示:

private List<Task> taskList;
private List<String> keys;

然后更改构造函数以接受两个列表:

public AvailableTaskListAdapter(List<Task> taskList, List<String> keys, Context mContext, FirebaseFirestore firestore) {
//                                                                ^^^^
    this.taskList = taskList;
    this.keys = keys; //Intialize the the second list
    this.mActivity = (Activity) mContext;
    this.firestore = firestore;
}

然后当你创建 AvailableTaskListAdapter 的新对象时类，旁边taskList ，还传递 keys列表。

AvailableTaskListAdapter adapter = new AvailableTaskListAdapter(taskList, keys, mContext, firestore);

基本上，键列表的创建方式与创建值列表的方式相同。因此，当您循环遍历集合以创建 Task 列表时对象，还可以像这样获取 id:

FirebaseFirestore rootRef = FirebaseFirestore.getInstance();
CollectionReference tasksRef = rootRef.collection("tasks");
tasksRef.get().addOnCompleteListener(new OnCompleteListener<QuerySnapshot>() {
    @Override
    public void onComplete(@NonNull Task<QuerySnapshot> task) {
        if (task.isSuccessful()) {
            List<Task> taskList = new ArrayList<>();
            List<String> keys = new ArrayList<>();
            for (QueryDocumentSnapshot document : task.getResult()) {
                Task t = document.toObject(Task.class);
                taskList.add(t);
                String key = document.getId();
                keys.add(key);
            }

            //Create/notify the adapter
        }
    }
});