android-recyclerview - 如何迭代 RecyclerView 项目

Question

在我的应用程序中，我有一个 RecyclerView，其中包含一个简单的项目 View ，每行包含一个 TextView 和一个 Spinner。

用户从操作栏中单击“保存”后，我需要遍历所有项目并获取 Spinner 选择的值。

有什么想法可以或应该如何实现？

更新:

我已经设法使用以下循环进行迭代，但是对于每一行调用 findViewById() 是否是一个很好的解决方案，因为它是一个调用性能明智的繁重函数？

for (int i = 0; i < rvAttendanceItems.getChildCount(); i++) {
    Spinner spinner = (Spinner) rvAttendanceItems.findViewHolderForAdapterPosition(i).itemView.findViewById(R.id.attendance_list_status);
    spinner.getSelectedItemId();
}

我的完整 RecyclerView 代码:

public class AttendanceAdapter extends RecyclerView.Adapter<AttendanceAdapter.AttendanceViewHolder> {

    private List<Student> studentItems;
    private Fragment frag;
    ArrayList<Status> statuses = new ArrayList<>();

    public AttendanceAdapter(List<Student> studentItems, Fragment frag) {
        this.studentItems = studentItems;
        this.frag = frag;

        DbHelper db = DbHelper.getInstance(frag.getContext());
        Cursor c = db.getStatuses("attendance");

        if (c != null) {
            while (c.moveToNext()) {
                Status tempStatus = new Status(c.getInt(c.getColumnIndex(DbHelper.STATUS_ID)), c.getInt(c.getColumnIndex(DbHelper.STATUS_COLOR)), c.getString(c.getColumnIndex(DbHelper.STATUS_DESC)), c.getString(c.getColumnIndex(DbHelper.STATUS_CATEGORY)));
                statuses.add(tempStatus);
            }
            c.close();
        } else {
            Toast.makeText(frag.getContext(), "Could not retrieve status list", Toast.LENGTH_SHORT).show();
        }
    }

    @Override
    public AttendanceViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        View itemView = LayoutInflater.from(parent.getContext()).inflate(R.layout.item_attendance, parent, false);
        return new AttendanceViewHolder(itemView);
    }

    @Override
    public void onBindViewHolder(final AttendanceViewHolder holder, int position) {

        final Student current = studentItems.get(position);

        SpinnerAdapter adapter = new SpinnerAdapter(frag.getContext(), R.layout.item_spinner_status, statuses);

        holder.sStatus.setAdapter(adapter);
        holder.tvName.setText(current.getFullName());
    }

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

    public class AttendanceViewHolder extends RecyclerView.ViewHolder {

        private final TextView tvName;
        private final Spinner sStatus;

        public AttendanceViewHolder(View itemView) {
            super(itemView);

            tvName = (TextView) itemView.findViewById(R.id.attendance_list_name);
            sStatus = (Spinner) itemView.findViewById(R.id.attendance_list_status);

            itemView.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View view) {

                    sStatus.performClick();
                }
            });
        }
    }
}

Answer 1

您已经调用了findViewById()在 View 持有者中，不需要再做一次:

for (int i = 0; i < rvAttendanceItems.getChildCount(); i++) {
    AttendanceViewHolder holder = (AttendanceViewHolder) rv.findViewHolderForAdapterPosition(i);
    holder.sStatus.getSelectedItemId();
}