java - RadioButton 的选中状态会在 RecyclerView 的滚动事件上自动更改

Question

我在 RecyclerView 项目中遇到了 RadioButton 的问题。根据“类型”，我更改了选中的RadioButton。但是加载所有数据后，当我单击未选中的单选按钮时，它就会被选中。但是，在滚动我刚刚单击的选中单选按钮后，该单选按钮就未被选中。我想要检查我刚刚单击的按钮。但它不会被检查。我怎样才能得到我想要的东西？谁能帮帮我!!!!!!

这是我的适配器类:

public class AttendanceAdapterLocal extends  RecyclerView.Adapter<AttendanceAdapterLocal.ViewHolder>{
    private ArrayList<StudentAttendance> attendanceArrayList;
    private Context context;

    public AttendanceAdapterLocal(ArrayList<StudentAttendance> attendanceArrayList) {
        this.attendanceArrayList = attendanceArrayList;
    }

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

    @Override
    public void onBindViewHolder(@NonNull final ViewHolder viewHolder, int i) {
        final String type = attendanceArrayList.get(i).getType();
        final String id = attendanceArrayList.get(i).getId();
        final String name = attendanceArrayList.get(i).getName();
        final String roll = attendanceArrayList.get(i).getRoll();
        viewHolder.setData(name, roll, type, id);

        final DatabaseHelper databaseHelper = new DatabaseHelper(context);
        final User user = new AccessStorage(context).getUserDetails();
        final String userId = user.getUserId();
        viewHolder.radioPresent.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                if (databaseHelper.updateStudentAttendanceData(id, userId, "P", "0") > 0) {
                    Toast.makeText(context, "Marked successfully.", Toast.LENGTH_LONG).show();
                    viewHolder.radioPresent.setChecked(true);
                } else {
                    Toast.makeText(context, "Unable to mark attendance.", Toast.LENGTH_LONG).show();
                }
            }
        });
        viewHolder.radioAbsent.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                if (databaseHelper.updateStudentAttendanceData(id, userId, "A", "0") > 0) {
                    Toast.makeText(context, "Marked successfully.", Toast.LENGTH_LONG).show();
                    viewHolder.radioAbsent.setChecked(true);
                } else {
                    Toast.makeText(context, "Unable to mark attendance.", Toast.LENGTH_LONG).show();
                }
            }
        });
        viewHolder.radioNone.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                if (databaseHelper.updateStudentAttendanceData(id, userId, "NA", "0") > 0) {
                    Toast.makeText(context, "Marked successfully.", Toast.LENGTH_LONG).show();
                    viewHolder.radioNone.setChecked(true);
                } else {
                    Toast.makeText(context, "Unable to mark attendance.", Toast.LENGTH_LONG).show();
                }
            }
        });
    }

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

    @Override
    public int getItemViewType(int position) {
        return position;
    }

    @Override
    public long getItemId(int position) {
        return position;
    }


    public class ViewHolder extends RecyclerView.ViewHolder {
        // Widgets
        private TextView textName;
        private RadioGroup radioGroup;
        private RadioButton radioPresent, radioAbsent, radioNone;
        // Vars
        private View view;
        public ViewHolder(@NonNull View itemView) {
            super(itemView);
            view = itemView;

            textName = view.findViewById(R.id.textName);
            radioGroup = view.findViewById(R.id.radioGroup);
            radioPresent = view.findViewById(R.id.radioPresent);
            radioAbsent = view.findViewById(R.id.radioAbsent);
            radioNone = view.findViewById(R.id.radioNone);
        }

        private void setData(String name, String roll, final String type, final String id) {
            textName.setText(roll + ". " + name);

            if (type.equals("P")) {
                radioPresent.setChecked(true);
            } else if(type.equals("A")) {
                radioAbsent.setChecked(true);
            }else if(type.equals("NA")) {
                radioNone.setChecked(true);
            }
        }
    }
}

Answer 1

只是一个小错误。在您的 onClick 方法中，更改状态时只需通知适配器。

 @Override
        public void onClick(View v) {
            if (databaseHelper.updateStudentAttendanceData(id, userId, "P", "0") > 0) {
                Toast.makeText(context, "Marked successfully.", Toast.LENGTH_LONG).show();
                viewHolder.radioPresent.setChecked(true);
            //Notify adapter 
             attendanceArrayList.notify();
            } else {
                Toast.makeText(context, "Unable to mark attendance.", Toast.LENGTH_LONG).show();
            }
        }

我可以看到，您在任何地方都做了同样的事情。在更改列表中的任何内容时通知适配器非常重要。您可以使用notifyDataSetChanged() 或notifyItemChanged(selectedPosition);