java - 从单选组值中选择一个并向下滚动并在 Recycler View 中自动选择一些项目(初学者)

Question

我正在制作一个考勤系统，我使用 RadioGroup 进行考勤，有两个选项。当我选择一些单选按钮并向下滚动时，会自动选择其他一些单选按钮。如果我改变它们，上面的也会改变。
主类

public class TeacherAttendanceActivity extends AppCompatActivity implements AttendanceAdapter.AttendanceAdapterListner {

    public static TeacherAttendanceActivity  teacherAttendanceActivity;
    private static final String TAG = TeacherAttendanceActivity.class.getSimpleName();

    List<AttendanceModel> listItems;
    private RecyclerView recyclerView;
    private RecyclerView.Adapter adapter;

    private AttendanceAdapter attendanceAdapter;
    ProgressDialog progressDialog;

    private SQLiteHandler db;
    private SessionManager session;

    private SearchView searchView;
    Button btnSubmit;
    JSONObject mainObj = new JSONObject();
    // date
    SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
    String currentDateandTime = sdf.format(new Date());

    String class_id,title;
    Boolean Error;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_teacher_attendance);
        //get data from intent
        class_id = super.getIntent().getExtras().getString("id"); //class_id
        title = super.getIntent().getExtras().getString("title");
        getSupportActionBar().setTitle("Class: "+title+", Date: "+currentDateandTime );



        // SqLite database handler
        db = new SQLiteHandler(getApplicationContext());
        // session manager
        session = new SessionManager(getApplicationContext());

        btnSubmit=findViewById(R.id.buttonAttendanceSubmit);

        btnSubmit.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Error=false;
                Gson gson=new Gson();
                final String newDataArray=gson.toJson(listItems); // dataarray is list aaray

                    for (int i = 0; i < AttendanceAdapter.listItems.size(); i++){
                    if(AttendanceAdapter.listItems.get(i).getAttendance()==null){
                        Toast.makeText(TeacherAttendanceActivity.this, "Check attendance at roll:"+AttendanceAdapter.listItems.get(i).getRoll(), Toast.LENGTH_SHORT).show();
                        Error =true;
                        break;
                    }

                }
                if (!Error){
                    request(class_id,currentDateandTime,newDataArray);
                }

            }
        });


        listItems = new ArrayList<>();
        attendanceAdapter = new AttendanceAdapter(listItems, this, (AttendanceAdapter.AttendanceAdapterListner) this);

        recyclerView = (RecyclerView) findViewById(R.id.list_attendance);
        recyclerView.setLayoutManager(new LinearLayoutManager(TeacherAttendanceActivity.this));
        progressDialog = new ProgressDialog(this);

        teacherAttendanceActivity = this;
        //refresh_list(class_id);

    }

    @Override
    protected void onStart() {
        refresh_list(class_id);
        super.onStart();
    }

    @Override
    public void onAttendanceAdapterSelected(AttendanceModel model) {

    }
    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.refresh, menu);
        getMenuInflater().inflate(R.menu.tool_bar, menu);

        return true;
    }


    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        int id = item.getItemId();
        switch (id){
            case R.id.action_settings:
                Toast.makeText(getApplicationContext(),"Sittings",Toast.LENGTH_LONG).show();
                return true;
            case R.id.action_logout:
                logoutUser();
                return true;
            case R.id.action_about:
                Toast.makeText(getApplicationContext(),"About",Toast.LENGTH_LONG).show();
                return true;
            case R.id.action_devinfo:
                Toast.makeText(getApplicationContext(),"Dev info",Toast.LENGTH_LONG).show();
                return true;
            case R.id.refresh:
                refresh_list(class_id);
                return true;
            default:
                return super.onOptionsItemSelected(item);
        }
    }

    void logoutUser() {
        session.setLogin(false);
        db.deleteUsers();
        // Launching the login activity
        Intent intent = new Intent(this, MainActivity.class);
        startActivity(intent);
        finish();
    }

    // refresh list
    public void refresh_list(String id) {
        // this method refresh list and get the json data
        listItems.clear();
        // adapter = new MyAdapter(listItems,getApplicationContext());
        recyclerView.setAdapter(attendanceAdapter);

        recyclerView.setItemAnimator(new DefaultItemAnimator());
        progressDialog.setMessage("Loading");
        progressDialog.show();

        StringRequest stringRequest = new StringRequest(Request.Method.GET, ApiConfig.URL_TEACHER_ATTENDANCE+id, new Response.Listener<String>() {
            @Override
            public void onResponse(String response) {
                progressDialog.dismiss();
                try {

                    progressDialog.hide();
                    JSONObject jsonObject = new JSONObject(response);
                    JSONArray jsonArray = jsonObject.getJSONArray("Data");  // finding data
                    Log.d(TAG, String.valueOf(jsonObject));

                    int len = jsonArray.length();
                    for (int i = 0; i < len; i++) {
                        JSONObject o = jsonArray.getJSONObject(i);
                        AttendanceModel item = new AttendanceModel(
                                o.getString("id"),
                                o.getString("name"),
                                o.getString("roll"),
                                o.getString("class_id"),
                                o.getString("status"),
                                null
                        );
                        listItems.add(item);

                        //adapter = new MyAdapter(listItems,getApplicationContext());
                        recyclerView.setAdapter(attendanceAdapter);   // setting them in list view

                    }
                } catch (JSONException e) {
                    e.printStackTrace();
                }
            }
        }, new Response.ErrorListener() {
            @Override
            public void onErrorResponse(VolleyError error) {
                progressDialog.hide();
                Toast.makeText(TeacherAttendanceActivity.this, "Failed", Toast.LENGTH_SHORT).show();
            }
        }) {
            /** Passing some request headers* */
            @Override
            public Map getHeaders() throws AuthFailureError {

                SQLiteHandler db = new SQLiteHandler(getApplicationContext());
                HashMap<String,String> userDetail= db.getUserDetails();
                String userToken = userDetail.get("token");
                Log.d(TAG, String.valueOf(userToken));
                HashMap headers = new HashMap();
                headers.put("Accept", "application/json");
                headers.put("Authorization", "Bearer "+userToken);
                return headers;
            }
        };
        stringRequest.setShouldCache(false);
        VolleyRequest.getInstance(TeacherAttendanceActivity.this).addToRequestQueue(stringRequest);
    }

    // take attendance
    private void request( final String classId,final String date,final String data ) {

        progressDialog.setMessage("Taking attendance");
        showDialog();

        StringRequest strReq = new StringRequest(Request.Method.POST,
                ApiConfig.URL_TEACHER_ATTENDANCE_STORE, new Response.Listener<String>() {

            @Override
            public void onResponse(String response) {
                Log.d(TAG, "Login Response: " + response);
                hideDialog();
                try {
                    JSONObject jObj = new JSONObject(response);
                    boolean error = jObj.getBoolean("error");

                    // Check for error node in json
                    if (!error) {
                        String attendance = jObj.getString("Attendance");
                        Toast.makeText(TeacherAttendanceActivity.this, attendance, Toast.LENGTH_LONG).show();
                        finish();

                    } else {
                        // Error in login. Get the error message
                        String errorMsg = jObj.getString("message");
                        Toast.makeText(TeacherAttendanceActivity.this,
                                errorMsg, Toast.LENGTH_LONG).show();
                    }
                } catch (JSONException e) {
                    // JSON error
                    e.printStackTrace();
                    Toast.makeText(TeacherAttendanceActivity.this, "Json error: " + e.getMessage(), Toast.LENGTH_LONG).show();
                }

            }
        }, new Response.ErrorListener() {

            @Override
            public void onErrorResponse(VolleyError error) {
                Log.e(TAG, "Login Error: " + error.getMessage());
                Toast.makeText(TeacherAttendanceActivity.this,
                        error.getMessage(), Toast.LENGTH_LONG).show();
                hideDialog();
            }
        }) {

            /** Passing some request headers* */
            @Override
            public Map getHeaders() throws AuthFailureError {

                SQLiteHandler db = new SQLiteHandler(TeacherAttendanceActivity.this);
                HashMap<String,String> userDetail= db.getUserDetails();
                String userToken = userDetail.get("token");
                Log.d(TAG, String.valueOf(userToken));
                HashMap headers = new HashMap();
                headers.put("Accept", "application/json");
                headers.put("Authorization", "Bearer "+userToken);
                return headers;
            }

            @Override
            protected Map<String, String> getParams() {
                // Posting parameters to login url
                Map<String, String> params = new HashMap<String, String>();
                params.put("class_id", classId);
                params.put("date", date);
                params.put("data", data);

                return params;
            }

        };
        strReq.setShouldCache(false);
        // Adding request to request queue
        VolleyRequest.getInstance(TeacherAttendanceActivity.this).addToRequestQueue(strReq);
    }
    private void showDialog() {
        if (!progressDialog.isShowing())
            progressDialog.show();
    }

    private void hideDialog() {
        if (progressDialog.isShowing())
            progressDialog.dismiss();
    }


}

型号类
'方便的模型类'

public class AttendanceModel {
    String id,name,roll,classId,previousAttendance,attendance;


    public AttendanceModel(String id, String name,String roll, String classId,String previousAttendance,String attedance ){
        this.id = id;
        this.name = name;
        this.classId =classId;
        this.roll=roll;
        this.attendance=attedance;
        this.previousAttendance=previousAttendance;
    }

    public String getAttendance() {
        return attendance;
    }

    public String getId() {
        return id;
    }
    public String getName() {
        return name;
    }
    public String getRoll() {
        return roll;
    }
    public String getClassId() {
        return classId;
    }
    public String getPreviousAttendance(){return previousAttendance;}

    public void setId(String id) {
        this.id = id;
    }

    public void setName(String name) {
        this.name = name;
    }

    public void setRoll(String roll) {
        this.roll = roll;
    }

    public void setClassId(String classId) {
        this.classId = classId;
    }

    public void setPreviousAttendance(String previousAttendance) {
        this.previousAttendance = previousAttendance;
    }

    public void setAttendance(String attendance) {
        this.attendance = attendance;
    }

 
}

适配器类
'适配器类'

public class AttendanceAdapter extends RecyclerView.Adapter<AttendanceAdapter.ViewHolder>  implements Filterable

{
    // date
    SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
    String currentDateandTime = sdf.format(new Date());

    private static final String TAG = AttendanceAdapter.class.getSimpleName();


    public static List<AttendanceModel> listItems;
    private List<AttendanceModel> listItemsFiltered;
    private Context context;
    private ProgressDialog dialog;
    private AttendanceAdapter.AttendanceAdapterListner listner;

    private ProgressDialog pDialog;
    private SQLiteHandler db;
    public static JSONObject jo = new JSONObject();
    public static JSONArray ja  = new JSONArray();




    public AttendanceAdapter(List<AttendanceModel> listItems, Context context, AttendanceAdapter.AttendanceAdapterListner listner) {
        this.listItems = listItems;
        this.listner=listner;
        this.context = context;
        this.listItemsFiltered =listItems;

        // SqLite database handler
        db = new SQLiteHandler(context);

        // Progress dialog
        pDialog = new ProgressDialog(context);


    }

    @Override
    public Filter getFilter() {
        return new Filter() {
            @Override
            protected FilterResults performFiltering(CharSequence charSequence) {
                String charString = charSequence.toString();
                if (charString.isEmpty()) {
                    listItemsFiltered = listItems;
                } else {
                    List<AttendanceModel> filteredList = new ArrayList<>();
                    for (AttendanceModel row : listItems) {

                        // name match condition. this might differ depending on your requirement
                        // here we are looking for name or phone number match
                        if (row.getName().toUpperCase().contains(charSequence.toString().toUpperCase())||row.getName().toLowerCase().contains(charSequence.toString().toLowerCase())) {

                            filteredList.add(row);
                        }
                    }

                    listItemsFiltered = filteredList;
                }

                FilterResults filterResults = new FilterResults();
                filterResults.values = listItemsFiltered;
                return filterResults;
            }

            @Override
            protected void publishResults(CharSequence charSequence, FilterResults filterResults) {
                listItemsFiltered = (ArrayList<AttendanceModel>) filterResults.values;
                notifyDataSetChanged();
            }
        };
    }


    public class ViewHolder extends RecyclerView.ViewHolder {

        public TextView name;
        public TextView roll;
        public TextView previous;

        RadioGroup radioAttendance;
        RadioButton radioAttendancePresent,radioAttendanceAbsent;


        public CardView card_view;


        public ViewHolder(View itemView) {
            super(itemView);
            name= (TextView) itemView.findViewById(R.id.textViewAttendanceStudentName);
            roll = (TextView) itemView.findViewById(R.id.textViewAttendanceStudentRoll);
            previous = (TextView) itemView.findViewById(R.id.textViewAttendanceStudentPreviousStatus);
            radioAttendance = itemView.findViewById(R.id.radioAttendance);
            radioAttendancePresent =itemView.findViewById(R.id.radioAttendancePresent);
            radioAttendanceAbsent =itemView.findViewById(R.id.radioAttendanceAbsent);

            //card_view = (CardView) itemView.findViewById(R.id.class_card_view); // card view for on click method
            itemView.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick( View view) {
                    // send selected contact in callback
                    listner.onAttendanceAdapterSelected(listItemsFiltered.get(getAdapterPosition()));  // selecting cardview and position (model)
                }
            });
            radioAttendance.setOnCheckedChangeListener(new RadioGroup.OnCheckedChangeListener() {
                @Override
                public void onCheckedChanged(RadioGroup radioGroup, int i) {
                    //Toast.makeText(TeacherAttendanceActivity.this, toString(i), Toast.LENGTH_SHORT).show();
                    // Toast.makeText(context,"clicked at position"+i+" "+id+""+name,Toast.LENGTH_SHORT).show();

                    if(radioAttendancePresent.isChecked())
                    {
                        listItems.get(getAdapterPosition()).setAttendance("present");


                    }
                    else {
                        listItems.get(getAdapterPosition()).setAttendance("absent");

                    }

                }
            });


        }


    }


    @Override
    public AttendanceAdapter.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        View v = LayoutInflater.from(parent.getContext()).inflate(R.layout.attendance_list, parent, false);
        return new AttendanceAdapter.ViewHolder(v);
    }

    @Override
    public void onBindViewHolder  (final AttendanceAdapter.ViewHolder holder, final int position) {
        final AttendanceModel listItem = listItemsFiltered.get(position);

        holder.name.setText(listItem.getName());
        holder.roll.setText(listItem.getRoll());
        holder.previous.setText(listItem.getPreviousAttendance());
 
      
    }

    public interface AttendanceAdapterListner {
        void onAttendanceAdapterSelected(AttendanceModel model);  // sending cardview to say the dialoge and model for sending context
    }

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

    private void showDialog() {
        if (!pDialog.isShowing())
            pDialog.show();
    }

    private void hideDialog() {
        if (pDialog.isShowing())
            pDialog.dismiss();
    }
}

Answer 1

您的问题将通过对您的 Recycler View 适配器进行小的更改来解决，请不要禁用可回收属性，这会使您的 recycler View 成为一个美化的 ListView 。

我可以看到您尝试使用稀疏 boolean 数组来保存单选按钮的状态，这很好，但您也不需要。使用稀疏 boolean 数组背后的想法是将每个项目的状态保留在回收站 View 中，这样当它们被回收时，您仍然可以引用每个项目的状态。

在您的适配器中，您已经有一些我们可以用来了解状态的东西，即 attendance您的模型的属性，在这种情况下，您可以通过检查出席属性是否为 present 来设置复选框的状态或 absent .

关于您的代码的另一件事是您正在使用 onCheckChangedListener作为单选按钮的单击事件处理程序，您不应使用它，因为它会响应所有检查更改的事件，即使它是由代码而非用户操作触发的，因此当您绑定(bind) View 并设置任何单选时按钮被选中或未选中，它调用这个回调。

这是您的 ViewHolder 类的修改版本，它通过应用上述解决方案来解决此问题。

 public class ViewHolder extends RecyclerView.ViewHolder {

    public TextView name;
    public TextView roll;
    public TextView previous;

    RadioGroup radioAttendance;
    RadioButton radioAttendancePresent, radioAttendanceAbsent;


    public CardView card_view;


    public ViewHolder(View itemView) {
        super(itemView);
        name = (TextView) itemView.findViewById(R.id.textViewAttendanceStudentName);
        roll = (TextView) itemView.findViewById(R.id.textViewAttendanceStudentRoll);
        previous = (TextView) itemView.findViewById(R.id.textViewAttendanceStudentPreviousStatus);
        radioAttendance = itemView.findViewById(R.id.radioAttendance);
        radioAttendancePresent = itemView.findViewById(R.id.radioAttendancePresent);
        radioAttendanceAbsent = itemView.findViewById(R.id.radioAttendanceAbsent);

        radioAttendancePresent.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                radioAttendancePresent.setChecked(true);
                listItems.get(getAdapterPosition()).setAttendance("present");
            }
        });

        radioAttendanceAbsent.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                radioAttendanceAbsent.setChecked(true);
                listItems.get(getAdapterPosition()).setAttendance("absent");
            }
        });

    }

    void bind(int position) {
        // use the sparse boolean array to check
        if (listItems.get(position).getAttendance() != null) {
            if (listItems.get(position).getAttendance().equals("present")) {
                radioAttendancePresent.setChecked(true);
            } else if (listItems.get(position).getAttendance().equals("absent")) {
                radioAttendanceAbsent.setChecked(true);
            }
        } else {
            radioAttendance.clearCheck();
        }

        name.setText(listItems.get(position).getName());
        roll.setText(listItems.get(position).getRoll());
        previous.setText(listItems.get(position).getPreviousAttendance());
    }
}

请注意，我们为每个单选按钮设置了单独的单击监听器，并在项目列表中设置状态，并在绑定(bind)时检查该状态，我们还删除了 onCheckChangedListener和稀疏 boolean 数组，最后一件事是我们确保当没有为出勤属性设置状态时，我们只需清除单选按钮，以便没有人被选中，代码更简单并且现在可以正常工作。