Android工作室，recyclerview

Posted 2023-02-26

【中文标题】Android工作室，recyclerview

【英文标题】：Android studio, recycle view

【发布时间】：2020-11-13 05:07:57

【问题描述】：

我在 android studio 中有一些错误。 当我尝试将符号 ('*') 添加到特殊项目时，它还会将该符号添加到从第一个开始放置在 +14 中的项目。 如果有人能解决这个问题，我会很高兴。 有关更多信息，您可以查看此链接，我在其中描述了问题。 https://youtu.be/CJFkt-Cck1A

public class RecyclerViewAdapter extends RecyclerView.Adapter<RecyclerViewAdapter.MyViewHolder> 

    private static final String TAG = "RecyclerViewAdapter";
    private Context context;
    private List<WorkDayItem> workDayItemList;

    //Complete
    public RecyclerViewAdapter(Context context, List<WorkDayItem> workDayItemList) 
        this.context = context;
        this.workDayItemList = workDayItemList;
    

    //Complete
    //Here we create view- itemWorkday and inflate it by layout- item_one_work_day
    @Override
    public MyViewHolder onCreateViewHolder(ViewGroup parent, int viewType) 

        View itemWorkDay = LayoutInflater.from(parent.getContext()).inflate(R.layout.item_one_work_day, parent, false);
        MyViewHolder myViewHolder = new MyViewHolder(itemWorkDay);
        return myViewHolder;
    

    @Override
    public void onBindViewHolder(final MyViewHolder holder, int position) 
        Log.d(TAG, "onBindViewHolder: called." + (position + 1) + "\n" + workDayItemList.get(position).toString());

        final WorkDayItem workDayItem = workDayItemList.get(position);
        String dateStart = (String) DateFormat.format("dd.MM", workDayItem.getDateStart());
        String timeStart = (String) DateFormat.format("HH:mm", workDayItem.getDateStart());
        String timeEnd = (String) DateFormat.format("HH:mm", workDayItem.getDateEnd());

        //Convert data from firebase String format to int hours and minutes format.
        Double convertingDataFromFirebase;
        try 
            convertingDataFromFirebase = Double.parseDouble(new DecimalFormat("##.##").format(workDayItem.getCount_hours()));
         catch (NumberFormatException e) 
            convertingDataFromFirebase = 0.0;
        

        int hours = convertingDataFromFirebase.intValue();

        convertingDataFromFirebase = (convertingDataFromFirebase - convertingDataFromFirebase.intValue()) * 60;
        int minutes = convertingDataFromFirebase.intValue();

        //Check if current item have description
        if (workDayItemList.get(position).getDesc().length() > 2) 
            Log.i(TAG, "TESTER: desc dote added");
            holder.doteOfDesc.setVisibility(View.VISIBLE);
        


        holder.dayPosition.setText((position + 1) + "");
        holder.dateStart.setText(dateStart);
        holder.timeStart.setText(timeStart);
        holder.timeEnd.setText(timeEnd);
        holder.countOfHours.setText(hours + ":" + minutes);


        //On click on current hold open alert dialog with some functions
        holder.parentLayout.setOnClickListener(new View.OnClickListener() 
            @Override
            public void onClick(View view) 
                initializeAlertDialogForItem(workDayItem, holder);
            
        );

    


    //initialize data about current work day and have button for changing information
    private void initializeAlertDialogForItem(final WorkDayItem workDayItem, final MyViewHolder holder) 

        //Initialize alert dialog
        final AlertDialog alertDialog = new AlertDialog.Builder(context).create();
        View itemWork = LayoutInflater.from(context)
                .inflate(R.layout.ad_item_desc, null, false);
        alertDialog.setView(itemWork);
        alertDialog.show();


        //initialize alert dialog buttons and views
        final ImageButton change = alertDialog.findViewById(R.id.itemAD_Edit);
        final ImageButton delete = alertDialog.findViewById(R.id.itemAD_Delete);

        TextView description = alertDialog.findViewById(R.id.itemADDescription);
        TextView date = alertDialog.findViewById(R.id.itemADDate);
        TextView from = alertDialog.findViewById(R.id.itemADFrom);
        TextView to = alertDialog.findViewById(R.id.itemADTO);

        String timeStart = (String) (DateFormat.format("HH:mm", workDayItem.getDateStart()));
        String timeEnd = (String) (DateFormat.format("HH:mm", workDayItem.getDateEnd()));
        String dateStart = (String) (DateFormat.format("dd.MM.yyyy", workDayItem.getDateStart()));


        date.setText(dateStart);
        from.setText(timeStart);
        to.setText(timeEnd);
        description.setText(workDayItem.getDesc());
        //Change button
        change.setOnClickListener(new View.OnClickListener() 
            @RequiresApi(api = Build.VERSION_CODES.M)
            @Override
            public void onClick(View v) 
                AlertDialogReport userReport = new AlertDialogReport(context, "replace-remove", workDayItem);
                userReport.initializeAlertDialog();
                alertDialog.dismiss();
            
        );

        delete.setOnClickListener(new View.OnClickListener() 
            @Override
            public void onClick(View v) 
                //Delete data from firebase

                Login.fc.databaseReference.addValueEventListener(new ValueEventListener() 
                    @Override
                    public void onDataChange(@NonNull DataSnapshot dataSnapshot) 
                        for (DataSnapshot snapshot : dataSnapshot.getChildren()) 
                            String itemTime = "" + workDayItem.getDateStart().getTime();
                            String firebaseTime = "" + snapshot.child("dateStart").child("time").getValue();
                            if (itemTime.equals(firebaseTime)) 
                                Login.fc.databaseReference.child(snapshot.getKey()).removeValue();
                            
                        
                    

                    @Override
                    public void onCancelled(@NonNull DatabaseError databaseError) 
                    
                );
                //Delete data from SqLiteDatabase
                mysqlDataBase dataBase = new MySQLDataBase(context);
                dataBase.deleteItem(workDayItem);

                //Finish with alert dialog and notify user
                alertDialog.dismiss();
                Toast.makeText(context, R.string.item_deleted, Toast.LENGTH_SHORT).show();
                holder.parentLayout.removeAllViews();
            
        );

    


    //Complete
    @Override
    public int getItemCount() 
        return workDayItemList.size();
    


    //Complete
    //Here we catch our view and getting reference between view and our objects
    public class MyViewHolder extends RecyclerView.ViewHolder 
        private LinearLayout parentLayout;
        private TextView doteOfDesc, dayPosition, dateStart, timeStart, timeEnd, countOfHours;

        public MyViewHolder(View view) 
            super(view);
            doteOfDesc = view.findViewById(R.id.itemDote);
            dayPosition = view.findViewById(R.id.itemDayPosition);
            dateStart = view.findViewById(R.id.itemDateStart);
            timeStart = view.findViewById(R.id.itemStartHour);
            timeEnd = view.findViewById(R.id.itemEndHour);
            countOfHours = view.findViewById(R.id.itemCountOfHours);
            parentLayout = view.findViewById(R.id.itemWorkDay);
        
    

【问题讨论】：

为什么要+14????????

我不知道，如果我像这样将 'onCreateViewHolder' 父级更改为 null，它将向前跳 11：查看 itemWorkDay = LayoutInflater.from(parent.getContext()).inflate(R. layout.item_one_work_day, null, false);

尝试清理并构建

【参考方案1】：

尝试添加这个：

    //Check if current item have description
    if (workDayItemList.get(position).getDesc().length() > 2) 
                Log.i(TAG, "TESTER: desc dote added");
                holder.doteOfDesc.setVisibility(View.VISIBLE);
            
    else if( workDayItemList.get(position).getDesc().length() < 2 
             && holder.doteOfDesc.getVisibility()== View.VISIBLE )
     holder.doteOfDesc.setVisibility(View.GONE);

发生这种情况的原因是RecyclerView 创建了覆盖整个屏幕所需的ViewHolders 以及一些额外的（在您的情况下为12），然后通过重新绑定值重用它们到意见。而你在 2.ViewHolder 中将 doteOfDesc 设置为 View.VISIBLE，但永远不要将其设置回 View.GONE，这就是为什么每次重用 ViewHolder 时它都会看到 doteOfDesc。

更漂亮的版本：

  Boolean hasDescription = workDayItemList.get(position).getDesc().length() > 2;
  holder.doteOfDesc.setVisibility( hasDescription ? View.VISIBLE : View.GONE);