RecyclerView 在新行中显示以前在 EditText 中输入的值

Question

我正在创建一个 android 应用程序，我在其中使用 recyclerView 并且 recyclerView 的行具有 editText。

这是我的ReadingAdapter 课程

public class ReadingAdapter extends RecyclerView.Adapter<ReadingAdapter.ViewHolder>  implements AdapterView.OnItemSelectedListener {

    Context context;
    String valOpenReading, valClosReading, valConsumption;
    private List<ReadingData> readingList;
    static String[] arrValOpenRead, arrValClosRead, arrValConsumption;
    public ReadingAdapter(Context context, List<ReadingData> readingList) {
        this.context = context;
        this.readingList = readingList;

        arrValOpenRead = new String[readingList.size()];
        arrValClosRead = new String[readingList.size()];
        arrValConsumption = new String[readingList.size()];
    }

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

    @Override
    public void onBindViewHolder(final ReadingAdapter.ViewHolder holder, final int position) {
        ReadingData tempData = readingList.get(position);
        holder.pdtName.setText(tempData.pdtName);
        holder.keyId.setText("Key "+tempData.keyId);

        holder.etClosRead.addTextChangedListener(new TextWatcher() {
            boolean ignore = false;
            @Override
            public void beforeTextChanged(CharSequence s, int start, int count, int after) {

            }
            @Override
            public void onTextChanged(CharSequence s, int start, int before, int count) {

            }
            @Override
            public void afterTextChanged(Editable s) {
                if (ignore)
                    return;
                ignore = true;
                valOpenReading = holder.etOpenRead.getText().toString();
                arrValOpenRead[position] = valOpenReading;
                valClosReading = s.toString().equals("") ? "0": s.toString();
                arrValClosRead[position] = valClosReading;
                if (!valOpenReading.equals("")) {
                    if (Integer.parseInt(valClosReading) < Integer.parseInt(valOpenReading)) {
                        Toast.makeText(context, "Check once! closing reading should be more than opening reading!", Toast.LENGTH_LONG).show();
                        valConsumption = "0";
                        holder.consumption.setText("");
                    } else {
                        valConsumption = (Integer.parseInt(valClosReading) - Integer.parseInt(valOpenReading))+"";
                        arrValConsumption[position] = valConsumption;
                        holder.consumption.setText(valConsumption);
                    }
                } else
                    Toast.makeText(context, "Please fill the opening reading!", Toast.LENGTH_SHORT).show();
                ignore = false;
            }
        });
    }

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

    @Override
    public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {

    }

    @Override
    public void onNothingSelected(AdapterView<?> parent) {

    }

    public class ViewHolder extends RecyclerView.ViewHolder{
        TextView pdtName, keyId, consumption;
        EditText etOpenRead, etClosRead;
        public ViewHolder(View view) {
            super(view);
            pdtName = (TextView)view.findViewById(R.id.txt_list_pdt_supp);
            keyId = (TextView)view.findViewById(R.id.key_set);
            etOpenRead = (EditText)view.findViewById(R.id.open_val_set);
            etClosRead = (EditText)view.findViewById(R.id.clos_val_set);
            consumption = (TextView)view.findViewById(R.id.consumption_val);
        }
    }
}

这是我的ReadingData.java

public class ReadingData {
    String pdtName, keyId, openReading, closReading, consumption;
    public ReadingData(String pdtName, String keyId) {
        this.pdtName = pdtName;
        this.keyId = keyId;
    }
}

在这里，如果我在 recyclerView 的起始项目中输入值，那么当我将项目向上滚动到列表底部时，最后一个项目将具有该值。

请忽略图像质量，因为我们无法上传超过 2MiB 的快照。

这里视图在列表滚动时被回收。如何防止将值复制到列表中的其他项目。

而且Toast 也重复了好几次。如何阻止这种情况。

更新： 通过LQ Gioan 到SO question How ListView's recycling mechanism works 的建议，我得到了ListView 实际如何与视图回收一起工作的逻辑。

但我不确定recyclerView 是否也同样有效。

但在我的情况下，我该如何实现这个过程。请有人在这里帮助我。

Answer 1

RecyclerView 重用视图，实际上它只生成与屏幕上可见的视图一样多的视图。因此，如果您可以看到为其他行设置的值，则可以预期

解决方案是将要更改的视图的所有属性设置为默认值或数据集中应显示的任何行

所以将addTextChangedListener insode ViewHolder 构造函数（您可以通过调用getAdapterPosition() 来获取位置）以获得更好的性能，并从您的数据集中将editText 值设置在onBindViewHolder 方法中

Answer 2

您的活动代码：

ListView listview = (ListView) findViewById(R.id.list_view);
listview.setItemsCanFocus(true);
Adapter adapter = new Adapter (YourActivity.this, YourArrayList);
listview .setAdapter(adapter);

适配器类

public class Adapter extends BaseAdapter {

// Declare Variables \\
Context mContext;
LayoutInflater inflater;
Activity act;
String[] temp;


public Adapter(Context context, ArrayList<String> list) {
    mContext = context;
    inflater = LayoutInflater.from(mContext);
    act = (Activity) context;
    //-------Temp String Array-------\\
    temp = new String[this.count];
    for (int i = 0; i < this.count; i++) {
        temp[i] = list.get(i);
    }
    //---------------------------\\

}

public class ViewHolder {
    TextView optionTitle;
    EditText optionText;
    int ref;
}

@Override
public int getCount() {
    return list.size;
}

@Override
public Object getItem(int position) {
    return temp[position];
}

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

public View getView(final int position, View view, ViewGroup parent) {
    final ViewHolder holder;
    if (view == null) {
        holder = new ViewHolder();
        view = inflater.inflate(R.layout.lv_items_add_ques_options_mcq, null);
        holder.optionTitle = (TextView) view.findViewById(R.id.add_ques_opts_count_mcq_tv);
        holder.optionText = (EditText) view.findViewById(R.id.add_ques_opts_title_mcq_et);
        view.setTag(holder);
    } else {
        holder = (ViewHolder) view.getTag();
    }
    holder.ref = position;

    holder.optionTitle.setText(getCharForNumber(position) + ":");

    holder.optionText.setText(temp[position]);
    holder.optionText.addTextChangedListener(new TextWatcher() {

        @Override
        public void onTextChanged(CharSequence arg0, int arg1, int arg2, int arg3) {
        }

        @Override
        public void beforeTextChanged(CharSequence arg0, int arg1, int arg2,
                                      int arg3) {
        }

        @Override
        public void afterTextChanged(Editable arg0) {
            temp[holder.ref] = arg0.toString().trim();
        }
    });

    return view;
}

public void getList() {
    StaticValues.arrayListOptions = new ArrayList<String>(Arrays.asList(temp));
    StaticValues.arrayListOptionsCount = new ArrayList<String>();
    for (int i = 0; i < count; i++) {
        StaticValues.arrayListOptionsCount.add(String.valueOf(i+1));
        Log.e("err_al", StaticValues.arrayListOptions.get(i));
        Log.e("err_al", StaticValues.arrayListOptionsCount.get(i));
    }
}

private String getCharForNumber(int i) {
    char[] alphabet = "ABCDEFGHIJKLMNOPQRSTUVWXYZ".toCharArray();
    if (i > 25) {
        return null;
    }
    return Character.toString(alphabet[i]);
}}