在RecyclerView中的复选框选择中复制

Question

下面是我的代码。

holder.followDiseaseCheckBox.setOnClickListener(new View.OnClickListener() {
        @RequiresApi(api = Build.VERSION_CODES.LOLLIPOP)
        @Override
        public void onClick(View view) {

            if (holder.followDiseaseCheckBox.isChecked()) {

                holder.followDiseaseCheckBox.setChecked(true);

                checkBoxClicked++;
                holder.followDiseaseCheckBox.setChecked(true);
                // for Follow.
                if (isFollowOrUnFollow.equals("FOLLOW")) {

                    ((FollowActivity) context).diseaseListFromAdapter.add(String.valueOf(diseaseMap.get("id")));
                    ((FollowActivity) context).setFollowButton(true);

                }
                // for Unfollow.
                else if (isFollowOrUnFollow.equals("UN_FOLLOW")) {

                    ((FollowTwoActivity) context).unFollowedDiseaseListFromAdapter.add(String.valueOf(diseaseMap.get("id")));
                    ((FollowTwoActivity) context).setUnFollowDiseaseButton(true);
                }


            } else {

                holder.followDiseaseCheckBox.setChecked(false);

                checkBoxClicked--;
                holder.followDiseaseCheckBox.setChecked(false);
                // for Follow.
                if (isFollowOrUnFollow.equals("FOLLOW")) {
                    ((FollowActivity) context).diseaseListFromAdapter.remove(String.valueOf(diseaseMap.get("id")));
                }
                // for Unfollow.
                else if (isFollowOrUnFollow.equals("UN_FOLLOW")) {
                    ((FollowTwoActivity) context).unFollowedDiseaseListFromAdapter.remove(String.valueOf(diseaseMap.get("id")));
                }

                if (checkBoxClicked == 0) {

                    // for Follow.
                    if (isFollowOrUnFollow.equals("FOLLOW")) {
                        ((FollowActivity) context).setFollowButton(false);
                        ((FollowActivity) context).diseaseListFromAdapter.clear();
                    }
                    // for Unfollow.
                    else if (isFollowOrUnFollow.equals("UN_FOLLOW")) {

                        ((FollowTwoActivity) context).setUnFollowDiseaseButton(false);
                        ((FollowTwoActivity) context).unFollowedDiseaseListFromAdapter.clear();
                    }
                }
            }

        }
    });

问题是当我选中一个复选框时，包括选中循环视图中的其他复选框。但当我签入适配器时，项目被正确添加，但复选框被复制。

例如：如果我选中了第一项复选框，向下滚动第16项复选框也会被选中。取消选中该复选框也将取消选中第一项。

Answer 1

public class CardViewDataAdapter extends RecyclerView.Adapter<CardViewDataAdapter.ViewHolder> {
    private List<Student> stList;
    public CardViewDataAdapter(List<Student> students) {
        this.stList = students;
    }

@Override
public CardViewDataAdapter.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
  // create a new view
    View itemLayoutView = LayoutInflater.from(parent.getContext()).inflate(
    R.layout.cardview_row, null);

  // create ViewHolder

  ViewHolder viewHolder = new ViewHolder(itemLayoutView);

  return viewHolder;
 }

 @Override
 public void onBindViewHolder(ViewHolder viewHolder, int position) {

  final int pos = position;

  viewHolder.tvName.setText(stList.get(position).getName());

  viewHolder.tvEmailId.setText(stList.get(position).getEmailId());

  viewHolder.chkSelected.setChecked(stList.get(position).isSelected());

  viewHolder.chkSelected.setTag(stList.get(position));


  viewHolder.chkSelected.setOnClickListener(new View.OnClickListener() {
    public void onClick(View v) {
    CheckBox cb = (CheckBox) v;
    Student contact = (Student) cb.getTag();

    contact.setSelected(cb.isChecked());
    stList.get(pos).setSelected(cb.isChecked());

    Toast.makeText(
      v.getContext(),
      "Clicked on Checkbox: " + cb.getText() + " is "
        + cb.isChecked(), Toast.LENGTH_LONG).show();
   }
  });

 }

 // Return the size arraylist
 @Override
 public int getItemCount() {
  return stList.size();
 }

 public static class ViewHolder extends RecyclerView.ViewHolder {

  public TextView tvName;
  public TextView tvEmailId;

  public CheckBox chkSelected;

  public Student singlestudent;

  public ViewHolder(View itemLayoutView) {
   super(itemLayoutView);

   tvName = (TextView) itemLayoutView.findViewById(R.id.tvName);

   tvEmailId = (TextView) itemLayoutView.findViewById(R.id.tvEmailId);
   chkSelected = (CheckBox) itemLayoutView.findViewById(R.id.chkSelected);

  }

 }

 // method to access in activity after updating selection
 public List<Student> getStudentist() {
  return stList;
 }
}

有关复选框选择的更多了解，请单击此链接

Answer 2

回收器视图回收OnBindViewHolder中的视图。因此，当单击项目时，它会反映在其他一些位置。创建一个全局SparseBooleanArray来存储单击的位置。

private final SparseBooleanArray array=new SparseBooleanArray();

然后在最终视图所有者中添加clickListener并onClick存储被点击项目的位置。

public class ViewHolder extends RecyclerView.ViewHolder {
    public YOURVIEW view;
    public ViewHolder(View v) {
        super(v);
        view = (YOURVIEW) v.findViewById(R.id.YOURVIEWID);
        view.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                array.put(getAdapterPosition(),true);
                notifyDataSetChanged();
            }
        });
    }
}

在内部的OnBindViewHolder中，

@Override
public void onBindViewHolder(final ViewHolder holder, final int position) {
    if(array.get(position)){
        holder.followDiseaseCheckBox.setChecked(true);
    }else{
        holder.followDiseaseCheckBox.setChecked(false);
    }
}

Answer 3

您可能缺少recylerview的一些概念。事实上，recyclerview在每9项之后绑定/回收相同的视图。因此，为了避免这种情况，只需在活动中使用setItemViewCacheSize（）。

示例：

contactListAdapter = new ContactsListAdapter(ContactActivity.this, contactArrayList);
        mRecyclerView.setItemViewCacheSize(contactArrayList.size());
        mRecyclerView.setAdapter(contactListAdapter);

public void setItemViewCacheSize（int size）设置将屏幕外视图添加到可能共享的回收视图池之前要保留的视图数。屏幕外视图缓存可以随时了解所连接适配器中的更改，从而允许LayoutManager重用那些未经修改的视图，而无需返回适配器重新绑定它们。参数：size-在将视图返回到常规回收视图池之前要缓存到屏幕外的视图数