如何在Recyclerview中仅选择一个复选框并更改notifydataset

Question

在我的代码中,我创建了具有复选框的recyclerview,并且已经选择了默认的一个项目.现在我想要选择其他项目复选框,所以取消选择所有其他项目意味着一个项目选择时间.

我的适配器代码:

public class SupportSchoolIdAdapter extends RecyclerView.Adapter<SupportSchoolIdAdapter.ViewHolder> {

ArrayList<SupportSchoolIdModel> supportSchoolIdModels;
DataPref mDataPref;
String supportSchoolId;

public SupportSchoolIdAdapter(List<SupportSchoolIdModel> supportSchoolIdModels) {
    this.supportSchoolIdModels = new ArrayList<>(supportSchoolIdModels);
}

@Override
public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
    Context context = parent.getContext();
    mDataPref = DataPref.getInstance(context);
    supportSchoolId = mDataPref.getSupportSchoolId();
    View v = LayoutInflater.from(parent.getContext()).inflate(R.layout.support_school_item, parent, false);
    return new ViewHolder(v);
}

@Override
public void onBindViewHolder(final ViewHolder holder, int position) {
    final SupportSchoolIdModel event = supportSchoolIdModels.get(position);
    holder.bindData(supportSchoolIdModels.get(position));

    //in some cases, it will prevent unwanted situations
    holder.checkbox.setOnCheckedChangeListener(null);

    //if true, your checkbox will be selected, else unselected
    holder.checkbox.setChecked(supportSchoolIdModels.get(position).isSelected());

    holder.checkbox.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
        @Override
        public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
            supportSchoolIdModels.get(holder.getAdapterPosition()).setSelected(isChecked);
        }
    });
    if (supportSchoolIdModels.get(position).getPkSchoolId().equalsIgnoreCase(supportSchoolId)) {
        holder.checkbox.setChecked(true);
    } else {
        holder.checkbox.setChecked(false);
    }
}
@Override
public int getItemCount() {
    return supportSchoolIdModels.size();
}
// Provide a reference to the views for each data item
// Complex data items may need more than one view per item, and
// you provide access to all the views for a data item in a view holder
public static class ViewHolder extends RecyclerView.ViewHolder {
    // each data item is just a string in this case
    private TextView schoolIdTxt;
    private TextView schoolNameTxt;
    private CheckBox checkbox;

    public ViewHolder(View v) {
        super(v);
        schoolIdTxt = (TextView) v.findViewById(R.id.schoolIdTxt);
        schoolNameTxt = (TextView) v.findViewById(R.id.schoolNameTxt);
        checkbox = (CheckBox) v.findViewById(R.id.checkbox);
    }
    public void bindData(SupportSchoolIdModel supportSchoolIdModel) {
        schoolIdTxt.setText(supportSchoolIdModel.getPkSchoolId());
        schoolNameTxt.setText(supportSchoolIdModel.getSchoolName());
    }
}
}

第二个问题是当我滚动循环视图时为什么选中的项目未选中.请帮我.

Answer 1

1-您可以在Adapter类中创建一个可用于保存所选位置的变量:

private int selectedPosition = -1;// no selection by default

2-内部onBindViewHolder设置检查状态:

holder.checkBox.setChecked(selectedPosition == position);

3-在setOnCheckedChangeListener里面你必须更新位置

this.selectedPosition = holder.getAdapterPosition();

4-刷新适配器

adapter.notifyDatasetChanged();

编辑

将为所有位置调用onBindViewHolder,

因此方法setChecked将调用所有CheckBoxes,此方法具有布尔输入.

在上面的例子中我写setChecked(selectedPosition == position).为了更具可读性,我可以写:

if(selectedPosition == position){ 
   holder.checkBox.setChecked(true);
}
else{
   holder.checkBox.setChecked(false) 
}

Answer 2

这是最好的代码！注意BindViewHolder

public class SupportSchoolIdAdapter extends RecyclerView.Adapter<SupportSchoolIdAdapter.ViewHolder > {

private Context context;
ArrayList<SupportSchoolIdModel> supportSchoolIdModels;
private int selectedPosition = 0;
private ArrayList<Integer> selectCheck = new ArrayList<>();

public SupportSchoolIdAdapter (Context context, ArrayList<SupportSchoolIdModel> supportSchoolIdModels) {
    this.context = context;
    this.supportSchoolIdModels = supportSchoolIdModels;

//initilize selectCheck 
    for (int i = 0; i < supportSchoolIdModels.size(); i++) {
        selectCheck.add(0);
    }

}

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

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

    if (selectCheck.get(position) == 1) {
        holder.checkbox.setChecked(true);
    } else {
        holder.checkbox.setChecked(false);
    }

    holder.checkbox.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            for(int k=0; k<selectCheck.size(); k++) {
                if(k==position) {
                    selectCheck.set(k,1);
                } else {
                    selectCheck.set(k,0);
                }
            }
            notifyDataSetChanged();

        }
    });
    holder.checkbox.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
        @Override
        public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {

            if(isChecked==true){
                //Do whatever you want to do with selected value
            }
        }
    });

}

@Override
public int getItemCount() {
    return supportSchoolIdModels== null? 0: supportSchoolIdModels.size();
}

class ViewHolder extends RecyclerView.ViewHolde {

    CheckBox checkbox;

    public ViewHolder(View v) {
        super(v);
        checkbox = (CheckBox) v.findViewById(R.id.checkbox);          
    }

}

}