Question

我已经实现了界面和其他必需的东西，但在onClick方法中我卡住了。

// this is inside ViewHolderClass that extends RecyclerView.ViewHolder 
     implements View.OnClickListener  //
             @Override
             public void onClick(View v) {

                 if (mOnClickListener != null) {
                     mOnClickListener.onListItemClick(v.getTag().toString(), getAdapterPosition());
                 }

在标记值的位置，我想获取用户点击的listItem值。

更详细的代码：

    public class ScannerListAdapter  extends 
    RecyclerView.Adapter<ScannerListAdapter.ScannerViewHolder> {

private Context mContext;
private Cursor mCursor;
// to store reference member variable is created
private final ListItemClickListener mOnClickListener;
// to initialize listener
public ScannerListAdapter(Context context, Cursor cursor, 
   ListItemClickListener listener ) {
    mContext = context;
    mCursor = cursor;
    mOnClickListener = listener;
}

@NonNull
@Override
public ScannerViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int 
    viewType) {
    LayoutInflater inflater = LayoutInflater.from(mContext);
    View view = inflater.inflate(R.layout.scanner_list_item, parent, false);

    return new ScannerViewHolder(view);

}

代码继续......

@Override
public void onBindViewHolder(@NonNull ScannerViewHolder holder, int position) 
{
    if (!mCursor.moveToPosition(position))
        return;
    ArrayList<Integer> values = new ArrayList<>();
    values.add(1);
    values.add(2);



    String name = mCursor.getString(mCursor.getColumnIndex(ScannerEntry.COLUMN_SCANNED_RESULT));
    int id = mCursor.getInt(mCursor.getColumnIndex(ScannerEntry._ID));
    String date = mCursor.getString(mCursor.getColumnIndex(ScannerEntry.COLUMN_TIMESTAMP));

    holder.resultTextView.setText(name);
 //        holder.itemView.setTag(key1,id);
    holder.dateTextView.setText(date);
//        holder.itemView.setTag(key2,name);
    holder.itemView.setTag(values);
}

@Override
public int getItemCount() {
    return mCursor.getCount();
}

public void swapCursor(Cursor newCursor) {
    // Always close the previous mCursor first
    if (mCursor != null) mCursor.close();
    mCursor = newCursor;
    if (newCursor != null) {
        // Force the RecyclerView to refresh
        this.notifyDataSetChanged();
    }
}

代码继续......

    // inner class is created to hold the data of different views         
 class ScannerViewHolder extends RecyclerView.ViewHolder implements 
    View.OnClickListener {

    TextView dateTextView;
    TextView resultTextView;

    //method required to cast in itemView
    public ScannerViewHolder(View itemView) {
        super(itemView);

        dateTextView = (TextView) itemView.findViewById(R.id.date_textView);
        resultTextView = (TextView) 
    itemView.findViewById(R.id.result_textView);

        // to  let view to invoke it
        itemView.setOnClickListener(this);
    }
             @Override
             public void onClick(View v) {
                 ArrayList<Integer> values = (ArrayList<Integer>) v.getTag();
   //        String value=v.getTag(2).toString();
                 if (mOnClickListener != null) {
                     mOnClickListener.onListItemClick(values.toString(), 
           getAdapterPosition());
                 }

                 /*int adapterPosition = getAdapterPosition();
             String weatherForDay = mWeatherData[adapterPosition];
             mOnClickListener.onListItemClick(adapterPosition, 
                weatherForDay);*/
    }

}
    //interface is created to define a listener
    public interface ListItemClickListener {
        // we just need index of the click item so int variable is created
        void onListItemClick(String v, int position);
    }

} 在这里你可以检查和评论。和onListItemClick（String v，int position）正在发送给MainActivity。

Answer 1

您可以在onBindViewHolder（）中使用setTag(value)方法，然后可以使用getTag()检索该值。

//set value
view.setTag(value);
//get value
String value = view.getTag().toString();

有多个值：

//set values
ArrayList<String> values = new ArrayList<>();
values.add("one");
values.add("two");
values.add("three");
view.setTag(values)

//get values
ArrayList<String> values = (ArrayList<String>) view.getTag();

Answer 2

您已经调用了RecyclerView.ViewHolder的getAdapterPosition()。这将返回数据集合中单击项的位置。所以你可以用它来获取数据。

如何从RecyclerView获取列表项值从数据库中获取？

2 个答案: