Question

在RecyclerViewAdapter课程中，我正在传递HashMap<String,ArrayList<Custom>>作为数据，现在我想获得关键＆amp;每个位置的价值，但我不知道我应该怎么做！提前谢谢

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



private Context mContext;
private HashMap<String,ArrayList<Products>> dataSet;

public Main_Recycler_Single_Row(Context mContext, HashMap<String,ArrayList<Products>> mDataSet) {
    this.mContext = mContext;
    this.dataSet = mDataSet;

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

    Map.Entry<String,ArrayList<Products>> entry=(Map.Entry<String,ArrayList<Products>>) dataSet.entrySet();//this line is my problem!


    holder.header.setText(entry.getKey());

    holder.mRecyclerView.setLayoutManager(new LinearLayoutManager(mContext,LinearLayoutManager.HORIZONTAL,false));
    holder.mRecyclerView.setHasFixedSize(true);
    holder.mRecyclerView.setAdapter(new Main_Recycler_Sinle_Item(mContext,entry.getValue()));

}

Answer 1

你必须使用entry.getvalue（）;获得价值

String key = entry.getKey(); ArrayList<Products> value = entry.getValue();

Answer 2

希望这适合你：

holder.header.setText(dataSet.getKey().toArray()[position]);// for key
holder.productDesc.setText(dataSet.get(position)
.get(productPosition).getDesc())  //sample for getting product description

Answer 3

如果您尝试使用Value从HashMap获取position，则还需要保留Array keys

keys = (String[])mDataSet.keySet().toArray();

您的ViewHolder课程将如下所示：

public Main_Recycler_Single_Row(Context mContext, HashMap<String,ArrayList<Products>> mDataSet) {
    this.mContext = mContext;
    this.dataSet = mDataSet;
    keys = (String[])mDataSet.keySet().toArray();

} @Override
public void onBindViewHolder(@NonNull final RecyclerView.ViewHolder holder, int position) {

    holder.header.setText(keys[position]);

    holder.mRecyclerView.setLayoutManager(new LinearLayoutManager(mContext,LinearLayoutManager.HORIZONTAL,false));
    holder.mRecyclerView.setHasFixedSize(true);
    holder.mRecyclerView.setAdapter(new Main_Recycler_Sinle_Item(mContext,dataSet.get(keys[position])));

}

Answer 4

获得价值：

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


    // key
    String key = (new ArrayList<>(tab.keySet())).get(position);
    // value
    String value = (String) tab.get(key);

    TextView textView = holder.textRecyclerView;
    textView.setText(value);
}

在Adapter类上如何从HashMap获取键和值

4 个答案: