Question

查看扩展BaseAdapter的自定义适配器：

public class DrawerAdapter extends BaseAdapter{

    static class ViewHolder{
        TextView        cat_Title;
        TextView        cat_Count;
    }

    private Activity                            mActivity;
    private ArrayList<HashMap<String, String>>  mData;
    private static LayoutInflater               mInflater;
    private JsonArray Categories                = null;
    public JsonObject Cat_Items                 = null;

    private static String                       CATEGORY_NAME;
    private static String                       CATEGORY_CNT;
    private static String                       CATEGORY_ID;

    public DrawerAdapter(Activity a, ArrayList<HashMap<String, String>> d){
        mActivity   = a;
        mData       = d;
        mInflater   = (LayoutInflater) mActivity.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
    }

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

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

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

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {

        View dView              = convertView;
        ViewHolder holder       = null;

        HashMap<String, String> dCategorise = new HashMap<String, String>();
        dCategorise             = mData.get(position);
        CATEGORY_NAME           = dCategorise.get("CATEGORY_NAME");
        CATEGORY_CNT            = dCategorise.get("CATEGORY_CNT");
        CATEGORY_ID             = dCategorise.get("CATEGORY_ID");


        if (convertView == null){
            dView               = mInflater.inflate(R.layout.layout_drawer_list_row, null);
            holder              = new ViewHolder();

            holder.cat_Title    = (TextView) dView.findViewById(R.id.category_title);
            holder.cat_Count    = (TextView) dView.findViewById(R.id.category_counter);

            dView.setTag(holder);

        }else{
            holder = (ViewHolder) dView.getTag();
        }


        holder.cat_Title.setTag(position);
        holder.cat_Title.setTypeface(MyriadRegular);
        holder.cat_Title.setText(CATEGORY_NAME);

        holder.cat_Count.setTypeface(Yagut);
        holder.cat_Count.setText(CATEGORY_CNT);


        holder.cat_Title.setOnClickListener(new OnClickListener() {

            @Override
            public void onClick(View v) {
                int pos         = (Integer) v.getTag();
                String cat_ID   = mData.get(pos).get(CATEGORY_ID);
            }
        });
        return dView;
    }

}

这是我的自定义适配器，我在导航抽屉中使用了它。我希望通过单击类别标题来获取类别ID，并将其发送到片段并根据此更改片段数据。但它为cat_ID

返回null

现在我的问题： 1.为什么它返回null？ 2.获取发送到片段的类别ID是正确的方法吗？

Answer 1

我建议您在从HashMap获取时将CATEGORY_ID直接添加到按钮的标记

<强>样品：

改变这个：

holder.cat_Title.setTag(position);

为：

holder.cat_Title.setTag(CATEGORY_ID);
public void onClick(View v) {
            String cat_ID        = (String) v.getTag();
        }

Answer 2

int pos = (Integer) v.getTag(); 你确定这是对的吗？ v.getTag()将获得ViewHolder，您不应将其转换为整数。

通过onClickListener按自定义适配器中的位置获取数据

2 个答案: