java - 来自远程数据库的 ListView onItemClickListener 未传递位置整数

Question

我查看了其他问题，但没有找到能解决我的具体问题的问题。如果我错过了，我深表歉意。

我有一个来自远程数据库的 ListView 。如果用户单击某个项目，我希望将项目信息传递到加载更多信息的详细 Activity 。当我运行应用程序并单击一个项目时，logcat 显示“整数无法转换为 RowData”。根据我在网上研究的内容以及我习惯在 Eclipse 中使用的内容，我认为获取该项目的位置是可行的。我正在使用 Android Studio 和 Volley。这是我的 onItemClickListener 和 RowData 类:

list.setOnItemClickListener(new AdapterView.OnItemClickListener() {
        @Override
        public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
            //Get item at position
            RowData item = (RowData) parent.getItemAtPosition(position);

            //Pass the image title and url to DetailsActivity
            Intent intent = new Intent(MainActivity.this, DetailActivity.class);
            intent.putExtra("title", item.getTitle());
            intent.putExtra("image", item.getImageURL());

            //Start details activity
            startActivity(intent);
        }
    });

行数据:

public class RowData {
private String demo_name;
private String demo_size;
private String demo_image;
private String demo_detail;
private String demo_region;
public RowData(String demo_name,String demo_size,String demo_image,String demo_detail,String demo_region){
    this.demo_name=demo_name;
    this.demo_size=demo_size;
    this.demo_image=demo_image;
    this.demo_detail=demo_detail;
    this.demo_region=demo_region;

    }

    public String getTitle(){
        return demo_name;

    }
    public String getDescription(){
        return demo_size;

    }
    public String getImageURL(){
        return demo_image;

    }
    public String getDetailURL(){
        return demo_detail;
    }
    public String getRegionURL(){
        return demo_region;
    }
}

自定义适配器:

public class CustomAdapter extends BaseAdapter implements Filterable{
private ArrayList<RowData> result;
private ArrayList<RowData> orig;
private Context context;
private static LayoutInflater inflater=null;
public CustomAdapter(MainActivity mainActivity, ArrayList<RowData> data) {
    // TODO Auto-generated constructor stub
    result=data;
    context=mainActivity;

    inflater = ( LayoutInflater )context.
            getSystemService(Context.LAYOUT_INFLATER_SERVICE);
}
@Override
public int getCount() {
    // TODO Auto-generated method stub
    return result.size();
}

@Override
public Object getItem(int position) {
    // TODO Auto-generated method stub
    return position;
}

@Override
public long getItemId(int position) {
    // TODO Auto-generated method stub
    return position;
}

public Filter getFilter() {
    return new Filter() {

        @Override
        protected FilterResults performFiltering(CharSequence constraint) {
            final FilterResults oReturn = new FilterResults();
            final ArrayList<RowData> results = new ArrayList<RowData>();
            if (orig == null)
                orig = result;
            if (constraint != null) {
                if (orig != null && orig.size() > 0) {
                    for (final RowData g : orig) {
                        if (g.getTitle().toLowerCase()
                                .contains(constraint.toString()))
                            results.add(g);
                    }
                }
                oReturn.values = results;
            }
            return oReturn;
        }

        @SuppressWarnings("unchecked")
        @Override
        protected void publishResults(CharSequence constraint,
                                      FilterResults results) {
            result = (ArrayList<RowData>) results.values;
            notifyDataSetChanged();
        }
    };
}

public class Holder
{
    TextView title;
    TextView description;
    NetworkImageView img;
}
@Override
public View getView(final int position, View convertView, ViewGroup parent) {
    // TODO Auto-generated method stub
    Holder holder=new Holder();
    View rowView;
    rowView = inflater.inflate(R.layout.list_item, null);
    holder.title=(TextView) rowView.findViewById(R.id.textView1);
    holder.description=(TextView) rowView.findViewById(R.id.textView2);
    holder.img=(NetworkImageView) rowView.findViewById(R.id.networkImageView);
    holder.title.setText(result.get(position).getTitle());
    holder.description.setText(result.get(position).getDescription());

    // If you are using NetworkImageView
    holder.img.setImageUrl(result.get(position).getImageURL(), VolleyController.getInstance().getImageLoader());

    return rowView;
}
}

Answer 1

问题出在这里:

@Override
public Object getItem(int position) {
    // TODO Auto-generated method stub
    return position;
}

您应该重写此方法，以便它返回指定位置的 RowData 对象。像这样的东西:

@Override
public Object getItem(int position) {
    if (result == null) {
        return null;
    }

    return result.get(position);
}

您的原始表示形式正在返回 int，您尝试将其转换为 RowData，这导致了崩溃。