Question

这是我从服务器检索数据的代码，每次调用listview。如果有人可以帮我追加或者某事

，那么这些项目就会重复

我的代码：

package NewsTabFragment;

import android.app.Activity;
import android.content.Context;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.TextView;

import com.android.volley.toolbox.ImageLoader;
import com.android.volley.toolbox.NetworkImageView;
import com.subhi.tabhost.AppController;
import com.subhi.tabhost.R;

import java.util.List;

/**
 * Created by tb_laota on 9/21/2015.
 */
public class Adapter extends BaseAdapter{
    private LayoutInflater inflater;
    private Activity activity;
    private List<Item> items;

    ImageLoader imageLoader= AppController.getmInstance().getmImageLoader();

    public Adapter(Activity activity,List<Item> items){
        this.activity=activity;
        this.items=items;
    }
    @Override
    public int getCount() {
        return items.size();
    }

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

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

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        if(inflater==null){
            inflater=(LayoutInflater) activity.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        }
        if(convertView ==null){
            convertView=inflater.inflate(R.layout.custom_layout,null);


        }
        if(imageLoader==null)
            imageLoader=AppController.getmInstance().getmImageLoader();


        NetworkImageView imageView= (NetworkImageView) convertView.findViewById(R.id.image_view);

        TextView news_title=(TextView)convertView.findViewById(R.id.news_title);
        TextView news_text= (TextView) convertView.findViewById(R.id.news_text);
        // TextView url= (TextView) convertView.findViewById(R.id.url);
        TextView time_stamp= (TextView) convertView.findViewById(R.id.time_stamp);
        TextView news_url= (TextView) convertView.findViewById(R.id.news_url);


        //getting data for row

            Item item=items.get(position);

            imageView.setImageUrl(item.getImage(), imageLoader);

        news_text.setText(item.getNews_text());
        news_url.setText(item.getUrl());
        time_stamp.setText(item.getTime_stamp());
        news_title.setText(item.getNews_title());


        return convertView;
    }
}

我在互联网上看过一些教程和博客，但对我来说没什么用。

Answer 1

执行以下操作：

public class Adapter extends BaseAdapter{
    private LayoutInflater inflater;
    private Activity activity;
    private List<Item> items;

    ImageLoader imageLoader= AppController.getmInstance().getmImageLoader();

    /* Create a class which contains view elements */
    static class Holder{
        NetworkImageView imageView;
        TextView news_title;
        TextView news_text;
        TextView news_url
        TextView time_stamp
    }

    public Adapter(Activity activity,List<Item> items){
        this.activity=activity;
        this.items=items;
    }


    /* Helper method to use, when updating the list */
    public void updateItems(List<Item> items){
       if(items != null){
          // Either clear the list, or do some logic for skipping duplicates
          this.items.clear();
          this.items.addAll(items);
       }
       notifyDataSetChanged();
    }

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

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

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

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        Holder rowHolder;
        if(convertView ==null){
            convertView = LayoutInflater.from(activity).inflate(R.layout.custom_layout,null);
           rowHolder = new Holder();
           rowHolder.imageView = (NetworkImageView) convertView.findViewById(R.id.image_view); 
           rowHolder.news_title =(TextView)convertView.findViewById(R.id.news_title);
           rowHolder.news_text= (TextView) convertView.findViewById(R.id.news_text);
           rowHolder.time_stamp= (TextView) convertView.findViewById(R.id.time_stamp);
           rowHolder.news_url= (TextView) convertView.findViewById(R.id.news_url);

           // tell convertView to set its Tag to the Holder object
           convertView.setTag(rowHolder);
        }else{
          // for recycling
            holder = (Holder) convertView.getTag();
        }

        if(imageLoader==null)
            imageLoader = AppController.getmInstance().getmImageLoader();


        //getting data for row
        final Item item = items.get(position);

        // null check the item
        if(item != null){
            holder.imageView.setImageUrl(item.getImage(), imageLoader);
            holder.news_text.setText(item.getNews_text());
            holder.news_url.setText(item.getUrl());
            holder.time_stamp.setText(item.getTime_stamp());
            holder.news_title.setText(item.getNews_title());
        }

        return convertView;
    }
}

然后当您从服务器获取新数据时，只需调用：

 mAdapter.updateItems(mItems);

其中mItems是您从服务器检索的List

Answer 2

每次调用WebService后都可能会添加对象。只需在将新对象添加到ArrayList之前清除数组。

Listview项目重复android

2 个答案: