Android ListView显示从URL获取的图像的错误位置

我的listview没有显示图像在其单个自定义适配器上的确切位置。我正在尝试使用AsyncTask加载图像。有时图像会重复，我不知道为什么。这是我的ArrayAdapter代码：

public class NewsPromoAdapter extends ArrayAdapter<NewsPromosDTO> {
    private final Context context;
    List<NewsPromosDTO> npList;
    LayoutInflater inflater;
    Bitmap src;

    public NewsPromoAdapter(Context context, List<NewsPromosDTO> npList) {
        super(context, R.layout.news_and_promos, npList);
        this.context = context;
        this.npList = npList;
        inflater = (LayoutInflater) context
                .getSystemService(Context.LAYOUT_INFLATER_SERVICE);
    }

    public static class ViewHolder {
        TextView nameText;
        TextView date1Text;
        ImageView imageView;
        ProgressBar prg;
        LoadImage loadImg;
    }

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

        if (convertView == null) {
            convertView = inflater.inflate(R.layout.news_and_promos, parent,
                    false);
            holder = new ViewHolder();
            holder.nameText = (TextView) convertView
                    .findViewById(R.id.newspromo_name);
            holder.date1Text = (TextView) convertView
                    .findViewById(R.id.newspromo_date);
            holder.imageView = (ImageView) convertView
                    .findViewById(R.id.newspromo_imageView);
            holder.prg = (ProgressBar) convertView
                    .findViewById(R.id.progressBar1);

            convertView.setTag(holder);
        } else {

            holder = (ViewHolder) convertView.getTag();
            holder.loadImg.cancel(true);
        }

        if (!(npList.get(position).getName().equals(""))) {
            holder.nameText.setVisibility(View.VISIBLE);
            holder.nameText.setText(npList.get(position).getName());

        } else {
            holder.nameText.setVisibility(View.GONE);
        }

        if (!(npList.get(position).getDate().equals(""))) {
            holder.date1Text.setVisibility(View.VISIBLE);
            holder.date1Text.setText(npList.get(position).getDate());

        } else {
            holder.date1Text.setVisibility(View.GONE);
        }

        if (!(npList.get(position).getImageURL().equals(""))) {
            holder.imageView.setVisibility(View.VISIBLE);
            holder.loadImg = new LoadImage(holder.imageView, npList.get(
                    position).getImageURL(), holder);
            holder.loadImg.execute();
        } else {
            holder.imageView.setVisibility(View.GONE);
            holder.prg.setVisibility(View.GONE);
        }

        return convertView;
    }

    class LoadImage extends AsyncTask<Object, Void, Bitmap> {
        ViewHolder viewH;
        private ImageView imv;
        private String url;

        public LoadImage(ImageView imv, String imageURL, ViewHolder viewH) {
            this.imv = imv;
            this.url = imageURL;
            this.viewH = viewH;

        }

        @Override
        protected Bitmap doInBackground(Object... params) {
            BitmapFromURL bmpURL = new BitmapFromURL();
            src = bmpURL.getBitmapFromURL(url);

            return src;
        }

        @Override
        protected void onPostExecute(Bitmap result) {

            // imv.setImageBitmap(result);
            // viewH.prg.setVisibility(View.GONE);
            viewH.prg.setVisibility(View.GONE);

            imv.setImageBitmap(result);

        }
    }

}

公共类NewsPromoAdapter扩展了ArrayAdapter{
私人最终语境；
名单；
充气机；
位图src；
公共NewsPromoAdapter（上下文，列表npList）{
超级（上下文、右布局、新闻和宣传片、npList）；
this.context=上下文；
this.npList=npList；
充气器=（充气器）上下文
.getSystemService（上下文布局\充气机\服务）；
}
公共静态类视图持有者{
文本视图名称文本；
text查看日期1文本；
图像视图图像视图；
ProgressBar prg；
LoadImage-loadImg；
}
@凌驾
公共视图getView（int位置、视图转换视图、视图组父视图）{
视窗座；
if（convertView==null）{
convertView=充气机。充气（R.layout.news和promos，父级，
假）；
holder=新的ViewHolder（）；
holder.nameText=（TextView）convertView
.findviewbyd（R.id.newspromo_name）；
holder.date1Text=（TextView）convertView
.findviewbyd（R.id.newspromo_日期）；
holder.imageView=（imageView）convertView
.findviewbyd（R.id.newspromo_imageView）；
holder.prg=（ProgressBar）convertView
.findViewById（R.id.progressBar1）；
convertView.setTag（支架）；
}否则{
holder=（ViewHolder）convertView.getTag（）；
holder.loadImg.cancel（真）；
}
if（！（npList.get（position.getName（）.equals（“”））{
holder.nameText.setVisibility（View.VISIBLE）；
holder.nameText.setText（npList.get（position.getName（））；
}否则{
holder.nameText.setVisibility（View.GONE）；
}
如果（！（npList.get（position.getDate（）.equals（“”））{
holder.date1Text.setVisibility（View.VISIBLE）；
holder.date1Text.setText（npList.get（position.getDate（））；
}否则{
holder.date1Text.setVisibility（View.GONE）；
}
if（！（npList.get（position.getImageURL（）.equals（“”））{
holder.imageView.setVisibility（View.VISIBLE）；
holder.loadImg=新的LoadImage（holder.imageView，npList.get(
位置）；
holder.loadImg.execute（）；
}否则{
holder.imageView.setVisibility（View.GONE）；
保持架.prg.设置可见性（视图.消失）；
}
返回视图；
}
类LoadImage扩展了异步任务{
持票人viewH；
私有ImageView imv；
私有字符串url；
公共加载映像（ImageView imv、字符串imageURL、ViewHolder viewH）{
this.imv=imv；
this.url=imageURL；
this.viewH=viewH；
}
@凌驾
受保护位图doInBackground（对象…参数）{
BitmapFromURL bmpURL=新的BitmapFromURL（）；
src=bmpURL.getBitmapFromURL（url）；
返回src；
}
@凌驾
受保护的void onPostExecute（位图结果）{
//imv.setImageBitmap（结果）；
//viewH.prg.SETVISION（View.GONE）；
viewH.prg.SETVISION（View.GONE）；
imv.setImageBitmap（结果）；
}
}
}

下面是处理适配器的活动。我正在实现一些大型网站使用的无休止的listview方法。如Facebook、Twitter等。滚动到底部时，会将新项目加载到listview中。我不确定我是否做得很好

public class ListNewsPromoActivity extends Activity {

    List<NewsPromosDTO> npList;
    String url, user_email;
    Bundle extras;
    int user_points;
    List<Integer> npIDs;
    private ProgressDialog progressDialog;
    BitmapFromURL bmpURL;
    JSONArray users = null;

    String TAG_ID = "id";
    String TAG_NAME = "name";
    String TAG_PHOTO = "photo";
    String TAG_DATE = "date";
    String TAG_DESC = "description";
    ListView list;
    NewsPromoAdapter newsAdapter;

    boolean loadingMore = false;
    private Runnable returnRes;
    int itemsPerPage = 3;
    int currentIndex = 0;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        requestWindowFeature(Window.FEATURE_NO_TITLE);
        setContentView(R.layout.news_promo_listview);
        list = (ListView) findViewById(R.id.mainView);
        extras = getIntent().getExtras();
        if (extras != null) {

            user_points = extras.getInt("user_points");
            user_email = extras.getString("user_email");
        }
        url = getString(R.string.app_url_news_promos);
        npIDs = new ArrayList<Integer>();
        npList = new ArrayList<NewsPromosDTO>();


        View footerView = ((LayoutInflater) this
                .getSystemService(Context.LAYOUT_INFLATER_SERVICE)).inflate(
                R.layout.footer, null, false);

        newsAdapter = new NewsPromoAdapter(ListNewsPromoActivity.this, npList);

        list.addFooterView(footerView);
        list.setAdapter(newsAdapter);

        list.setOnScrollListener(new OnScrollListener() {
            // useless here, skip!
            @Override
            public void onScrollStateChanged(AbsListView view, int scrollState) {
            }

            @Override
            public void onScroll(AbsListView view, int firstVisibleItem,
                    int visibleItemCount, int totalItemCount) {
                // what is the bottom item that is visible
                int lastInScreen = firstVisibleItem + visibleItemCount;
                // is the bottom item visible & not loading more already ? Load
                if ((lastInScreen == totalItemCount) && !(loadingMore)) {
                    Thread thread = new Thread(null, getRunnable());
                    thread.start();

                }
            }
        });

        // Runnable to load the items
        // Since we cant update our UI from a thread this Runnable takes care of
        // that!
        returnRes = new Runnable() {
            @Override
            public void run() {

                // Loop thru the new items and add them to the adapter

                for (NewsPromosDTO np : npList) {
                    System.out.println(np.getName() + " andito ako!!");
                    newsAdapter.add(np);
                }

                newsAdapter.notifyDataSetChanged();


                              // Done loading more.
                loadingMore = false;
            }
        };

    }

    protected class loadNewsPromo extends AsyncTask<Void, Void, String> {

        @Override
        protected void onPreExecute() {

            super.onPreExecute();

        }

        protected String doInBackground(Void... params) {
            // Creating JSON Parser instance

            loadingMore = true;
            JSONParser jParser = new JSONParser();
            JSONObject json;

            if (jParser.checkServer(url)) {
                try {
                    // Getting Array of UserNews
                    json = jParser.getJSONFromUrl(url);
                    users = json.getJSONArray(user_email);
                    // looping through All UserNews

                    for (int i = currentIndex; i < itemsPerPage; i++) {
                        if (itemsPerPage == i) {
                            // currentIndex--;
                            break;
                        } else {
                            JSONObject c = users.getJSONObject(i);
                            // Storing each json item in variable
                            NewsPromosDTO npDTO = new NewsPromosDTO();

                            npDTO.setImageURL(c.getString(TAG_PHOTO));
                            npDTO.setId(c.getInt(TAG_ID));
                            npDTO.setName(c.getString(TAG_NAME));
                            npDTO.setDate(c.getString(TAG_DATE));
                            npDTO.setDescription(c.getString(TAG_DESC));
                            npList.add(npDTO);
                            currentIndex++;
                        }

                    }

                } catch (JSONException e) {
                    e.printStackTrace();
                    return null;
                } finally {

                }
            } 
            }

            return null;
        }

        @Override
        protected void onPostExecute(String result) { //
            // progressDialog.dismiss();
            loadingMore = false;
            list();
        }
    }

    public void list() {
        // add the footer before adding the adapter, else the footer will not
        // load!
        View footerView = ((LayoutInflater) this
                .getSystemService(Context.LAYOUT_INFLATER_SERVICE)).inflate(
                R.layout.footer, null, false);

        newsAdapter = new NewsPromoAdapter(ListNewsPromoActivity.this, npList);

        list.addFooterView(footerView);
        list.setAdapter(newsAdapter);
    }



    public Runnable getRunnable() {
        Runnable loadMoreListItems = new Runnable() {
            @Override
            public void run() {
                // Set flag so we cant load new items 2 at the same time
                loadingMore = true;
                // Reset the array that holds the new items

                // Simulate a delay, delete this on a production environment!
                try {
                    Thread.sleep(1000);
                } catch (InterruptedException e) {
                }
                // Get 15 new listitems
                JSONParser jParser = new JSONParser();
                JSONObject json;
                npList = new ArrayList<NewsPromosDTO>();
                if (jParser.checkServer(url)) {
                    try {
                        // Getting Array of Contacts
                        json = jParser.getJSONFromUrl(url);
                        users = json.getJSONArray(user_email);
                        // looping through All Contacts

                        // if (itemsPerPage > users.length() - currentIndex) {
                        // itemsPerPage = users.length();
                        // }
                        npList = new ArrayList<NewsPromosDTO>();
                        System.out.println(users.length() + " Laman ng users");
                        int counter = 0;
                        for (int i = currentIndex; i < users.length(); i++) {

                            if (itemsPerPage == counter) {

                                break;
                            } else {
                                JSONObject c = users.getJSONObject(i);
                                // Storing each json item in variable
                                NewsPromosDTO npDTO = new NewsPromosDTO();

                                npDTO.setImageURL(c.getString(TAG_PHOTO));
                                npDTO.setId(c.getInt(TAG_ID));
                                npDTO.setName(c.getString(TAG_NAME));
                                npDTO.setDate(c.getString(TAG_DATE));
                                npDTO.setDescription(c.getString(TAG_DESC));
                                npList.add(npDTO);
                                currentIndex++;
                            }
                            counter++;
                        }

                    } catch (JSONException e) {
                        e.printStackTrace();

                    } finally {

                    }
                }
                // Done! now continue on the UI thread
                runOnUiThread(returnRes);
            }
        };

        return loadMoreListItems;

    }

}

公共类ListNewsPromoActivity扩展活动{
名单；
字符串url，用户\电子邮件；
捆绑附加；
int用户点；
列出NPID；
私有进程对话；
BitmapFromURL bmpURL；
JSONArray用户=null；
字符串标记_ID=“ID”；
String TAG_NAME=“NAME”；
字符串TAG_PHOTO=“PHOTO”；
字符串TAG_DATE=“DATE”；
String TAG_DESC=“description”；
列表视图列表；
新闻适配器；
boolean loadingMore=false；
私人可运行的返回；
int itemsPerPage=3；
int currentIndex=0；
@凌驾
创建时的公共void（Bundle savedInstanceState）{
super.onCreate（savedInstanceState）；
requestWindowFeature（窗口。功能\u无\u标题）；
setContentView（R.layout.news\u promo\u listview）；
list=（ListView）findViewById（R.id.mainView）；
extras=getIntent（）.getExtras（）；
如果（附加值！=null）{
user_points=extras.getInt（“user_points”）；
user_email=extras.getString（“user_email”）；
}
url=getString（R.string.app\uURL\uNews\uPromos）；
npIDs=新的ArrayList（）；
npList=newarraylist（）；
视图页脚视图=（（LayoutFlater）此
.getSystemService（Context.LAYOUT\u filler\u SERVICE））.充气(
R.layout.footer，null，false）；
newsAdapter=NewsPromoAdapter（ListNewsPromoActivity.this，npList）；
list.addFooterView（footerView）；
list.setAdapter（newsAdapter）；
setOnScrollListener（新的OnScrollListener（）{
//这里没用，斯基普！
@凌驾
公共无效onScrollStateChanged（AbsListView视图，int scrollState）{
}
@凌驾
public void onScroll（AbsListView视图，int firstVisibleItem，
int visibleItemCount，int totalItemCount）{
//可见的底部项目是什么
int lastInScreen=firstVisibleItem+visibleItemCount；
//底部项目是否可见&尚未加载更多？加载
如果（（lastInScreen==总计