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从互联网文本数据加载并链接到图像。我不明白如何在列表视图中加载图像。看了，需要用到毕加索或者万能图片加载器，但是不明白怎么用。请更正我的代码

    public class JsonReadTask extends AsyncTask<String, Void, String> {

      @Override
      protected String doInBackground(String... params) {
       HttpClient httpclient = new DefaultHttpClient();
       HttpPost httppost = new HttpPost(params[0]);
       try {
        HttpResponse response = httpclient.execute(httppost);
        jsonResult = inputStreamToString(
          response.getEntity().getContent()).toString();
       }

       catch (ClientProtocolException e) {
        e.printStackTrace();
       } catch (IOException e) {
        e.printStackTrace();
       }
       return null;
      }

      private StringBuilder inputStreamToString(InputStream is) {
       String rLine = "";
       StringBuilder answer = new StringBuilder();
       BufferedReader rd = new BufferedReader(new InputStreamReader(is));

       try {
        while ((rLine = rd.readLine()) != null) {
         answer.append(rLine);
        }
       }

       catch (IOException e) {
        // e.printStackTrace();
        Toast.makeText(getActivity(),
          "Error..." + e.toString(), Toast.LENGTH_LONG).show();
       }
       return answer;
      }

      @Override
      protected void onPostExecute(String result) {
       ListDrwaer();
      }
     }// end async task

     public void accessWebService() {
      JsonReadTask task = new JsonReadTask();
      // passes values for the urls string array
      task.execute(new String[] { url });
     }
     private final String ATTRIBUTE1 = "header"; 
     private final String ATTRIBUTE2 = "short_text";
     private final String ATTRIBUTE3 = "team";
     private final String ATTRIBUTE4 = "datatime";
     private final String ATTRIBUTE5 = "photo_url";
     Drawable drawable;
     // build hash set for list view
     public void ListDrwaer() {          
        // упаковываем данные в понятную для адаптера структуру
            ArrayList<Map<String, Object>> data = new ArrayList<Map<String, Object>>();
                    Map<String, Object> m;

            // массив имен атрибутов, из которых будут читаться данные
            String[] from = {ATTRIBUTE1, ATTRIBUTE2, ATTRIBUTE3, ATTRIBUTE4, ATTRIBUTE5};

            // массив ID View-компонентов, в которые будут вставлять данные
            int[] to = { R.id.header, R.id.short_text,  R.id.team, R.id.datatime, R.id.img_news};

      try {
       JSONObject jsonResponse = new JSONObject(jsonResult);
       JSONArray jsonMainNode = jsonResponse.optJSONArray("news");
       for (int i = 0; i < jsonMainNode.length(); i++) {
        JSONObject jsonChildNode = jsonMainNode.getJSONObject(i);
        String header = jsonChildNode.optString("header");
        String short_text = jsonChildNode.optString("short_text");
        String team = jsonChildNode.optString("team");
        String datatime = jsonChildNode.optString("datatime");
        String photo_url = jsonChildNode.optString("photo_url");    


        // создаем новый Map
        m = new HashMap<String, Object>();
        m.put(ATTRIBUTE1, header);
        m.put(ATTRIBUTE2, short_text);
        m.put(ATTRIBUTE3, team);
        m.put(ATTRIBUTE4, datatime);
     //   m.put(ATTRIBUTE5, url_photo);
        // добавляем его в коллекцию
        data.add(m);
       }
      } catch (JSONException e) {
       Toast.makeText(getActivity(), "Error" + e.toString(),
         Toast.LENGTH_SHORT).show();
      }

      SimpleAdapter simpleAdapter = new SimpleAdapter(getActivity(), data,
        R.layout.news_details,
        from, to);        
      Parcelable state = listView.onSaveInstanceState();
      listView.setAdapter(simpleAdapter);
      listView.onRestoreInstanceState(state);
     }

}

4

2 回答 2

5

创建您自己的从 ArrayAdapter 扩展的适配器。有很多例子：

然后在你的 getView 方法调用中（类似的东西取决于你的实现）：

Picasso.with(context).load(getItem(position).get(ATTRIBUTE5)).into(holder.imageView);

有关详细信息，请参阅毕加索文档。

于 2014-01-02T23:25:55.780 回答
0

使用 Picasso，您可以为 ListView 创建一个自定义适配器，并将 .load(url) 调用放在 getView() 中的 ImageView 上。可能您提到的其他库的解决方案是相同的。

但是，在您的情况下，您需要提前在 AsycTask 中获取图像的 url。在这种情况下，您还需要一些逻辑来在创建适配器之前获取 url，或者在适配器中需要一些奇特的逻辑来加载 url，然后重新加载视图。

于 2014-01-02T23:22:04.523 回答