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我在列表视图中添加从 web 服务（json 响应）获得的图像和数据。有时图像存在于数组中，有时没有图像，如果图像存在于数组中，那么我得到正确的输出，图像和数据都将显示在列表视图中，但如果数组中没有图像，那么即使数据存在但它不会显示列表视图中的任何内容。在这里挣扎 if 语句下面是我的代码任何答案将不胜感激任何人都可以帮助？

    ArrayList<HashMap<String, String>> songsList = new ArrayList<HashMap<String, String>>();


    // Creating JSON Parser instance
            JSONParser jParser = new JSONParser();

            // getting JSON string from URL
            JSONObject json = jParser.getJSONFromUrl(URL);
            try {
                JSONArray posts = json.getJSONArray(KEY_POSTS);

    // looping through all song nodes <song>
            for(int i = 0; i < posts.length(); i++){
                JSONObject c = posts.getJSONObject(i);
                // Storing each json item in variable
                String id = c.getString(KEY_ID);
                String title = c.getString(KEY_TITLE);
                String date = c.getString(KEY_DATE);
                String content = c.getString(KEY_CONTENT);
                // to remove all <P> </p> and <br /> and replace with ""
                 content = content.replace("<br />", "");
                 content = content.replace("<p>", "");
                 content = content.replace("</p>", "");

                //authornumber is agin  JSON Object
                JSONObject author = c.getJSONObject(KEY_AUTHOR);
                String name = author.getString(KEY_NAME);


                JSONArray atta = c.getJSONArray("attachments");
                for(int j = 0; j < atta.length(); j++){
                    JSONObject d = atta.getJSONObject(j);

                    String slug = d.getString(KEY_SLUG);

                    JSONObject images = d.getJSONObject(KEY_IMAGES);

                    JSONObject thumbnail = images.getJSONObject(KEY_THUMB_URL);
                    String url = thumbnail.getString(KEY_URL);



        // creating new HashMap
        HashMap<String, String> map = new HashMap<String, String>();

        // adding each child node to HashMap key => value
        map.put(KEY_ID, id);
        map.put(KEY_TITLE, title);
        map.put(KEY_DATE, date);
        map.put(KEY_NAME, name);
        map.put(KEY_CONTENT, content);
        map.put(KEY_SLUG, slug);
        map.put(KEY_URL, url);


        // adding HashList to ArrayList
        songsList.add(map);
            }   }
            } catch (JSONException e) {
                e.printStackTrace();

                }


    list=(ListView)findViewById(android.R.id.list);
    list.setOnScrollListener(this);
    // Getting adapter by passing json data ArrayList
    adapter=new LazyAdapter(this, songsList);        
    list.setAdapter(adapter);
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2 回答 2

1

在您的 listAdapter 的 getView() 方法中检查 url 值。如果它为空或为空，则显示一些存根图像（一些图像，如无可用图像-> 将其保存在 res 中）。

于 2013-01-09T06:50:52.777 回答
1

这是因为你在一个try-catch块内做所有事情。当没有图像时，它会抛出一个错误，跳出你的循环。您应该try-catch单独添加一个块来读取图像：

    ArrayList<HashMap<String, String>> songsList = new ArrayList<HashMap<String, String>>();


    // Creating JSON Parser instance
            JSONParser jParser = new JSONParser();

            // getting JSON string from URL
            JSONObject json = jParser.getJSONFromUrl(URL);
            try {
                JSONArray posts = json.getJSONArray(KEY_POSTS);

    // looping through all song nodes <song>
            for(int i = 0; i < posts.length(); i++){
                JSONObject c = posts.getJSONObject(i);
                // Storing each json item in variable
                String id = c.getString(KEY_ID);
                String title = c.getString(KEY_TITLE);
                String date = c.getString(KEY_DATE);
                String content = c.getString(KEY_CONTENT);
                // to remove all <P> </p> and <br /> and replace with ""
                 content = content.replace("<br />", "");
                 content = content.replace("<p>", "");
                 content = content.replace("</p>", "");

                //authornumber is agin  JSON Object
                JSONObject author = c.getJSONObject(KEY_AUTHOR);
                String name = author.getString(KEY_NAME);

                String url = null;
                String slug = null;
                try {
                JSONArray atta = c.getJSONArray("attachments");
                for(int j = 0; j < atta.length(); j++){
                    JSONObject d = atta.getJSONObject(j);

                    slug = d.getString(KEY_SLUG);

                    JSONObject images = d.getJSONObject(KEY_IMAGES);

                    JSONObject thumbnail = images.getJSONObject(KEY_THUMB_URL);
                    url = thumbnail.getString(KEY_URL);
                } catch (Exception e) {}




        // creating new HashMap
        HashMap<String, String> map = new HashMap<String, String>();

        // adding each child node to HashMap key => value
        map.put(KEY_ID, id);
        map.put(KEY_TITLE, title);
        map.put(KEY_DATE, date);
        map.put(KEY_NAME, name);
        map.put(KEY_CONTENT, content);
        map.put(KEY_SLUG, slug);
        map.put(KEY_URL, url);


        // adding HashList to ArrayList
        songsList.add(map);
            }   }
            } catch (JSONException e) {
                e.printStackTrace();

                }


    list=(ListView)findViewById(android.R.id.list);
    list.setOnScrollListener(this);
    // Getting adapter by passing json data ArrayList
    adapter=new LazyAdapter(this, songsList);        
    list.setAdapter(adapter);
于 2013-01-09T06:54:50.783 回答