Question

我从json获取缩略图。我已经解析了json并加载了缩略图，但是一旦我打开应用程序，我的应用程序就崩溃了。 LogCat在NullpointerException中显示AppController.getInstance().getImageLoader()。我参考了here。

代码：

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.layout_sales_return);
 private class MyAdapter extends BaseAdapter {
    private LayoutInflater inflater = null;
    private ViewHolder holder = null;
    private Model_BarcodeDetail data;
    ImageLoader imageLoader = AppController.getInstance().getImageLoader(); // getting NullPointerException here

    public MyAdapter() {
        inflater = LayoutInflater.from(Activity_Sales_Return.this);
    }

    @Override
    public int getCount() {
        // TODO Auto-generated method stub
        return list.size();
    }

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

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

    @Override
    public boolean isEnabled(int position) {
        // TODO Auto-generated method stub
        return true;
    }

    @Override
    public View getView(final int position, View convertView,
            final ViewGroup parent) {
        try {
            if (convertView == null) {
                holder = new ViewHolder();
                inflater = (LayoutInflater) getSystemService(Context.LAYOUT_INFLATER_SERVICE);
                convertView = inflater.inflate(
                        R.layout.table_row_sales_return, null);

                if (imageLoader == null)
                    imageLoader =    
                    AppController.getInstance().getImageLoader();
                 holder.thumbNail = (NetworkImageView) convertView
                        .findViewById(R.id.thumbnail);


                convertView.setTag(holder);
            } else {
                holder = (ViewHolder) convertView.getTag();
            }

            data = (Model_BarcodeDetail) getItem(position);
            scannedBarcode = list.get(position).getBarcode();

            }
            }
            }

解析json代码：

public Model_BarcodeDetail GetBarcodeDetail(String api_token, String barcode) {
    HttpClient httpClient = new DefaultHttpClient();
    HttpPost postRequest = new HttpPost(Utility.BASE_URL
            + "?q=webservice/pdt/barcode_detail&token=" + api_token
            + "&barcode=" + barcode + "&return=json");

    String result = "";
    Model_BarcodeDetail data = null;

    try {
        ResponseHandler<String> responseHandler = new BasicResponseHandler();
        result = httpClient.execute(postRequest, responseHandler);
        JSONObject jsonObj = new JSONObject(result);
        JSONObject obj1 = jsonObj.getJSONObject("t2tapi");
        boolean error = obj1.has("errors");
        if (!error) {
            data = new Model_BarcodeDetail();
            data.setDatetime(obj1.getString("datetime"));
            data.setSuccess(obj1.getString("success"));
            JSONObject obj2 = obj1.getJSONObject("data");
            data.setName(obj2.getString("name"));

            data.setThumbnailUrl(obj2.getString("image"));

        }
    } catch (Exception e) {
        e.printStackTrace();
    }
    return data;
}

Json Logcat警告：

04-01 11:20:26.834: W/System.err(3844): org.json.JSONException: No value for image
04-01 11:20:26.854: W/System.err(3844):     at org.json.JSONObject.get(JSONObject.java:355)
04-01 11:20:26.854: W/System.err(3844):     at org.json.JSONObject.getString(JSONObject.java:515)
04-01 11:20:26.854: W/System.err(3844):     at com.example.pdt.Activity_Sales_Return.GetBarcodeDetail(Activity_Sales_Return.java:3282)
04-01 11:20:26.864: W/System.err(3844):     at com.example.pdt.Activity_Sales_Return$BackgroundTask.doInBackground(Activity_Sales_Return.java:3186)
04-01 11:20:26.864: W/System.err(3844):     at com.example.pdt.Activity_Sales_Return$BackgroundTask.doInBackground(Activity_Sales_Return.java:1)
04-01 11:20:26.864: W/System.err(3844):     at android.os.AsyncTask$2.call(AsyncTask.java:288)
04-01 11:20:26.864: W/System.err(3844):     at java.util.concurrent.FutureTask.run(FutureTask.java:237)
04-01 11:20:26.864: W/System.err(3844):     at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:231)
04-01 11:20:26.864: W/System.err(3844):     at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1112)
04-01 11:20:26.864: W/System.err(3844):     at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:587)
04-01 11:20:26.864: W/System.err(3844):     at java.lang.Thread.run(Thread.java:841)

原json：

  <?xml version="1.0" encoding="UTF-8"?>
  <skudetail>
      <datetime>Wed, 30 Mar 2016 07:13:26 +0000</datetime>
   <success>1</success>
  <data>
    <name>AM X COL38/44</name>
    <reference>000086</reference>
    <description>EB 3 X COL  DURA 38/44</description>
    <barcode>000086004004</barcode>
    <price>24.00</price>
    <color>NAVY S</color>
    <size>40</size>
    <stock>11</stock>
    <branch>MDT</branch>
    <supplier>KAY</supplier>
    <supplier_name>DURABLEPRESS BY KAYMANS</supplier_name>
    <location></location>
    <basesell></basesell>
    <vat>A</vat>
    <avg_cost>5.600</avg_cost>
    <last_cost>0.000</last_cost>
    <next_cost>5.600</next_cost>
    <group_code>MEN</group_code>
    <alias_code></alias_code>
    <type>TRF</type>
    <remarks1>x</remarks1>
    <remarks2></remarks2>
    <listed_days></listed_days>
    <title></title>
    <type_name>FLAT FRONT TROUSERS</type_name>
    <user1_name></user1_name>
    <user2_name></user2_name>
    <meta_keywords></meta_keywords>
    <meta_description></meta_description>
    <image>http://staging.gait-
 way.com/files/product/32106/1459320344_410cCvu-IsL._UX466_.jpg</image>
</data>

 </skudetail>

Answer 1

我认为你错了，因为你有 XML数据但不是JSON数据，你可以用

验证

http://www.w3schools.com/xml/xml_validator.asp

您可以使用XMLDomParser获取Image标记中的值并根据需要使用它，您可以参考下面的链接获取XML解析的参考

http://www.tutorialspoint.com/java_xml/java_dom_parse_document.htm

并且也可以参考这可能有帮助

http://www.tutorialspoint.com/json/json_comparison.htm

并且您可能还想使用Picasso（更轻）或Glide（更多功能），因为它可以减轻您对图像加载到视图中的担忧

希望这有帮助

从json Android获取缩略图

1 个答案: