android - 如何使用未命名数组从URL解析JSON

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Get JSONArray without array name?
                                
                                    （4个答案）
                                
                        
                                5年前关闭。
            
                    
很抱歉我的新手问题，但是请告诉我我做错了什么。我正在尝试从包含以下字符串的URL解析JSON：


  [{“ Date”：“ 25”，“ Time”：“ 10:00”，“ Place”：“”，“ Text”：“ \ u0414 \ u041e \ u0411 \ u0420 \ u041e
  \ u041f \ u041e \ u0416 \ u0410 \ u041b \ u041e \ u0412 \ u0410 \ u0422 \ u042c \ u0412
  \ u00ab \ u041f \ u0410 \ u0420 \ u041a
  \ u0414 \ u0417 \ u042e \ u0414 \ u041e \ u00bb！“}，{” Date“：” 25“，” Time“：” 10:00“，” Place“：” \ u041a \ u0440 \ u044b \ u0448 \ u0430
  \ u041b \ u0410
  \ u00ab \ u0422 \ u0420 \ u0410 \ u041a \ u0422 \ u041e \ u0420 \ u00bb“，”文字“：”露天：
  \ u0432 \ u0430 \ u0441
  \ u043f \ u0440 \ u0438 \ u0432 \ u0435 \ u0442 \ u0441 \ u0442 \ u0432 \ u0443 \ u0435 \ u0442
  \ u043e \ u0444 \ u0438 \ u0446 \ u0438 \ u0430 \ u043b \ u044c \ u043d \ u044b \ u0439
  \ u0434 \ u0438- \ u0434 \ u0436 \ u0435 \ u0439 \ u041f \ u0430 \ u0440 \ u043a \ u0430
  \ u0414 \ u0417 \ u042e \ u0414 \ u041e DJ \ u0420 \ u043e \ u043c \ u0430 \ u043d
  \ u041a \ u0438 \ u0442 \ u0430 \ u0435 \ u0446“}]


如您所见，这是一个没有名称且内部带有对象的JSON数组。那么如何解析它以显示在ListView中呢？我做的事 ：

public class NewsActivity extends ListActivity {

private ProgressDialog pDialog;

// URL to get contacts JSON
private static String url = "http://mysitehere.com/news.php";

// JSON Node names

private static final String TAG_DATE = "Date";
private static final String TAG_TIME = "Time";
private static final String TAG_PLACE = "Place";
private static final String TAG_TEXT = "Text";;


// Hashmap for ListView
ArrayList<HashMap<String, String>> AfishaList;

protected  void onCreate(Bundle savedInstanceState){
    super.onCreate(savedInstanceState);
    setContentView(R.layout.news_activity);

    new GetInfo().execute();
}

private class GetInfo extends AsyncTask<Void, Void, Void> {

    @Override
    protected void onPreExecute() {
        super.onPreExecute();
        Log.d("LOG_TAG","PROGRESS STARTS");
        // Showing progress dialog
        pDialog = new ProgressDialog(NewsActivity.this);
        pDialog.setMessage("Please wait...");
        pDialog.setCancelable(false);
        pDialog.show();

    }

    @Override
    protected Void doInBackground(Void... arg0) {
        // Creating service handler class instance
        ServiceHandler sh = new ServiceHandler();

        // Making a request to url and getting response
        String jsonStr = sh.makeServiceCall(url, ServiceHandler.GET);

        Log.d("Response: ", "> " + jsonStr);

        if (jsonStr != null) {
            try {
                //JSONObject jsonObj = new JSONObject(jsonStr);

                // Getting JSON Array node
                JSONArray mJSONArray = new JSONArray(jsonStr);

                // looping through All Contacts
                for (int i = 0; i < mJSONArray.length(); i++) {

                    // tmp hashmap for single contact
                    HashMap<String, String> contact = new HashMap<String, String>();
                    JSONObject e = mJSONArray.getJSONObject(i);

                    // adding each child node to HashMap key => value
                    contact.put(TAG_DATE, e.getString("Date"));
                    contact.put(TAG_TIME, e.getString("Time"));
                    contact.put(TAG_PLACE, e.getString("Place"));
                    contact.put(TAG_TEXT, e.getString("Text"));

                    // adding contact to contact list
                    AfishaList.add(contact);
                    Log.d("LOG_TAG","SOMETHING IS GOING ON");
                }
            } catch (JSONException e) {
                e.printStackTrace();
            }
        } else {
            Log.e("ServiceHandler", "Couldn't get any data from the url");
        }

        return null;
    }

    @Override
    protected void onPostExecute(Void result) {
        super.onPostExecute(result);
        // Dismiss the progress dialog
        if (pDialog.isShowing())
            pDialog.dismiss();
        /**
         * Updating parsed JSON data into ListView
         * */
        ListAdapter adapter = new SimpleAdapter(
                NewsActivity.this, AfishaList,
                R.layout.list_item, new String[] { TAG_DATE, TAG_TIME,
                TAG_PLACE, TAG_TEXT }, new int[] { R.id.date,
                R.id.time, R.id.place, R.id.text });

       setListAdapter(adapter);
        Log.w("FINAL","!!!");
    }

}

}

编辑：

我已经更改了doInBackground中的方法，现在logcat向我显示了以下日志：

 07-31 10:05:35.682    3920-3934/com.project1.2014 E/AndroidRuntime﹕ FATAL EXCEPTION: AsyncTask #1
java.lang.RuntimeException: An error occured while executing doInBackground()
        at android.os.AsyncTask$3.done(AsyncTask.java:299)
        at java.util.concurrent.FutureTask$Sync.innerSetException(FutureTask.java:273)
        at java.util.concurrent.FutureTask.setException(FutureTask.java:124)
        at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:307)
        at java.util.concurrent.FutureTask.run(FutureTask.java:137)
        at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:230)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1076)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:569)
        at java.lang.Thread.run(Thread.java:856)
    Caused by: java.lang.NullPointerException
        at com.project1.2014.NewsActivity$GetInfo.doInBackground(NewsActivity.java:110)
        at com.project1.2014.NewsActivity$GetInfo.doInBackground(NewsActivity.java:65)
        at android.os.AsyncTask$2.call(AsyncTask.java:287)
        at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:305)

最佳答案

在您的响应中，第一个元素是JSON Array而不是JSON Object。这就是为什么您得到JSON Exception的原因。从您的代码中删除此行

JSONObject jsonObj = new JSONObject(jsonStr);

之后，如果您遇到任何异常或崩溃，请执行logcat。

编辑：1

@Override
protected void onPostExecute(Void result) {
        super.onPostExecute(result);
        // Dismiss the progress dialog
        if (pDialog.isShowing()) {
            pDialog.dismiss();
        /**
         * Updating parsed JSON data into ListView
         * */
        ListAdapter adapter = new SimpleAdapter(
                NewsActivity.this, AfishaList,
                R.layout.list_item, new String[] { TAG_DATE, TAG_TIME,
                TAG_PLACE, TAG_TEXT }, new int[] { R.id.date,
                R.id.time, R.id.place, R.id.text });

       setListAdapter(adapter);
    }
  }

尝试将此代码用于onPostExecute(...)，如果显示其他Dialog，则将其关闭。这将导致Windowleak。清理您的项目，然后运行它。


Android Error: Window Leaked in AsyncTask


编辑：2
NewsActivity的第110行是AfishaList.add(contact);，因此在访问之前创建AfishaList的Object。