java - JSON解析Android

我需要关于我的代码的建议。
我试图解析php函数json_encode()生成的json数组。
我的JSON：
{"data": [{"streamer":"froggen","yt_length":"25078"},{"streamer":"wingsofdeath","yt_length":"8979"},{"streamer":"guardsmanbob","yt_length":"4790"},{"streamer":"kaostv","yt_length":"4626"},{"streamer":"kungentv","yt_length":"3883"},{"streamer":"destiny","yt_length":"3715"},{"streamer":"zekent","yt_length":"3428"},{"streamer":"athenelive","yt_length":"1673"},{"streamer":"frommaplestreet","yt_length":"1614"},{"streamer":"keyorikeys","yt_length":"1410"},{"streamer":"riotgamesturkish","yt_length":"1397"},{"streamer":"vman7","yt_length":"1022"},{"streamer":"tiensinoakuma","yt_length":"967"},{"streamer":"affenklappe","yt_length":"748"},{"streamer":"teamkeyd","yt_length":"747"},{"streamer":"lagtvmaximusblack","yt_length":"683"},{"streamer":"lolgameru","yt_length":"665"},{"streamer":"gruntartv","yt_length":"585"},{"streamer":"entenzwerg","yt_length":"579"},{"streamer":"lolgameru_cauthonpro","yt_length":"506"},{"streamer":"basickz","yt_length":"488"},{"streamer":"ilysuiteheart","yt_length":"491"},{"streamer":"kireiautumn","yt_length":"485"},{"streamer":"ultimavv","yt_length":"471"}]}
Java类：

public class JSONParser {
static InputStream is = null;
static JSONObject jObj = null;
static String json = "";
String response = "";

// constructor
public JSONParser() {
}

public JSONObject getJSONFromUrl(String url) {
    // Making HTTP request
    try {
        // defaultHttpClient
        DefaultHttpClient httpClient = new DefaultHttpClient();
        HttpGet httpPost = new HttpGet(url);

        HttpResponse httpResponse = httpClient.execute(httpPost);
        HttpEntity httpEntity = httpResponse.getEntity();
        is = httpEntity.getContent();
    } catch (UnsupportedEncodingException e) {
        e.printStackTrace();
    } catch (ClientProtocolException e) {
        e.printStackTrace();
    } catch (IOException e) {
        e.printStackTrace();
    }

    try {
        BufferedReader reader = new BufferedReader(new InputStreamReader(
                is), 8);
        StringBuilder sb = new StringBuilder();
        String line = null;
        while ((line = reader.readLine()) != null) {
            sb.append(line + "\n");
        }
        is.close();
        json = sb.toString();
    } catch (Exception e) {
        Log.e("Buffer Error", "Error converting result " + e.toString());
    }

    // try parse the string to a JSON object
    try {
        jObj = new JSONObject(json);
    } catch (JSONException e) {
        Log.e("JSON Parser", "Error parsing data " + e.toString());
    }

    // return JSON String
    return jObj;
}
}

以及我的活动：

public class AndroidJSONParsingActivity extends ListActivity {
// url to make request
private static String url = "http://ololo.tv/vasa";

// JSON Node names
private static final String TAG_DATA = "data";
private static final String TAG_STREAMER = "streamer";
private static final String TAG_VIEWERS = "yt_length";

// contacts JSONArray
JSONArray data = null;

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);

    // Hashmap for ListView
    ArrayList<HashMap<String, String>> dataList = new ArrayList<HashMap<String, String>>();

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

    // getting JSON string from URL
    JSONObject json = null;

        json = Parser.getJSONFromUrl(url);


    try {
        // Getting Array of Contacts
        data = json.getJSONArray(TAG_DATA);

        // looping through All Contacts
        for(int i = 0; i < data.length(); i++){
            JSONObject c = data.getJSONObject(i);

            // Storing each json item in variable
            String streamer = c.getString(TAG_STREAMER);
            String viewers = c.getString(TAG_VIEWERS);
            //String link = c.getString();

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

            // adding each child node to HashMap key => value
            map.put(TAG_STREAMER, streamer);
            map.put(TAG_VIEWERS, viewers);
            //map.put(TAG_URL, link);

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


    /**
     * Updating parsed JSON data into ListView
     * */
    ListAdapter adapter = new SimpleAdapter(this, dataList,
            R.layout.list_item,
            new String[] { TAG_STREAMER, TAG_VIEWERS /*TAG_URL*/ }, new int[] {
                    R.id.streamer, R.id.viewers /*R.id.url*/ });

    setListAdapter(adapter);

    // selecting single ListView item
    ListView lv = getListView();

    // Launching new screen on Selecting Single ListItem
    lv.setOnItemClickListener(new OnItemClickListener() {

        @Override
        public void onItemClick(AdapterView<?> parent, View view,
                int position, long id) {
            // getting values from selected ListItem
            String name = ((TextView) view.findViewById(R.id.streamer)).getText().toString();
            String viewers_count = ((TextView) view.findViewById(R.id.viewers)).getText().toString();
            //String url = ((TextView) view.findViewById(R.id.url)).getText().toString();

            // Starting new intent
            Intent in = new Intent(getApplicationContext(), SingleMenuItemActivity.class);
            in.putExtra(TAG_STREAMER, name);
            in.putExtra(TAG_VIEWERS, viewers_count);
            //in.putExtra(TAG_PHONE_MOBILE, url);
            startActivity(in);
        }
    });
}
}

我尝试使用断点，并看到当我在GetEntity之后放置断点时，程序不会到达那里，因为它很早就崩溃了，或者是其他什么原因。
这是我的异步任务。

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


JSONParser Parser = new JSONParser();

protected Void doInBackground(String... urls) {

    ArrayList<HashMap<String, String>> dataList = new ArrayList<HashMap<String, String>>();
    JSONObject json = Parser.getJSONFromUrl(url);

    try {
        // Getting Array of Contacts
        data = json.getJSONArray(TAG_DATA);

        // looping through All Contacts
        for(int i = 0; i < data.length(); i++){
            JSONObject c = data.getJSONObject(i);

            // Storing each json item in variable
            String streamer = c.getString(TAG_STREAMER);
            String viewers = c.getString(TAG_VIEWERS);
            //String link = c.getString();

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

            // adding each child node to HashMap key => value
            map.put(TAG_STREAMER, streamer);
            map.put(TAG_VIEWERS, viewers);
            //map.put(TAG_URL, link);

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

    /**
     * Updating parsed JSON data into ListView
     * */
    ListAdapter adapter = new SimpleAdapter(this, dataList,
            R.layout.list_item,
            new String[] { TAG_STREAMER, TAG_VIEWERS /*TAG_URL*/ }, new int[] {
            R.id.streamer, R.id.viewers /*R.id.url*/ });

    setListAdapter(adapter);

    return null;
}
protected void onProgressUpdate() {

}
protected void onPostExecute() {

}

}

listadapter错误，似乎是“this”中的错误。这个我的版本如何切断代码，在哪里停止返回变量。对不起，英语不好，但我希望你能理解我：）
添加我的php json maker。有MB问题吗？啊！

<?php
mysql_connect("localhost","root","");
 if (!mysql_select_db("ololo")) {
    echo "Unable to select ololo: " . mysql_error();
    }
$sql=mysql_query("select streamer, yt_length from pm_videos where category='1'");
if(!$sql) exit("Error - ".mysql_error().", ".$tmp_q);
while($row=mysql_fetch_assoc($sql)){
$output[]=$row;
}
$json = json_encode($output);
header('Content-Type: application/json');
print "{\"data\": ${json}}";
mysql_close();
?>

最佳答案

你的程序崩溃是因为你正在运行

json = Parser.getJSONFromUrl(url);

在ui线程上下文中。你必须使用AsyncTask
代码看起来不错。唯一的问题是

 public class  ParsingTask extends AsyncTask<String, Void, ArrayList<HashMap<String, String>>>{


 JSONParser Parser = new JSONParser();

 protected Void doInBackground(String... urls) {

ArrayList<HashMap<String, String>> dataList = new ArrayList<HashMap<String, String>>();
JSONObject json = Parser.getJSONFromUrl(url);

try {
    // Getting Array of Contacts
    data = json.getJSONArray(TAG_DATA);

    // looping through All Contacts
    for(int i = 0; i < data.length(); i++){
        JSONObject c = data.getJSONObject(i);

        // Storing each json item in variable
        String streamer = c.getString(TAG_STREAMER);
        String viewers = c.getString(TAG_VIEWERS);
        //String link = c.getString();

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

        // adding each child node to HashMap key => value
        map.put(TAG_STREAMER, streamer);
        map.put(TAG_VIEWERS, viewers);
        //map.put(TAG_URL, link);

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

/**
 * Updating parsed JSON data into ListView
 * */


return dataList;
  }

 protected void onPostExecute(ArrayList<HashMap<String, String>> dataList) {
  ListAdapter adapter = new SimpleAdapter(AndroidJSONParsingActivity.this, dataList,
        R.layout.list_item,
        new String[] { TAG_STREAMER, TAG_VIEWERS /*TAG_URL*/ }, new int[] {
        R.id.streamer, R.id.viewers /*R.id.url*/ });

setListAdapter(adapter);
    }

关于java - JSON解析Android，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/16882037/