Android 使用AsynTask从JSON显示Listview

我在使用

asyntask

从

JSON

显示

listview

时遇到了一些问题。我想在单击特定的

单选按钮下显示数据，但DDMS结果显示
“原因：java.lang.NullPointerException”

listreult.java

public class ListResult extends ListActivity implements OnClickListener {
private ProgressDialog pDialog;
String paramString;
JSONParser jsonParser = new JSONParser();
ArrayList<HashMap<String, String>> busList; 
RadioButton rbSUN;
RadioButton rbFRI;
RadioButton rbSAT;
ListView lv;
private int success;
private static String url_insert_new = "http://10.0.2.2/onlineLibrary/getallbus.php";
private static final String TAG_SUCCESS = "success";
private static final String TAG_IDIOMS = "idioms";
private static final String TAG_ID = "id";
private static final String TAG_TIME = "time";
private static final String TAG_STATUS = "status";  
JSONArray idioms = null;
@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_list_result);
    busList = new ArrayList<HashMap<String, String>>();  
    lv = getListView();
    rbSUN = (RadioButton) findViewById(R.id.radioSUN);
    rbFRI = (RadioButton) findViewById(R.id.radioFRI);
    rbSAT = (RadioButton) findViewById(R.id.radioSAT);
    rbSUN.setOnClickListener(this);
    rbFRI.setOnClickListener(this);
    rbSAT.setOnClickListener(this);   
    new InsertNewIdiom().execute();
}
@Override
public void onClick(View v) {
    if (v.getId()==R.id.radioSUN){
        new InsertNewIdiom().execute();
        if (success==1){
            Toast.makeText(getApplicationContext(), "New item saved...", Toast.LENGTH_LONG).show();
        }else{
            Toast.makeText(getApplicationContext(), "New item FAILED to saved...", Toast.LENGTH_LONG).show();
        }
        paramString="SUN";
    }    
    if (v.getId()==R.id.radioFRI){
        new InsertNewIdiom().execute();
        if (success==1){
            Toast.makeText(getApplicationContext(), "New item saved...", Toast.LENGTH_LONG).show();
        }else{
            Toast.makeText(getApplicationContext(), "New item FAILED to saved...", Toast.LENGTH_LONG).show();
        }
        paramString="FRI";
    }
    if (v.getId()==R.id.radioSAT){
        new InsertNewIdiom().execute();
        if (success==1){
            Toast.makeText(getApplicationContext(), "New item saved...", Toast.LENGTH_LONG).show();
        }else{
            Toast.makeText(getApplicationContext(), "New item FAILED to saved...", Toast.LENGTH_LONG).show();
        }
        paramString="SAT";
    } 
}
class InsertNewIdiom extends AsyncTask<String, String, String> {
    @Override
    protected void onPreExecute() {
        super.onPreExecute();
        pDialog = new ProgressDialog(ListResult.this);
        pDialog.setMessage("Loading ...");
        pDialog.setIndeterminate(false);
        pDialog.setCancelable(true);
        pDialog.show();
    }
    protected String doInBackground(String... args) {
        List<NameValuePair> params = new ArrayList<NameValuePair>();
        params.add(new BasicNameValuePair("time", TAG_TIME));
        params.add(new BasicNameValuePair("status", TAG_STATUS));
        JSONObject json = jsonParser.makeHttpRequest(url_insert_new,
                "GET", params);
        Log.d("Insert New item Response", json.toString());
        try {
            success = json.getInt(TAG_SUCCESS);

            if (success == 1) {
                  idioms = json.getJSONArray(TAG_IDIOMS);
                  for (int i = 0; i < idioms.length(); i++) {
                      JSONObject c = idioms.getJSONObject(i);
                      String id = c.getString(TAG_ID);
                      String time = c.getString(TAG_TIME);
                      String status = c.getString(TAG_STATUS);
                      HashMap<String, String> map = new HashMap<String, String>();
                      map.put(TAG_ID, id);
                      map.put(TAG_TIME, time);
                      map.put(TAG_STATUS, status);
                      busList.add(map);
                  }               
            } else {
            }
        } catch (JSONException e) {
            e.printStackTrace();
        }
        return null;
    }
    protected void onPostExecute(String file_url) {
        pDialog.dismiss();
       // pDialog.dismiss();
        runOnUiThread(new Runnable() {
            public void run() {
                ListAdapter adapter = new SimpleAdapter(
                        ListResult.this, busList,
                        R.layout.list_view, new String[] 
{ TAG_ID,   TAG_TIME, TAG_STATUS},
                        new int[] { R.id.id, R.id.time, R.id.status});
               setListAdapter(adapter);
            }
        });
    }
}
}

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

}
public JSONObject makeHttpRequest(String url, String method,
        List<NameValuePair> params) {
    try {
        if(method == "POST"){
            DefaultHttpClient httpClient = new DefaultHttpClient();
            HttpPost httpPost = new HttpPost(url);
            httpPost.setEntity(new UrlEncodedFormEntity(params));

            HttpResponse httpResponse = httpClient.execute(httpPost);
            HttpEntity httpEntity = httpResponse.getEntity();
            is = httpEntity.getContent();

        }else if(method == "GET"){
            DefaultHttpClient httpClient = new DefaultHttpClient();
            String paramString = URLEncodedUtils.format(params, "utf-8");
            url += "?" + paramString;
            HttpGet httpGet = new HttpGet(url);

            HttpResponse httpResponse = httpClient.execute(httpGet);
            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, "iso-8859-1"), 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 {
        jObj = new JSONObject(json);
    } catch (JSONException e) {
        Log.e("JSON Parser", "Error parsing data " + e.toString());
    }
    return jObj;

 }

 }

公共类ListResult扩展ListActivity实现OnClickListener{
私人对话；
字符串参数字符串；
JSONParser JSONParser=新的JSONParser（）；
ArrayList总线列表；
无线按钮rbSUN；
无线电按钮；
无线按钮卫星；
ListView lv；
个人成功；
私有静态字符串url_insert_new=”http://10.0.2.2/onlineLibrary/getallbus.php";
私有静态最终字符串标记_SUCCESS=“SUCCESS”；
私有静态最终字符串TAG_IDIOMS=“IDIOMS”；
私有静态最终字符串标记\u ID=“ID”；
私有静态最终字符串标记\u TIME=“TIME”；
私有静态最终字符串标记_STATUS=“STATUS”；
JSONArray习语=null；
@凌驾
创建时的公共void（Bundle savedInstanceState）{
super.onCreate（savedInstanceState）；
setContentView（R.layout.activity\u list\u result）；
busList=newarraylist（）；
lv=getListView（）；
rbSUN=（RadioButton）findViewById（R.id.radioSUN）；
rbFRI=（RadioButton）findViewById（R.id.radioFRI）；
rbSAT=（RadioButton）findViewById（R.id.radioSAT）；
rbSUN.setOnClickListener（this）；
rbFRI.setOnClickListener（此）；
rbSAT.setOnClickListener（这个）；
新InsertNewIdiom（）.execute（）；
}
@凌驾
公共void onClick（视图v）{
if（v.getId（）==R.id.radioSUN）{
新InsertNewIdiom（）.execute（）；
如果（成功==1）{
Toast.makeText（getApplicationContext（），“新项目已保存…”，Toast.LENGTH\u LONG.show（）；
}否则{
Toast.makeText（getApplicationContext（），“新项目未能保存…”，Toast.LENGTH\u LONG.show（）；
}
paramString=“SUN”；
}    
如果（v.getId（）==R.id.radioFRI）{
新InsertNewIdiom（）.execute（）；
如果（成功==1）{
Toast.makeText（getApplicationContext（），“新项目已保存…”，Toast.LENGTH\u LONG.show（）；
}否则{
Toast.makeText（getApplicationContext（），“新项目未能保存…”，Toast.LENGTH\u LONG.show（）；
}
paramString=“FRI”；
}
if（v.getId（）==R.id.radioSAT）{
新InsertNewIdiom（）.execute（）；
如果（成功==1）{
Toast.makeText（getApplicationContext（），“新项目已保存…”，Toast.LENGTH\u LONG.show（）；
}否则{
Toast.makeText（getApplicationContext（），“新项目未能保存…”，Toast.LENGTH\u LONG.show（）；
}
paramString=“SAT”；
} 
}
类InsertNewSigmon扩展了AsyncTask{
@凌驾
受保护的void onPreExecute（）{
super.onPreExecute（）；
pDialog=新建进度对话框（ListResult.this）；
设置消息（“加载…”）；
pDialog.setUndeterminate（假）；
pDialog.setCancelable（真）；
pDialog.show（）；
}
受保护的字符串doInBackground（字符串…args）{
List params=new ArrayList（）；
参数添加（新的BasicNameValuePair（“时间”，标记时间））；
参数添加（新的BasicNameValuePair（“状态”，标记状态））；
JSONObject json=jsonParser.makeHttpRequest（url\u insert\u new，
“得到”，params）；
Log.d（“插入新项响应”，json.toString（））；
试一试{
success=json.getInt（TAG_success）；
如果（成功==1）{
idioms=json.getJSONArray（TAG_-idioms）；
for（inti=0；i

JsonParser.java

public class ListResult extends ListActivity implements OnClickListener {
private ProgressDialog pDialog;
String paramString;
JSONParser jsonParser = new JSONParser();
ArrayList<HashMap<String, String>> busList; 
RadioButton rbSUN;
RadioButton rbFRI;
RadioButton rbSAT;
ListView lv;
private int success;
private static String url_insert_new = "http://10.0.2.2/onlineLibrary/getallbus.php";
private static final String TAG_SUCCESS = "success";
private static final String TAG_IDIOMS = "idioms";
private static final String TAG_ID = "id";
private static final String TAG_TIME = "time";
private static final String TAG_STATUS = "status";  
JSONArray idioms = null;
@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_list_result);
    busList = new ArrayList<HashMap<String, String>>();  
    lv = getListView();
    rbSUN = (RadioButton) findViewById(R.id.radioSUN);
    rbFRI = (RadioButton) findViewById(R.id.radioFRI);
    rbSAT = (RadioButton) findViewById(R.id.radioSAT);
    rbSUN.setOnClickListener(this);
    rbFRI.setOnClickListener(this);
    rbSAT.setOnClickListener(this);   
    new InsertNewIdiom().execute();
}
@Override
public void onClick(View v) {
    if (v.getId()==R.id.radioSUN){
        new InsertNewIdiom().execute();
        if (success==1){
            Toast.makeText(getApplicationContext(), "New item saved...", Toast.LENGTH_LONG).show();
        }else{
            Toast.makeText(getApplicationContext(), "New item FAILED to saved...", Toast.LENGTH_LONG).show();
        }
        paramString="SUN";
    }    
    if (v.getId()==R.id.radioFRI){
        new InsertNewIdiom().execute();
        if (success==1){
            Toast.makeText(getApplicationContext(), "New item saved...", Toast.LENGTH_LONG).show();
        }else{
            Toast.makeText(getApplicationContext(), "New item FAILED to saved...", Toast.LENGTH_LONG).show();
        }
        paramString="FRI";
    }
    if (v.getId()==R.id.radioSAT){
        new InsertNewIdiom().execute();
        if (success==1){
            Toast.makeText(getApplicationContext(), "New item saved...", Toast.LENGTH_LONG).show();
        }else{
            Toast.makeText(getApplicationContext(), "New item FAILED to saved...", Toast.LENGTH_LONG).show();
        }
        paramString="SAT";
    } 
}
class InsertNewIdiom extends AsyncTask<String, String, String> {
    @Override
    protected void onPreExecute() {
        super.onPreExecute();
        pDialog = new ProgressDialog(ListResult.this);
        pDialog.setMessage("Loading ...");
        pDialog.setIndeterminate(false);
        pDialog.setCancelable(true);
        pDialog.show();
    }
    protected String doInBackground(String... args) {
        List<NameValuePair> params = new ArrayList<NameValuePair>();
        params.add(new BasicNameValuePair("time", TAG_TIME));
        params.add(new BasicNameValuePair("status", TAG_STATUS));
        JSONObject json = jsonParser.makeHttpRequest(url_insert_new,
                "GET", params);
        Log.d("Insert New item Response", json.toString());
        try {
            success = json.getInt(TAG_SUCCESS);

            if (success == 1) {
                  idioms = json.getJSONArray(TAG_IDIOMS);
                  for (int i = 0; i < idioms.length(); i++) {
                      JSONObject c = idioms.getJSONObject(i);
                      String id = c.getString(TAG_ID);
                      String time = c.getString(TAG_TIME);
                      String status = c.getString(TAG_STATUS);
                      HashMap<String, String> map = new HashMap<String, String>();
                      map.put(TAG_ID, id);
                      map.put(TAG_TIME, time);
                      map.put(TAG_STATUS, status);
                      busList.add(map);
                  }               
            } else {
            }
        } catch (JSONException e) {
            e.printStackTrace();
        }
        return null;
    }
    protected void onPostExecute(String file_url) {
        pDialog.dismiss();
       // pDialog.dismiss();
        runOnUiThread(new Runnable() {
            public void run() {
                ListAdapter adapter = new SimpleAdapter(
                        ListResult.this, busList,
                        R.layout.list_view, new String[] 
{ TAG_ID,   TAG_TIME, TAG_STATUS},
                        new int[] { R.id.id, R.id.time, R.id.status});
               setListAdapter(adapter);
            }
        });
    }
}
}

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

}
public JSONObject makeHttpRequest(String url, String method,
        List<NameValuePair> params) {
    try {
        if(method == "POST"){
            DefaultHttpClient httpClient = new DefaultHttpClient();
            HttpPost httpPost = new HttpPost(url);
            httpPost.setEntity(new UrlEncodedFormEntity(params));

            HttpResponse httpResponse = httpClient.execute(httpPost);
            HttpEntity httpEntity = httpResponse.getEntity();
            is = httpEntity.getContent();

        }else if(method == "GET"){
            DefaultHttpClient httpClient = new DefaultHttpClient();
            String paramString = URLEncodedUtils.format(params, "utf-8");
            url += "?" + paramString;
            HttpGet httpGet = new HttpGet(url);

            HttpResponse httpResponse = httpClient.execute(httpGet);
            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, "iso-8859-1"), 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 {
        jObj = new JSONObject(json);
    } catch (JSONException e) {
        Log.e("JSON Parser", "Error parsing data " + e.toString());
    }
    return jObj;

 }

 }

公共类JSONParser{
静态InputStream为空；
静态JSONObject jObj=null；
静态字符串json=“”；
公共JSONParser（）{
}
公共JSONObject makeHttpRequest（字符串url、字符串方法、，
列表参数）{
试一试{
如果（方法==“POST”）{
DefaultHttpClient httpClient=新的DefaultHttpClient（）；
HttpPost HttpPost=新的HttpPost（url）；
setEntity（新的UrlEncodedFormEntity（参数））；
HttpResponse HttpResponse=httpClient.execute（httpPost）；
HttpEntity HttpEntity=httpResponse.getEntity（）；
is=httpEntity.getContent（）；
}else if（方法==“GET”）{
DefaultHttpClient httpClient=新的DefaultHttpClient（）；
String paramString=URLEncodedUtils.format（params，“utf-8”）；
url+=“？”+参数字符串；
HttpGet HttpGet=新的HttpGet（url）；
HttpResponse HttpResponse=httpClient.execute（httpGet）；
HttpEntity HttpEntity=httpResponse.getEntity（）；
is=httpEntity.getContent（）；
}           
}捕获（不支持的编码异常e）{
e、 printStackTrace（）；
}捕获（客户端协议例外e）
  <?php
  $response=array();
  $paramString=$_REQUEST[''];

  require_once __DIR__.'/db_connect.php';
  $db=new DB_CONNECT();
  $sql="SELECT * FROM getbus WHERE day='$paramString'";

  $result=mysql_query($sql);

   if(!empty($result))
  {
    if(mysql_num_rows($result)>0)
    {
        $response['idioms']=array();
       while ($row = mysql_fetch_array($result)) {
            $book=array();
            $book['day']=$row['day'];
            $book['time']=$row['time'];
            $book['status']=$row['status'];

            array_push($response['idioms'], $book);
        }
        $response['success']=1;
        echo json_encode($response);
    }
    else {
        $response['success']=0;
        $response['message']='No data found';

        echo json_encode($response);
    }
  }
 ?>

02-07 14:37:09.761: E/JSON Parser(1195): Error parsing data org.json.JSONException: Value <br of type java.lang.String cannot be converted to JSONObject 
02-07 14:37:19.091: E/JSON Parser(1195): Error parsing data org.json.JSONException: Value <br of type java.lang.String cannot be converted to JSONObject 

getallbus.php?requestParam=[yourRequestParam] // aka `GET`

$paramString = $_GET['requestParam']; 

$paramString = $_POST['requestParam'];