我有一个很大的错误.. 我不知道为什么我有这个......
我的代码：
public class MainActivity extends ListActivity {
// URL to get contacts JSON
private static String url = "https://jordyruiz.herokuapp.com/clubs.json";
// JSON Node names
private static final String TAG_Allclub = "Allclub";
private static final String TAG_ID = "id";
private static final String TAG_NAME = "NomClub";
private static final String TAG_LIGUE = "Ligue";
private static final String TAG_DISTRICT = "District";
private static final String TAG_NOMBREEQUIPE = "NombreEquipe";
private static final String TAG_CORRESPONDANT = "Correspondant";
private static final String TAG_ADRESSE = "Adresse";
private static final String TAG_EMAIL = "Email";
private static final String TAG_TELEPHONE = "Telephone";
private static final String TAG_LATITUDE = "Latitude";
private static final String TAG_LONGITUDE = "Longitude";
private static final String TAG_URL = "url";
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
// Calling async task to get json
new GetClubs().execute();
}
/**
* Async task class to get json by making HTTP call
*/
private class GetClubs extends AsyncTask<Void, Void, Void> {
// Hashmap for ListView
ArrayList<HashMap<String, String>> clubList;
ProgressDialog pDialog;
@Override
protected void onPreExecute() {
super.onPreExecute();
// Showing progress dialog
pDialog = new ProgressDialog(MainActivity.this);
pDialog.setMessage("Chargement...");
pDialog.setCancelable(false);
pDialog.show();
}
@Override
protected Void doInBackground(Void... arg0) {
// Creating service handler class instance
WebRequest webreq = new WebRequest();
// Making a request to url and getting response
String jsonStr = webreq.makeWebServiceCall(url, WebRequest.GET);
Log.d("Response: ", "> " + jsonStr);
clubList = ParseJSON(jsonStr);
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(
MainActivity.this, clubList,
R.layout.list_item, new String[]{TAG_NAME, TAG_LIGUE,
TAG_DISTRICT, TAG_NOMBREEQUIPE}, new int[]{R.id.name,
R.id.Ligue, R.id.district, R.id.nombreequipe});
setListAdapter(adapter);
}
}
private ArrayList<HashMap<String, String>> ParseJSON(String json) {
if (json != null) {
try {
// Hashmap for ListView
ArrayList<HashMap<String, String>> clubList = new ArrayList<HashMap<String, String>>();
JSONObject jsonObj = new JSONObject(json);
// Getting JSON Array node
JSONArray clubs = jsonObj.getJSONArray(TAG_Allclub);
// looping through All clubs
for (int i = 0; i < clubs.length(); i++) {
JSONObject c = clubs.getJSONObject(i);
String id = c.getString(TAG_ID);
String name = c.getString(TAG_NAME);
String ligue = c.getString(TAG_LIGUE);
String district = c.getString(TAG_DISTRICT);
String nombreequipe = c.getString(TAG_NOMBREEQUIPE);
String correspondant = c.getString(TAG_CORRESPONDANT);
String adresse = c.getString(TAG_ADRESSE);
String email = c.getString(TAG_EMAIL);
String telephone = c.getString(TAG_TELEPHONE);
String latitude = c.getString(TAG_LATITUDE);
String longitude = c.getString(TAG_LONGITUDE);
String urlweb = c.getString(TAG_URL);
// Phone node is JSON Object
// JSONObject phone = c.getJSONObject(TAG_PHONE);
// String mobile = phone.getString(TAG_PHONE_MOBILE);
// String home = phone.getString(TAG_PHONE_HOME);
// tmp hashmap for single club
HashMap<String, String> club = new HashMap<String, String>();
// adding each child node to HashMap key => value
club.put(TAG_ID, id);
club.put(TAG_NAME, name);
club.put(TAG_LIGUE, ligue);
club.put(TAG_DISTRICT, district);
club.put(TAG_NOMBREEQUIPE, nombreequipe);
// adding club to clubs list
clubList.add(club);
}
return clubList;
} catch (JSONException e) {
e.printStackTrace();
return null;
}
} else {
Log.e("ServiceHandler", "Couldn't get any data from the url");
return null;
}
}
}
和我的json：
{
"Allclub":[{
"id": 1,
"NomClub": "Alfortville US",
"Ligue": " LIGUE DE PARIS ILE DE FRANCE",
"District": "DISTRICT VAL DE MARNE",
"NombreEquipe": 23,
"Correspondant": "SAMIR ABDELAZIZ",
"Adresse": "COMPLEXE VAL DE SEINE-Parc Sport, 4 allée Jean Baptiste Preux, - 94140 - ALFORTVILLE",
"Email": "usalfortville@lpiff.fr",
"Telephone": 148935240,
"Latitude": 48.7781247,
"Longitude": 2.42247699999996,
"url": "https://jordyruiz.herokuapp.com/clubs/1.json"},
{ "id": 2,
"NomClub": "PEROU UNI F.C.",
"Ligue": "LIGUE DE PARIS ILE DE FRANCE",
"District": "DISTRICT DES HAUTS-DE-SEINE",
"NombreEquipe": 1,
"Correspondant": "CLAVO DIAZ HUGO",
"Adresse": "2 RUE LOUIS ARMAND - 75015 - PARIS 15",
"Email": "clavodiaz15@hotmail.com",
"Telephone": 672803527,
"Latitude": 48.8325026,
"Longitude": 2.2759969,
"url": "https://jordyruiz.herokuapp.com/clubs/2.json"
}
]}
错误日志：
你能帮帮我吗... 感谢12-28 12：36：41.751 32074-32074 /？ E / SELinux：[DEBUG] get_category：变量seinfo：默认灵敏度：NULL，cateogry：NULL 12-28 12：36：46.041 32074-32074 / org.esiea.jordy_ruiz_elisabeth_duong.footballclub E / AndroidRuntime：FATAL EXCEPTION：main 12-28 12：36：46.041 32074-32074 / org.esiea.jordy_ruiz_elisabeth_duong.footballclub E / AndroidRuntime：流程：org.esiea.jordy_ruiz_elisabeth_duong.footballclub，PID：32074 12-28 12：36：46.041 32074-32074 / org.esiea.jordy_ruiz_elisabeth_duong.footballclub E / AndroidRuntime：java.lang.NullPointerException：尝试在空对象上调用接口方法'int java.util.List.size（）'参考 12-28 12：36：46.041 32074-32074 / org.esiea.jordy_ruiz_elisabeth_duong.footballclub E / AndroidRuntime：at android.widget.SimpleAdapter.getCount（SimpleAdapter.java:93） 12-28 12：36：46.041 32074-32074 / org.esiea.jordy_ruiz_elisabeth_duong.footballclub E / AndroidRuntime：在android.widget.ListView.setAdapter（ListView.java:502） 12-28 12：36：46.041 32074-32074 / org.esiea.jordy_ruiz_elisabeth_duong.footballclub E / AndroidRuntime：at android.app.ListActivity.setListAdapter（ListActivity.java:265） 12-28 12：36：46.041 32074-32074 / org.esiea.jordy_ruiz_elisabeth_duong.footballclub E / AndroidRuntime：at org.esiea.jordy_ruiz_elisabeth_duong.footballclub.MainActivity $ GetClubs.onPostExecute（MainActivity.java:97） 12-28 12：36：46.041 32074-32074 / org.esiea.jordy_ruiz_elisabeth_duong.footballclub E / AndroidRuntime：at org.esiea.jordy_ruiz_elisabeth_duong.footballclub.MainActivity $ GetClubs.onPostExecute（MainActivity.java:50） 12-28 12：36：46.041 32074-32074 / org.esiea.jordy_ruiz_elisabeth_duong.footballclub E / AndroidRuntime：at android.os.AsyncTask.finish（AsyncTask.java:636） 12-28 12：36：46.041 32074-32074 / org.esiea.jordy_ruiz_elisabeth_duong.footballclub E / AndroidRuntime：at android.os.AsyncTask.access $ 500（AsyncTask.java:177） 12-28 12：36：46.041 32074-32074 / org.esiea.jordy_ruiz_elisabeth_duong.footballclub E / AndroidRuntime：at android.os.AsyncTask $ InternalHandler.handleMessage（AsyncTask.java:653） 12-28 12：36：46.041 32074-32074 / org.esiea.jordy_ruiz_elisabeth_duong.footballclub E / AndroidRuntime：at android.os.Handler.dispatchMessage（Handler.java:102） 12-28 12：36：46.041 32074-32074 / org.esiea.jordy_ruiz_elisabeth_duong.footballclub E / AndroidRuntime：在android.os.Looper.loop（Looper.java:145） 12-28 12：36：46.041 32074-32074 / org.esiea.jordy_ruiz_elisabeth_duong.footballclub E / AndroidRuntime：在android.app.ActivityThread.main（ActivityThread.java:6837） 12-28 12：36：46.041 32074-32074 / org.esiea.jordy_ruiz_elisabeth_duong.footballclub E / AndroidRuntime：at java.lang.reflect.Method.invoke（Native Method） 12-28 12：36：46.041 32074-32074 / org.esiea.jordy_ruiz_elisabeth_duong.footballclub E / AndroidRuntime：at java.lang.reflect.Method.invoke（Method.java:372） 12-28 12：36：46.041 32074-32074 / org.esiea.jordy_ruiz_elisabeth_duong.footballclub E / AndroidRuntime：at com.android.internal.os.ZygoteInit $ MethodAndArgsCaller.run（ZygoteInit.java:1404） 12-28 12：36：46.041 32074-32074 / org.esiea.jordy_ruiz_elisabeth_duong.footballclub E / AndroidRuntime：at com.android.internal.os.ZygoteInit.main（ZygoteInit.java:1199）
的Jordy
答案 0 :(得分：0)
对于解析JSON字符串，我建议使用优秀的JsonReader。
它是Google创建的API的一部分，名为GSON，自Android 3.0起即可使用。如果您需要在早期的Android版本上使用它，您可以使用独立的JAR文件。更多详情：https://stackoverflow.com/a/10174066/3535408
至于代码，这是使用GSON的json解析器的简短示例：
private static final String TAG_Allclub = "Allclub";
private static final String TAG_ID = "id";
private static final String TAG_NAME = "NomClub";
private static final String TAG_LIGUE = "Ligue";
private static final String TAG_DISTRICT = "District";
private static final String TAG_NOMBREEQUIPE = "NombreEquipe";
private static final String TAG_CORRESPONDANT = "Correspondant";
private static final String TAG_ADRESSE = "Adresse";
private static final String TAG_EMAIL = "Email";
private static final String TAG_TELEPHONE = "Telephone";
private static final String TAG_LATITUDE = "Latitude";
private static final String TAG_LONGITUDE = "Longitude";
private static final String TAG_URL = "url";
public final static ArrayList<HashMap<String, String>> parseClubJson(final String json) {
if (TextUtils.isEmpty(json)) // checks if string is null or empty
throw new IllegalArgumentException("json MUST NOT be NULL or EMPTY!");
try {
final InputStreamReader inputStreamReader = new InputStreamReader(new ByteArrayInputStream(json.getBytes("UTF-8")));
final JsonReader jsonReader = new JsonReader(inputStreamReader);
final ArrayList<HashMap<String, String>> allClubs = new ArrayList<HashMap<String, String>>();
jsonReader.beginObject(); // if the json starts with a JSON Object
while (jsonReader.hasNext()){
// declare the values here, they will be initialized later
String id;
String name;
String ligue;
String district;
String nombreequipe;
String correspondant;
String adresse;
String email;
String telephone;
String latitude;
String longitude;
String urlweb;
final String node = jsonReader.nextName(); // get the next available JSON node
if (node.equals(TAG_Allclub)) {// according to your JSON this looks like an array of JSON Object
jsonReader.beginArray(); // so we begin a new array
while (jsonReader.hasNext()) { // while there are nodes inside this array
jsonReader.beginObject(); // we know it's an array of json objects
final String subNode = jsonReader.nextName();
if (subNode.equals(TAG_ID))
id = jsonReader.nextString(); // we retrieve the value of this node as a String
else if (subNode.equals(TAG_NAME))
name = jsonReader.nextString();
else if (subNode.equals(TAG_LIGUE))
ligue = jsonReader.nextString();
// etc -> keep checking for each single possible value
// don't forget to add an else in case of an unexpected node ...
else
jsonReader.skipValue(); // ... that we can safely skip
jsonReader.endObject(); //once we are over with this object, we close it
}
jsonReader.endArray(); // never forget to close the array
}
// Once done parsing through current club :
final HashMap<String, String> currentClub = new HashMap<>();
// put values here
allClubs.add(currentClub);
}
jsonReader.endObject(); // never forget to close an object
// Once you are done with parsing the json you can build your return your ArrayList of HasMap here
// Exception Catching requiered
} catch (final UnsupportedEncodingException uee) { // in case json.getBytes fails
Log.e(TAG, "Error while parsing JSON - Wrong Encoding! ->\n" + uee.getMessage());
Log.getStackTraceString(uee);
return null;
} catch (final IOException ioe) { // might VERY RARELY occur while reading the current stream.
Log.e(TAG, "Error while converting from JSON ->\n" + ioe.getMessage());
return null;
}
}
不要忘记在compile 'com.google.code.gson:gson:2.3.1'文件中添加build.gradle或使用import android.util.JsonReader
注意：使用HasMap资源非常昂贵且ArrayList使用大量内存，具体取决于要保留的对象数量（此处为HashMaps）。你最好使用POJO，以便最终得到Club[];
希望它有所帮助！
来自IN＆＃39; TECH的干杯; - ）
答案 1 :(得分：0)
1）在“Void doInBackground”clublist = pareJson（jsonStr）doesent work.Do可以在doInBackground中更改？
2）在“onPostExecute”中它是正确的吗？
3）对于put值，其代码为：“currentClub.put（TAG_ID，id）;” ？
4）在“Log.e（TAG，...）doesent work：Error：（165,19）error：找不到符号变量TAG。
public class MainActivity extends ListActivity {
// URL to get contacts JSON
private static String url = "https://jordyruiz.herokuapp.com/clubs.json";
// JSON Node names
private static final String TAG_Allclub = "Allclub";
private static final String TAG_ID = "id";
private static final String TAG_NAME = "NomClub";
private static final String TAG_LIGUE = "Ligue";
private static final String TAG_DISTRICT = "District";
private static final String TAG_NOMBREEQUIPE = "NombreEquipe";
private static final String TAG_CORRESPONDANT = "Correspondant";
private static final String TAG_ADRESSE = "Adresse";
private static final String TAG_EMAIL = "Email";
private static final String TAG_TELEPHONE = "Telephone";
private static final String TAG_LATITUDE = "Latitude";
private static final String TAG_LONGITUDE = "Longitude";
private static final String TAG_URL = "url";
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
// Calling async task to get json
new GetClubs().execute();
}
/**
* Async task class to get json by making HTTP call
*/
private class GetClubs extends AsyncTask<Void, Void, Void> {
ProgressDialog pDialog;
@Override
protected void onPreExecute() {
super.onPreExecute();
// Showing progress dialog
pDialog = new ProgressDialog(MainActivity.this);
pDialog.setMessage("Chargement...");
pDialog.setCancelable(false);
pDialog.show();
}
@Override
protected Void doInBackground(Void... arg0) {
// Creating service handler class instance
WebRequest webreq = new WebRequest();
// Making a request to url and getting response
String jsonStr = webreq.makeWebServiceCall(url, WebRequest.GET);
Log.d("Response: ", "> " + jsonStr);
// clubList = ParseJSON(jsonStr);
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(
MainActivity.this, parseClubJson(TAG_ID),
R.layout.list_item, new String[]{TAG_NAME, TAG_LIGUE,
TAG_DISTRICT, TAG_NOMBREEQUIPE}, new int[]{R.id.name,
R.id.Ligue, R.id.district, R.id.nombreequipe});
setListAdapter(adapter);
}
}
public final static ArrayList<HashMap<String, String>> parseClubJson(final String json) {
if (TextUtils.isEmpty(json)) // checks if string is null or empty
throw new IllegalArgumentException("json MUST NOT be NULL or EMPTY!");
try {
final InputStreamReader inputStreamReader = new InputStreamReader(new ByteArrayInputStream(json.getBytes("UTF-8")));
final JsonReader jsonReader = new JsonReader(inputStreamReader);
final ArrayList<HashMap<String, String>> allClubs = new ArrayList<HashMap<String, String>>();
jsonReader.beginObject(); // if the json starts with a JSON Object
while (jsonReader.hasNext()){
// declare the values here, they will be initialized later
String id;
String name;
String ligue;
String district;
String nombreequipe;
String correspondant;
String adresse;
String email;
String telephone;
String latitude;
String longitude;
String urlweb;
final String node = jsonReader.nextName(); // get the next available JSON node
if (node.equals(TAG_Allclub)) {// according to your JSON this looks like an array of JSON Object
jsonReader.beginArray(); // so we begin a new array
while (jsonReader.hasNext()) { // while there are nodes inside this array
jsonReader.beginObject(); // we know it's an array of json objects
final String subNode = jsonReader.nextName();
if (subNode.equals(TAG_ID))
id = jsonReader.nextString(); // we retrieve the value of this node as a String
else if (subNode.equals(TAG_NAME))
name = jsonReader.nextString();
else if (subNode.equals(TAG_LIGUE))
ligue = jsonReader.nextString();
// etc -> keep checking for each single possible value
// don't forget to add an else in case of an unexpected node ...
else
jsonReader.skipValue(); // ... that we can safely skip
jsonReader.endObject(); //once we are over with this object, we close it
}
jsonReader.endArray(); // never forget to close the array
}
// Once done parsing through current club :
final HashMap<String, String> currentClub = new HashMap<>();
// put values here
currentClub.put(TAG_ID, id);
currentClub.put(TAG_ID, name);
currentClub.put(TAG_ID, ligue);
allClubs.add(currentClub);
}
jsonReader.endObject(); // never forget to close an object
// Once you are done with parsing the json you can build your return your ArrayList of HasMap here
// Exception Catching requiered
} catch (final UnsupportedEncodingException uee) { // in case json.getBytes fails
Log.e(TAG, "Error while parsing JSON - Wrong Encoding! ->\n" + uee.getMessage());
Log.getStackTraceString(uee);
return null;
} catch (final IOException ioe) { // might VERY RARELY occur while reading the current stream.
Log.e(TAG, "Error while converting from JSON ->\n" + ioe.getMessage());
return null;
}
}}
非常感谢！
来自ESIEA的欢呼声
的Jordy