我有这个 jsonArray 和一个 jsonArray 有一个 jsonobject（alergenos），我想把它解析成一个 android listview 但是当我尝试 listview.setAdapter(JsonAdapter); 时我总是得到 NullPointerException；
这是我的 json 回复：
{"valor":
[{
"barcode":"8416400610992",
"nombre":"Chicles Trident",
"foto":"alood-52224273e4b90-foto1.jpg",
"revision":{
"date":"2013-08-31 21:22:27","timezone_type":3,"timezone":"Europe\/Paris"},
"alergenos":[
{"id":4,"alergeno":"Melocoton","valor":0},
{"id":3,"alergeno":"Cacahuetes","valor":1}
],
"calorias":250,
"puntos":0,
"fabricante":"Sonia"
}]
}
我正确获得了过敏原数据，如下所示：
JSONArray jArray = respJSON.getJSONArray("alergenos");
for (int n = 0; n < jArray.length(); n++) {
JSONObject str_value = jArray.getJSONObject(n);
String id = str_value.getString("id");
String name = str_value.getString("alergeno");
int value = str_value.getInt("valor");
}
AlergProdAdapter jSONAdapter = new AlergProdAdapter(Scan_Result.this, jArray);
listview.setAdapter(jSONAdapter);
这是我的适配器：
class AlergProdAdapter extends BaseAdapter {
private final Activity activity;
private final JSONArray jsonArray;
final static ArrayList<AlergenosProducto> alergProd = new ArrayList<AlergenosProducto>();
AlergProdAdapter(Activity activity, JSONArray jsonArray) {
assert activity != null;
assert jsonArray != null;
this.jsonArray = jsonArray;
this.activity = activity;
String name = null;
int value = 0;
String id = null;
String image = null;
for (int position = 0; position < jsonArray.length(); position++) {
JSONObject json_data = getItem(position);
if (null != json_data) {
try {
id = json_data.getString("id");
Log.i("da", id);
name = json_data.getString("alergeno");
Log.i("da", name);
value = json_data.getInt("valor");
if(value == 1){
image = "imagenroja";
}else{
image = "imagenverde";
}
} catch (JSONException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
AlergenosProducto alerg = new AlergenosProducto(id, name, value);
alergProd.add(alerg);
}
}
@Override
public int getCount() {
if (null == jsonArray)
return 0;
else
return jsonArray.length();
}
@Override
public JSONObject getItem(int position) {
if (null == jsonArray)
return null;
else
return jsonArray.optJSONObject(position);
}
@Override
public long getItemId(int position) {
JSONObject jsonObject = getItem(position);
return jsonObject.optLong("id");
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
if (convertView == null)
convertView = activity.getLayoutInflater().inflate(
R.layout.allergy_listitems, null);
TextView text = (TextView) convertView.findViewById(R.id.secondLine);
text.setText(alergProd.get(position).getAlergeno());
Log.i("value", alergProd.get(position).getAlergeno());
return convertView;
}
有谁知道我该如何解决这个问题？
谢谢！
编辑：
添加了日志猫。
09-05 00:23:18.217: E/AndroidRuntime(26828): FATAL EXCEPTION: main
09-05 00:23:18.217: E/AndroidRuntime(26828): java.lang.NullPointerException
09-05 00:23:18.217: E/AndroidRuntime(26828): at com.example.alood.Scan_Result$algResultados.onPostExecute(Scan_Result.java:230)
09-05 00:23:18.217: E/AndroidRuntime(26828): at com.example.alood.Scan_Result$algResultados.onPostExecute(Scan_Result.java:1)
09-05 00:23:18.217: E/AndroidRuntime(26828): at android.os.AsyncTask.finish(AsyncTask.java:631)
09-05 00:23:18.217: E/AndroidRuntime(26828): at android.os.AsyncTask.access$600(AsyncTask.java:177)
09-05 00:23:18.217: E/AndroidRuntime(26828): at android.os.AsyncTask$InternalHandler.handleMessage(AsyncTask.java:644)
09-05 00:23:18.217: E/AndroidRuntime(26828): at android.os.Handler.dispatchMessage(Handler.java:99)
09-05 00:23:18.217: E/AndroidRuntime(26828): at android.os.Looper.loop(Looper.java:137)
09-05 00:23:18.217: E/AndroidRuntime(26828): at android.app.ActivityThread.main(ActivityThread.java:4898)
09-05 00:23:18.217: E/AndroidRuntime(26828): at java.lang.reflect.Method.invokeNative(Native Method)
09-05 00:23:18.217: E/AndroidRuntime(26828): at java.lang.reflect.Method.invoke(Method.java:511)
09-05 00:23:18.217: E/AndroidRuntime(26828): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1006)
09-05 00:23:18.217: E/AndroidRuntime(26828): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:773)
09-05 00:23:18.217: E/AndroidRuntime(26828): at dalvik.system.NativeStart.main(Native Method)
编辑添加孔异步任务：
public class algResultados extends AsyncTask<Void, Void, String> {
HttpResponse response;
BufferedReader reader;
StringBuilder builder;
String barcode;
public algResultados(String data) {
super();
this.barcode = data;
}
@Override
protected String doInBackground(Void... arg0) {
HttpClient httpClient = new DefaultHttpClient();
String logusuario = SaveSharedPreference
.getUserName(getApplicationContext());
String logpass = SaveSharedPreference
.getPassword(getApplicationContext());
// Petition get
HttpGet httpGet = new HttpGet("http://www.alood.es/api/resultado/"
+ barcode + '/');
httpGet.addHeader(BasicScheme.authenticate(
new UsernamePasswordCredentials(logusuario, logpass),
"UTF-8", false));
// Execute Get and get Response
response = null;
try {
response = httpClient.execute(httpGet);
reader = new BufferedReader(new InputStreamReader(response
.getEntity().getContent(), "UTF-8"));
builder = new StringBuilder();
for (String line = null; (line = reader.readLine()) != null;) {
builder.append(line).append("\n");
}
} catch (Exception e) {
e.printStackTrace();
alert("Error de protocolo", "Lo sentimos, ha ocurrido un error");
}
// Return code (exit, fail, error, etc)
return builder.toString();
}
@Override
protected void onPostExecute(String result) {
String nombre = null;
String fabricante = null;
String barcode = null;
String calorias = null;
String fech = null;
JSONArray jArray = null;
Log.i("GET RESPONSE", "POSTTTTT");
Log.i("GET RESPONSE", result);
JSONTokener tokener = new JSONTokener(result);
try {
String cca = ((JSONObject) tokener.nextValue())
.getString("valor");
Log.i("GET CCA", cca);
JSONArray resparray = new JSONArray(cca);
List<AlergenosProducto> objList = new ArrayList<AlergenosProducto>();
for (int i = 0; i < resparray.length(); i++) {
JSONObject respJSON = resparray.getJSONObject(i);
nombre = respJSON.getString("nombre");
fabricante = respJSON.getString("fabricante");
String foto = respJSON.getString("foto");
calorias = respJSON.getString("calorias");
int puntos = respJSON.getInt("calorias");
barcode = respJSON.getString("barcode");
String fecha = respJSON.getJSONObject("revision").getString("date");
fech = fecha.substring(0, 10);
jArray = respJSON.getJSONArray("alergenos");
for (int n = 0; n < jArray.length(); n++) {
JSONObject str_value = jArray.getJSONObject(n);
String id = str_value.getString("id");
String name = str_value.getString("alergeno");
int value = str_value.getInt("valor");
Log.i("GET CCA", id);
AlergenosProducto setAlerg = new AlergenosProducto(id, name, value);
objList.add(setAlerg);
}
}
TextView nombText = (TextView) findViewById(R.id.titleTxt);
nombText.setText(nombre);
TextView fabText = (TextView) findViewById(R.id.fabricanteTxt);
fabText.setText("Fabricante: " + fabricante);
TextView codText = (TextView) findViewById(R.id.codigoTxt);
codText.setText("Código: " + barcode);
TextView calText = (TextView) findViewById(R.id.caloriasTxt);
calText.setText("Calorías: " + calorias + "Kcal");
TextView revisText = (TextView) findViewById(R.id.revisadoTxt);
revisText.setText("Revisado: " + fech);
listview = (ListView) findViewById(R.id.alProdList);
AlergProdAdapter jSONAdapter = new AlergProdAdapter(Scan_Result.this, jArray);
listview.setAdapter(jSONAdapter);
//ArrayList<AlergenosProducto> alergenos = AlergProdAdapter.alergProd;
} catch (JSONException e) {
Log.i("EX", e.toString());
alert("Ups!",
"Lo sentimos, pero no estás registrado como usuario");
}
}
}