下面我附上了我的代码。我想要实现的是将一个String数组打印到TextView，但是我甚至在它到达目前之前就得到了一个NPE。为了描述我的代码，数组masteriesArray [i] [x]拥有单独的掌握页面，i和与该页面对应的杰作x。我认为我遇到的问题是x是一个可变大小。我已经评论过我的代码，或许可以帮助它有所帮助。
错误在于：
masteriesArray[i][x] = singleMastery.getString("name"); // Error here
I have confirmed that i = 0, x = 0, and singleMastery.getString("name") is valid and in the case before the error returns "Block."
我的代码：
public class MasteriesActivity extends BaseActivity {
private Spinner spinner;
ArrayAdapter<String> adapter;
public String[][] masteriesArray;
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.masteries_activity);
getActionBar().setTitle("Masteries");
GetMasteries getMasteries = new GetMasteries();
getMasteries.execute();
spinner = (Spinner) findViewById(R.id.mastery_selector);
}
class GetMasteries extends AsyncTask<String, String, JSONObject> {
private String api_key="d96236d2-6ee3-4cfd-afa7-f41bdbc11128";
String region = MainActivity.region.toLowerCase();
String id = StatsActivity.sumID;
String encodedKey = null;
String encodedRegion = null;
String encodedId = null;
String url = null;
String url2 = null;
// JSON Node Names
String TAG_NAME = "name";
String TAG_CURRENT = "current";
@Override
protected void onPreExecute() {
super.onPreExecute();
try {
// Encode URL variables
encodedId = URLEncoder.encode(id, "UTF-8");
encodedKey = URLEncoder.encode(api_key, "UTF-8");
encodedRegion = URLEncoder.encode(region, "UTF-8");
url = "http://prod.api.pvp.net/api/lol/" + region + "/v1.4/summoner/" + id + "/masteries?api_key=" + api_key;
url2 = "https://prod.api.pvp.net/api/lol/static-data/" + region + "/v1.2/mastery?api_key=" + api_key;
} catch (UnsupportedEncodingException e) {
e.printStackTrace();
}
}
@Override
protected JSONObject doInBackground(String... arg0) {
JSONParser jParser = new JSONParser();
// Get JSON from URL
JSONObject json = jParser.getJSONFromUrl(url);
JSONObject masteriesList = jParser.getJSONFromUrl(url2);
// Get JSON containing Rune Info and cache it
try {
ObjectOutput out = new ObjectOutputStream(new FileOutputStream(new File(getCacheDir(),"")+"cacheFile2.srl"));
out.writeObject(masteriesList.toString());
out.close();
} catch (IOException e) {
e.printStackTrace();
}
return json;
}
@Override
protected void onPostExecute(JSONObject json) {
try {
// Get JSON Object
JSONObject masteries = json.getJSONObject(encodedId);
// Get JSON Array node
JSONArray mastery = masteries.getJSONArray("pages");
// Load Saved file
ObjectInputStream in = new ObjectInputStream(new FileInputStream(new File(new File(getCacheDir(),"")+"cacheFile2.srl")));
String storedMasteryInfo = (String) in.readObject();
JSONObject jsonObject = new JSONObject(storedMasteryInfo);
JSONObject dataObject = jsonObject.getJSONObject("data");
Log.i("Mastery data object", dataObject + "");
// Loop through pages, page names stored in string array
String[] name = new String[mastery.length()];
String curr;
ArrayList<String> masteryPageNames = new ArrayList<String>();
Log.d("Mastery Length", mastery.length() + ""); // Number of pages user has: 20 Max
masteriesArray = new String[mastery.length()][];
for(int i = 0; i < mastery.length(); i++) {
JSONObject c = mastery.getJSONObject(i);
name[i] = c.getString(TAG_NAME);
curr = c.getString(TAG_CURRENT);
JSONArray masteryInfo = c.getJSONArray("masteries");
Log.d("Mastery Info", masteryInfo + ""); // Each Individual Page i
for(int x = 0; x < masteryInfo.length(); x++) {
JSONObject s = masteryInfo.getJSONObject(x);
String masteryId = s.getString("id");
JSONObject singleMastery = dataObject.getJSONObject(masteryId);
try {
Log.d("X", x + ""); // 0 then error
masteriesArray[i][x] = singleMastery.getString("name"); // Error here
Log.d("MasteriesArray[i][x]", masteriesArray[i][x]);
Log.d("I", i + "");
}
catch (JSONException e) {
masteriesArray[i][x] = "";
}
}
if(curr.equals("true"))
name[i] = name[i] + " [Active]";
masteryPageNames.add(name[i]);
}
adapter = new ArrayAdapter(MasteriesActivity.this,
android.R.layout.simple_spinner_dropdown_item,
masteryPageNames);
spinner.setAdapter(adapter);
spinner.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
@Override
public void onItemSelected(AdapterView<?> adapterView, View view, int pos, long l) {
((TextView) adapterView.getChildAt(0)).setTextColor(Color.parseColor("#C49246"));
Toast.makeText(adapterView.getContext(),
"Page Selected: " + adapterView.getItemAtPosition(pos).toString(),
Toast.LENGTH_SHORT).show();
TextView masteriesText = (TextView) findViewById(R.id.masteries);
masteriesText.setText("Masteries: " + "\n");
for(int j = 0; j<masteriesArray.length; j++) {
Log.d("Iteration: ", j + "");
masteriesText.append(masteriesArray[pos][j]);
masteriesText.append("\n");
}
}
@Override
public void onNothingSelected(AdapterView<?> adapterView) {
}
});
} catch (JSONException e) {
e.printStackTrace();
} catch (ClassNotFoundException e) {
e.printStackTrace();
} catch (OptionalDataException e) {
e.printStackTrace();
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (StreamCorruptedException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}
}
}
JSON：
{"23591778": {
"pages": [
{
"masteries": [
{
"id": 4211,
"rank": 2
},
{
"id": 4214,
"rank": 2
},
{
"id": 4134,
"rank": 3
},
{
"id": 4124,
"rank": 1
},
{
"id": 4114,
"rank": 1
},
{
"id": 4222,
"rank": 3
},
{
"id": 4112,
"rank": 4
},
{
"id": 4221,
"rank": 1
},
{
"id": 4144,
"rank": 1
},
{
"id": 4122,
"rank": 3
},
{
"id": 4152,
"rank": 3
},
{
"id": 4141,
"rank": 1
},
{
"id": 4111,
"rank": 1
},
{
"id": 4132,
"rank": 1
},
{
"id": 4232,
"rank": 1
},
{
"id": 4162,
"rank": 1
},
{
"id": 4131,
"rank": 1
}
],
"id": 34787712,
"name": "Blind",
"current": false
},
{
"masteries": [
{
"id": 4212,
"rank": 2
},
{
"id": 4233,
"rank": 3
},
{
"id": 4242,
"rank": 1
},
{
"id": 4214,
"rank": 2
},
{
"id": 4114,
"rank": 1
},
{
"id": 4251,
"rank": 1
},
{
"id": 4112,
"rank": 4
},
{
"id": 4222,
"rank": 3
},
{
"id": 4122,
"rank": 3
},
{
"id": 4262,
"rank": 1
},
{
"id": 4224,
"rank": 1
},
{
"id": 4252,
"rank": 3
},
{
"id": 4132,
"rank": 1
},
{
"id": 4241,
"rank": 3
},
{
"id": 4232,
"rank": 1
}
],
"id": 34787713,
"name": "AD/Tank Jungle",
"current": false
},
{
"masteries": [
{
"id": 4242,
"rank": 1
},
{
"id": 4233,
"rank": 3
},
{
"id": 4243,
"rank": 1
},
{
"id": 4211,
"rank": 2
},
{
"id": 4214,
"rank": 2
},
{
"id": 4213,
"rank": 2
},
{
"id": 4114,
"rank": 1
},
{
"id": 4252,
"rank": 2
},
{
"id": 4222,
"rank": 3
},
{
"id": 4113,
"rank": 4
},
{
"id": 4221,
"rank": 1
},
{
"id": 4123,
"rank": 3
},
{
"id": 4262,
"rank": 1
},
{
"id": 4224,
"rank": 1
},
{
"id": 4133,
"rank": 1
},
{
"id": 4234,
"rank": 1
},
{
"id": 4232,
"rank": 1
}
],
"id": 34787714,
"name": "Mumu",
"current": true
},
{
"masteries": [
{
"id": 4211,
"rank": 2
},
{
"id": 4121,
"rank": 1
},
{
"id": 4214,
"rank": 2
},
{
"id": 4134,
"rank": 3
},
{
"id": 4114,
"rank": 1
},
{
"id": 4222,
"rank": 3
},
{
"id": 4112,
"rank": 4
},
{
"id": 4144,
"rank": 1
},
{
"id": 4221,
"rank": 1
},
{
"id": 4152,
"rank": 3
},
{
"id": 4122,
"rank": 3
},
{
"id": 4141,
"rank": 1
},
{
"id": 4111,
"rank": 1
},
{
"id": 4132,
"rank": 1
},
{
"id": 4232,
"rank": 1
},
{
"id": 4162,
"rank": 1
},
{
"id": 4131,
"rank": 1
}
],
"id": 34787715,
"name": "vi/j4/wuk/xin/noc",
"current": false
},
{
"masteries": [
{
"id": 4212,
"rank": 2
},
{
"id": 4353,
"rank": 3
},
{
"id": 4211,
"rank": 2
},
{
"id": 4311,
"rank": 1
},
{
"id": 4362,
"rank": 1
},
{
"id": 4322,
"rank": 3
},
{
"id": 4334,
"rank": 1
},
{
"id": 4332,
"rank": 1
},
{
"id": 4352,
"rank": 1
},
{
"id": 4222,
"rank": 3
},
{
"id": 4314,
"rank": 1
},
{
"id": 4221,
"rank": 1
},
{
"id": 4331,
"rank": 3
},
{
"id": 4324,
"rank": 1
},
{
"id": 4313,
"rank": 3
},
{
"id": 4232,
"rank": 1
},
{
"id": 4342,
"rank": 1
},
{
"id": 4341,
"rank": 1
}
],
"id": 34787716,
"name": "Support",
"current": false
},
{
"masteries": [
{
"id": 4211,
"rank": 2
},
{
"id": 4214,
"rank": 2
},
{
"id": 4124,
"rank": 1
},
{
"id": 4114,
"rank": 1
},
{
"id": 4112,
"rank": 4
},
{
"id": 4222,
"rank": 3
},
{
"id": 4113,
"rank": 4
},
{
"id": 4122,
"rank": 3
},
{
"id": 4152,
"rank": 3
},
{
"id": 4224,
"rank": 1
},
{
"id": 4132,
"rank": 1
},
{
"id": 4142,
"rank": 3
},
{
"id": 4232,
"rank": 1
},
{
"id": 4162,
"rank": 1
}
],
"id": 34787717,
"name": "AD Jungle",
"current": false
},
{
"masteries": [
{
"id": 4212,
"rank": 2
},
{
"id": 4211,
"rank": 2
},
{
"id": 4121,
"rank": 1
},
{
"id": 4134,
"rank": 3
},
{
"id": 4124,
"rank": 1
},
{
"id": 4114,
"rank": 1
},
{
"id": 4222,
"rank": 3
},
{
"id": 4112,
"rank": 4
},
{
"id": 4221,
"rank": 1
},
{
"id": 4122,
"rank": 3
},
{
"id": 4152,
"rank": 3
},
{
"id": 4141,
"rank": 1
},
{
"id": 4142,
"rank": 1
},
{
"id": 4132,
"rank": 1
},
{
"id": 4232,
"rank": 1
},
{
"id": 4162,
"rank": 1
},
{
"id": 4131,
"rank": 1
}
],
"id": 34787718,
"name": "ADC",
"current": false
},
],
"summonerId": 23591778
}}