私は AsyncTask を初めて使用するので、いくつかのエラーに遭遇しました。私は、何が間違っていて、それを修正するために何をする必要があるかを教えてくれる人です。このコードを試すたびに FATAL EXCEPTION: AsyncTask #1 が表示されるので、誰か助けてください。
07-25 03:47:57.526: W/dalvikvm(799): threadid=11: thread exiting with uncaught exception (group=0x40a71930)
07-25 03:47:57.666: E/AndroidRuntime(799): FATAL EXCEPTION: AsyncTask #1
07-25 03:47:57.666: E/AndroidRuntime(799): java.lang.RuntimeException: An error occured while executing doInBackground()
07-25 03:47:57.666: E/AndroidRuntime(799): at android.os.AsyncTask$3.done(AsyncTask.java:299)
07-25 03:47:57.666: E/AndroidRuntime(799): at java.util.concurrent.FutureTask.finishCompletion(FutureTask.java:352)
07-25 03:47:57.666: E/AndroidRuntime(799): at java.util.concurrent.FutureTask.setException(FutureTask.java:219)
07-25 03:47:57.666: E/AndroidRuntime(799): at java.util.concurrent.FutureTask.run(FutureTask.java:239)
07-25 03:47:57.666: E/AndroidRuntime(799): at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:230)
07-25 03:47:57.666: E/AndroidRuntime(799): at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1080)
07-25 03:47:57.666: E/AndroidRuntime(799): at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:573)
07-25 03:47:57.666: E/AndroidRuntime(799): at java.lang.Thread.run(Thread.java:856)
07-25 03:47:57.666: E/AndroidRuntime(799): Caused by: java.lang.NullPointerException
07-25 03:47:57.666: E/AndroidRuntime(799): at com.theproblemsolver.JSONParsser.getJSONFromURI(JSONParsser.java:35)
07-25 03:47:57.666: E/AndroidRuntime(799): at com.theproblemsolver.asynctask.doInBackground(MainActivity.java:60)
07-25 03:47:57.666: E/AndroidRuntime(799): at com.theproblemsolver.asynctask.doInBackground(MainActivity.java:1)
07-25 03:47:57.666: E/AndroidRuntime(799): at android.os.AsyncTask$2.call(AsyncTask.java:287)
07-25 03:47:57.666: E/AndroidRuntime(799): at java.util.concurrent.FutureTask.run(FutureTask.java:234)
主な活動
public class MainActivity extends Activity {
EditText et;
Button getanswer;
JSONArray ResultsSet = null; {}
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Button getanswer = (Button) findViewById(R.id.button1);
getanswer.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
new asynctask().execute();
}
});
}
}
class asynctask extends AsyncTask<String, Void, JSONObject> {
private static final String TAG_RESULTS = "ResultsSet";
private static final String TAG_SUBJECT = "Subject";
private static final String TAG_NUMANSWERS = "NumAnswers";
private static final String TAG_QUESTION = "Question";
private static final String TAG_QUESTION_CONTENT = "Content";
private static final String TAG_QUESTION_CHOSENANSWER = "ChosenAnswer";
private static final String TAG_QUESTION_ANSWERS = "Answers";
public JSONArray json;
@Override
protected JSONObject doInBackground(String... params) {
JSONParsser jParser = new JSONParsser();
String uRI = null;
JSONObject json = jParser.getJSONFromURI(uRI);
return json ;
}{ }
@Override
protected void onPostExecute(JSONObject json) {
JSONArray ResultsSet = null; {
try {
ResultsSet = json.getJSONArray(TAG_RESULTS);
} catch (JSONException e) {
e.printStackTrace();
}
return;
}}}
JSONParser クラス
public class JSONParsser {
static InputStream is = null;
static JSONObject jObj = null;
static String json = "";
EditText et;
public JSONParsser () {
}
public JSONObject getJSONFromURI(String uRI) {
try{
HttpClient client = new DefaultHttpClient();
try {
URI website = new URI("http://answers.yahooapis.com/AnswerService/V1/questionSearch?appid=vcE15nV34EYK7oAge17Ws6nF3DOzc5ccb4PsWtQjW2YTG3gjKbz8exOHYQr6Psizg&query=" + et.getText() + "sort&type=resolved&results&output=json");
HttpGet request = new HttpGet();
request.setURI(website);
try {
HttpResponse response = client.execute(request);
HttpEntity httpEntity = response.getEntity();
is = httpEntity.getContent();
} catch (ClientProtocolException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
} catch (URISyntaxException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return jObj;
}finally{}
}{
}}
InstanceofJSONParser クラス
public class JSONParserInstance {
JSONParsser jParser = new JSONParsser();
public String uRI;
JSONObject json = jParser.getJSONFromURI(uRI);
private static final String TAG_RESULTS = "ResultsSet";
private static final String TAG_SUBJECT = "Subject";
private static final String TAG_NUMANSWERS = "NumAnswers";
private static final String TAG_QUESTION = "Question";
private static final String TAG_QUESTION_CONTENT = "Content";
private static final String TAG_QUESTION_CHOSENANSWER = "ChosenAnswer";
private static final String TAG_QUESTION_ANSWERS = "Answers";
JSONArray ResultsSet = null; {
try {
ResultsSet = json.getJSONArray(TAG_RESULTS);
for(int i = 0; i < ResultsSet.length(); i++){
JSONObject r = ResultsSet.getJSONObject(i);
String Subject = r.getString(TAG_SUBJECT);
String NmAnswers = r.getString(TAG_NUMANSWERS);
JSONObject Question = r.getJSONObject(TAG_QUESTION);
String Content = Question.getString(TAG_QUESTION_CONTENT);
String ChosenAnswer = Question.getString(TAG_QUESTION_CHOSENANSWER);
String Answers = Question.getString(TAG_QUESTION_ANSWERS);
}
} catch (JSONException e) {
e.printStackTrace();
}}}