我意识到我的异步任务有一点问题。我意识到，当我按下 android 设备上的后退按钮以关闭我的进度对话框和我的异步任务时，只有我的进度对话框被关闭并且我的异步任务仍在执行。我真的不知道为什么会这样，所以我只是希望有人能让我回到正确的轨道上并帮助我解决这个问题。
@Override
public void onBackPressed()
{
/** If user Pressed BackButton While Running Asynctask
this will close the ASynctask. */
if (mTask != null && mTask.getStatus() != AsyncTask.Status.FINISHED)
{
mTask.cancel(true);
}
super.onBackPressed();
finish();
}
@Override
protected void onDestroy()
{
// TODO Auto-generated method stub
/** If Activity is Destroyed While Running Asynctask
this will close the ASynctask. */
if (mTask != null && mTask.getStatus() != AsyncTask.Status.FINISHED)
{
mTask.cancel(true);
}
super.onDestroy();
}
@Override
protected void onPause()
{
// TODO Auto-generated method stub
if (pDialog != null)
{
if(pDialog.isShowing())
{
pDialog.dismiss();
}
super.onPause();
}
}
protected String doInBackground(String... args) {
if (isCancelled()){break;}
try {
Intent in = getIntent();
String searchTerm = in.getStringExtra("TAG_SEARCH");
String query = URLEncoder.encode(searchTerm, "utf-8");
String URL = "example.com";
JSONParsser jParser = new JSONParsser();
JSONObject json = jParser.readJSONFeed(URL);
try {
JSONArray questions = json.getJSONObject("all").getJSONArray("questions");
for(int i = 0; i < questions.length(); i++) {
JSONObject question = questions.getJSONObject(i);
String Subject = question.getString(TAG_QUESTION_SUBJECT);
String ChosenAnswer = question.getString(TAG_QUESTION_CHOSENANSWER);
String Content = question.getString(TAG_QUESTION_CONTENT);
//JSONArray Answers = question.getJSONObject(TAG_ANSWERS).getJSONArray(TAG_ANSWER);
//JSONObject Answer = Answers.getJSONObject(0);
//String Content = Answer.getString(TAG_ANSWERS_CONTENT);
HashMap<String, String> map = new HashMap<String, String>();
map.put(TAG_QUESTION_SUBJECT, Subject);
map.put(TAG_QUESTION_CONTENT, Content);
map.put(TAG_QUESTION_CHOSENANSWER, ChosenAnswer);
questionList.add(map);
}
} catch (JSONException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
} catch (UnsupportedEncodingException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return TAG_QUESTION ;
}
JSON解析器：
public class JSONParsser {
InputStream is = null;
JSONObject jObj = null;
String json = "";
public EditText et;
public JSONParsser () {
}
public JSONObject readJSONFeed(String URL) {
try{
HttpClient client = new DefaultHttpClient();
HttpPost request = new HttpPost(URL);
//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();
}
try {
BufferedReader reader = new BufferedReader(new InputStreamReader(
is, "iso-8859-1"), 8);
StringBuilder sb = new StringBuilder();
String line;
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());
}
Log.d("JSON String",json);
return jObj;
}finally{}
}{
}
}