我在try塊內的代碼沒有在android中執行。沒有其他線程似乎解釋這

Question

我有一個通過android的服務器請求的代碼。這是我try塊的片段：

try{ 
       post.setEntity(new UrlEncodedFormEntity(dataToSend)); 
       HttpResponse httpResponse = client.execute(post); 

       HttpEntity entity = httpResponse.getEntity(); 
       String result = EntityUtils.toString(entity); 
       JSONObject jsonObject = new JSONObject(result); 
       Toast.makeText(context,jsonObject.length()+"i ran",Toast.LENGTH_SHORT).show(); 

       if(jsonObject.length() != 0){ 
        Log.v("happened", "2"); 
        String dbname = jsonObject.getString("dbname"); 
        String userloggedin = jsonObject.getString("userloggedin"); 
        String username = jsonObject.getString("username");String password = jsonObject.getString("password"); 
        String email = jsonObject.getString("email");String name = jsonObject.getString("name"); 
        String dob = jsonObject.getString("dob"); String mobile = jsonObject.getString("mobile"); 
        String imagelink = jsonObject.getString("imagelink");String country = jsonObject.getString("country"); 
        String currency = jsonObject.getString("currency");String recentcount = jsonObject.getString("recentcount"); 
        String lowoncashlevel = jsonObject.getString("lowoncashlevel"); 
        returnedUser = new User(dbname,Boolean.getBoolean(userloggedin),username,password,name,dob,mobile,email,imagelink,country,currency,Integer.getInteger(recentcount),Integer.getInteger(lowoncashlevel)); 
       } 
      }catch (Exception e){ 
       e.printStackTrace(); 
      } 

我知道，因爲有在後臺運行過一個進度對話框中的麪包會導致錯誤，但它沒有，這就是我發現，try塊是問題出在哪裏。

這是有這個方法的類：

public class FetchUserDataAsyncTask extends AsyncTask<Void,Void,User> { 

     User user; 
     GetUserCallBack userCallBack; 

     public FetchUserDataAsyncTask(User user, GetUserCallBack userCallBack){ 
      this.user=user; 
      this.userCallBack=userCallBack; 
     } 

     @Override 
     protected User doInBackground(Void... params) { 
      ArrayList<NameValuePair> dataToSend = new ArrayList<>(); 
      dataToSend.add(new BasicNameValuePair("username",user.username)); 
      dataToSend.add(new BasicNameValuePair("password",user.password)); 

      HttpParams httpRequestParams = new BasicHttpParams(); 
      HttpConnectionParams.setConnectionTimeout(httpRequestParams, CONNECTION_TIMEOUT); 
      HttpConnectionParams.setSoTimeout(httpRequestParams, CONNECTION_TIMEOUT); 

      HttpClient client = new DefaultHttpClient(httpRequestParams); 
      HttpPost post = new HttpPost(SERVER_ADDRESS + "FetchUserData2.php"); 

      User returnedUser = null; 

      try{ 
       post.setEntity(new UrlEncodedFormEntity(dataToSend)); 
       HttpResponse httpResponse = client.execute(post); 

       HttpEntity entity = httpResponse.getEntity(); 
       String result = EntityUtils.toString(entity); 
       JSONObject jsonObject = new JSONObject(result); 
       Toast.makeText(context,jsonObject.length()+"i ran",Toast.LENGTH_SHORT).show(); 

       if(jsonObject.length() != 0){ 
        Log.v("happened", "2"); 
        String dbname = jsonObject.getString("dbname"); 
        String userloggedin = jsonObject.getString("userloggedin"); 
        String username = jsonObject.getString("username");String password = jsonObject.getString("password"); 
        String email = jsonObject.getString("email");String name = jsonObject.getString("name"); 
        String dob = jsonObject.getString("dob"); String mobile = jsonObject.getString("mobile"); 
        String imagelink = jsonObject.getString("imagelink");String country = jsonObject.getString("country"); 
        String currency = jsonObject.getString("currency");String recentcount = jsonObject.getString("recentcount"); 
        String lowoncashlevel = jsonObject.getString("lowoncashlevel"); 
        returnedUser = new User(dbname,Boolean.getBoolean(userloggedin),username,password,name,dob,mobile,email,imagelink,country,currency,Integer.getInteger(recentcount),Integer.getInteger(lowoncashlevel)); 
//     returnedUser = new User(jsonObject.getString("dbname"),Boolean.getBoolean(jsonObject.getString("userloggedin")), 
//       jsonObject.getString("username"),jsonObject.getString("password"),jsonObject.getString("name"), 
//       jsonObject.getString("dob"),jsonObject.getString("mobile"),jsonObject.getString("email"), 
//       jsonObject.getString("imagelink"),jsonObject.getString("country"),jsonObject.getString("currency"), 
//       Integer.getInteger(jsonObject.getString("recentcount")),Integer.getInteger(jsonObject.getString("lowoncashlevel"))); 
       } 
      }catch (Exception e){ 
       e.printStackTrace(); 
      } 
      return returnedUser; 
     } 
     @Override 
     protected void onPostExecute(User returnedUser) { 
      progressDialog.dismiss(); 
      userCallBack.done(returnedUser); 
      super.onPostExecute(returnedUser); 
     } 
    } 

執行方法是從這個公共方法叫：

public void fetchUserDataInBackground(User user,GetUserCallBack userCallBack){ 
     progressDialog.show(); 
     new FetchUserDataAsyncTask(user,userCallBack).execute(); 
    } 

Answer 1

的問題是太寬泛，得到適當的答案，但即使您發佈代碼的所有相關部分，並且您的問題將得到解決，我認爲從這個問題中可以得到的最好結果是您必須學會使用調試器！

Android Studio中使用調試器是一塊蛋糕，真的。

如果您添加多個斷點並在調試模式下運行您的應用程序，只需幾分鐘時間，您就可以精確定位導致問題的確切線路並自行解決問題，或詢問更具體的問題。

調試程序教程：https://developer.android.com/tools/debugging/debugging-studio.html

編輯：

我的猜測是，該代碼被執行，並拋出異常，但你忽略它在你的catch塊（除了打印堆棧跟蹤），因此看起來沒有例外。關於該事項幾點：

1. 永遠不要寫catch (Exception e) - 總是寫catch條款對特定類型ecxeptions
2. 的藏在心裏try代碼到最低限度。在你的情況下，實在沒有必要對所有這些代碼由try - catch（或者，至少不是單一try - catch塊）是守衛