我在try块内的代码没有在android中执行。没有其他线程似乎解释这

Question

我有一个通过android的服务器请求的代码。这是我try块的片段：

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，因为有在后台运行过一个进度对话框中的面包会导致错误，但它没有，这就是我发现，try块是问题出在哪里。

这是有这个方法的类：

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); 
     } 
    } 

执行方法是从这个公共方法叫：

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

Answer 1

的问题是太宽泛，得到适当的答案，但即使您发布代码的所有相关部分，并且您的问题将得到解决，我认为从这个问题中可以得到的最好结果是您必须学会使用调试器！

Android Studio中使用调试器是一块蛋糕，真的。

如果您添加多个断点并在调试模式下运行您的应用程序，只需几分钟时间，您就可以精确定位导致问题的确切线路并自行解决问题，或询问更具体的问题。

调试程序教程：https://developer.android.com/tools/debugging/debugging-studio.html

编辑：

我的猜测是，该代码被执行，并抛出异常，但你忽略它在你的catch块（除了打印堆栈跟踪），因此看起来没有例外。关于该事项几点：

1. 永远不要写catch (Exception e) - 总是写catch条款对特定类型ecxeptions
2. 的藏在心里try代码到最低限度。在你的情况下，实在没有必要对所有这些代码由try - catch（或者，至少不是单一try - catch块）是守卫