doInbackground不叫

Question

當按鈕被點擊

new HttpAsyncTasks().execute("http://www.demo.com/xyz"); 

這是上面的執行

private class HttpAsyncTasks extends AsyncTask<String, Void, String> { 

    @Override 
    protected String doInBackground(String... urls) { 

     return POSTS(urls[0]); 

    } 
    // onPostExecute displays the results of the AsyncTask. 
    @Override 
    protected void onPostExecute(String result) { 
     Toast.makeText(getBaseContext(), "successfull!", Toast.LENGTH_LONG).show(); 
     //call main activity activity upon successful registration 


     Intent callMain = new Intent(getApplicationContext(), 
       MainActivity.class); 
     startActivity(callMain); 

    } 
} 

以上的doInbackground永遠不會被執行，但中的AsyncTask執行此網址onPostExecute方法。

這就是所謂的doInbackground

public String POSTS(String url){ 

    InputStream inputStream = null; 
     String result = ""; 
     try { 

      // 1. create HttpClient 
      HttpClient httpclient = new DefaultHttpClient(); 

      // 2. make POST request to the given URL 
      HttpPost httpPost = new HttpPost(url); 

      String json = ""; 


      // 3. build jsonObject 
      JSONObject jsonObject = new JSONObject(); 
      jsonObject.accumulate("xyz", "xyz"); 
      jsonObject.accumulate("amount", "800"); 
      jsonObject.accumulate("demo", "demo"); 
      jsonObject.accumulate("demo2", demo2); 

      // 4. convert JSONObject to JSON to String 
      json = jsonObject.toString(); 

      // ** Alternative way to convert Person object to JSON string usin Jackson Lib 
      // ObjectMapper mapper = new ObjectMapper(); 
      // json = mapper.writeValueAsString(person); 

      // 5. set json to StringEntity 
      StringEntity se = new StringEntity(json); 

      // 6. set httpPost Entity 
      httpPost.setEntity(se); 

      // 7. Set some headers to inform server about the type of the content 
      httpPost.setHeader("Accept", "application/json"); 
      httpPost.setHeader("Content-type", "application/json"); 

      // 8. Execute POST request to the given URL 
      HttpResponse httpResponse = httpclient.execute(httpPost); 

      // 9. receive response as inputStream 
      inputStream = httpResponse.getEntity().getContent(); 

      // 10. convert inputstream to string 
      if(inputStream != null) 
       result = convertInputStreamToString(inputStream); 
      else 
       result = "Did not work!"; 

     } catch (Exception e) { 
      Log.d("InputStream", e.getLocalizedMessage()); 
     } 

     // 11. return result 
     return result; 
    } 

的帖子方法請什麼地方出錯了？

Answer 1

你可以試試這種方式。它正在檢查你的POSTS方法。 如果吐司顯示空行，您在WebProcess上的POSTS方法中出錯。

private class HttpAsyncTasks extends AsyncTask<String, Void, String> { 
    private String myResult="check"; 
    @Override 
    protected String doInBackground(String... urls) { 
     try 
     { 
      myResult = POSTS(urls[0]); 

     } 
     catch(Exception e) 
     { 
      return e; 
     } 
     return myResult; 
    } 
    @Override 
    protected void onPostExecute(String result) { 
     Toast.makeText(getBaseContext(), result, Toast.LENGTH_LONG).show(); 


     /* other codes */ 
    } 
} 

Answer 2

您的文章（網址[0]）的呼叫必須被賦予一個例外，當它的代碼的其餘部分被跳過，它繞過你的麪包。嘗試刪除異常，你可以在logcat中找到它。