ProgressDialog不会出现在OnPreExecute

Question

我试图在解析JSON对象的过程中创建ProgressDialog。所以我使用AsyncTask：

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

    //getting activity context like that since outer activity is not enclosing 
    public JsonUtility(Activity activity){ 
     super(); 
     mActivity = activity; 

    } 

    public JsonUtility(){} 

    @Override 
    protected void onPreExecute(){ 
     super.onPreExecute(); 
     dialog = ProgressDialog.show(mActivity, "Loading...", "Please wait...", true); 
    } 

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

//...operate with JSON 

    } 

    @Override 
    protected void onPostExecute(String s) { 
     super.onPostExecute(s); 
     dialog.hide(); 
    } 
} 

，我从JSON获取信息这样的：

public ArrayList<CoursesData> getCourses(Activity activity){ 
    ArrayList<CoursesData> resultArrayList = new ArrayList<>(); 
    try { 
     JSONArray jArray = new JSONArray(new JsonUtility(activity).execute(coursesUrl).get()); 
//...and so on 
} 

活动传递给JsonUtility时getActivity()创建片段：

ArrayList<CoursesData> coursesDatas = parserJson.getCourses(getActivity()); 

从片段传递活动上下文是否正确？

或者可能问题出在别的地方？尽管加载大约需要2-3秒，但这个ProgressDialog根本不会出现。

请帮我解决这个问题。

Answer 1

将mAbility更改为getParent（）...它为我工作