How to return value after calling API android (every time call function and return value)?

Question

Below is my code in Util.java;

public static String getToken() {
    JSONObject postdata = new JSONObject();
    try {
        AppUtill.getJsonWithHTTPPost(context, 1, new ServiceCallBack() {
            @Override
            public void serviceCallback(int id, JSONObject jsonResult) {
                try {
                    if (jsonResult.getString("Status").equalsIgnoreCase("Success")) {
                        JSONObject jsonObject = jsonResult.getJSONObject("Data");
                        String apptime = jsonObject.optString("apptime");
                        SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
                        String currentDateandTime = sdf.format(new Date());
                        SimpleDateFormat dateFormat = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
                        Calendar calendar1 = Calendar.getInstance();
                        Calendar calendar2 = Calendar.getInstance();

                        Date date1 = dateFormat.parse(apptime);
                        Date date2 = dateFormat.parse(currentDateandTime);

                        calendar1.setTime(date1);
                        calendar2.setTime(date2);

                        long diff = date1.getTime() - date2.getTime();
                        long seconds = diff / 1000;

                        calendar2.add(Calendar.SECOND, (int) seconds);
                        SimpleDateFormat sdf1 = new SimpleDateFormat("yyyy-MM-dd");
                         new_date = "FoodHIT" + sdf1.format(calendar2.getTime());
                        new_date = encryptStringmd5(new_date);
                        System.out.println("Compare Result : " + seconds);
                        System.out.println("AppTime: " + jsonObject.optString("apptime"));
                        System.out.println("token : " + new_date);

                        Prefs.putString("security_token",new_date);

                        Log.e("NNNNNNNNNNNNNNNN",""+new_date);
                    } else {
                        Toast.makeText(context, jsonResult.getString("Message"), Toast.LENGTH_SHORT).show();
                    }
                } catch (JSONException e) {
                    e.printStackTrace();
                } catch (ParseException e) {
                    e.printStackTrace();
                }
            }
        }, AppUtill.getapptime, postdata);
    } catch (Exception e) {
        e.printStackTrace();
    }

    Log.e("new_date........",""+new_date);
    return new_date;
}

In Activity.java file when I call this function it gives first time null;

String token= AppUtill.getToken()   // gives null for first time

Actually in this code, it returns value before web service call @PozzoApps — Vishal Vaishnav, Mar 27 '19 at 06:29
your method is asynchronous, therefore it shoudl not return anything, instead it should call the callback — Vladyslav Matviienko, Mar 27 '19 at 06:43
Possible duplicate of [How to get the result of OnPostExecute() to main activity because AsyncTask is a separate class?](https://stackoverflow.com/questions/12575068/how-to-get-the-result-of-onpostexecute-to-main-activity-because-asynctask-is-a) — Mohammed Atif, Mar 27 '19 at 09:19

score 3 · Answer 1 · answered Mar 27 '19 at 07:00

3

Please try interface call back functionality

Step1: create a interface

Ex.

public interface Result {

    public void success(String result);
}

Step2: create an interface object

    Result result=new Result() {

                @Override
                public void success(String result) {
                   String token=result;
                    // it will return result here....

                }
            };

pass interface object to getToken() ex.

AppUtill.getToken(result);

your method

  public static String getToken(Result result) {

// here your logic to call API

 //after result call
    result.success(result)//pass your result here
    }

answered Mar 27 '19 at 07:00

Ganesh Gudghe

1,327
1
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if you still need more help i am glad to help you – Ganesh Gudghe Mar 27 '19 at 07:04
But Is there any way so that I can return value only if web service call complete because I used many places String token= AppUtill.getToken() – Vishal Vaishnav Mar 27 '19 at 07:04
1

your getToken() is async call and it not possible to return from async. – Ganesh Gudghe Mar 27 '19 at 07:05
By this solution I have to write everywhere step 2 and it will take too much time – Vishal Vaishnav Mar 27 '19 at 07:07
Can you tell me what is aync call? – Vishal Vaishnav Mar 27 '19 at 07:09
2

async call means it will perform some background operation seprate thread withough interepting main thread https://developer.android.com/reference/android/os/AsyncTask – Ganesh Gudghe Mar 27 '19 at 07:11
Let us [continue this discussion in chat](https://chat.stackoverflow.com/rooms/190748/discussion-between-ganesh-gudghe-and-vishal-vaishnav). – Ganesh Gudghe Mar 27 '19 at 07:12
There is no any way without using interface? Can it possible using asynctask ? – Vishal Vaishnav Mar 27 '19 at 07:16
1

your AppUtill.getJsonWithHTTPPost() is alredy async call – Ganesh Gudghe Mar 27 '19 at 07:17
Let us [continue this discussion in chat](https://chat.stackoverflow.com/rooms/190759/discussion-between-vishal-vaishnav-and-ganesh-gudghe). – Vishal Vaishnav Mar 27 '19 at 10:20

score 0 · Answer 2 · answered Mar 27 '19 at 10:16

I got answer via below solution:

    public static class Example extends AsyncTask<String, String, String> {

    @Override
    protected String doInBackground(String... params) {
        JSONObject postdata = new JSONObject();
        try {
            AppUtill.getJsonWithHTTPPost(context, 1, new ServiceCallBack() {
                @Override
                public void serviceCallback(int id, JSONObject jsonResult) {
                    try {
                        if (jsonResult.getString("Status").equalsIgnoreCase("Success")) {
                            JSONObject jsonObject = jsonResult.getJSONObject("Data");
                            String apptime = jsonObject.optString("apptime");
                            SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
                            String currentDateandTime = sdf.format(new Date());
                            SimpleDateFormat dateFormat = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
                            Calendar calendar1 = Calendar.getInstance();
                            Calendar calendar2 = Calendar.getInstance();

                            Date date1 = dateFormat.parse(apptime);
                            Date date2 = dateFormat.parse(currentDateandTime);

                            calendar1.setTime(date1);
                            calendar2.setTime(date2);

                            long diff = date1.getTime() - date2.getTime();
                            long seconds = diff / 1000;

                            calendar2.add(Calendar.SECOND, (int) seconds);
                            SimpleDateFormat sdf1 = new SimpleDateFormat("yyyy-MM-dd");
                            new_date = "FoodHIT" + sdf1.format(calendar2.getTime());
                            new_date = encryptStringmd5(new_date);
                            System.out.println("Compare Result : " + seconds);
                            System.out.println("AppTime: " + jsonObject.optString("apptime"));
                            System.out.println("token : " + new_date);

                            Prefs.putString("security_token", new_date);

                            Log.e("NNNNNNNNNNNNNNNN",""+ new_date);
                        } else {
                            Toast.makeText(context, jsonResult.getString("Message"), Toast.LENGTH_SHORT).show();
                        }
                    } catch (JSONException e) {
                        e.printStackTrace();
                    } catch (ParseException e) {
                        e.printStackTrace();
                    }
                }
            }, AppUtill.getapptime, postdata);
        } catch (Exception e) {
            e.printStackTrace();
        }

        return new_date;
    }


    @Override
    protected void onPostExecute(String result) {
        // execution of result of Long time consuming operation
      new_date=result;
    }


}

store in below function:

 public static String getTokenn()  {
    try {
        return new Example().execute().get();
    } catch (InterruptedException e) {
        e.printStackTrace();
    } catch (ExecutionException e) {
        e.printStackTrace();
    }
    return null;
}

and get value by below code:

String token= AppUtill.getTokenn();

what about return null? and what will happen if service takes 1 or 2 minutes to get the response from the server? because it is an async call — Ganesh Gudghe, Mar 27 '19 at 10:29
What will happen by using async call ? and this will not wait for response from server if any delay from response? — Vishal Vaishnav, Mar 27 '19 at 10:34
in async, you can show loading/progress to the user until the response came from the server — Ganesh Gudghe, Mar 27 '19 at 10:35
no, for you current method will not wait until the reponse came from server — Ganesh Gudghe, Mar 27 '19 at 10:37
Let us [continue this discussion in chat](https://chat.stackoverflow.com/rooms/190761/discussion-between-ganesh-gudghe-and-vishal-vaishnav). — Ganesh Gudghe, Mar 27 '19 at 10:38

How to return value after calling API android (every time call function and return value)?

2 Answers2