My Android app is really slow when getting simple data from PHP

Question

I have a PHP API which echoes some data depending on the parameters in the URL:

URL = "MyWebsite.com/MyAPI.php/username/password"

When I try to access this API with Postman, I get the result within 5 seconds, however, using any Android device, I get the result at least 15 seconds later, under same network.

Now I suspect there might be a delay in the way I'm processing the data, but I'm also doubting that it's taking +10 seconds.

Here's the result from the API call:

{'Data1': Value1, 'Data2': 'Value2', 'Data3': 'Value3', 'Data4': 'Value4', 'Data5': 'Value5', 'Data6': 'Value6', 'Data7': 'Value7'}

Only the first value is integer, the rest are all string.

API Call code:

    apiTEST = view.findViewById(R.id.apiTEST);//Text View
    Button getUserData = view.findViewById(R.id.getUserData);
    String apiURL = "https://MyWebsite.com/MyAPI.php/username/password";
    new Handler().postDelayed(() -> {
        getUserData.performClick();
        apiTEST.setText(getResources().getString(R.string.please_wait));//Show please wait line
    }, 1000);//Automatically press the invisible button a second after loading the activity
    getUserData.setOnClickListener(v -> {
        StringRequest stringRequest = new StringRequest(apiURL,
                response -> showJSONS(view, response),
                error -> {
                    apiTEST.setText(error.getMessage());
                    getUserData.performClick(); //Sometimes an error occurs (null), so this line will just click the button automatically to make the request again
                });
        RequestQueue requestQueue = Volley.newRequestQueue(getActivity());
        requestQueue.add(stringRequest);
    });

Data processing/showing:

   private void showJSONS(View view, String response) {
    response = response.replace("'", "").replace("\"", "").replace("{", "").replace("}","");
    String[] theValues = response.split(",");
    apiTEST = view.findViewById(R.id.apiTEST);
    for (String theValue : theValues) {
        if (theValue.contains("Data1")){
            String[] data1Line = theValue.split(":");
            String Data1 = data1Line[1];
            Data1 = Data1.replace("'", "");
            data1_field.setText(Data1);
        }
        else if (theValue.contains("Data2")){
            String[] data2Line = theValue.split(":");
            String data2 = data2Line[1];
            data2 = data2.replace("'", "");
            data2_field.setText(data2);
            data2ProgressBar[0] = data2;
        }
        else if (theValue.contains("Data3")){
            String[] data3Line = theValue.split(":");
            String data3 = data3Line[1];
            data3 = data3.replace("\"", "");
            data3_field.setText(data3);
            data3ProgressBar[0] = data3;
        }
        else if (theValue.contains("Data4")){
            String[] data4Line = theValue.split(":");
            String data4Value = data4Line[1];
            data4Value = data4Value.replace("\"", "");
            data4Value = data4Value.replace("}]}", "");
            data4_field.setText(data4Value);
            data4ProgressBar[0] = data4Value;
        }
        ... same for data5, data6 & data7
    }
    setButtonsVisibility(view, true);//Show buttons to interact with the values
    apiTest.setText("");//Remove the "Please Wait" line
  }

Although I have set the buttons visibility before removing the "Please wait" line, what actually happens in the app is that the "Please wait" line gets removed, then about 7 seconds later the buttons appear!

Is there a better approach to retrieving the data from the API? Or to process the data more effectively?

About the auto clicking the button automatically when an error occurs: If I try to use Postman, I get the result 10/10, never failed or showed any error, but through the app, sometimes I just get "null" so I can only get the result after retrying few times. Thanks.

Answer 1

When approaching optimization problems (and it kinda is one as you want to make a call faster) its generally best to first make sure that you understand exactly what is happening so when in doubt - measure and debug.

Before doing any changes in the code I'd first set up debugger and probably some logs with timestamps (assuming you are testing on separate physical device - maybe emulator would be more useful?).

After you have tools that allow you to measure the code runtime - don't guess, locate the hotspot. When hotspot is known usually the solution becomes obvious (if its not then its a good moment to ask further questions).

Sorry if this is not the answer you were counting for but I believe that giving advice on code performance without specific measurement is exactly wrong - and amount of data you have provided is insufficient (mainly because there is too much difference between using postman from your development machine and app working on a android device - does it have enough ram? what exactly spans those 15 seconds - changes in the UI or it is time between http request and response? what does it mean they are on the same network? etc...).

BTW "https://MyWebsite.com/MyAPI.php/username/password" - passing username and password like this makes me uneasy in terms of security see: https://owasp.org/www-community/vulnerabilities/Information_exposure_through_query_strings_in_url#

Also, I'd strongly recommend using json parsing library instead of current solution like jackson object mapper (simple tutorial: https://www.baeldung.com/jackson-object-mapper-tutorial)