How To Add Auto Refresh In The Below Code Android Api Service

How to make a background refresh interval for 5 second.As per my code when I post a new name it won't displaying hence when I reopen the app its showing so I need a auto refresh. W

Solution 1:

See the changes, basically use a Handler for periodic thing-

public class MainActivity extends AppCompatActivity {

    ListView listView;

    Handler handler = new Handler();
    int apiDelayed = 5*1000; //1 second=1000 milisecond, 5*1000=5seconds
    Runnable runnable;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        listView = (ListView) findViewById(R.id.listViewHeroes);

        //calling the method to display the heroes
        getHeroes();
    }

    @Override
    protected void onResume() {
        super.onResume();

        handler.postDelayed( runnable = new Runnable() {
            public void run() {
                //do your function;
                getHeroes();
                handler.postDelayed(runnable, apiDelayed);
            }
        }, apiDelayed); // so basically after your getHeroes(), from next time it will be 5 sec repeated
    }
    @Override
    protected void onPause() {
        super.onPause();
        handler.removeCallbacks(runnable); //stop handler when activity not visible
    }

    private void getHeroes() {
        Retrofit retrofit = new Retrofit.Builder()
                .baseUrl(Api.BASE_URL)
                .addConverterFactory(GsonConverterFactory.create()) //Here we are using the GsonConverterFactory to directly convert json data to object
                .build();

        Api api = retrofit.create(Api.class);

        Call<List<Hero>> call = api.getHeroes();

        call.enqueue(new Callback<List<Hero>>() {
            @Override
            public void onResponse(Call<List<Hero>> call, Response<List<Hero>> response) {
                List<Hero> heroList = response.body();

                //Creating an String array for the ListView
                String[] heroes = new String[heroList.size()];

                //looping through all the heroes and inserting the names inside the string array
                for (int i = 0; i < heroList.size(); i++) {
                    heroes[i] = heroList.get(i).getName();
                }


                //displaying the string array into listview
                listView.setAdapter(new ArrayAdapter<String>(getApplicationContext(), android.R.layout.simple_list_item_1, heroes));

            }

            @Override
            public void onFailure(Call<List<Hero>> call, Throwable t) {
                Toast.makeText(getApplicationContext(), t.getMessage(), Toast.LENGTH_SHORT).show();
            }
        });
    }
}