Android, Retrofit 2: How to make calls every 5 second?

Question

this is my code:

 private void getUserData(){
    //create Retrofit instance
    Retrofit.Builder builder = new Retrofit.Builder()
            .baseUrl(Constants.BASE_URL)
            .addConverterFactory(GsonConverterFactory.create())
            .addCallAdapterFactory(RxJava2CallAdapterFactory.create());

    Retrofit retrofit = builder.build();

    //get client & call object for the request
    APIService userService = retrofit.create(APIService.class);

    Map<String, Object> map = new HashMap<>();
    map.put("device_id", Utils.GetDeviceID(DashboardActivity.this));

    Call call = userService.getUser(map);

    //execute network request
    call.enqueue(new Callback() {
        @Override
        public void onResponse(Call call, Response response) {
            if(response.isSuccessful() && response.body() != null){
                response.body();
                UserDataManager.$().setUserDataResponse(new com.google.gson.Gson().toJson(response.body()));
                if(UserDataManager.$().getUserData() != null){
                    Log.d(TAG, "USER ID: " + UserDataManager.$().getUserData().getId());
                }
            }
        }

        @Override
        public void onFailure(Call call, Throwable t) {

        }
    });
}

Question: How can i call this method every 5 second, to check is the new data coming from backend or not?

Will be glad for suggestions and hints, thanks

Answer 1

RxAndroid will be very useful in this case. You can create loop like this

Subscription subscription = Observable.interval(1000, 5000, 
 TimeUnit.MILLISECONDS)
        .observeOn(AndroidSchedulers.mainThread())
        .subscribe(new Action1<Long>() {
            public void call(Long aLong) {
                // here is the task that should repeat
            }
        });

If you want to stop the loop just call

subscription.unsubscribe()

Answer 2

You can use Handler to achieve making call every 5 seconds.

boolean shouldStopLoop = false;
Handler mHandler = new Handler();

Runnable runnable = new Runnable() {
    @Override
    public void run() {
        getUserData();
        if (!shouldStopLoop) {
            mHandler.postDelayed(this, 5000);
        }
    }
};

and call mHandler.post(runnable); to start the call.

Answer 3

Completable.timer(5, TimeUnit.SECONDS)
                .observeOn(AndroidSchedulers.mainThread())
                .subscribe(this::doYourThing, this::onError)) 

But a better option would be to ask your backend developer to send a firebase notification in case of a data change since Network calls are expensive operations.

Answer 4

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