How get counts of repeat elements in Array. Java

Issue

I need to get the count of records for the current day, from the database. The entries in the Firebase Realtime are in timestamp, I parse them using SimpleDateFormat.

But I could not get the count of records, for example, for today's date. Tell me what to do? Thanks

IMAGE RECORDS IN FIREBASE REALTIME

private void fetchDataWaterCount() {
    currDate = null;
    String uid = firebaseAuth.getUid();
    if (android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.O) {
        currDate = LocalDate.now().toString();
    }
    waterRef = FirebaseDatabase.getInstance().getReference("Users").child(uid).child("body").child("water");
    waterRef.addListenerForSingleValueEvent(new ValueEventListener() {
        @Override
        public void onDataChange(@NonNull DataSnapshot snapshot) {
            if (snapshot.exists()) {
                for (DataSnapshot ds : snapshot.getChildren()) {
                    waterModel = ds.getValue(WaterModel.class);
                    waterArray.add(waterModel);
                    waterModel.setWaterModelList(waterArray);
                    ArrayList listDate = new ArrayList();
                        for (int i = 0; i < waterModel.getWaterModelList().size(); i++) {
                            long dateList = waterModel.getWaterModelList().get(i).getDate();
                            SimpleDateFormat formatter = new SimpleDateFormat("yyyy-MM-dd", Locale.US);
                            String dateFormat = formatter.format(new Date(dateList));
                            listDate.add(dateFormat);
                            if(listDate.contains(currDate)){
                                int water_count = (int) listDate.size();
                                drawable = getActivity().getDrawable(R.drawable.circut_progress_bar);
                                progressBar.setProgress(water_count);
                                progressBar.setMax(12);
                                progressBar.setSecondaryProgress(water_count);
                                progressBar.setProgressDrawable(drawable);
                                textViewWaterCount.setText(String.valueOf(water_count));
                                if (water_count >= 12) {
                                    textViewWaterCount.setText("Done");
                                    textViewWaterCount.setTextColor(getResources().getColor(R.color.colorGreen_900));
                                    drawable = getActivity().getDrawable(R.drawable.circut_progressbar_green);
                                    progressBar.setProgressDrawable(drawable);
                                }
                            }
                        }
                }
            }
        }

        @Override
        public void onCancelled(@NonNull DatabaseError error) {

        }
    });
}

Solution

If you want to know the amount of WaterModels that match a specific date then you need to count them as they appear.

You are currently adding every date to the list regardless if it matches the currDate, so your count is the total dates not the specific amount of specific dates.

//Add this
int dateCount = 0;

for (int i = 0; i < waterModel.getWaterModelList().size(); i++) {
    long dateList = waterModel.getWaterModelList().get(i).getDate();
    SimpleDateFormat formatter = new SimpleDateFormat("yyyy-MM-dd", Locale.US);
    String dateFormat = formatter.format(new Date(dateList));
    listDate.add(dateFormat);


    //Add this
    if(dateFormat == currDate){
             dateCount++;
    }


    //I don't know what your doing here but this will return true
    //if there is at least 1 match. You can't use this to track how many dates
    //match
    if (listDate.contains(currDate)) {
        int water_count = (int) listDate.size();
        drawable = getActivity().getDrawable(R.drawable.circut_progress_bar);
        progressBar.setProgress(water_count);
        progressBar.setMax(12);
        progressBar.setSecondaryProgress(water_count);
        progressBar.setProgressDrawable(drawable);
        textViewWaterCount.setText(String.valueOf(water_count));
        if (water_count >= 12) {
            textViewWaterCount.setText("Done");
            textViewWaterCount.setTextColor(getResources().getColor(R.color.colorGreen_900));
            drawable = getActivity().getDrawable(R.drawable.circut_progressbar_green);
            progressBar.setProgressDrawable(drawable);
        }
    }
}

dateCount will contain the total amount of Dates that match the currDate.

Answered By - avalerio