How to sort string elements in RecyclerView?

Question

I have 5 elements in RecyclerView(elements taken from DB) with dates and texts. Two different lists. For dates and for strings. One fragment contains 1 date and 1 string text. So, im need to sort elements by date, like that

Result which i want

text1 10.09.2021
text2 13.09.2021
text3 30.09.2021
text4 1.12.2021

Result which i have

text3 30.09.2021
text4 1.12.2021
text1 10.09.2021
text2 13.09.2021

texts and dates is a two different Lists

The question is, how i can sort dates as strings(may be?) with no text loss, and where im supposed to do that (after getting from db and before retrieve data in adapter? or after loading elements in adapter and then getting them back for sort (looks bad)

thats how im get data from DB and retrieve in adapter

        List<String> reminder = new ArrayList<>();
        List<String> date = new ArrayList<>();

        Calendar test = Calendar.getInstance();
        long pars = test.getTimeInMillis();
        System.out.println(pars);


        dbf.child("Reminders").addValueEventListener(new ValueEventListener() {
            @Override
            public void onDataChange(@NonNull DataSnapshot snapshot) {

                reminder.clear();
                date.clear();


                for(DataSnapshot child2 : snapshot.getChildren()) { // getting a data from DB to ArrayList for dropping into Adapter

                    for(DataSnapshot tChild : child2.getChildren()) {
                        if (tChild.getKey().equals("text")) {
                            reminder.add(tChild.getValue().toString());
                            rem = reminder.toArray(new String[reminder.size()]);

                        }
                        if (tChild.getKey().equals("date")) {
                            date.add(tChild.getValue().toString());
                            dat = date.toArray(new String[date.size()]);


                        }

                    }



                    mainRowAdapter rAdapter = new mainRowAdapter(MainActivity.this, rem,dat);
                    rv.setAdapter(rAdapter);
                    rv.setLayoutManager(new LinearLayoutManager(MainActivity.this));

                }
            }

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

            }
        });

setText in AdapterClass

        holder.reminder.setText(reminder[position]);
        holder.date.setText(date[position]);

in another topic i saw this one, but this cannot help me in my situation? may be some analogies exist?

Collections.sort(categories, new Comparator<Categories>() {
            @Override
            public int compare(Categories lhs, Categories rhs) {
                return lhs.title.compareTo(rhs.title);
            }
        });

Would you mind rephrasing your question? And maybe provide examples of the existing vs intended behaviours. — ttyip, Oct 02 '21 at 19:05

score 0 · Answer 1 · edited Oct 05 '21 at 06:36

0

the best place to sort your data is when you get your data from db by a query, but if you want to do it manually on your list the best format for saving your date is like this:

because string sort can apply to your date. To sort the dates in descending order, you can simply use:

collections.reverseorder();

edited Oct 05 '21 at 06:36

Dev4Life

2,328
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22

answered Oct 03 '21 at 17:03

Alireza Mahfouzian

338
1
8

but how i can sort my text array too? with same positions as dates? – Spectator Oct 03 '21 at 17:59

How to sort string elements in RecyclerView?

1 Answers1