如何从 Firebase 数据库中读取数据？ - 爪哇

Question

I'm making a game, if the player wins, then the victory is added to the database. How can I read the data from here?

and paste here:

I read the player's name in a different way, which cannot be repeated with victories and defeats.

Answer 1

To be able to read the data under the jjjj node, please use the following lines of code:

DatabaseReference db = FirebaseDatabase.getInstance().getReference();
DatabaseReference nameRef = db.child("players").child("jjjj");
nameRef.get().addOnCompleteListener(new OnCompleteListener<DataSnapshot>() {
    @Override
    public void onComplete(@NonNull Task<DataSnapshot> task) {
        if (task.isSuccessful()) {
            DataSnapshot snapshot = task.getResult();
            String loses = snapshot.child("loses").getValue(Long.class);
            String name = snapshot.child("name").getValue(String.class);
            String wins = snapshot.child("wins").getValue(Long.class);
            Log.d("TAG", loses + "/" + name + "/" + wins);
        } else {
            Log.d("TAG", task.getException().getMessage()); //Never ignore potential errors!
        }
    }
});

The result in the logcat will be:

3/jjjj/4

Things to notice:

• Always create a reference that points to the node that you want to read.
• If your database is located in another lcoation than the default, check this answer out.

Answer 2

use this method

This is the method of fetching data from the firebase realtime database

DatabaseReference reference = FirebaseDatabase.getInstance().getReference();

    reference.child("players").child(name).addValueEventListener(new ValueEventListener() {
        @Override
        public void onDataChange(@NonNull DataSnapshot snapshot) {
            for (DataSnapshot dataSnapshot : snapshot.getChildren()){

            }
        }

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

        }
    });