dbRef.addValueEventListener(new ValueEventListener() {    @Override    public void onDataChange(@NonNull DataSnapshot dataSnapshot) {        for(DataSnapshot ds:dataSnapshot.getChildren()){           // Toast.makeText(getApplicationContext(), ds.getKey(), Toast.LENGTH_SHORT).show();            talks.child(ds.getKey()).limitToFirst(1).addListenerForSingleValueEvent(new ValueEventListener() {                @Override                public void onDataChange(@NonNull DataSnapshot dataSnapshot) {                    for(DataSnapshot a:dataSnapshot.getChildren()){                          yazilan=a.getValue().toString();                      gonder(yazilan);                       // Toast.makeText(getApplicationContext(), yazilan, Toast.LENGTH_SHORT).show();                    }                }                @Override                public void onCancelled(@NonNull DatabaseError databaseError) {                }            });            Toast.makeText(getApplicationContext(), "dışarıdaki yazılan "+yazilan, Toast.LENGTH_SHORT).show();            Toast.makeText(getApplicationContext(), "yazilan al "+yazilanal(), Toast.LENGTH_SHORT).show();;            fillArrayList(persons,ds.getKey(),"Boy",yazilanal(),"buda ismim");            //listView.invalidate();            listViewAdapter.notifyDataSetChanged();        }    }    public String yazilanal() {        return yazilan;    }    public void gonder(String b) {       // Toast.makeText(getApplicationContext(), "gelen "+b, Toast.LENGTH_SHORT).show();        yazilan=b;      //  Toast.makeText(getApplicationContext(), "yazilan "+yazilan, Toast.LENGTH_SHORT).show();    }    @Override    public void onCancelled(@NonNull DatabaseError databaseError) {    }});