如何在Android上的Firebase Databse上检索特定列表项

Question

teamapp-25ba7
  schedules
    -LHc3zKZhNFLq536dpA1
      UID:    
      date:
      details:
      time:
      title:
    -LHc7MBAoNwLWCNgkZ_y
      UID:
      date:
      details:
      time:
      title: 

from the above example of my nodes, i would like to just get details and time values ,my question is how do i retrieve just those 2 values . i tried iterating through all the values but that just gets me everything

Answer 1

Assuming that you want to get the values of details and time properties from all objects and also assuming that the details property is of type String and the time is ServerValue.TIMESTAMP , to solve this please use the following code:

DatabaseReference rootRef = FirebaseDatabase.getInstance().getReference();
DatabaseReference schedulesRef = rootRef.child("schedules");
ValueEventListener valueEventListener = new ValueEventListener() {
    @Override
    public void onDataChange(DataSnapshot dataSnapshot) {
        for(DataSnapshot ds : dataSnapshot.getChildren()) {
            String details = ds.child("details").getValue(String.class);
            long time = ds.child("time").getValue(Long.class);
            Log.d("TAG", details + " / " + time);
        }
    }

    @Override
    public void onCancelled(@NonNull DatabaseError databaseError) {}
};
schedulesRef.addListenerForSingleValueEvent(valueEventListener);