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[英]android studio firebase database: how to get data from sub child
[英]Android Studio how to get data from the Firebase database?
我有这段代码,我想从包含用户的“ Usuarios”中的Firebase数据库中获取值String(例如,用户的名称),将其放在txtName变量中。
public class HomeFragment extends Fragment {
private FirebaseAuth.AuthStateListener mAuthListener;
private FirebaseAuth mAuth = FirebaseAuth.getInstance();
private Button btnLogOut;
private int CAMERA_REQUEST_CODE = 0;
private TextView textName;
private DatabaseReference mDatabase = FirebaseDatabase.getInstance().getReference();
FirebaseDatabase database = FirebaseDatabase.getInstance();
DatabaseReference myRef = database.getReference("Usuarios");
public HomeFragment() {
// Required empty public constructor
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.fragment_home, container, false);
TextView textName = (TextView) view.findViewById(R.id.txtName);
return view;
}
@Override
public void onPause() {
super.onPause();
}
}
非常感谢你,如果你能解决这个问题,你会很感激:)
要显示所有这些子项,请使用以下代码:
DatabaseReference rootRef = FirebaseDatabase.getInstance().getReference();
DatabaseReference usuariosRef = rootRef.child("Usuarios");
ValueEventListener eventListener = new ValueEventListener() {
@Override
public void onDataChange(DataSnapshot dataSnapshot) {
for(DataSnapshot ds : dataSnapshot.getChildren()) {
String name = ds.child("name").getValue(String.class);
Log.d("TAG", name);
}
}
@Override
public void onCancelled(DatabaseError databaseError) {}
};
usuariosRef.addListenerForSingleValueEvent(eventListener);
输出将是:
Eric
Julian Ramos
//And so on
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