Android: How to retrieve data from a current user in firebase?

Question

I'm creating an application where a user can create an account and also can log in. Also I have a profile page where the user can see his personal information. My question is how can I retrieve data like fullname, email, password, etc from a specific or current user into my profile class?

In addition, I'm using a fragment for my profile class.

Here is my database structure:

Here is my code:

_8_ViewEventMember_Profile.java

public class _8_ViewEventMember_Profile extends Fragment {

private FirebaseAuth auth;
TextView name, email, password, bday, country, mobileno;

View myView;

@Nullable
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
    myView = inflater.inflate(R.layout.activity__8__view_event_member_profile, container, false);

    ((AppCompatActivity) getActivity()).getSupportActionBar().setTitle("Profile");

    name = (TextView) getActivity().findViewById(R.id.textName);
    email = (TextView) getActivity().findViewById(R.id.textEmail);
    password = (TextView) getActivity().findViewById(R.id.textPassword);
    bday = (TextView) getActivity().findViewById(R.id.textCountry);
    country = (TextView) getActivity().findViewById(R.id.textCountry);
    mobileno = (TextView) getActivity().findViewById(R.id.textMobileNumber);

    auth = FirebaseAuth.getInstance();

    FirebaseAuth.AuthStateListener authListener = new FirebaseAuth.AuthStateListener() {
        @Override
        public void onAuthStateChanged(@NonNull FirebaseAuth firebaseAuth) {
            FirebaseUser firebaseUser = firebaseAuth.getCurrentUser();
            if(firebaseUser != null){
                String userName = firebaseUser.getDisplayName();
                String userEmail = firebaseUser.getEmail();

                FirebaseDatabase db = FirebaseDatabase.getInstance();
                String key  = db.getReference("accounts").push().getKey();

                Map<String, Object> childUpdates = new HashMap<>();
                childUpdates.put("fullname", userName);


                name.setText(userName);
                email.setText(userEmail);

            }
        }
    };
    return myView;
}
}

activity__8__view_event_member_profile.xml

   <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical" android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_margin="20dp">

<LinearLayout
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:orientation="horizontal"
    android:layout_marginTop="20dp">

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Name:"
        android:textColor="@color/colorBlack"
        android:textSize="20sp"/>

    <TextView
        android:id="@+id/textName"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Name"
        android:textColor="@color/colorBlack"
        android:textSize="20sp"
        android:layout_marginLeft="55dp"/>

</LinearLayout>

<LinearLayout
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:orientation="horizontal"
    android:layout_marginTop="20dp">

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Email:"
        android:textColor="@color/colorBlack"
        android:textSize="20sp"/>

    <TextView
        android:id="@+id/textEmail"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Email"
        android:textColor="@color/colorBlack"
        android:textSize="20sp"
        android:layout_marginLeft="60dp"/>

</LinearLayout>

<LinearLayout
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:orientation="horizontal"
    android:layout_marginTop="20dp">

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Password:"
        android:textColor="@color/colorBlack"
        android:textSize="20sp"/>

    <TextView
        android:id="@+id/textPassword"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Password"
        android:textColor="@color/colorBlack"
        android:textSize="20sp"
        android:layout_marginLeft="23dp"/>

</LinearLayout>

<LinearLayout
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:orientation="horizontal"
    android:layout_marginTop="20dp">

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Birthday:"
        android:textColor="@color/colorBlack"
        android:textSize="20sp"/>

    <TextView
        android:id="@+id/textBday"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Birthday"
        android:textColor="@color/colorBlack"
        android:textSize="20sp"
        android:layout_marginLeft="40dp"/>

</LinearLayout>

<LinearLayout
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:orientation="horizontal"
    android:layout_marginTop="20dp">

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Country:"
        android:textColor="@color/colorBlack"
        android:textSize="20sp"/>

    <TextView
        android:id="@+id/textCountry"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Country"
        android:textColor="@color/colorBlack"
        android:textSize="20sp"
        android:layout_marginLeft="45dp"/>

</LinearLayout>

<LinearLayout
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:orientation="horizontal"
    android:layout_marginTop="20dp">

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Mobile No.:"
        android:textColor="@color/colorBlack"
        android:textSize="20sp"/>

    <TextView
        android:id="@+id/textMobileNumber"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Mobile Number"
        android:textColor="@color/colorBlack"
        android:textSize="20sp"
        android:layout_marginLeft="20dp"/>

  </LinearLayout>

</LinearLayout>

I hope you could help me! Thank you!

Answer 1

Before going to the development you have to structure you data denormalize,flatten and duplicate your data in a user prescriptive way. And before you decide your final structure, you should know that how and when you retrieve that data. If you plan well for your database structure you will simplify your programming process and you will save a lot of time.

My solution for this would be duplicating the key of the user inside the user tree as an user ID as follows:

acounts:
---- -KSOMEKEYVALUE
--------brithday:*****
--------fullname:*****
--------id: KSOMEKEYVALUE

Then when the log in process succeed, you retrieve the data for that specific user based on their unique ID as follows:

    DatabaseReference ref = database.getReference("accounts");
    login=ref.child(userID); //here user will sign in using his name so it is
                           //based on userID, directory will change dynamically

Then you attach your listener to that specific userID as follows:

// Attach a listener to read the data at our posts reference
    login.addValueEventListener(new ValueEventListener() {
    @Override
    public void onDataChange(DataSnapshot dataSnapshot) {
        FirebaseUser firebaseUser = dataSnapshot.getValue(Post.class);

    }

    @Override
    public void onCancelled(DatabaseError databaseError) {
        System.out.println("The read failed: " + databaseError.getCode());
    }
});

The firebaseUser object should contain the data for the logged in user.