How to get user uid from firebase on android?

问题

I want to save data to firebase. This is my Activity Code :

private Firebase firebaseRef;
Firebase.setAndroidContext(this);

try {
    mUserId = firebaseRef.getAuth().getUid();
} catch (Exception e) {
    //  loginWithMailView();
}
itemsUrl = Constants.FIREBASE_URL + "/Person/" + mUserId +"/Information/";

//Person + null (?) + the other information

and this is for my button code :

buttonSave = (Button) findViewById(R.id.btnKaydolKayit);
buttonSave.setOnClickListener(new View.OnClickListener() {

    @Override
    public void onClick(View v) {
        firebaseRef = new Firebase(Constants.FIREBASE_URL);
        String name = editTextName.getText().toString().trim();
        String surname = editTextSurname.getText().toString().trim();
        String gender = final_result.getText().toString();
        String mail = editTextMail.getText().toString();
        String pass = editTextPass.getText().toString().trim();
        String phone = editTextPhone.getText().toString().trim();
        String trom = final_resultT.getText().toString();
        String bloodGroup = spinnerBlood.getSelectedItem().toString();
        String dateBlood = dateTextViewBlood.getText().toString();
        String dateTrombo = dateTextViewTrom.getText().toString();

        if (pass.isEmpty() || mail.isEmpty()) {
            AlertDialog.Builder builder = new AlertDialog.Builder(KaydolActivity.this);
            builder.setMessage(R.string.signup_error_message)
                    .setTitle(R.string.signup_error_title)
                    .setPositiveButton(android.R.string.ok, null);
            AlertDialog dialog = builder.create();
            dialog.show();
        } else {
            firebaseRef.createUser(mail, pass, new Firebase.ResultHandler(){

                @Override
                public void onSuccess() {
                    firebaseRef = new Firebase(Constants.FIREBASE_URL);
                    //  firebaseRef.setValue();
                    AlertDialog.Builder builder = new AlertDialog.Builder(KaydolActivity.this);
                    builder.setMessage("Hesap başarılı bir şekilde oluşturuldu!").setPositiveButton(R.string.login_button_label, new DialogInterface.OnClickListener() {
                        @Override
                        public void onClick(DialogInterface dialogInterface, int i) {
                            Intent intent = new Intent(KaydolActivity.this, loginWithMail.class);
                            intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
                            intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TASK);
                            startActivity(intent);
                        }
                    });
                    AlertDialog dialog = builder.create();
                    dialog.show();
                }

                @Override
                public void onError(FirebaseError firebaseError) {
                    AlertDialog.Builder builder = new AlertDialog.Builder(KaydolActivity.this);
                    builder.setMessage(firebaseError.getMessage())
                            .setTitle(R.string.signup_error_title)
                            .setPositiveButton(android.R.string.ok, null);
                    AlertDialog dialog = builder.create();
                    dialog.show();
                }
            });
        }

        new Firebase(itemsUrl).push().child("name").setValue(name);
        new Firebase(itemsUrl).push().child("surname").setValue(surname);
        new Firebase(itemsUrl).push().child("gender").setValue(gender);
        new Firebase(itemsUrl).push().child("mail").setValue(mail);
        new Firebase(itemsUrl).push().child("pass").setValue(pass);
        new Firebase(itemsUrl).push().child("phone").setValue(phone);
        new Firebase(itemsUrl).push().child("trom").setValue(trom);
        new Firebase(itemsUrl).push().child("bloodGroup").setValue(bloodGroup);
        new Firebase(itemsUrl).push().child("trom").setValue(trom);
        new Firebase(itemsUrl).push().child("dateBlood").setValue(dateBlood);
        new Firebase(itemsUrl).push().child("dateTrombo").setValue(dateTrombo);
    }
});

my source code (for help / for example ) : https://www.sitepoint.com/creating-a-cloud-backend-for-your-android-app-using-firebase/

When I save a data to firebase as the following photo ( Login&Auth )

but mUserId is null. so when I look database mUserid is null ( like a photo )

回答1:

You can use these lines of code to get Current User Uid with Android Firebase Framework

FirebaseUser currentFirebaseUser = FirebaseAuth.getInstance().getCurrentUser() ;
Toast.makeText(this, "" + currentFirebaseUser.getUid(), Toast.LENGTH_SHORT).show();

回答2:

To get Current User UID, you just need this line of code:

String currentuser = FirebaseAuth.getInstance().getCurrentUser().getUid();

回答3:

the problem is that in firebase when you create a user it doesn't sign in the user. Here is from the docs:

Creates a new email / password user with the provided credentials. This method does not authenticate the user. After the account is created, the user may be authenticated with authWithPassword(). https://www.firebase.com/docs/web/api/firebase/createuser.html

Firebase ref = new Firebase("https://<YOUR-FIREBASE-APP>.firebaseio.com");
    ref.authWithPassword(mail, pass, new Firebase.AuthResultHandler() {
        @Override
        public void onAuthenticated(AuthData authData) {
            System.out.println("User ID: " + authData.getUid() + ", Provider: " + authData.getProvider());
        }
        @Override
        public void onAuthenticationError(FirebaseError firebaseError) {
            // there was an error
        }
    });

So once your user is created call the authWithPassword function. Hope it helps!

回答4:

in REACT NATIVE it's just like this.

  import firebase as 'firebase';

    HandleGetUserId=()=>{
    let userId = firebase.auth().currentUser.uid;
    return userId;
    }

just call the function HandleGetUserId to get the id like this

this.HandleGetUserId();

回答5:

I was also having the same problem with getting the uid. When i had it printed on the log (Log.i), i could see the uid, however when trying to use it as one of the fields in one of my objects being created, the field does not get created.

I was doing thing : String currentUId = FirebaseAuth.getInstance().getCurrentUser().getUid();

This didn't work well for me.

SOLUTION I FOUND OUT - (worked for me - try it out)

Use : FirebaseUser currentU = FirebaseAuth.getInstance().getCurrentUser(); String uId = currentU.getUid();

来源：https://stackoverflow.com/questions/37566911/how-to-get-user-uid-from-firebase-on-android