Java – If the user has already been created, check Firebase for the correct code location?

If the user has already been created, check Firebase for the correct code location?… here is a solution to the problem.

If the user has already been created, check Firebase for the correct code location?

I created a way to get a user’s Facebook data, log them in, and create a “user” for them in my Firebase database. This method addUser() also creates and sets variables for the said user. But I have to keep the method, log in so that it creates my variables, and then comment out the method for future testing, otherwise it will reset all values.
So where can I add “addUser()” to create said user for the first time and make sure it never calls it again, as long as the user already exists?

MainActivity (startup and login).

public class MainActivity extends AppCompatActivity {
    CallbackManager callbackManager;
    ShareDialog shareDialog;
    LoginButton login;
    ProfilePictureView profile;
    Dialog details_dialog;
    TextView details_txt;
    JSONObject response;

/* Used to track user logging in/out off Facebook */
    private AccessTokenTracker mFacebookAccessTokenTracker;

/* A reference to the Firebase */
    private Firebase mFirebaseRef;

/* A reference to the Firebase */
    private Firebase userRef;

/* Data from the authenticated user */
    public static AuthData mAuthData;

/* Listener for Firebase session changes */
    private Firebase.AuthStateListener mAuthStateListener;

public static String uName = null;

public static String uEmail = null;

public static String uUrl = null;

public static int mTokens = 50;

public static String uID = null;

public static int getLiveTokens() {
        return liveTokens;
    }

public static void setLiveTokens(int liveTokens) {
        MainActivity.liveTokens = liveTokens;
    }

public static int liveTokens = 0;

public static int getLiveSpins() {
        return liveSpins;
    }

public static void setLiveSpins(int liveSpins) {
        MainActivity.liveSpins = liveSpins;
    }

public static int liveSpins = 0;

@Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

setContentView(R.layout.activity_main);

mFirebaseRef = new Firebase("https://<url>.firebaseio.com/");

callbackManager = CallbackManager.Factory.create();
        login = (LoginButton) findViewById(R.id.login_button);

profile = (ProfilePictureView) findViewById(R.id.picture);
        shareDialog = new ShareDialog(this);
        login.setReadPermissions("public_profile email");

details_dialog = new Dialog(this);
        details_dialog.setContentView(R.layout.dialog_details);
        details_dialog.setTitle("Details");
        details_txt = (TextView) details_dialog.findViewById(R.id.details);

getLoginDetails(login);

mFacebookAccessTokenTracker = new AccessTokenTracker() {
            @Override
            protected void onCurrentAccessTokenChanged(AccessToken oldAccessToken, AccessToken currentAccessToken) {
                Log.i(Tag, "Facebook.AccessTokenTracker.OnCurrentAccessTokenChanged");
                Toast.makeText(getApplicationContext(), "FBAccessTokenChange", Toast.LENGTH_LONG).show();

MainActivity.this.onFacebookAccessTokenChange(currentAccessToken);
            }
        };

if (AccessToken.getCurrentAccessToken() != null) {
            RequestData();
            getLoginDetails(login);
            getUserInfo();

Toast.makeText(getApplicationContext(), "Already Logged In", Toast.LENGTH_LONG).show();
        }

login.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                if (AccessToken.getCurrentAccessToken() != null) {
                    profile.setProfileId(null);
                }
            }
        });

mAuthStateListener = new Firebase.AuthStateListener() {
            @Override
            public void onAuthStateChanged(AuthData authData) {
                mAuthProgressDialog.hide();
                setAuthenticatedUser(authData);
            }
        };
        /* Check if the user is authenticated with Firebase already. If this is the case we can set the authenticated
         * user and hide hide any login buttons */
        mFirebaseRef.addAuthStateListener(mAuthStateListener);
    }

public void addUser() {

this.uID = mAuthData.getUid();

Toast.makeText(getApplicationContext(), "Setting Up User Account", Toast.LENGTH_LONG).show();

Firebase rootRef = new Firebase("https://<url>.firebaseio.com/users/");
        Firebase userRef = rootRef.child(mAuthData.getUid() + "/");
        userRef.child("name").setValue(mAuthData.getProviderData().get("displayName"));
        userRef.child("provider").setValue(mAuthData.getProvider());
        userRef.child("email").setValue(mAuthData.getProviderData().get("email"));
        userRef.child("tokens").setValue("100");
        userRef.child("spins").setValue("100");
        userRef.child("totalspins").setValue("0");
        userRef.child("topwin").setValue("0");
    }

protected void getLoginDetails(LoginButton login){

login.registerCallback(callbackManager, new FacebookCallback<LoginResult>() {

@Override
            public void onSuccess(LoginResult login_Result) {
                getUserInfo();
            }

@Override
            public void onCancel() {
            }

@Override
            public void onError(FacebookException exception) {
            }
        });
    }

 LoginResult login_result
    protected void getUserInfo() {

 LoginResult login_result.getAccessToken()

GraphRequest data_request = GraphRequest.newMeRequest(AccessToken.getCurrentAccessToken(), new GraphRequest.GraphJSONObjectCallback() {

@Override
            public void onCompleted(JSONObject json_object, GraphResponse response) {

Intent intent = new Intent(MainActivity.this, HomeActivity.class);
                intent.putExtra("jsondata", json_object.toString());
                intent.putExtra("Uid", uID);
                startActivity(intent);
            }
        });

Bundle permission_param = new Bundle();
        permission_param.putString("fields", "id,name,email,picture.width(120).height(120)");
        data_request.setParameters(permission_param);
        data_request.executeAsync();
    }

public void RequestData() {
        GraphRequest request = GraphRequest.newMeRequest(AccessToken.getCurrentAccessToken(), new GraphRequest.GraphJSONObjectCallback() {
            @Override
            public void onCompleted(JSONObject object, GraphResponse response) {

JSONObject json = response.getJSONObject();
                try {
                    if (json != null) {
                        String text = "<b>Name :</b> " + json.getString("name") + "<br><br><b>Email :</b> " + json.getString("email") + "<br><br><b> Profile link :</b> " + json.getString("link");
                        details_txt.setText(Html.fromHtml(text));
                        profile.setProfileId(json.getString("id"));
                        uName = json.getString("name");
                        uEmail = json.getString("email");

uUrl = json.getString("id");
                    }
                } catch (JSONException e) {
                    e.printStackTrace();
                }
            }
        });

Bundle parameters = new Bundle();
        parameters.putString("fields", "id,name,link,email,picture");
        request.setParameters(parameters);
        request.executeAsync();
    }

/**
     * This method will attempt to authenticate a user to firebase given an oauth_token (and other
     * necessary parameters depending on the provider)
     */
    private void authWithFirebase(final String provider, Map<String, String> options) {
        if (options.containsKey("error")) {
           showErrorDialog(options.get("error"));
        } else {
            mAuthProgressDialog.show();

 if the provider is not twitter, we just need to pass in the oauth_token
                mFirebaseRef.authWithOAuthToken(provider, options.get("oauth_token"), new AuthResultHandler(provider));
            }
    }

@Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        super.onActivityResult(requestCode, resultCode, data);
        callbackManager.onActivityResult(requestCode, resultCode, data);
    }

private void setAuthenticatedUser(AuthData authData) {
        if (authData != null) {

/* show a provider specific status text */
            String name = null;
            if (authData.getProvider().equals("facebook")) {
                name = (String) authData.getProviderData().get("displayName");
            } else if (authData.getProvider().equals("anonymous")
                    || authData.getProvider().equals("password")) {
                name = authData.getUid();
            } else {
                Toast.makeText(getApplicationContext(), "invalid provider", Toast.LENGTH_LONG).show();
            }
            if (name != null) {

success
                Toast.makeText(getApplicationContext(), "Log " + name + " (" + authData.getProvider() + ")", Toast.LENGTH_LONG).show();

}

} else {

}

 Firebase Authenticated

this.mAuthData = authData;

MainActivity.uID = mAuthData.getUid();

addUser();
        /* invalidate options menu to hide/show the logout button */
        supportInvalidateOptionsMenu();
    }

/**
     * Show errors to users
     */
    private void showErrorDialog(String message) {
        new AlertDialog.Builder(this)
                .setTitle("Error")
                .setMessage(message)
                .setPositiveButton(android. R.string.ok, null)
                .setIcon(android. R.drawable.ic_dialog_alert)
                .show();
    }

private class AuthResultHandler implements Firebase.AuthResultHandler {

private final String provider;

public AuthResultHandler(String provider) {
            this.provider = provider;
        }

@Override
        public void onAuthenticated(AuthData authData) {
            mAuthProgressDialog.hide();
            Toast.makeText(getApplicationContext(), "Auth Success", Toast.LENGTH_LONG).show();
            Toast.makeText(getApplicationContext(), authData.getUid(), Toast.LENGTH_LONG).show();

 createUser();

setAuthenticatedUser(authData);

String mEmail = authData.getUid();

 uID = authData.getUid();

String mProvide = mAuthData.getProvider();

}

@Override
        public void onAuthenticationError(FirebaseError firebaseError) {
            mAuthProgressDialog.hide();
            showErrorDialog(firebaseError.toString());
        }
    }

public void createUser(){

Firebase rootRef = new Firebase("https://<url>.firebaseio.com/");
       Firebase userRef = rootRef.child("users").child(mAuthData.getUid());

userRef.child("provider").setValue(mAuthData.getProvider());
        userRef.child("provider").setValue(mAuthData.getProviderData().get("displayName)"));

rootRef.createUser(mAuthData.getProviderData().get("email").toString(), mAuthData.getProviderData().get("id").toString(), new Firebase.ValueResultHandler<Map< String, Object>>() {

@Override
            public void onSuccess(Map<String, Object> result){
                Toast.makeText(getApplicationContext(), "Yes-UID=" + result.get("Uid") , Toast.LENGTH_LONG).show();

}

@Override
            public void onError(FirebaseError firebaseError){
                Toast.makeText(getApplicationContext(), "Not Created", Toast.LENGTH_LONG).show();

}

});

}

private void logout() {
        if (this.mAuthData != null) {
            /* logout of Firebase */
            mFirebaseRef.unauth();
            /* Logout of any of the Frameworks. This step is optional, but ensures the user is not logged into
             * Facebook/Google+ after logging out of Firebase. */
            if (this.mAuthData.getProvider().equals("facebook")) {
                /* Logout from Facebook */
                LoginManager.getInstance().logOut();
            }
            /* Update authenticated user and show login buttons */
            setAuthenticatedUser(null);
        }
    }

@Override
    protected void onResume() {

super.onResume();
        AppEventsLogger.activateApp(this);

}

@Override
    protected void onPause() {

super.onPause();
        AppEventsLogger.deactivateApp(this);

}

/* ************************************
     *             FACEBOOK               *
     **************************************
     */
    private void onFacebookAccessTokenChange(AccessToken token) {
        if (token != null) {
            mAuthProgressDialog.show();
            mFirebaseRef.authWithOAuthToken("facebook", token.getToken(), new AuthResultHandler("facebook"));
        } else {
             Logged out of Facebook and currently authenticated with Firebase using Facebook, so do a logout
            if (this.mAuthData != null && this.mAuthData.getProvider().equals("facebook")) {
                mFirebaseRef.unauth();
                setAuthenticatedUser(null);
            }
        }
    }

public static int getmTokens() {

return getLiveTokens();

}

public static void setmTokens(int mTokens) {
        MainActivity.mTokens = mTokens;
    }

public static void takemTokens(int mTokens) {
        MainActivity.mTokens -= mTokens;
    }

public static void givemTokens(final int ttokens) {
        MainActivity.mTokens += tokens;

 TODO
        if (ttokens > MainActivity.getmTopWin()){
            MainActivity.setmTopWin(ttokens);
        //}

Firebase ref = new Firebase("https://<url>.firebaseio.com/users/" +  MainActivity.uID + "/");
        final Firebase tokensRef = ref.child("tokens");
        tokensRef.addListenerForSingleValueEvent(new ValueEventListener() {
            @Override
            public void onDataChange(DataSnapshot dataSnapshot) {
                int iii = new Integer(dataSnapshot.getValue().toString());

iii += ttokens;

tokensRef.setValue(iii);

setLiveTokens(iii);

checkmTopWin(ttokens);

}

@Override
            public void onCancelled(FirebaseError firebaseError) {
            }

});
        tokensRef.removeEventListener(MainActivity);

}

public static int mSpins = 30;

public static int getmSpins() {
        return getLiveSpins();
    }

public static void setmSpins(int mspins) {
        MainActivity.mSpins = mspins;
    }

public static void takemSpins(final int mspins) {

Firebase ref = new Firebase("https://<url>.firebaseio.com/users/" +  MainActivity.uID + "/");
        final Firebase tokensRef = ref.child("spins");
        tokensRef.addListenerForSingleValueEvent(new ValueEventListener() {
            @Override
            public void onDataChange(DataSnapshot dataSnapshot) {
                int i = Integer.valueOf(dataSnapshot.getValue().toString());

i -= mspins;

tokensRef.setValue(i);
                setLiveSpins(i);

}
            @Override
            public void onCancelled(FirebaseError firebaseError) {}
        });

}

public static void givemSpins(final int mspins){

Firebase ref = new Firebase("https://<url>.firebaseio.com/users/" +  MainActivity.uID + "/");
        final Firebase tokensRef = ref.child("spins");
        tokensRef.addListenerForSingleValueEvent(new ValueEventListener() {
            @Override
            public void onDataChange(DataSnapshot dataSnapshot) {
                int i = Integer.valueOf(dataSnapshot.getValue().toString());

i += mspins;

tokensRef.setValue(i);
            }
            @Override
            public void onCancelled(FirebaseError firebaseError) {}
        });

}

public static int slotVari = 0;

public static int getSlotVari() {
        return slotVari;
    }

public static void setSlotVari(int slotVari) {
        MainActivity.slotVari = slotVari;
    }

public static int mTotalSpins;

public static int getmTotalSpins() {
        return mTotalSpins;
    }

public static void setmTotalSpins(int mTotalSpins) {
        MainActivity.mTotalSpins = mTotalSpins;
    }

public static void incmTotalSpins(){

Firebase ref = new Firebase("https://<url>.firebaseio.com/users/" +  MainActivity.uID + "/");
        final Firebase tokensRef = ref.child("totalspins");
        tokensRef.addListenerForSingleValueEvent(new ValueEventListener() {
            @Override
            public void onDataChange(DataSnapshot dataSnapshot) {
                int i = Integer.valueOf(dataSnapshot.getValue().toString());

i++;

tokensRef.setValue(i);
            }
            @Override
            public void onCancelled(FirebaseError firebaseError) {}
        });

MainActivity.mTotalSpins++;
    }

public static int mTopWin;

public static int getmTopWin() {
        return mTopWin;
    }

public static void setmTopWin(int mTopWin) {

Firebase ref = new Firebase("https://<url>.firebaseio.com/users/" +  MainActivity.uID + "/");
        Firebase tokensRef = ref.child("topwin");

tokensRef.setValue(mTopWin);

MainActivity.mTopWin = mTopWin;
    }

public static void checkmTopWin(final int mTokensWon) {

Firebase ref = new Firebase("https://<url>.firebaseio.com/users/" +  MainActivity.uID + "/");
        final Firebase tokensRef = ref.child("topwin");
        tokensRef.addListenerForSingleValueEvent(new ValueEventListener() {
            @Override
            public void onDataChange(DataSnapshot dataSnapshot) {
                int i = Integer.valueOf(dataSnapshot.getValue().toString());

if (i < mTokensWon){

tokensRef.setValue(mTokensWon);

}

}
            @Override
            public void onCancelled(FirebaseError firebaseError) {}
        });
    }
}

Solution

You need to set a preference like FIRST_LAUNCH and check if it’s true every time a user logs in. The first time you start the application, FIRST_LAUNCH preferences are not established. So call your addUser() function to create a new entry in your FireBase database.

SharedPreferences pref = getSharedPreferences(Constants.ApplicationTag, Activity.MODE_PRIVATE);

if (!pref.contains(Constants.FIRST_LAUNCH)) {
    addUser();
    pref.edit().putBoolean(Constants.FIRST_LAUNCH, true).commit();
}

So you might think that if the user uninstalls your app and then reinstalls it, the preference will disappear and the addUser() function will be called again. No problem, as long as the path to the sub-attribute is the same, you won’t get a new Firebase entry. These values are replaced with a specific path, if it exists, along with the user’s current information.

Now if you

want to check if your user already exists in the Firebase database, you need to add a listener like this. I’ve attached a code example for better understanding.

Firebase rootRef = new Firebase("https://<url>.firebaseio.com/users/");
Firebase userRef = rootRef.child(mAuthData.getUid() + "/");

userRef.addListenerForSingleValueEvent(new ValueEventListener() {
    @Override
    public void onDataChange(DataSnapshot dataSnapshot) {
        if (dataSnapshot.exists()) {

 User exists. Do nothing

} else addUser();

}

@Override
    public void onCancelled(FirebaseError firebaseError) {}
});

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