Fix bug: Prevent redirecting to second page on login failed

sbis04 · Sep 4, 2020 · ad503dc · ad503dc
1 parent 74ec403
commit ad503dc
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Showing 2 changed files with 41 additions and 29 deletions.
diff --git a/lib/login_page.dart b/lib/login_page.dart
@@ -53,14 +53,16 @@ class _LoginPageState extends State<LoginPage> {
     return OutlineButton(
       splashColor: Colors.grey,
       onPressed: () {
-        signInWithGoogle().whenComplete(() {
-          Navigator.of(context).push(
-            MaterialPageRoute(
-              builder: (context) {
-                return FirstScreen();
-              },
-            ),
-          );
+        signInWithGoogle().then((result) {
+          if (result != null) {
+            Navigator.of(context).push(
+              MaterialPageRoute(
+                builder: (context) {
+                  return FirstScreen();
+                },
+              ),
+            );
+          }
         });
       },
       shape: RoundedRectangleBorder(borderRadius: BorderRadius.circular(40)),

diff --git a/lib/sign_in.dart b/lib/sign_in.dart
@@ -19,6 +19,7 @@
 // SOFTWARE.
 
 import 'package:firebase_auth/firebase_auth.dart';
+import 'package:firebase_core/firebase_core.dart';
 import 'package:google_sign_in/google_sign_in.dart';
 
 final FirebaseAuth _auth = FirebaseAuth.instance;
@@ -29,43 +30,52 @@ String email;
 String imageUrl;
 
 Future<String> signInWithGoogle() async {
+  await Firebase.initializeApp();
+
   final GoogleSignInAccount googleSignInAccount = await googleSignIn.signIn();
   final GoogleSignInAuthentication googleSignInAuthentication =
       await googleSignInAccount.authentication;
 
-  final AuthCredential credential = GoogleAuthProvider.getCredential(
+  final AuthCredential credential = GoogleAuthProvider.credential(
     accessToken: googleSignInAuthentication.accessToken,
     idToken: googleSignInAuthentication.idToken,
   );
 
-  final AuthResult authResult = await _auth.signInWithCredential(credential);
-  final FirebaseUser user = authResult.user;
+  final UserCredential authResult =
+      await _auth.signInWithCredential(credential);
+  final User user = authResult.user;
 
-  // Checking if email and name is null
-  assert(user.email != null);
-  assert(user.displayName != null);
-  assert(user.photoUrl != null);
+  if (user != null) {
+    // Checking if email and name is null
+    assert(user.email != null);
+    assert(user.displayName != null);
+    assert(user.photoURL != null);
 
-  name = user.displayName;
-  email = user.email;
-  imageUrl = user.photoUrl;
+    name = user.displayName;
+    email = user.email;
+    imageUrl = user.photoURL;
 
-  // Only taking the first part of the name, i.e., First Name
-  if (name.contains(" ")) {
-    name = name.substring(0, name.indexOf(" "));
-  }
+    // Only taking the first part of the name, i.e., First Name
+    if (name.contains(" ")) {
+      name = name.substring(0, name.indexOf(" "));
+    }
+
+    assert(!user.isAnonymous);
+    assert(await user.getIdToken() != null);
 
-  assert(!user.isAnonymous);
-  assert(await user.getIdToken() != null);
+    final User currentUser = _auth.currentUser;
+    assert(user.uid == currentUser.uid);
 
-  final FirebaseUser currentUser = await _auth.currentUser();
-  assert(user.uid == currentUser.uid);
+    print('signInWithGoogle succeeded: $user');
+
+    return '$user';
+  }
 
-  return 'signInWithGoogle succeeded: $user';
+  return null;
 }
 
-void signOutGoogle() async {
+Future<void> signOutGoogle() async {
   await googleSignIn.signOut();
 
-  print("User Sign Out");
+  print("User Signed Out");
 }