可在仿真器中运行，但不能在真实设备中运行

Question

此代码可在仿真器上正常工作：

1. 登录到Google
2. 选择帐户
3. 自动转到下一页

但是在真实设备中：

1. 登录到Google
2. 选择帐户

3. 不要转到下一页

   class LoginPageWidget extends StatelessWidget {
   final GoogleSignIn _googleSignIn = GoogleSignIn();
   final FirebaseAuth _auth = FirebaseAuth.instance;
   Future<FirebaseUser> _handleSignIn() async {
   FirebaseUser user;
   bool isSignedIn = await _googleSignIn.isSignedIn();
   if (isSignedIn) {user = await _auth.currentUser();
   } else {
     final GoogleSignInAccount googleUser = await _googleSignIn.signIn();
     final GoogleSignInAuthentication googleAuth =
     await googleUser.authentication;
     final AuthCredential credential = GoogleAuthProvider.getCredential(
         accessToken: googleAuth.accessToken, idToken: googleAuth.idToken);
     user = (await _auth.signInWithCredential(credential)).user;}
   return user;}
   void onGoogleSignIn(BuildContext context) async {
   FirebaseUser user = await _handleSignIn();
   Navigator.push(context,MaterialPageRoute(builder: (context) => Home(user, _googleSignIn)));}
   @override
   Widget build(BuildContext context) {
   return Scaffold(
     body: Container(
       padding: EdgeInsets.all(50),
       child: Center(
         child: Column(
           mainAxisAlignment: MainAxisAlignment.center,
           crossAxisAlignment: CrossAxisAlignment.center,
           children: <Widget>[
             Hero(tag: 'logo',
                 child: Container(width: 120.0,
                   child: Image.asset("assets/logo.png"),)),
             SizedBox(height: 40,),
             FittedBox(fit: BoxFit.fitWidth,
               child: FlatButton(
                 shape: RoundedRectangleBorder(borderRadius: BorderRadius.circular(20)),
                 onPressed: () {onGoogleSignIn(context);},
                 color: Colors.blueAccent,
                 child: Padding(
                   padding: EdgeInsets.all(10),
                   child: Row(
                     mainAxisAlignment: MainAxisAlignment.center,
                     crossAxisAlignment: CrossAxisAlignment.center,
                     children: <Widget>[
                       Image(image: AssetImage("assets/google_logo.png"), height: 35.0),
                       SizedBox(width: 15),
                       Text('Entrar com Google',style: TextStyle(color: Colors.white, fontSize:20
   ),),],),),),),],),),),);}}
   

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