如何在firebase auth错误上显示警报颤动

Question

我想在 Firebase 身份验证中出现错误时显示警报对话框。 Firebase 已经在 UI 中打印了错误，但我想向用户显示一个对话框。

这是我的 createUser 和 signInUser 功能以及我的注册按钮功能

  Future registerWithEmailAndPassword({String email,password,username,image,phoneNumber}) async {
    try {
      UserCredential userCredential = await _firebaseAuth
          .createUserWithEmailAndPassword(
        email: email,
        password: password,
      );
    } on FirebaseAuthException catch (e) {
      if (e.code == 'weak-password') {
        print('The password provided is too weak.');
      } else if (e.code == 'email-already-in-use') {
        print('The account already exists for that email.');
      }
    } catch (e) {
      print(e);
    }
  }

 Future signInWithEmailAndPassword({String email, String password}) async {
    try {
      UserCredential userCredential = await _firebaseAuth
          .signInWithEmailAndPassword(
          email: email,
          password: password
      );
      User user = userCredential.user;
      assert(user.uid != null);
      email = user.email;
    } on FirebaseAuthException catch (e) {
      if (e.code == 'user-not-found') {
        print('No user found for that email.');
      } else if (e.code == 'wrong-password') {
        print('Wrong password provided for that user.');
      }
    }
  }

            press: () {
              if (formKey.currentState.validate()) {
                formKey.currentState.save();
                    context
                    .read<Authentication>()
                    .signInWithEmailAndPassword(
                    email: emailController.text,
                    password: passwordController.text)
                    .whenComplete(() => Navigator.pushReplacement(
                    context,
                    MaterialPageRoute(
                        builder: (context) =>
                            HomeScreen())));
              }
            },

Answer 1

您可以设置与此类似的AlertDialog 小部件。在您的情况下，Yes/No 按钮可能是多余的，如果是这样，只需转换为 ok 按钮，然后您就不必检查返回结果。

Future<String> showYesNoAlertDialog({
  @required BuildContext context,
  @required String titleText,
  @required String messageText,
}) async {
  // set up the buttons
  final Widget yesButton = FlatButton(
    onPressed: () => Navigator.pop(context, 'yes'),
    child: const Text('Yes'),
  );
  final Widget noButton = FlatButton(
    onPressed: () => Navigator.pop(context, 'no'),
    child: const Text('No'),
  );

  // set up the AlertDialog
  final alert = AlertDialog(
    title: Text(titleText),
    content: Text(messageText),
    actions: [
      yesButton,
      noButton,
    ],
  );

  // show the dialog
  return showDialog(
    context: context,
    builder: (context) => alert,
  );
}

然后你的打印语句输出错误，你会像这样调用上面的小部件

final dr = await showYesNoAlertDialog(
  context: context,
  titleText: 'Authentication Error',
  messageText:
      'There has been an error during authentication.  Would you like to retry?',
);

if (dr == 'yes') {
  // Yes button clicked
}
else {
  // No button clicked
}