Cant check if user account exists?

Question

Helo, I am trying to check if user's account exists, if no, I want to run text 'account is deleted'.

But the problem is that when I start the app there is screen for existing account and only after reset I can get the real result.

Looks like check for account is done after running app for the first time, but I don't know where is the mistake.

Here is the code, thank you in advance:

class CheckIfDeletedAccount extends StatelessWidget {
  String isAccountDeleted;

  getData() async {
    var userType = await Firestore.instance
        .collection('users')
        .where('userEmail', isEqualTo: email)
        .getDocuments();
    userType.documents.forEach((result) {
      log(result.data["deleted"]);
      isAccountDeleted = result.data["deleted"].toString();
    });
  }

  @override
  Widget build(BuildContext context) {
    getData();
    //log(isAccountDeleted);
    if (isAccountDeleted == "true") {
      return Scaffold(
        body: Container(
          child: Center(
            child: Text("account is deleted"),
          ),
        ),
      );
    }
    return MaterialApp(
      theme: themeData,
      home: Scaffold(
        body: Bar(),
      ),
    );
  }
}

Answer 1

You need to wait for the result from Firebase. You are trying to build the widget before the isAccountDeleted is initialized.

In your scenario, you can use FutureBuilder as follows:

class CheckIfDeletedAccount extends StatelessWidget {
  String isAccountDeleted;

  Future<String> getData() async {
    var userType = await Firestore.instance
        .collection('users')
        .where('userEmail', isEqualTo: email)
        .getDocuments();
    userType.documents.forEach((result) {
      log(result.data["deleted"]);
      isAccountDeleted = result.data["deleted"].toString();
    });
    return isAccountDeleted;
  }

  @override
  Widget build(BuildContext context) {
    return FutureBuilder(
    future: getData(),
    builder: (BuildContext context, AsyncSnapshot snapshot) {
    if(snapshot.connectionState == ConnectionState.done &&
         snapshot.hasData) {
        final isAccountDeleted = snapshot.data;

        if (isAccountDeleted == "true") {
          return Scaffold(
            body: Container(
              child: Center(
                child: Text("account is deleted"),
              ),
            ),
          );
        }

        return MaterialApp(
          theme: themeData,
          home: Scaffold(
            body: Bar(),
          ),
        );
    }
      return Center(child: const CircularProgressIndicator());
      },
    );
  }
}

Answer 2

Based on savke comment you can use the following code using FutureBuilder:

import 'package:flutter/material.dart';
import 'package:cloud_firestore/cloud_firestore.dart';

class CheckIfDeletedAccount extends StatelessWidget {

  Future getData() async {
    String  isAccountDeleted;
    var userType = await Firestore.instance
        .collection('users')
        .where('userEmail', isEqualTo: email)
        .getDocuments();
    userType.documents.forEach((result) {
      log(result.data["deleted"]);
      isAccountDeleted = result.data["deleted"].toString();
    });
    return isAccountDeleted;
  }

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
        theme: themeData,
        home: Scaffold(
          body: FutureBuilder(
              future: getData(),
              builder: (context, AsyncSnapshot snapshot) {
                if (!snapshot.hasData) {
                  return Center(
                    child: CircularProgressIndicator(
                      strokeWidth: 6,
                      valueColor: AlwaysStoppedAnimation<Color>(Colors.red),
                    ),
                  );
                } else {
                  if (snapshot.data == "true") {
                      return  Container(
                        child: Center(
                          child: Text("account is deleted"),
                        ),
                      );
                    }
                   else {
                    return Bar();
                  }
                }
              }),
        ));
  }
}