Flutter for iOS 12.1: black screen instead of an app

Question

Good afternoon, I developed a basic app in Flutter with main target on smartphone users. I made Android app and Google Play Market accepted it to publish. Then I generated an app for Apple Store and applied it but got a rejection with the following description:

"Guideline 2.1 - Performance - App Completeness

We discovered one or more bugs in your app when reviewed on iPad running iOS 12.1 on Wi-Fi.

Specifically, your app didn’t load any content - only black page was displayed."

Yes, they attached a screenshot of black screen but I am confused how to fix this problem for exactly this version of iOS. I have checked my app for different versions of iPhones and the app works as fine and smoothly as in Android smartphones too.

Hence, my questions are (as a newbie in work with Apple Store):

1. is it possible to apply an app only for iPhones, not for iPods?
2. what may be the reason of black screen instead of an app in the iPod with iOS 12.1?
3. does this error is the last one and after solving this problem the app will be approved? I mean if they did not write anything about UI or concept of the app - does this mean that they approved it?

Thank you in advance for your support and any comments.

Sincerely, Mary

Updates: I created initial app for iOS using Xcode 8 and run it on emulators there, app works. However, when I run this app in Xcode 10.1, I see a black screen even in iPhone X (on Xcode 8 it run smoothly).

Solution

This is a known issue and here's how to solve it :

Before archiving your iOS app you need to run this command in terminal (Pointing to your project's directory)

flutter build ios --release

And then archive your build, it should work fine.

Comments

[Günter Zöchbauer]

Ensure you have the latest Flutter version.

[diegoveloper]

Yeah, update Flutter to the latest version, the bug was fixed few days ago : github.com/flutter/flutter/issues/24563

[Mary Seleznova]

Thanks a lot, that's work! But now I had another related problem - on real device IPad 12.1 instead of an app I got a blank page. Interesting, but in Simulator (Ipad, 2nd generation, 12.1) it works completely fine and app is running properly.

[innich]

If it throws any errors, try "flutter clean" and then "flutter build ios --release". Same here for iOS 12.3, Flutter 1.4.9, Xcode 10.1. But screen is not black, it is blank.