# iOS FlutterViewController splashScreenView made nullable

> FlutterViewController splashScreenView changed from nonnull to nullable.




:::important
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:::


## Summary

The `FlutterViewController` property `splashScreenView` has
been changed from `nonnull` to `nullable`.

Old declaration of `splashScreenView`:

```objc
@property(strong, nonatomic) UIView* splashScreenView;
```

New declaration of `splashScreenView`:

```objc
@property(strong, nonatomic, nullable) UIView* splashScreenView;
```

## Context

Prior to this change, on iOS the `splashScreenView` property returned `nil`
when no splash screen view was set, and
setting the property to `nil` removed the splash screen view.
However, the `splashScreenView` API was incorrectly marked `nonnull`.
This property is most often used when transitioning to
Flutter views in iOS add-to-app scenarios.

## Description of change

While it was possible in Objective-C to work around the
incorrect `nonnull` annotation by setting `splashScreenView` to
a `nil` `UIView`, in Swift this caused a compilation error:

```plaintext
error build: Value of optional type 'UIView?' must be unwrapped to a value of type 'UIView'
```

[PR #34743][] updates the property attribute to `nullable`.
It can return `nil` and can be set to `nil` to
remove the view in both Objective-C and Swift.

## Migration guide

If `splashScreenView` is stored in a `UIView` variable in Swift,
update to an optional type `UIView?`.

Code before migration:

```swift
  var splashScreenView = UIView()
  var flutterEngine = FlutterEngine(name: "my flutter engine")
  let flutterViewController = FlutterViewController(engine: flutterEngine, nibName: nil, bundle: nil)
  splashScreenView = flutterViewController.splashScreenView // compilation error: Value of optional type 'UIView?' must be unwrapped to a value of type 'UIView'
```

Code after migration:

```swift
  var splashScreenView : UIView? = UIView()
  var flutterEngine = FlutterEngine(name: "my flutter engine")
  let flutterViewController = FlutterViewController(engine: flutterEngine, nibName: nil, bundle: nil)
  let splashScreenView = flutterViewController.splashScreenView // compiles successfully
  if let splashScreenView = splashScreenView {
  }
```

## Timeline

In stable release: 3.7

## References

Relevant PR:

* [Make splashScreenView of FlutterViewController nullable][]

[Make splashScreenView of FlutterViewController nullable]: https://github.com/flutter/engine/pull/34743
[PR #34743]: https://github.com/flutter/engine/pull/34743