SwiftUI with UIViewControllerRepresentable - ios

Question

I am trying to use a UIViewController representable in a swiftUi project. Specifically I am trying to press one button (assetOne) that allows the EU to select a video and then press another button (assetTwo) and it allows the user to select another video. Then the user will have the option to merge the videos (with a third button). I assumed that I would need to use a Coordinator to accomplish this but after seeing a SO solution without it I tried to do it without one. But when I run my project the build is successful but when I click on any of the buttons from the content view I get the error message below. What am I doing wrong? Do I need a Coordinator and how do I incorporate it with my current configuration?
Warning: Attempt to present <UIImagePickerController: 0x7fa05f827600>
on <TempTest.MergeVideoViewController: 0x7fa05ed088c0> whose view is
not in the window hierarchy!
Content View:
import SwiftUI
struct ContentView: View {
let someView = ImagePicker()
var body: some View {
VStack {
Button(action: {
print("SwiftUI: assetOne button tapped")
// Call func in SomeView()
self.someView.assetOne()
}) {
Text("Asset One").foregroundColor(Color.black)
}
.background(Color.blue)
.padding(10)
.clipShape(Capsule())
}
//...
ImagePicker: UIViewControllerRepresentable
struct ImagePicker: UIViewControllerRepresentable{
let someView = MergeVideoViewController()
func makeUIViewController(context: Context) -> MergeVideoViewController {
someView
}
func updateUIViewController(_ uiViewController: MergeVideoViewController, context: Context) {}
func assetOne() {
someView.loadAssetOne()
}
//...
}
My UIViewController class:
class MergeVideoViewController: UIViewController {
var firstAsset: AVAsset?
var secondAsset: AVAsset?
var audioAsset: AVAsset?
var loadingAssetOne = false
var activityMonitor: UIActivityIndicatorView!
func exportDidFinish(_ session: AVAssetExportSession) {
// Cleanup assets
activityMonitor.stopAnimating()
firstAsset = nil
secondAsset = nil
audioAsset = nil
//...
func loadAssetOne() {
// func loadAssetOne(_ sender: AnyObject) {
if savedPhotosAvailable() {
loadingAssetOne = true
VideoHelper.startMediaBrowser(delegate: self, sourceType: .savedPhotosAlbum)
}
}
//...

Answer 1

The ImagePicker is-a View, it should be somewhere in body.
Here is possible approach - the idea is to get controller reference back in SwiftUI and call its actions directly when needed.
struct ImagePicker: UIViewControllerRepresentable{
let configure: (MergeVideoViewController) -> ()
func makeUIViewController(context: Context) -> MergeVideoViewController {
let someView = MergeVideoViewController()
configure(someView)
return someView
}
func updateUIViewController(_ uiViewController: MergeVideoViewController, context: Context) {}
}
struct ContentView: View {
#State private var controller: MergeVideoViewController?
var body: some View {
VStack {
ImagePicker {
self.controller = $0
}
Button(action: {
print("SwiftUI: assetOne button tapped")
self.controller?.loadAssetOne()
}) {
Text("Asset One").foregroundColor(Color.black)
}
.background(Color.blue)
.padding(10)
.clipShape(Capsule())
}
}
}