didSelectItemAt causes UI to reflow/redraw every time value for lastSelectedIndex is changed, causing performance issue. I'm not sure if I have used @State properly to propagate value from child to parent. P.S. I need to use UICollectionView for a reason instead of swiftui List or ScrollView. import Foundation import SwiftUI struct ContentView: View { 		@State var lastSelectedIndex : Int = -1 		var body: some View { 				ZStack { 						CustomCollectionView(lastSelectedIndex: $lastSelectedIndex) 						Text("Current Selected Index \(lastSelectedIndex)") 				} 		} } struct CustomCollectionView: UIViewRepresentable { 		@Binding var lastSelectedIndex : Int 		 		func makeUIView(context: Context) -> UICollectionView { 				let flowLayout = UICollectionViewFlowLayout() 				flowLayout.itemSize = CGSize(width: 400, height: 300) 				let collectionView = UICollectionView(frame: .zero, collectionViewLayout: flowLayout) 				collectionView.register(CustomCollectionViewCell.self, forCellWithReuseIdentifier: CustomCollectionViewCell.reuseId) 				collectionView.delegate = context.coordinator 				collectionView.dataSource = context.coordinator 				collectionView.backgroundColor = .systemBackground 				collectionView.isDirectionalLockEnabled = true 				 				collectionView.backgroundColor = UIColor.black 				collectionView.showsVerticalScrollIndicator = false 				collectionView.showsHorizontalScrollIndicator = false 				collectionView.alwaysBounceVertical = false 				return collectionView 		} 		func updateUIView(_ uiView: UICollectionView, context: Context) { 				uiView.reloadData() 		} 		func makeCoordinator() -> CustomCoordinator { 				CustomCoordinator(self) 		} } class CustomCoordinator: NSObject, UICollectionViewDataSource, UICollectionViewDelegate { 		let parent:CustomCollectionView 		 		init(_ parent:CustomCollectionView) { 				self.parent = parent 		} 		 		func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int { 				100 		} 		func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell { 				let cell = collectionView.dequeueReusableCell(withReuseIdentifier: CustomCollectionViewCell.reuseId, for: indexPath) as! CustomCollectionViewCell 				cell.backgroundColor = UIColor.red 				cell.label.text = "Current Index is \(indexPath.row)" 				NSLog("Called for Index \(indexPath.row)") 				return cell 		} 		 		func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) { 				parent.lastSelectedIndex = indexPath.row 		} } class CustomCollectionViewCell: UICollectionViewCell { 		static let reuseId = "customCell" 		let label = UILabel() 		override init(frame: CGRect) { 				super.init(frame: frame) 				label.numberOfLines = 0 				contentView.addSubview(label) 				label.translatesAutoresizingMaskIntoConstraints = false 				label.topAnchor.constraint(equalTo: contentView.topAnchor).isActive = true 				label.leadingAnchor.constraint(equalTo: contentView.leadingAnchor).isActive = true 				label.trailingAnchor.constraint(equalTo: contentView.trailingAnchor).isActive = true 				label.bottomAnchor.constraint(equalTo: contentView.bottomAnchor).isActive = true 		} 		required init?(coder aDecoder: NSCoder) { 				fatalError("init(coder:) has not been implemented") 		} } struct ContentView_Previews: PreviewProvider { 		static var previews: some View { 				ContentView() 		} }