How SwiftUI TabView Page handles big data - swiftui

Question

I use TabView to browse albums because I need a paging function, but my album has thousands of pictures, and TabView is very slow to process.
Is there any way to lazy loading so that TabView can handle thousands of data.
TabView(selection: $assetModel.identifier) {
ForEach(0..<7000) { index in
let asset = assetModel.assetArray[index]
AssetPreviewItemView(asset: asset)
.tag(asset.localIdentifier)
}
}
.tabViewStyle(.page(indexDisplayMode: .always))
.indexViewStyle(.page(backgroundDisplayMode: .always))

Answer 1

At the moment (Xcode13.2.1), TabView will init all of your 7000 AssetPreviewItemView each time you change your TabView's selection (everytime you swipe images), so that's why it's so laggy.
As I've found out so far (really hope that i was wrong) the only way you can swipe through page tab view without loading everything is using #State for index only (replace your $assetModel.identifier with something like $identifier from #State var identifier).
to get rid of 7000 inits, you have to keep index as private use
struct TestTabPageView: View {
#State var index = 0
var body: some View {
VStack {
TabView(selection: $index) {
ForEach((0..<7000), id: \.self) { i in
TestTabPageViewCell(content: "\(i)").tag(i)
}
}
.tabViewStyle(.page(indexDisplayMode: .always))
}
}
}