Today I will show you how to insert new items into a List (demo with NavigationView).
import SwiftUI
struct ContentView: View {
/// 1. Use an array as the data source for the List.
@State var colors = ["Red", "Green", "Blue"]
var body: some View {
/// 2. Add a NavigationView. The function of NavigationView is similar to that of UINavigationController, which is mostly used to switch between views.
NavigationView {
/// 3. create a List to show how to add new items.
List {
/// 4. Add a forEach method to iterate over the array.
ForEach(colors, id: \.self) { color in
/// 5. Use Text to show the elements.
Text(color)
}
/// 6. Add an onInsert method to insert new items to the array.
.onInsert(of: ["public.text"], perform: onInsert)
}
/// 8. Set NavigationView's title.
.navigationTitle("Insert new items")
.navigationBarTitleDisplayMode(.large)
/// 9. Add a navigation button to the upper right corner of the NavigationView.
.navigationBarItems(
trailing:
/// 10. When you click on the Button, the addItem method will be called.
Button(action: addItem, label: {
Text("Add")
})
)
}
}
/** 7.
Add onInsert method.
Call this method when elements are inserted into the original view.
*/
func onInsert(at index: Int, _ items: [NSItemProvider]) {
for item in items {
_ = item.loadObject(ofClass: String.self) { droppedString, _ in
if let text = droppedString {
DispatchQueue.main.async {
colors.insert(text, at: index)
}
}
}
}
}
/** 11.
Add addItem method.
It is used to respond when the navigation button is clicked.
When the navigation button is clicked, a new string is added to the end of the array.
*/
func addItem() {
colors.append("White")
}
}
#if DEBUG
struct ContentView_Previews: PreviewProvider {
static var previews: some View {
ContentView()
}
}
#endif
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