The fileImporter View Modifier in SwiftUI (iOS 14+)

SwiftUI is a declarative framework for building user interfaces on Apple platforms. It provides a number of built-in view modifiers that allow you to easily customize the appearance and behavior of your views. One of these view modifiers is fileImporter, which allows you to present a document picker to the user and import one or more files from their device.

To use the fileImporter view modifier, you first need to import the SwiftUI module. Then, you can apply the view modifier to any view by calling the fileImporter method on the view and passing it the necessary parameters.

The fileImporter view modifier has four parameters:

• isPresented: a binding to a state variable that determines whether the document picker is currently being presented. When this value is true, the document picker is shown, and when it is false, the document picker is dismissed.

• allowedContentTypes: an array of UTType values that specify the types of files that the document picker should allow the user to select.

• allowsMultipleSelection: a boolean value that determines whether the document picker should allow the user to select multiple files at once.

• onCompletion: a closure parameter, which is called when the document picker is dismissed. The closure is passed a Result object, which either contains an array of URLs for the selected files (if the import was successful) or an error (if the import failed).

Here is an example of how to use the fileImporter view modifier in a SwiftUI view:

import SwiftUI

struct ContentView: View {
    
    @State private var isShowDocumentPicker = false
    @State private var fileURL: URL?
    
    var body: some View {
        VStack {
            Text(fileURL?.lastPathComponent ?? "")
            
            Button("Open file") {
                isShowDocumentPicker = true
            }
        }
        .fileImporter(isPresented: $isShowDocumentPicker,
                        allowedContentTypes: [.pdf, .text],
                        allowsMultipleSelection: true) { result in
            fileURL = try? result.get().first
        }
    }
}

In this example, the fileImporter view modifier is applied to a VStack containing a Text