问题
I need to open the ImagePicker in my app using SwiftUI, how can I do that?
I thought about using the UIImagePickerController, but I don't know how to do that in SwiftUI.
回答1:
Here's a "rough around the edges" implementation.
You need to wrap UIImagePickerController in a struct implementing UIViewControllerRepresentable.
For more about UIViewControllerRepresentable, please check this amazing WWDC 2019 talk:
Integrating SwiftUI
struct ImagePicker: UIViewControllerRepresentable {
@Environment(\.presentationMode)
var presentationMode
@Binding var image: Image?
class Coordinator: NSObject, UINavigationControllerDelegate, UIImagePickerControllerDelegate {
@Binding var presentationMode: PresentationMode
@Binding var image: Image?
init(presentationMode: Binding<PresentationMode>, image: Binding<Image?>) {
_presentationMode = presentationMode
_image = image
}
func imagePickerController(_ picker: UIImagePickerController,
didFinishPickingMediaWithInfo info: [UIImagePickerController.InfoKey : Any]) {
let uiImage = info[UIImagePickerController.InfoKey.originalImage] as! UIImage
image = Image(uiImage: uiImage)
presentationMode.dismiss()
}
func imagePickerControllerDidCancel(_ picker: UIImagePickerController) {
presentationMode.dismiss()
}
}
func makeCoordinator() -> Coordinator {
return Coordinator(presentationMode: presentationMode, image: $image)
}
func makeUIViewController(context: UIViewControllerRepresentableContext<ImagePicker>) -> UIImagePickerController {
let picker = UIImagePickerController()
picker.delegate = context.coordinator
return picker
}
func updateUIViewController(_ uiViewController: UIImagePickerController,
context: UIViewControllerRepresentableContext<ImagePicker>) {
}
}
Here's a simple view to test it.
It's rough in the sense that:
- the picker is displayed in a sheet
- the selected image appears without any sort of animation, and replaces the
Show image pickerbutton
struct ContentView: View {
@State var showImagePicker: Bool = false
@State var image: Image? = nil
var body: some View {
ZStack {
VStack {
Button(action: {
withAnimation {
self.showImagePicker.toggle()
}
}) {
Text("Show image picker")
}
image?.resizable().frame(width: 100, height: 100)
}
.sheet(isPresented: $showImagePicker) {
ImagePicker(image: self.$image)
}
}
}
}
I hope this helps as a starting point!
I'm sure Apple will make this easier to do once SwiftUI is out of beta.
Tested on Xcode 11.1
回答2:
Based on @user:2890168 I made a version that:
- retrieves
UIImageinstead ofImage - use
.sheetto present theImagePicker. - shows
ActionSheetto help users to remove or change the image.
struct LibraryImage: View {
@State var showAction: Bool = false
@State var showImagePicker: Bool = false
@State var uiImage: UIImage? = nil
var sheet: ActionSheet {
ActionSheet(
title: Text("Action"),
message: Text("Quotemark"),
buttons: [
.default(Text("Change"), action: {
self.showAction = false
self.showImagePicker = true
}),
.cancel(Text("Close"), action: {
self.showAction = false
}),
.destructive(Text("Remove"), action: {
self.showAction = false
self.uiImage = nil
})
])
}
var body: some View {
VStack {
if (uiImage == nil) {
Image(systemName: "camera.on.rectangle")
.accentColor(Color.App.purple)
.background(
Color.App.gray
.frame(width: 100, height: 100)
.cornerRadius(6))
.onTapGesture {
self.showImagePicker = true
}
} else {
Image(uiImage: uiImage!)
.resizable()
.frame(width: 100, height: 100)
.cornerRadius(6)
.onTapGesture {
self.showAction = true
}
}
}
.sheet(isPresented: $showImagePicker, onDismiss: {
self.showImagePicker = false
}, content: {
ImagePicker(isShown: self.$showImagePicker, uiImage: self.$uiImage)
})
.actionSheet(isPresented: $showAction) {
sheet
}
}
}
The default body of LibraryImage is an Image that shows a camera icon that is tappable by the users.
On tap event, the image picker is shown with a sheet modifier. After the image selection, the LibraryImage body is recomputed and now shows the Image defined in else statement (because uiImage property now contains the image picked by the user).
Now, on tap event the ActionSheet is shown.
The edited image picker:
struct ImagePicker: UIViewControllerRepresentable {
@Binding var isShown: Bool
@Binding var uiImage: UIImage?
class Coordinator: NSObject, UINavigationControllerDelegate, UIImagePickerControllerDelegate {
@Binding var isShown: Bool
@Binding var uiImage: UIImage?
init(isShown: Binding<Bool>, uiImage: Binding<UIImage?>) {
_isShown = isShown
_uiImage = uiImage
}
func imagePickerController(_ picker: UIImagePickerController,
didFinishPickingMediaWithInfo info: [UIImagePickerController.InfoKey : Any]) {
let imagePicked = info[UIImagePickerController.InfoKey.originalImage] as! UIImage
uiImage = imagePicked
isShown = false
}
func imagePickerControllerDidCancel(_ picker: UIImagePickerController) {
isShown = false
}
}
func makeCoordinator() -> Coordinator {
return Coordinator(isShown: $isShown, uiImage: $uiImage)
}
func makeUIViewController(context: UIViewControllerRepresentableContext<ImagePicker>) -> UIImagePickerController {
let picker = UIImagePickerController()
picker.delegate = context.coordinator
return picker
}
func updateUIViewController(_ uiViewController: UIImagePickerController,
context: UIViewControllerRepresentableContext<ImagePicker>) {
}
}
default behaviour:
回答3:
Here's a version that works in Xcode 11 beta 4.
It uses a BindableObject singleton (ImagePicker.shared) with two properties: .view and .image.
See usage below (ImagePickerTestView)
import SwiftUI
import Combine
final class ImagePicker : BindableObject {
static let shared : ImagePicker = ImagePicker()
private init() {} //force using the singleton: ImagePicker.shared
let view = ImagePicker.View()
let coordinator = ImagePicker.Coordinator()
// Bindable Object part
let willChange = PassthroughSubject<Image?, Never>()
@Published var image: Image? = nil {
didSet {
if image != nil {
willChange.send(image)
}
}
}
}
extension ImagePicker {
class Coordinator: NSObject, UINavigationControllerDelegate, UIImagePickerControllerDelegate {
// UIImagePickerControllerDelegate
func imagePickerController(_ picker: UIImagePickerController,
didFinishPickingMediaWithInfo info: [UIImagePickerController.InfoKey : Any]) {
let uiImage = info[UIImagePickerController.InfoKey.originalImage] as! UIImage
ImagePicker.shared.image = Image(uiImage: uiImage)
picker.dismiss(animated:true)
}
func imagePickerControllerDidCancel(_ picker: UIImagePickerController) {
picker.dismiss(animated:true)
}
}
struct View: UIViewControllerRepresentable {
func makeCoordinator() -> Coordinator {
ImagePicker.shared.coordinator
}
func makeUIViewController(context: UIViewControllerRepresentableContext<ImagePicker.View>) -> UIImagePickerController {
let picker = UIImagePickerController()
picker.delegate = context.coordinator
return picker
}
func updateUIViewController(_ uiViewController: UIImagePickerController,
context: UIViewControllerRepresentableContext<ImagePicker.View>) {
}
}
}
struct ImagePickerTestView: View {
@State var showingPicker = false
@State var image : Image? = nil
// you could use ImagePicker.shared.image directly
var body: some View {
VStack {
Button("Show image picker") {
self.showingPicker = true
}
image?
.resizable()
.aspectRatio(contentMode: .fit)
.frame(width: 300)
}.sheet(isPresented: $showingPicker,
onDismiss: {
// do whatever you need here
}, content: {
ImagePicker.shared.view
})
.onReceive(ImagePicker.shared.$image) { image in
// This gets called when the image is picked.
// sheet/onDismiss gets called when the picker completely leaves the screen
self.image = image
}
}
}
#if DEBUG
struct ImagePicker_Previews : PreviewProvider {
static var previews: some View {
ImagePickerTestView()
}
}
#endif
回答4:
I'm very new at Swift, but I was able to get it with the following.
This will load up an image picker modal and let you select a photo, and it will then update an @State variable from a parent.
If this works for you, you can replace the @State with something that can span across multiple components, such as @EnvironmentObject so other components can get updated as well.
Hope this helps!
// ImagePicker.swift
struct ImagePicker : View {
@State var image: UIImage? = nil
var body: some View {
ImagePickerViewController(image: $image)
}
}
// ImagePickerViewController.swift
import UIKit
import AVFoundation
import SwiftUI
struct ImagePickerViewController: UIViewControllerRepresentable {
@Binding var image: UIImage?
func updateUIViewController(_ uiViewController: UIImagePickerController, context: UIViewControllerRepresentableContext<ImagePickerViewController>) {
}
func makeUIViewController(context: UIViewControllerRepresentableContext<ImagePickerViewController>) -> UIImagePickerController {
let imagePicker = UIImagePickerController()
imagePicker.sourceType = UIImagePickerController.SourceType.photoLibrary
imagePicker.allowsEditing = false
imagePicker.delegate = context.coordinator
return imagePicker
}
func makeCoordinator() -> Coordinator {
return Coordinator(self)
}
class Coordinator: NSObject, UIImagePickerControllerDelegate, UINavigationControllerDelegate, AVCapturePhotoCaptureDelegate {
var parent: ImagePickerViewController
init(_ parent: ImagePickerViewController) {
self.parent = parent
}
func imagePickerController(_ picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [UIImagePickerController.InfoKey : Any]) {
let imagePicked = info[.originalImage] as! UIImage
parent.image = imagePicked
picker.dismiss(animated: true, completion: nil)
}
}
}
Usage:
// SampleView.swift
struct SampleView : View {
var body: some View {
PresentationLink(destination: ImagePicker().environmentObject(self.userData), label: {
Text("Import Photo")
})
}
}
Once again, I am fresh into Swift so if anyone has some comments, please let me know! Happy to learn more.
回答5:
I implemented a version that I think is more general and extensible. I used a Subject instead of a Binding to solve the problem where it's undoable/inappropriate to add another Binding in your view.
For example, you created a List showing a set of images stored in the underlying storage and you wanted to add an image with the image picker. In this case, it's very hard/ugly to have that image added to your underlying storage.
So I used a subject to transfer the image and you can simply observe it and add the new images to some storage, or if you want it to behave just like a Binding, it's one line of code, too. (modifying your State in your observation)
Then I wrapped the preferences into a ViewModel so it won't get cluttered if you want to have more subjects or configurations.
import SwiftUI
import Combine
struct ImagePickerView : UIViewControllerRepresentable {
@Binding var model: ImagePickerViewModel
typealias UIViewControllerType = UIImagePickerController
func makeCoordinator() -> Coordinator {
Coordinator(self)
}
func makeUIViewController(context: UIViewControllerRepresentableContext<Self>) -> UIImagePickerController {
let controller = UIImagePickerController()
controller.delegate = context.coordinator
controller.allowsEditing = false
controller.mediaTypes = ["public.image"]
controller.sourceType = .photoLibrary
return controller
}
func updateUIViewController(_ uiViewController: UIImagePickerController, context: UIViewControllerRepresentableContext<ImagePickerView>) {
// run right after making
}
class Coordinator : NSObject, UIImagePickerControllerDelegate, UINavigationControllerDelegate {
var parentView: ImagePickerView
init(_ parentView: ImagePickerView) {
self.parentView = parentView
}
func imagePickerControllerDidCancel(_ picker: UIImagePickerController) {
parentView.model.isPresented = false
}
func imagePickerController(_ picker: UIImagePickerController,
didFinishPickingMediaWithInfo info: [UIImagePickerController.InfoKey: Any]) {
guard let uiImage = info[.originalImage] as? UIImage else { return }
let image = Image(uiImage: uiImage)
parentView.model.pickedImagesSubject?.send([image])
parentView.model.isPresented = false
}
}
}
struct ImagePickerViewModel {
var isPresented: Bool = false
let pickedImagesSubject: PassthroughSubject<[Image], Never>! = PassthroughSubject<[Image], Never>()
}
Usage:
struct SomeView : View {
@EnvironmentObject var storage: Storage
@State var imagePickerViewModel = ImagePickerViewModel()
var body: some View {
Button(action: { self.imagePickerViewModel.isPresented.toggle() }) { ... }
.sheet(isPresented: $imagePickerViewModel.isPresented) {
ImagePickerView(model: self.$imagePickerViewModel)
}
.onReceive(imagePickerViewModel.pickedImagesSubject) { (images: [Image]) -> Void in
withAnimation {
// modify your storage here
self.storage.images += images
}
}
}
}
回答6:
I implemented it like this:
import SwiftUI
final class ImagePickerCoordinator: NSObject {
@Binding var image: UIImage?
@Binding var takePhoto: Bool
init(image: Binding<UIImage?>, takePhoto: Binding<Bool>) {
_image = image
_takePhoto = takePhoto
}
}
struct ShowImagePicker: UIViewControllerRepresentable {
@Binding var image: UIImage?
@Binding var takePhoto: Bool
func makeCoordinator() -> ImagePickerCoordinator {
ImagePickerCoordinator(image: $image, takePhoto: $takePhoto)
}
func makeUIViewController(context: Context) -> UIImagePickerController {
let pickerController = UIImagePickerController()
pickerController.delegate = context.coordinator
guard UIImagePickerController.isSourceTypeAvailable(.camera) else { return pickerController }
switch self.takePhoto {
case true:
pickerController.sourceType = .camera
case false:
pickerController.sourceType = .photoLibrary
}
pickerController.allowsEditing = true
return pickerController
}
func updateUIViewController(_ uiViewController: UIImagePickerController, context: Context) {}
}
extension ImagePickerCoordinator: UINavigationControllerDelegate, UIImagePickerControllerDelegate {
func imagePickerController(_ picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [UIImagePickerController.InfoKey : Any]) {
guard let uiImage = info[UIImagePickerController.InfoKey.originalImage] as? UIImage else { return }
self.image = uiImage
picker.dismiss(animated: true, completion: nil)
}
func imagePickerControllerDidCancel(_ picker: UIImagePickerController) {
picker.dismiss(animated: true, completion: nil)
}
}
Add the logic of just two buttons to your View that's enough...))
来源：https://stackoverflow.com/questions/56515871/how-to-open-the-imagepicker-in-swiftui