UIImagePickerController
搭建UI
構(gòu)建如下UI：
設(shè)置按鈕的是否可用：
cameraButton.isEnabled = UIImagePickerController.isSourceTypeAvailable(.camera)
UIImagePickerControllerDelegate的Rx實(shí)現(xiàn)
UIImagePickerController的代理對象需要遵守UIImagePickerControllerDelegate和UINavigationControllerDelegate兩個(gè)協(xié)議的：
weak open var delegate: (UIImagePickerControllerDelegate & UINavigationControllerDelegate)?
由于RxCocoa已經(jīng)實(shí)現(xiàn)UINavigationControllerDelegate為RxNavigationControllerDelegateProxy涂滴，沒有實(shí)現(xiàn)UIImagePickerControllerDelegate柔纵，所以需要我們自己實(shí)現(xiàn)搁料。
構(gòu)建RxImagePickerDelegateProxy
從前面Delegate章節(jié)的DelegateProxyType講到系羞，擁有delegates的視圖可能是繼承的郭计，RxCocoa需要?jiǎng)?chuàng)建的那些代理也是繼承的。
由于UIImagePickerController繼承自UINavigationController椒振，定義RxImagePickerDelegateProxy類繼承RxNavigationControllerDelegateProxy基類昭伸，遵守UIImagePickerControllerDelegate協(xié)議：
class RxImagePickerDelegateProxy: RxNavigationControllerDelegateProxy, UIImagePickerControllerDelegate {
public init(imagePicker: UIImagePickerController) {
super.init(navigationController: imagePicker)
}
}
首先由于繼承自RxNavigationControllerDelegateProxy，所以實(shí)現(xiàn)了DelegateProxyType協(xié)議中定義的函數(shù)澎迎。
UIImagePickerControllerDelegate協(xié)議中定義的函數(shù)都沒有實(shí)現(xiàn)勋乾，最終會(huì)走消息轉(zhuǎn)發(fā)的方式實(shí)現(xiàn)Rx序列發(fā)送元素宋下。
擴(kuò)展Reactive
首先定義一個(gè)func dismissViewController(viewController: UIViewController, animated: Bool)函數(shù)，用來安全有效地關(guān)閉模態(tài)視圖辑莫，方便后面使用：
func dismissViewController(viewController: UIViewController, animated: Bool) {
/// 是否有控制器在進(jìn)程中沒有顯示或消失
if viewController.isBeingPresented || viewController.isBeingDismissed {
DispatchQueue.main.async {// 異步遞歸調(diào)用
dismissViewController(viewController: viewController, animated: animated)
}
} else if viewController.presentingViewController != nil {
viewController.dismiss(animated: animated, completion: nil)
}
}
定義一個(gè)private func castOrThrow<T>(resultType: T.Type, object: Any) throws -> T函數(shù)学歧，用于將Any類型數(shù)據(jù)轉(zhuǎn)換為特定類型，方便后面使用：
private func castOrThrow<T>(resultType: T.Type, object: Any) throws -> T {
guard let resultValue = object as? T else {
throw RxCocoaError.castingError(object: object, targetType: resultType)
}
return resultValue
}
為了方便使用各吨，基于UIImagePickerController擴(kuò)展Reactive：
extension Reactive where Base: UIImagePickerController {
public var didCancel: Observable<()> {
return delegate.methodInvoked(#selector(UIImagePickerControllerDelegate.imagePickerControllerDidCancel(_:))).map { (_) -> () in }
}
public var didFinishPickingMediaWithInfo: Observable<[UIImagePickerController.InfoKey: AnyObject]> {
return delegate.methodInvoked(#selector(UIImagePickerControllerDelegate.imagePickerController(_:didFinishPickingMediaWithInfo:))).map { (a) in
return try castOrThrow(resultType: Dictionary<UIImagePickerController.InfoKey, AnyObject>.self, object: a[1])
}
}
/// 創(chuàng)建圖片選擇控制器Observable
/// - Parameters:
/// - parent: 父控制器
/// - animated: 動(dòng)畫
/// - configureImagePicker: 配置閉包
static func createWithParent(parent: UIViewController?, animated: Bool = true, configureImagePicker: @escaping (UIImagePickerController) throws -> Void) -> Observable<UIImagePickerController> {
return Observable.create { [weak parent] (observer) -> Disposable in
let imagePicker = UIImagePickerController()
// 取消操作
let dismissDisposable = imagePicker.rx.didCancel.subscribe(onNext: { [weak imagePicker] (_) in
guard let imagePicker = imagePicker else {
return
}
dismissViewController(viewController: imagePicker, animated: animated)
})
// 處理配置閉包
do {
try configureImagePicker(imagePicker)
} catch let error {
observer.onError(error)
return Disposables.create()
}
guard let parent = parent else {
observer.onCompleted()
return Disposables.create()
}
parent.present(imagePicker, animated: animated, completion: nil)
observer.on(.next(imagePicker))
return Disposables.create(dismissDisposable, Disposables.create {
dismissViewController(viewController: imagePicker, animated: animated)
})
}
}
}
代碼分析：
- 使用消息轉(zhuǎn)發(fā)的方式實(shí)現(xiàn)
didCancel序列，并使用map操作符更改序列元素為空 - 使用消息轉(zhuǎn)發(fā)的方式實(shí)現(xiàn)
didFinishPickingMediaWithInfo序列欺冀，并使用map操作符更改序列元素 -
createWithParent序列的實(shí)現(xiàn)是使用create操作符創(chuàng)建，在創(chuàng)建的閉包中創(chuàng)建UIImagePickerController职车、執(zhí)行配置閉包、present控制器积瞒、訂閱didCancel序列進(jìn)行關(guān)閉控制器等
綁定UI
在iOS中使用相機(jī)庐船、相冊資源，需要在info.plist文件中配置相機(jī)李破、相冊權(quán)限詢問框的描述嗤攻，如下所示：
[圖片上傳失敗...(image-f2b960-1604572278262)]
因?yàn)樵谑褂?code>rx.*之前(例如appDidFinishLaunching)暴区，在registerKnownImplementations或程序的其他一些地方使用執(zhí)行注冊Rx實(shí)現(xiàn)的代理房交。
然而RxImagePickerDelegateProxy沒有實(shí)現(xiàn)registerKnownImplementations函數(shù)口猜，也沒有再父類中注冊川抡，所以選擇在程序啟動(dòng)時(shí)的appDidFinishLaunching中注冊RxImagePickerDelegateProxy：
func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?) -> Bool {
RxImagePickerDelegateProxy.register { (p) -> RxImagePickerDelegateProxy in
return RxImagePickerDelegateProxy(imagePicker: p)
}
return true
}
數(shù)據(jù)綁定
/// 拍照是否可用
cameraButton.isEnabled = UIImagePickerController.isSourceTypeAvailable(.camera)
cameraButton.rx.tap.flatMapLatest { [weak self] _ in
return UIImagePickerController.rx.createWithParent(parent: self, animated: true) { (picker) in
picker.sourceType = .camera
picker.allowsEditing = false
}.flatMap { $0.rx.didFinishPickingMediaWithInfo }.take(1)
}.map { $0[.originalImage] as? UIImage }.bind(to: imageView.rx.image).disposed(by: bag)
galleryButton.rx.tap.flatMapLatest { [weak self] (_) in
return UIImagePickerController.rx.createWithParent(parent: self) { (picker) in
picker.sourceType = .photoLibrary
picker.allowsEditing = false
}.flatMap { $0.rx.didFinishPickingMediaWithInfo }.take(1)
}.map { $0[.originalImage] as? UIImage }.bind(to: imageView.rx.image).disposed(by: bag)
cropButton.rx.tap.flatMapLatest { [weak self] (_) in
return UIImagePickerController.rx.createWithParent(parent: self) { (picker) in
picker.sourceType = .photoLibrary
picker.allowsEditing = true
}.flatMap { $0.rx.didFinishPickingMediaWithInfo }.take(1)
}.map { $0[.editedImage] as? UIImage }.bind(to: imageView.rx.image).disposed(by: bag)
