swift3.0 保存图片到本地，申请权限

<key>NSCameraUsageDescription</key>
<string>需要您的同意才能读取媒体资料库</string>
<key>NSLocationWhenInUseUsageDescription</key>
<string>需要您的同意才能读取媒体资料库</string>
<key>NSPhotoLibraryUsageDescription</key>
<string>需要您的同意才能读取媒体资料库</string>
<key>Privacy - Photo Library Usage Description</key>
<string>需要您的同意才能读取媒体资料库</string>

import Photos//操作结果枚举
enum PhotoAlbumUtilResult {
case success, error, denied
}//相册操作工具类
class PhotoAlbumUtil: NSObject { public typealias completion = ((_ result: PhotoAlbumUtilResult) -> ())
//判断是否授权
class func isAuthorized() -> Bool {
return PHPhotoLibrary.authorizationStatus() == .authorized ||
PHPhotoLibrary.authorizationStatus() == .notDetermined } //保存图片到相册
class func saveImageInAlbum(image: UIImage, albumName: String,
completion: completion?) {
//权限验证
if !isAuthorized() {
completion?(.denied)
return
}
var assetAlbum: PHAssetCollection? //如果指定的相册名称为空，则保存到相机胶卷。（否则保存到指定相册）
if albumName.isEmpty {
let list = PHAssetCollection
.fetchAssetCollections(with: .smartAlbum, subtype: .smartAlbumUserLibrary,
options: nil)
assetAlbum = list[0]
} else {
//看保存的指定相册是否存在
let list = PHAssetCollection
.fetchAssetCollections(with: .album, subtype: .any, options: nil)
list.enumerateObjects({ (album, index, stop) in
let assetCollection = album
if albumName == assetCollection.localizedTitle {
assetAlbum = assetCollection
stop.initialize(to: true)
}
})
//不存在的话则创建该相册
if assetAlbum == nil {
PHPhotoLibrary.shared().performChanges({
PHAssetCollectionChangeRequest
.creationRequestForAssetCollection(withTitle: albumName)
}, completionHandler: { (isSuccess, error) in
self.saveImageInAlbum(image: image, albumName: albumName,
completion: completion)
})
return
}
} //保存图片
PHPhotoLibrary.shared().performChanges({
//添加的相机胶卷
let result = PHAssetChangeRequest.creationRequestForAsset(from: image)
//是否要添加到相簿
if !albumName.isEmpty {
let assetPlaceholder = result.placeholderForCreatedAsset
let albumChangeRequset = PHAssetCollectionChangeRequest(for:
assetAlbum!)
albumChangeRequset!.addAssets([assetPlaceholder!] as NSArray)
}
}) { (isSuccess: Bool, error: Error?) in
if isSuccess {
completion?(.success)
} else{
print(error!.localizedDescription)
completion?(.error)
}
}
}
}

PhotoAlbumUtil.saveImageInAlbum(image: image, albumName: "APP") { (result) in
DispatchQueue.main.async {
switch result{
case .success:
//"保存成功"
break
case .denied:
//没有权限，去设置里打开权限
let a = MyAlertController()
a.addOKView("去设置"){ (a) in
let url = URL(string: UIApplicationOpenSettingsURLString)
if let url = url, UIApplication.shared.canOpenURL(url) {
if #available(iOS 10, *) {
UIApplication.shared.open(url, options: [:],
completionHandler: {
(success) in
})
} else {
UIApplication.shared.openURL(url)
}
}
}
a.addCancelView()
a.show(self,title: "没有相册权限",message: "请您到 \"设置\" -> \"APP\" 开启相册权限", style: .alert )
break
case .error:
//"保存失败"
}
}
}