在实现访问相册和拍照功能之前需要先询问用户以获取权限，这就需要在info.plist里面写入

Privacy - Camera Usage Description
Privacy - Photo Library Usage Description

如图所示

String的后面填入提示框要显示的文字

上述步骤完成后，在需要访问相册和拍照功能的页面导入包和添加代理

import AVFoundation
import Photos

UIActionSheetDelegate
UIImagePickerControllerDelegate
UINavigationControllerDelegate

实现如下方法

//点击按钮
@IBAction func editHeadImgButton(_ sender: AnyObject) {
        
        let actionSheet = UIActionSheet.init(title: nil, delegate: self, cancelButtonTitle: "取消", destructiveButtonTitle: nil, otherButtonTitles: "拍照", "从相册选取")
        
        actionSheet.show(in: self.view)
}

//选择进入相册或拍照
func actionSheet(_ actionSheet: UIActionSheet, clickedButtonAt buttonIndex: Int) {

        if buttonIndex == 1 {

            self.takePhoto()

        } else if buttonIndex == 2 {

            self.infoImage()

        }
}

//从相册
func infoImage() {
        //判断有无打开相册的权限
        if self.PhotoLibraryPermissions() {

            let imagePicker = UIImagePickerController.init()
            
            imagePicker.delegate = self
            imagePicker.sourceType = UIImagePickerControllerSourceType.photoLibrary
            imagePicker.modalTransitionStyle = UIModalTransitionStyle.coverVertical
            imagePicker.allowsEditing = true
            
            //进入相册
            self.navigationController?.present(imagePicker, animated: true, completion: nil)

        } else {
            UIAlertView.init(title: "提示", message: "请在设置中打开相册权限", delegate: nil, cancelButtonTitle: "确定").show()
        }
}
    
//拍照
func takePhoto() {
        //判断有无打开照相机的权限
        if self.cameraPermissions() {

            let imagePicker = UIImagePickerController.init()
            
            imagePicker.delegate = self
            imagePicker.sourceType = UIImagePickerControllerSourceType.camera
            imagePicker.modalTransitionStyle = UIModalTransitionStyle.coverVertical
            imagePicker.allowsEditing = true
            
            //打开照相机
            self.navigationController?.present(imagePicker, animated: true, completion: nil)
        } else {
            UIAlertView.init(title: "提示", message: "请在设置中打开摄像头权限", delegate: nil, cancelButtonTitle: "确定").show()
        }
}

其中判断权限的方法如下

//判断相机访问权限
    func cameraPermissions() -> Bool{
        
        let authStatus:AVAuthorizationStatus = AVCaptureDevice.authorizationStatus(forMediaType: AVMediaTypeVideo)
        
        if(authStatus == AVAuthorizationStatus.denied || authStatus == AVAuthorizationStatus.restricted) {
            return false
        } else {
            return true
        }
    }
    
//判断相册访问权限
func PhotoLibraryPermissions() -> Bool {
        
        let library:PHAuthorizationStatus = PHPhotoLibrary.authorizationStatus()
        if(library == PHAuthorizationStatus.denied || library == PHAuthorizationStatus.restricted){
            return false
        }else {
            return true
        }
}

获取到图片之后会触发代理方法

//图片选择后
func imagePickerController(_ picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [String : Any]) {

        let image = info["UIImagePickerControllerEditedImage"] as! UIImage
        
        //如果是拍照的图片
        if picker.sourceType == UIImagePickerControllerSourceType.camera {
            UIImageWriteToSavedPhotosAlbum(image, nil, nil, nil)
        }
        
        //这就是你要的图片
        print(image)
        
        self.dismiss(animated: true, completion: nil)
}