周精益分享 - Swift入门专题

『图像和滤镜』 - 图像选择器

我们可以使用以下常规的图像获取方式

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图库与相册

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系统自带

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override func touchesBegan(touches: Set<UITouch>, withEvent event: UIEvent?) {
    
    let sheet = UIAlertController(title: "图片选择", message: "简单版的三种选择", preferredStyle: .ActionSheet)
    // 判断设备是否支持相机（iPod & Simulator）
    if (UIImagePickerController.isSourceTypeAvailable(.Camera)) {
        sheet.addAction(UIAlertAction.init(title: "Camera", style: .Default, handler: { _ in
            self.showPhotoes(.Camera)
        }))
    }
    sheet.addAction(UIAlertAction.init(title: "PhotoLibrary", style: .Default, handler: { _ in
        self.showPhotoes(.PhotoLibrary)
    }))
    sheet.addAction(UIAlertAction.init(title: "SavedPhotosAlbum", style: .Default, handler: { _ in
        self.showPhotoes(.SavedPhotosAlbum)
    }))
    sheet.addAction(UIAlertAction.init(title: "Cancel", style: .Cancel, handler: nil))
    presentViewController(sheet, animated: true, completion: nil)
}
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func showPhotoes(source: UIImagePickerControllerSourceType) {
    let controller = UIImagePickerController()
    controller.delegate = self
    controller.sourceType = source
    controller.allowsEditing = source == .SavedPhotosAlbum ? true:false
    self.presentViewController(controller, animated: true, completion: nil)
}

UIImagePickerController的代理

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func imagePickerControllerDidCancel(picker: UIImagePickerController) {
    dismissViewControllerAnimated(true, completion: nil)
}
// 非常坑，这个方法废弃了但代码提示只有它
//	func imagePickerController(picker: UIImagePickerController, didFinishPickingImage image: UIImage, editingInfo: [String : AnyObject]?) {
//	}
func imagePickerController(picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [String : AnyObject]) {
}

#####info字典介绍

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UIImagePickerControllerMediaType: String
UIImagePickerControllerOriginalImage: UIImage
UIImagePickerControllerEditedImage: UIImage
UIImagePickerControllerCropRect: NSValue -> CGRect
// MediaURL只为视频提供
UIImagePickerControllerMediaURL:  NSURL
// LivePhoto是一张图片，保留那个moment的前后动作和声音
UIImagePickerControllerLivePhoto: String
// 摄像摄影时返回media的信息字典
UIImagePickerControllerMediaMetadata: NSDictionary

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// SavedPhotosAlbum 的 info 示例
▿ 5 elements
  ▿ [0] : 2 elements
    - .0 : "UIImagePickerControllerCropRect"
  ▿ [1] : 2 elements
    - .0 : "UIImagePickerControllerOriginalImage"
  ▿ [2] : 2 elements
    - .0 : "UIImagePickerControllerReferenceURL"
    - .1 : assets-library://asset/asset.JPG?id=99D53A1F-FEEF-40E1-8BB3-7DD55A43C8B7&ext=JPG
  ▿ [3] : 2 elements
    - .0 : "UIImagePickerControllerMediaType"
    - .1 : public.image
  ▿ [4] : 2 elements
    - .0 : "UIImagePickerControllerEditedImage"

自定义

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遍历相册的所有图片

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// AssetsLibrary.framework
// ALAssetsLibrary 的使用,但是它慢慢的被放弃了
    func loadLocalPhotoes(){
        var countOne = 0
        //ALAssetsGroupSavedPhotos表示只读取相机胶卷（ALAssetsGroupAll则读取全部相簿）
        assetsLibrary.enumerateGroupsWithTypes(ALAssetsGroupSavedPhotos, usingBlock: {
            (group: ALAssetsGroup!, stop) in
            print("is goin")
            if group != nil {
                let assetBlock : ALAssetsGroupEnumerationResultsBlock = {
                    (result: ALAsset!, index: Int, stop) in
                    if result != nil {
                        self.assets.append(result)
                        countOne++
                    }
                }
                group.enumerateAssetsUsingBlock(assetBlock)
                print("assets:\(countOne)")
                self.startChangeLocalImages(0)
            }
            }, failureBlock: { (fail) in
                print(fail)
        })
    }
    
// 展现本地图片
func startChangeLocalImages(var index: Int){
        if index==assets.count {
            index = 0
        }
        let myAsset = assets[index]
        let image = UIImage(CGImage:myAsset.thumbnail().takeUnretainedValue())
        self.backImageView.image = image
        
        let popTime = dispatch_time(DISPATCH_TIME_NOW, Int64(1 * Double(NSEC_PER_SEC)))
        dispatch_after(popTime, dispatch_get_main_queue()) {
            self.startChangeLocalImages(index+1)
        }
    }

iOS9 开始使用新库
PHPhotoLibrary