迅速IOS数据持久性的UIImage

Question

我创建类如以下和要保存数组：[costCategory]到磁盘，

class costCategory : NSObject, NSCoding { 
var name : String 
var defaultValue : Int 
var thisMonthsEstimate : Int 
var sumOfThisMonthsActuals : Int 
var riskFactor : Float 
var monthlyAverage : Float 
var icon: UIImage! 

init (name:String, defaultValue:Int, thisMonthsEstimate:Int, sumOfThisMonthsActuals:Int, riskFactor:Float, monthlyAverage:Float, icon: UIImage) { 
    self.name = name 
    self.defaultValue = defaultValue 
    self.thisMonthsEstimate = thisMonthsEstimate 
    self.sumOfThisMonthsActuals = sumOfThisMonthsActuals 
    self.riskFactor = riskFactor 
    self.monthlyAverage = monthlyAverage 
    self.icon = icon 
} 

// MARK: NSCoding 

required init(coder decoder: NSCoder) { 
    //Error here "missing argument for parameter name in call 
    self.name = decoder.decodeObjectForKey("name") as! String 
    self.defaultValue = decoder.decodeIntegerForKey("defaultValue") 
    self.thisMonthsEstimate = decoder.decodeIntegerForKey("thisMonthsEstimate") 
    self.sumOfThisMonthsActuals = decoder.decodeIntegerForKey("sumOfThisMonthsActuals") 
    self.riskFactor = decoder.decodeFloatForKey("riskFactor") 
    self.monthlyAverage = decoder.decodeFloatForKey("monthlyAverage") 
    self.icon = decoder.decodeObjectForKey("icon") as! UIImage! 
    super.init() 
} 

func encodeWithCoder(coder: NSCoder) { 
    coder.encodeObject(self.name, forKey: "name") 
    coder.encodeInt(Int32(self.defaultValue), forKey: "defaultValue") 
    coder.encodeInt(Int32(self.thisMonthsEstimate), forKey: "thisMonthsEstimate") 
    coder.encodeInt(Int32(self.sumOfThisMonthsActuals), forKey: "sumOfThisMonthsActuals") 
    coder.encodeFloat(self.riskFactor, forKey: "riskFactor") 
    coder.encodeFloat(self.monthlyAverage, forKey: "monthlyAverage") 
    coder.encodeObject(self.icon, forKey: "icon") 
} 

}

我保存的数据中的viewController如下：

class ViewController：UIViewController {

@IBOutlet weak var photo: UIImageView! 
override func viewDidLoad() { 
    super.viewDidLoad() 
    // Do any additional setup after loading the view, typically from a nib. 
    let defaults = NSUserDefaults.standardUserDefaults() 
    let arrayOfObjectsKey = "arrayOfObjectsKey" 
    var arrayOfObjects = [costCategory]() 
    arrayOfObjects.append(costCategory(name: "Mark", defaultValue: 50, thisMonthsEstimate: 60, sumOfThisMonthsActuals: 70, riskFactor:80, monthlyAverage:90, icon: UIImage(named:"Mark.JPG")!)) 
    arrayOfObjects.append(costCategory(name: "Mary", defaultValue: 50, thisMonthsEstimate: 60, sumOfThisMonthsActuals: 70, riskFactor:80, monthlyAverage:90, icon: UIImage(named:"Mary.JPG")!)) 
    var arrayOfObjectsData = NSKeyedArchiver.archivedDataWithRootObject(arrayOfObjects) 
    var arrayOfObjectsUnarchivedData = defaults.dataForKey("arrayOfObjectsKey")! 
    var arrayOfObjectsUnarchived = NSKeyedUnarchiver.unarchiveObjectWithData(arrayOfObjectsUnarchivedData) as! [costCategory] 
    **println(arrayOfObjectsUnarchived[0].icon)** 
    **photo.image = arrayOfObjectsUnarchived[0].icon** 
} 

}

我println（arrayOfObjectsUnarchived [0] .icon）发现它是零，无法获取我保存的原始图像，为什么？并使用以下方法保存就足够了？任何人都有其他的方法，如fileManger？谢谢！！！！

设默认= NSUserDefaults.standardUserDefaults（）

VAR arrayOfObjectsUnarchivedData = defaults.dataForKey（ “arrayOfObjectsKey”）！

var arrayOfObjectsUnarchived = NSKeyedUnarchiver.unarchiveObjectWithData（arrayOfObjectsUnarchivedData）as！ [costCategory] ​​

Answer 1

存储UIImage在NSUserDefaults不是一个好主意。

我建议将图像保存在文件系统中，并且可以将它们的文件系统路径存储在您的模型中，然后可以将其存放在NSUserDefaults中。

但是，如果你真的有兴趣，这是如何将图像保存为NSUserDefaults：

写作UIImage：

let imageData = UIImageJPEGRepresentation(image, 1) 
let relativePath = "image_\(NSDate.timeIntervalSinceReferenceDate()).jpg" 
let path = self.documentsPathForFileName(relativePath) 
imageData.writeToFile(path, atomically: true) 
NSUserDefaults.standardUserDefaults().setObject(relativePath, forKey: "path") 
NSUserDefaults.standardUserDefaults().synchronize() 

阅读UIImage：

let possibleOldImagePath = NSUserDefaults.standardUserDefaults().objectForKey("path") as String? 

if let oldImagePath = possibleOldImagePath { 
    let oldFullPath = self.documentsPathForFileName(oldImagePath) 
    let oldImageData = NSData(contentsOfFile: oldFullPath) 
    // here is your saved image: 
    let oldImage = UIImage(data: oldImageData) 
} 

编辑：在OP请求

步骤1：编写一个方法，该方法将文件系统中的图像名称返回给图像路径。在这里，我将文件保存在Documents目录中。

- (NSString *)imagePathForImage:(NSString *)iImageName { 
    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES); 
    NSString *documentsDirectory = [paths objectAtIndex:0]; 
    NSString *imagePath = [documentsDirectory stringByAppendingPathComponent:iImageName]; 

    return imagePath; 
} 

第2步：调用上面的方法，并保存在您的costCategory图像路径。我不写这个代码。我希望你能连接它。

第3步：将文件保存到文件系统。传递你从上面的方法得到的图像和路径。

- (void)saveImage:(UIImage *)iImage toPath:(NSString *)iImagePath { 
    NSData *imageData = UIImagePNGRepresentation(iImage); 
    [imageData writeToFile:iImagePath atomically:NO]; 
} 

第4步：最后，当你从NSUserDefaults读你的对象，获取图像路径属性并调用下面的方法来获取&渲染图像：

- (UIImage *)imageForPath:(NSString *)iImagePath { 
    return [UIImage imageWithContentsOfFile:iImagePath]; 
}