blocks|key|842088|text|要在NSUserDefaults中保存图像：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|842089|[[NSUserDefaults+standardUserDefaults]+setObject:UIImagePNGRepresentation(image)+forKey:key];|code-block|syntax|javascript|842090|要从NSUserDefaults检索图像：|842091|NSData*+imageData+=+[[NSUserDefaults+standardUserDefaults]+objectForKey:key];
UIImage*+image+=+[UIImage+imageWithData:imageData];|842092|entityMap^0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|N|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|O|8|@]|9|@]|A|$]]|$1|I|3|J|5|D|7|P|8|@]|9|@]|A|$E|F]]|$1|K|3|-4|5|6|7|Q|8|@]|9|@]|A|$]]]|L|$]]

To save an image in NSUserDefaults:

<pre><code>[[NSUserDefaults standardUserDefaults] setObject:UIImagePNGRepresentation(image) forKey:key];
</code></pre>

To retrieve an image from NSUserDefaults:

<pre><code>NSData* imageData = [[NSUserDefaults standardUserDefaults] objectForKey:key];
UIImage* image = [UIImage imageWithData:imageData];
</code></pre>

blocks|key|842205|text|是的，技术上是可行的，就像在|type|unstyled|depth|inlineStyleRanges|entityRanges|data|842206|[[NSUserDefaults+standardUserDefaults]+setObject:UIImagePNGRepresentation(image)+forKey:@"foo"];|code-block|syntax|javascript|842207|但这并不可取，因为plist不适合存放大块的二进制数据，尤其是用户首选项。最好将图像保存到用户文档文件夹中，并将对该对象的引用存储为URL或路径。|842208|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|L|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|M|8|@]|9|@]|A|$]]|$1|I|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|J|$]]

Yes , technically possible as in
<pre><code>[[NSUserDefaults standardUserDefaults] setObject:UIImagePNGRepresentation(image) forKey:@&quot;foo&quot;];
</code></pre>
But not advisable because plists are not appropriate places for large blobs of binary data especially User Prefs. It would be better to save image to user docs folder and store the reference to that object as a URL or path.

blocks|key|842289|text|这在技术上是可行的，但并不可取。而是将图像保存到磁盘。NSUserDefaults适用于小设置，而不是大的二进制数据文件。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|842290|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|D|8|@]|9|@]|A|$]]|$1|B|3|-4|5|6|7|E|8|@]|9|@]|A|$]]]|C|$]]

It's technically possible, but it's not advisable. Save the image to disk instead. NSUserDefaults is meant for small settings, not big binary data files.

blocks|key|842163|text|是的，你可以使用。但由于它用于存储首选项，您可以更好地将图像保存到document文件夹。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|842164|如果需要，您可以将路径放在NSUserDefaults中。|offset|length|style|CODE|842165|entityMap^0|0|D|E|0^^$0|@$1|2|3|4|5|6|7|J|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|K|8|@$D|L|E|M|F|G]]|9|@]|A|$]]|$1|H|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|I|$]]

Yes, you can use. But since it is for storage of preferences, you can better save images to document folder.

And you can have the path in the <code>NSUserDefaults</code>, if required.

blocks|key|842262|text|将图像保存到NSUserDefault：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|842263|NSData+*imageData;+
//+create+NSData-object+from+image
imageData+=+UIImagePNGRepresentation([dic+objectForKey:[NSString+stringWithFormat:@"%25d",i]]);+
//+save+NSData-object+to+UserDefaults
[[NSUserDefaults+standardUserDefaults]+setObject:imageData+forKey:[NSString+stringWithFormat:@"%25d",i]];|code-block|syntax|javascript|842264|从NSUserDefault加载图像：|842265|NSData+*imageData;
//+Load+NSData-object+from+NSUserDefault
imageData+=+[[NSUserDefaults+standardUserDefaults]+valueForKey:[NSString+stringWithFormat:@"%25d",i]];
//+get+Image+from+NSData
[image+setObject:[UIImage+imageWithData:imageData]+forKey:[NSString+stringWithFormat:@"%25d",i]];|842266|entityMap^0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|N|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|O|8|@]|9|@]|A|$]]|$1|I|3|J|5|D|7|P|8|@]|9|@]|A|$E|F]]|$1|K|3|-4|5|6|7|Q|8|@]|9|@]|A|$]]]|L|$]]

Save image to NSUserDefault:

<pre><code>NSData *imageData; 
// create NSData-object from image
imageData = UIImagePNGRepresentation([dic objectForKey:[NSString stringWithFormat:@"%d",i]]); 
// save NSData-object to UserDefaults
[[NSUserDefaults standardUserDefaults] setObject:imageData forKey:[NSString stringWithFormat:@"%d",i]];
</code></pre>

Load Image from NSUserDefault:

<pre><code>NSData *imageData;
// Load NSData-object from NSUserDefault
imageData = [[NSUserDefaults standardUserDefaults] valueForKey:[NSString stringWithFormat:@"%d",i]];
// get Image from NSData
[image setObject:[UIImage imageWithData:imageData] forKey:[NSString stringWithFormat:@"%d",i]];
</code></pre>

blocks|key|626657|text|由于这个问题有很高的谷歌搜索索引--这里是@NikitaTook在当今时代的答案，即Swift+3和4(具有异常处理)。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|626658|注意:这个类是专门用来读写JPG格式的图像到文件系统的。Userdefaults的事情应该在它之外处理。|offset|length|style|CODE|626659|writeFile接受jpg映像的文件名(扩展名为.jpg+)和UIImage本身，如果能够保存，则返回true；如果无法写入映像，则返回false。此时，您可以将映像存储在Userdefaults中，这将是您的备份计划，或者只需再重试一次。readFile函数接受图像文件名并返回一个UIImage，如果找到传递给此函数的图像名称，则返回该图像，否则它只返回应用程序资产文件夹中的默认占位符图像(这样可以避免严重的崩溃或其他奇怪的行为)。|626660|import+Foundation
import+UIKit

class+ReadWriteFileFS{

++++func+writeFile(_+image:+UIImage,+_+imgName:+String)+->+Bool{
++++++++let+imageData+=+UIImageJPEGRepresentation(image,+1)
++++++++let+relativePath+=+imgName
++++++++let+path+=+self.documentsPathForFileName(name:+relativePath)

++++++++do+{
++++++++++++try+imageData?.write(to:+path,+options:+.atomic)
++++++++}+catch+{
++++++++++++return+false
++++++++}
++++++++return+true
++++}

++++func+readFile(_+name:+String)+->+UIImage{
++++++++let+fullPath+=+self.documentsPathForFileName(name:+name)
++++++++var+image+=+UIImage()

++++++++if+FileManager.default.fileExists(atPath:+fullPath.path){
++++++++++++image+=+UIImage(contentsOfFile:+fullPath.path)!
++++++++}else{
++++++++++++image+=+UIImage(named:+"user")!++//a+default+place+holder+image+from+apps+asset+folder
++++++++}
++++++++return+image
++++}
}

extension+ReadWriteFileFS{
++++func+documentsPathForFileName(name:+String)+->+URL+{
++++++++let+paths+=+FileManager.default.urls(for:+.documentDirectory,+in:+.userDomainMask)
++++++++let+path+=+paths[0]
++++++++let+fullPath+=+path.appendingPathComponent(name)
++++++++return+fullPath
++++}
}|code-block|syntax|javascript|626661|entityMap^0|0|S|C|0|0|9|W|7|2F|C|3D|8|3Z|7|0|0^^$0|@$1|2|3|4|5|6|7|Q|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|R|8|@$D|S|E|T|F|G]]|9|@]|A|$]]|$1|H|3|I|5|6|7|U|8|@$D|V|E|W|F|G]|$D|X|E|Y|F|G]|$D|Z|E|10|F|G]|$D|11|E|12|F|G]|$D|13|E|14|F|G]]|9|@]|A|$]]|$1|J|3|K|5|L|7|15|8|@]|9|@]|A|$M|N]]|$1|O|3|-4|5|6|7|16|8|@]|9|@]|A|$]]]|P|$]]

Since this question has a high google search index - here's @NikitaTook's answer in today's day and age i.e. Swift 3 and 4 (with exception handling). 

Note: This class is solely written to read and write images of JPG format to the filesystem. The <code>Userdefaults</code> stuff should be handled outside of it.

<code>writeFile</code> takes in the file name of your jpg image (with .jpg extension) and the <code>UIImage</code> itself and returns true if it is able to save or else returns false if it is unable to write the image, at which point you can store the image in <code>Userdefaults</code> which would be your backup plan or simply retry one more time. The <code>readFile</code> function takes in the image file name and returns a <code>UIImage</code>, if the image name passed to this function is found then it returns that image else it just returns a default placeholder image from the app's asset folder (this way you can avoid nasty crashes or other weird behaviors).

<pre><code>import Foundation
import UIKit

class ReadWriteFileFS{

 func writeFile(_ image: UIImage, _ imgName: String) -&gt; Bool{
 let imageData = UIImageJPEGRepresentation(image, 1)
 let relativePath = imgName
 let path = self.documentsPathForFileName(name: relativePath)

 do {
 try imageData?.write(to: path, options: .atomic)
 } catch {
 return false
 }
 return true
 }

 func readFile(_ name: String) -&gt; UIImage{
 let fullPath = self.documentsPathForFileName(name: name)
 var image = UIImage()

 if FileManager.default.fileExists(atPath: fullPath.path){
 image = UIImage(contentsOfFile: fullPath.path)!
 }else{
 image = UIImage(named: "user")! //a default place holder image from apps asset folder
 }
 return image
 }
}

extension ReadWriteFileFS{
 func documentsPathForFileName(name: String) -&gt; URL {
 let paths = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask)
 let path = paths[0]
 let fullPath = path.appendingPathComponent(name)
 return fullPath
 }
}
</code></pre>

blocks|key|626702|text|Swift+4.x|type|unstyled|depth|inlineStyleRanges|entityRanges|data|626703|Xcode+11.x|626704|func+saveImageInUserDefault(img:UIImage,+key:String)+{
++++UserDefaults.standard.set(img.pngData(),+forKey:+key)
}

func+getImageFromUserDefault(key:String)+->+UIImage?+{
++++let+imageData+=+UserDefaults.standard.object(forKey:+key)+as?+Data
++++var+image:+UIImage?+=+nil
++++if+let+imageData+=+imageData+{
++++++++image+=+UIImage(data:+imageData)
++++}
++++return+image
}|code-block|syntax|javascript|626705|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|L|8|@]|9|@]|A|$]]|$1|D|3|E|5|F|7|M|8|@]|9|@]|A|$G|H]]|$1|I|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|J|$]]

Swift 4.x 
Xcode 11.x

<pre><code>func saveImageInUserDefault(img:UIImage, key:String) {
 UserDefaults.standard.set(img.pngData(), forKey: key)
}

func getImageFromUserDefault(key:String) -&gt; UIImage? {
 let imageData = UserDefaults.standard.object(forKey: key) as? Data
 var image: UIImage? = nil
 if let imageData = imageData {
 image = UIImage(data: imageData)
 }
 return image
}
</code></pre>

Is it possible to save images into <code>NSUserDefaults</code> as an object and then retrieve for further use?

Save images in NSUserDefaults?

文件系统

Swift

Xcode

是否可以将图像作为对象保存到NSUserDefaults中，然后检索以供进一步使用？

问是否在NSUserDefaults中保存图像？
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问是否在NSUserDefaults中保存图像？
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