小开

最佳答案

没事的，伙计，不要伤害自己和别人。

您可能不希望将这些映像存储在 Core Data 中，因为如果数据集过大，会影响性能。最好将图像写入文件。

NSData *pngData = UIImagePNGRepresentation(image);

这会提取出你捕捉到的图像的 PNG 数据，从这里，你可以把它写到一个文件中:

NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *documentsPath = [paths objectAtIndex:0]; //Get the docs directory
NSString *filePath = [documentsPath stringByAppendingPathComponent:@"image.png"]; //Add the file name
[pngData writeToFile:filePath atomically:YES]; //Write the file

以后再阅读也是同样的道理。像我们上面所做的那样构建路径，然后:

NSData *pngData = [NSData dataWithContentsOfFile:filePath];
UIImage *image = [UIImage imageWithData:pngData];

您可能想要做的是创建一个为您创建路径字符串的方法，因为您不希望该代码到处都是。它可能看起来像这样:

- (NSString *)documentsPathForFileName:(NSString *)name
{
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory,NSUserDomainMask, YES);
NSString *documentsPath = [paths objectAtIndex:0];


return [documentsPath stringByAppendingPathComponent:name];
}

希望对你有帮助。

小开

斯威夫特:

let paths: [NSString?] = NSSearchPathForDirectoriesInDomains(.DocumentDirectory, .LocalDomainMask, true)
if let path = paths[0]?.stringByAppendingPathComponent(imageName) {
do {
try UIImagePNGRepresentation(image)?.writeToFile(path, options: .DataWritingAtomic)
} catch {
return
}
}

小开

Swift 3.0版本

let documentDirectoryPath = NSSearchPathForDirectoriesInDomains(.documentDirectory, .userDomainMask, true)[0] as NSString
        

let img = UIImage(named: "1.jpg")!// Or use whatever way to get the UIImage object
let imgPath = URL(fileURLWithPath: documentDirectoryPath.appendingPathComponent("1.jpg"))// Change extension if you want to save as PNG


do{
try UIImageJPEGRepresentation(img, 1.0)?.write(to: imgPath, options: .atomic)//Use UIImagePNGRepresentation if you want to save as PNG
}catch let error{
print(error.localizedDescription)
}

小开

这是方明宁的回答 斯威夫特4.2版，使用推荐和更迅捷的方法进行更新，以检索文档目录路径，并使用更好的文档。这个新方法也要归功于方明宁。

guard let documentDirectoryPath = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask).first else {
return
}


//Using force unwrapping here because we're sure "1.jpg" exists. Remember, this is just an example.
let img = UIImage(named: "1.jpg")!


// Change extension if you want to save as PNG.
let imgPath = documentDirectoryPath.appendingPathComponent("1.jpg")


do {
//Use .pngData() if you want to save as PNG.
//.atomic is just an example here, check out other writing options as well. (see the link under this example)
//(atomic writes data to a temporary file first and sending that file to its final destination)
try img.jpegData(compressionQuality: 1)?.write(to: imgPath, options: .atomic)
} catch {
print(error.localizedDescription)
}

点击这里查看所有可能的数据写入选项。

小开

Swift 4 with extension

extension UIImage{


func saveImage(inDir:FileManager.SearchPathDirectory,name:String){
guard let documentDirectoryPath = FileManager.default.urls(for: inDir, in: .userDomainMask).first else {
return
}
let img = UIImage(named: "\(name).jpg")!


// Change extension if you want to save as PNG.
let imgPath = URL(fileURLWithPath: documentDirectoryPath.appendingPathComponent("\(name).jpg").absoluteString)
do {
try UIImageJPEGRepresentation(img, 0.5)?.write(to: imgPath, options: .atomic)
} catch {
print(error.localizedDescription)
}
}
}

用法例子

 image.saveImage(inDir: .documentDirectory, name: "pic")

小开

#pragma mark - Save Image To Local Directory


- (void)saveImageToDocumentDirectoryWithImage:(UIImage *)capturedImage {
NSError *error;
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *documentsDirectory = [paths objectAtIndex:0]; // Get documents folder
NSString *dataPath = [documentsDirectory stringByAppendingPathComponent:@"/images"];
    

//Create a folder inside Document Directory
if (![[NSFileManager defaultManager] fileExistsAtPath:dataPath])
[[NSFileManager defaultManager] createDirectoryAtPath:dataPath withIntermediateDirectories:NO attributes:nil error:&error]; //Create folder


NSString *imageName = [NSString stringWithFormat:@"%@/img_%@.png", dataPath, [self getRandomNumber]] ;
// save the file
if ([[NSFileManager defaultManager] fileExistsAtPath:imageName]) {
// delete if exist
[[NSFileManager defaultManager] removeItemAtPath:imageName error:nil];
}
    

NSData *imageDate = [NSData dataWithData:UIImagePNGRepresentation(capturedImage)];
[imageDate writeToFile: imageName atomically: YES];
}




#pragma mark - Generate Random Number


- (NSString *)getRandomNumber {
NSTimeInterval time = ([[NSDate date] timeIntervalSince1970]); // returned as a double
long digits = (long)time; // this is the first 10 digits
int decimalDigits = (int)(fmod(time, 1) * 1000); // this will get the 3 missing digits
//long timestamp = (digits * 1000) + decimalDigits;
NSString *timestampString = [NSString stringWithFormat:@"%ld%d",digits ,decimalDigits];
return timestampString;
}

将图像从 IOS 上的 UIView 保存到应用程序文档文件夹

Swift 3.0版本