有人知道如何将一个UIImage转换为Base64字符串,然后反转它吗?
我有以下代码;编码前的原始图像是好的,但编码解码后只得到一个空白图像。
NSData *imageData = UIImagePNGRepresentation(viewImage);
NSString *b64EncStr = [self encode: imageData];
NSString *base64String = [self encodeBase64:imageData];
有人知道如何将一个UIImage转换为Base64字符串,然后反转它吗?
我有以下代码;编码前的原始图像是好的,但编码解码后只得到一个空白图像。
NSData *imageData = UIImagePNGRepresentation(viewImage);
NSString *b64EncStr = [self encode: imageData];
NSString *base64String = [self encodeBase64:imageData];
当前回答
对于iOS 7+, Objective-C,下面是如何从一个图像URL开始转换:
NSURL *url = [NSURL URLWithString:self.groove.thumbnailURL];
UIImage *image = [UIImage imageWithData:[NSData dataWithContentsOfURL:url]];
NSString *base64String = [UIImagePNGRepresentation(image)
base64EncodedStringWithOptions:NSDataBase64Encoding64CharacterLineLength];
其他回答
很好理解你是否传递了Tyler Sheaffer所说的前缀。 但出于某种原因,你可能需要这个前缀来描述base64字符串开头的mime类型,所以我建议这段代码在编码之前传递一些选项(Swift 5):
extension UIImage {
enum Format: String {
case png = "png"
case jpeg = "jpeg"
}
func toBase64(type: Format = .jpeg, quality: CGFloat = 1, addMimePrefix: Bool = false) -> String? {
let imageData: Data?
switch type {
case .jpeg: imageData = jpegData(compressionQuality: quality)
case .png: imageData = pngData()
}
guard let data = imageData else { return nil }
let base64 = data.base64EncodedString(options: Data.Base64EncodingOptions.lineLength64Characters)
var result = base64
if addMimePrefix {
let prefix = "data:image/\(type.rawValue);base64,"
result = prefix + base64
}
return result
}
}
解码使用方便的初始化器- Swift 5
extension UIImage {
convenience init?(base64String: String) {
guard let data = Data(base64Encoded: base64String) else { return nil }
self.init(data: data)
}
}
Swift版本-创建base64镜像
在我看来,在UIImagePNGRepresenatation()的情况下隐式Unwrapped Optional是不安全的,所以我建议使用扩展如下:
extension UIImage {
func toBase64() -> String? {
let imageData = UIImagePNGRepresentation(self)
return imageData?.base64EncodedStringWithOptions(NSDataBase64EncodingOptions.Encoding64CharacterLineLength)
}
}
斯威夫特
首先我们需要image的NSData
//Use image name from bundle to create NSData
let image : UIImage = UIImage(named:"imageNameHere")!
//Now use image to create into NSData format
let imageData:NSData = UIImagePNGRepresentation(image)!
//OR next possibility
//Use image's path to create NSData
let url:NSURL = NSURL(string : "urlHere")!
//Now use image to create into NSData format
let imageData:NSData = NSData.init(contentsOfURL: url)!
Swift 2.0 >编码
let strBase64:String = imageData.base64EncodedStringWithOptions(.Encoding64CharacterLineLength)
Swift 2.0 >解码
let dataDecoded:NSData = NSData(base64EncodedString: strBase64, options: NSDataBase64DecodingOptions.IgnoreUnknownCharacters)!
Swift 3.0 >解码
let dataDecoded : Data = Data(base64Encoded: strBase64, options: .ignoreUnknownCharacters)!
编码:
let strBase64 = imageData.base64EncodedString(options: .lineLength64Characters)
print(strBase64)
解码:
let dataDecoded:NSData = NSData(base64EncodedString: strBase64, options: NSDataBase64DecodingOptions(rawValue: 0))!
let decodedimage:UIImage = UIImage(data: dataDecoded)!
print(decodedimage)
yourImageView.image = decodedimage
斯威夫特3.0
let dataDecoded : Data = Data(base64Encoded: strBase64, options: .ignoreUnknownCharacters)!
let decodedimage = UIImage(data: dataDecoded)
yourImageView.image = decodedimage
objective - c
iOS7 >版本
你可以使用NSData的base64EncodedStringWithOptions
编码:
- (NSString *)encodeToBase64String:(UIImage *)image {
return [UIImagePNGRepresentation(image) base64EncodedStringWithOptions:NSDataBase64Encoding64CharacterLineLength];
}
解码:
- (UIImage *)decodeBase64ToImage:(NSString *)strEncodeData {
NSData *data = [[NSData alloc]initWithBase64EncodedString:strEncodeData options:NSDataBase64DecodingIgnoreUnknownCharacters];
return [UIImage imageWithData:data];
}
iOS 6.1和<版本
第一个选项:使用这个链接来编码和解码图像
在项目中添加Base64类。
编码:
NSData* data = UIImageJPEGRepresentation(yourImage, 1.0f);
NSString *strEncoded = [Base64 encode:data];
解码:
NSData* data = [Base64 decode:strEncoded ];;
image.image = [UIImage imageWithData:data];
另一种选择:使用qutilities进行编码和解码
斯威夫特iOS8
// prgm mark ----
// convert images into base64 and keep them into string
func convertImageToBase64(image: UIImage) -> String {
var imageData = UIImagePNGRepresentation(image)
let base64String = imageData.base64EncodedStringWithOptions(.allZeros)
return base64String
}// end convertImageToBase64
// prgm mark ----
// convert images into base64 and keep them into string
func convertBase64ToImage(base64String: String) -> UIImage {
let decodedData = NSData(base64EncodedString: base64String, options: NSDataBase64DecodingOptions(rawValue: 0) )
var decodedimage = UIImage(data: decodedData!)
return decodedimage!
}// end convertBase64ToImage