我有一个应用程序，它使用 Core Data 中的 Transformable 属性来存储 NSAttributedStrings 并获取编译器警告
Object.property is using a nil or insecure value transformer. Please switch to NSSecureUnarchiveFromDataTransformerName or a custom NSValueTransformer subclass of NSSecureUnarchiveFromDataTransformer [2]
NSSecureUnarchiveFromDataTransformerName 不支持 NSAttributedStrings 的归档和取消归档，因此据我所知，我必须创建一个自定义转换器，在 AppDelegate 中注册它并在核心数据模型对象属性详细信息中输入转换器类名称。
下面是自定义转换器类，但是在尝试解码现有属性字符串时出现错误。任何人都可以对此有所了解吗？为什么新的 unarchiver 无法处理 NSFileWrapper ，因为这是 NSTextAttachment 的一个属性并且可以与已弃用的 unarchiver 一起正常工作？
这是一个错误还是故意的？
有没有办法添加对取消归档 NSFileWrapper 的支持？
@implementation NSAttributedStringValueTransformer
+(Class)transformedValueClass {
return [NSAttributedString class];
}
+(void)initialize {
[NSValueTransformer setValueTransformer:[[self alloc]init] forName:@"NSAttributedStringValueTransformer"];
}
+(BOOL)allowsReverseTransformation {
return YES;
}
-(NSData*)transformedValue:(NSAttributedString*)value {
NSError *error;
NSData* stringAsData = [NSKeyedArchiver archivedDataWithRootObject:value requiringSecureCoding:false error:&error];
if (error != nil) {
NSLog(@"Error encoding attributed string: %@", error.localizedDescription);
return nil;
}
return stringAsData;
}
-(NSAttributedString*)reverseTransformedValue:(NSData*)value {
NSError *error;
// This works
// NSAttributedString* string = [NSKeyedUnarchiver unarchiveObjectWithData: value];
// This fails with the error 'The data couldn’t be read because it isn’t in the correct format.'
NSAttributedString* string = [NSKeyedUnarchiver unarchivedObjectOfClass:[NSAttributedString class] fromData:value error:&error];
if (error != nil) {
NSLog(@"Error decoding attributed string: %@", error);
return nil;
}
return string;
}
@end
结果错误：
Error decoding attributed string: Error Domain=NSCocoaErrorDomain Code=4864 "value for key 'NSFileWrapper' was of unexpected class 'NSFileWrapper (0x1c9d40d48) [/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Library/Developer/CoreSimulator/Profiles/Runtimes/iOS.simruntime/Contents/Resources/RuntimeRoot/System/Library/Frameworks/Foundation.framework]'. Allowed classes are '{(
"NSURL (0x1c9d1b988) [/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Library/Developer/CoreSimulator/Profiles/Runtimes/iOS.simruntime/Contents/Resources/RuntimeRoot/System/Library/Frameworks/CoreFoundation.framework]",
"NSAttributedString (0x1c9d36668) [/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Library/Developer/CoreSimulator/Profiles/Runtimes/iOS.simruntime/Contents/Resources/RuntimeRoot/System/Library/Frameworks/Foundation.framework]",
"NSFont (0x1c9e1a3c8) [/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Library/Developer/CoreSimulator/Profiles/Runtimes/iOS.simruntime/Contents/Resources/RuntimeRoot/System/Library/PrivateFrameworks/UIFoundation.framework]",
"NSDictionary (0x1c9d1adf8) [/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Library/Developer/CoreSimulator/Profiles/Runtimes/iOS.simruntime/Contents/Resources/RuntimeRoot/System/Library/Frameworks/CoreFoundation.framework]",
"NSArray (0x1c9d1ab28) [/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Library/Developer/CoreSimulator/Profiles/Runtimes/iOS.simruntime/Contents/Resources/RuntimeRoot/System/Library/Frameworks/CoreFoundation.framework]",
"NSColor (0x1c9ec2198) [/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Library/Developer/CoreSimulator/Profiles/Runtimes/iOS.simruntime/Contents/Resources/RuntimeRoot/System/Library/PrivateFrameworks/UIKitCore.framework]",
"NSTextAttachment (0x1c9e1aad0) [/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Library/Developer/CoreSimulator/Profiles/Runtimes/iOS.simruntime/Contents/Resources/RuntimeRoot/System/Library/PrivateFrameworks/UIFoundation.framework]",
"NSGlyphInfo (0x1c9e198d8) [/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Library/Developer/CoreSimulator/Profiles/Runtimes/iOS.simruntime/Contents/Resources/RuntimeRoot/System/Library/PrivateFrameworks/UIFoundation.framework]",
"NSParagraphStyle (0x1c9e19db0) [/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Library/Developer/CoreSimulator/Profiles/Runtimes/iOS.simruntime/Contents/Resources/RuntimeRoot/System/Library/PrivateFrameworks/UIFoundation.framework]",
"NSString (0x1c9d3e868) [/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Library/Developer/CoreSimulator/Profiles/Runtimes/iOS.simruntime/Contents/Resources/RuntimeRoot/System/Library/Frameworks/Foundation.framework]",
"UIFont (0x1c9e1acb0) [/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Library/Developer/CoreSimulator/Profiles/Runtimes/iOS.simruntime/Contents/Resources/RuntimeRoot/System/Library/PrivateFrameworks/UIFoundation.framework]",
"UIColor (0x1c9ec25f8) [/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Library/Developer/CoreSimulator/Profiles/Runtimes/iOS.simruntime/Contents/Resources/RuntimeRoot/System/Library/PrivateFrameworks/UIKitCore.framework]",
"NSNumber (0x1c9d3f510) [/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Library/Developer/CoreSimulator/Profiles/Runtimes/iOS.simruntime/Contents/Resources/RuntimeRoot/System/Library/Frameworks/Foundation.framework]"
)}'." UserInfo={NSDebugDescription=value for key 'NSFileWrapper' was of unexpected class 'NSFileWrapper (0x1c9d40d48) [/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Library/Developer/CoreSimulator/Profiles/Runtimes/iOS.simruntime/Contents/Resources/RuntimeRoot/System/Library/Frameworks/Foundation.framework]'. Allowed classes are '{(
"NSURL (0x1c9d1b988) [/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Library/Developer/CoreSimulator/Profiles/Runtimes/iOS.simruntime/Contents/Resources/RuntimeRoot/System/Library/Frameworks/CoreFoundation.framework]",
"NSAttributedString (0x1c9d36668) [/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Library/Developer/CoreSimulator/Profiles/Runtimes/iOS.simruntime/Contents/Resources/RuntimeRoot/System/Library/Frameworks/Foundation.framework]",
"NSFont (0x1c9e1a3c8) [/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Library/Developer/CoreSimulator/Profiles/Runtimes/iOS.simruntime/Contents/Resources/RuntimeRoot/System/Library/PrivateFrameworks/UIFoundation.framework]",
"NSDictionary (0x1c9d1adf8) [/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Library/Developer/CoreSimulator/Profiles/Runtimes/iOS.simruntime/Contents/Resources/RuntimeRoot/System/Library/Frameworks/CoreFoundation.framework]",
"NSArray (0x1c9d1ab28) [/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Library/Developer/CoreSimulator/Profiles/Runtimes/iOS.simruntime/Contents/Resources/RuntimeRoot/System/Library/Frameworks/CoreFoundation.framework]",
"NSColor (0x1c9ec2198) [/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Library/Developer/CoreSimulator/Profiles/Runtimes/iOS.simruntime/Contents/Resources/RuntimeRoot/System/Library/PrivateFrameworks/UIKitCore.framework]",
"NSTextAttachment (0x1c9e1aad0) [/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Library/Developer/CoreSimulator/Profiles/Runtimes/iOS.simruntime/Contents/Resources/RuntimeRoot/System/Library/PrivateFrameworks/UIFoundation.framework]",
"NSGlyphInfo (0x1c9e198d8) [/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Library/Developer/CoreSimulator/Profiles/Runtimes/iOS.simruntime/Contents/Resources/RuntimeRoot/System/Library/PrivateFrameworks/UIFoundation.framework]",
"NSParagraphStyle (0x1c9e19db0) [/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Library/Developer/CoreSimulator/Profiles/Runtimes/iOS.simruntime/Contents/Resources/RuntimeRoot/System/Library/PrivateFrameworks/UIFoundation.framework]",
"NSString (0x1c9d3e868) [/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Library/Developer/CoreSimulator/Profiles/Runtimes/iOS.simruntime/Contents/Resources/RuntimeRoot/System/Library/Frameworks/Foundation.framework]",
"UIFont (0x1c9e1acb0) [/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Library/Developer/CoreSimulator/Profiles/Runtimes/iOS.simruntime/Contents/Resources/RuntimeRoot/System/Library/PrivateFrameworks/UIFoundation.framework]",
"UIColor (0x1c9ec25f8) [/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Library/Developer/CoreSimulator/Profiles/Runtimes/iOS.simruntime/Contents/Resources/RuntimeRoot/System/Library/PrivateFrameworks/UIKitCore.framework]",
"NSNumber (0x1c9d3f510) [/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Library/Developer/CoreSimulator/Profiles/Runtimes/iOS.simruntime/Contents/Resources/RuntimeRoot/System/Library/Frameworks/Foundation.framework]"
)}'.}