以下是我的想法，感谢下面的人们......

Question

我遇到了一些我最终想到的东西，但认为可能有更有效的方法来实现它。

我有一个对象（一个采用MKAnnotation协议的NSObject），它有许多属性（标题，副标题，纬度，经度，信息等）。我需要能够将此对象传递给另一个对象，该对象希望使用objectForKey方法从中提取信息，作为NSDictionary（因为这是从另一个视图控制器获取的内容）。

我最终做的是创建一个新的NSMutableDictionary并在其上使用setObject：forKey来传输每条重要信息，然后我就传递了新创建的字典。

是否有更容易的方式来执行此操作？

以下是相关代码：

// sender contains a custom map annotation that has extra properties...

- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender
{    
    if ([[segue identifier] isEqualToString:@"showDetailFromMap"]) 
{
    DetailViewController *dest =[segue destinationViewController];

    //make a dictionary from annotaion to pass info
    NSMutableDictionary *myValues =[[NSMutableDictionary alloc] init];
    //fill with the relevant info
    [myValues setObject:[sender title] forKey:@"title"] ;
    [myValues setObject:[sender subtitle] forKey:@"subtitle"];
    [myValues setObject:[sender info] forKey:@"info"];
    [myValues setObject:[sender pic] forKey:@"pic"];
    [myValues setObject:[sender latitude] forKey:@"latitude"];
    [myValues setObject:[sender longitude] forKey:@"longitude"];
    //pass values
    dest.curLoc = myValues;
    }
}

提前感谢您的集体智慧。

以下是我的想法，感谢下面的人们......

- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender
{    
if ([[segue identifier] isEqualToString:@"showDetailFromMap"]) 
{
    DetailViewController *dest =[segue destinationViewController];
    NSArray *myKeys = [NSArray arrayWithObjects:
@"title",@"subtitle",@"info",@"pic",@"latitude",@"longitude", nil];

    //make a dictionary from annotaion to pass info
    NSDictionary *myValues =[sender dictionaryWithValuesForKeys:myKeys];

    //pass values
    dest.curLoc = myValues;
}

}

更简单的修复，如下所示......

使用valueForKey代替key来检索信息。

Answer 1

当然可以！使用objc-runtime和KVC！

#import <objc/runtime.h>

@interface NSDictionary(dictionaryWithObject)

+(NSDictionary *) dictionaryWithPropertiesOfObject:(id) obj;

@end
@implementation NSDictionary(dictionaryWithObject)

+(NSDictionary *) dictionaryWithPropertiesOfObject:(id)obj
{
    NSMutableDictionary *dict = [NSMutableDictionary dictionary];

    unsigned count;
    objc_property_t *properties = class_copyPropertyList([obj class], &count);

    for (int i = 0; i < count; i++) {
        NSString *key = [NSString stringWithUTF8String:property_getName(properties[i])];
        [dict setObject:[obj valueForKey:key] forKey:key];
    }

    free(properties);

    return [NSDictionary dictionaryWithDictionary:dict];
}

@end

你会这样使用：

MyObj *obj = [MyObj new];    
NSDictionary *dict = [NSDictionary dictionaryWithPropertiesOfObject:obj];
NSLog(@"%@", dict);

Answer 2

这是一篇老帖子，Richard J. Ross III的回答非常有用，但是在自定义对象的情况下（自定义类中有另一个自定义对象）。但是，有时属性是其他对象，等等，使序列化有点复杂。

Details * details = [[Details alloc] init];
details.tomato = @"Tomato 1";
details.potato = @"Potato 1";
details.mangoCount = [NSNumber numberWithInt:12];

Person * person = [[Person alloc]init];
person.name = @"HS";
person.age = @"126 Years";
person.gender = @"?";
person.details = details;

为了将这些类型的对象（多个自定义对象）转换为字典，我不得不修改Richard J. Ross III的答案。

+(NSDictionary *) dictionaryWithPropertiesOfObject:(id)obj
{
  NSMutableDictionary *dict = [NSMutableDictionary dictionary];

  unsigned count;
  objc_property_t *properties = class_copyPropertyList([obj class], &count);

  for (int i = 0; i < count; i++) {
      NSString *key = [NSString stringWithUTF8String:property_getName(properties[i])];
      Class classObject = NSClassFromString([key capitalizedString]);
      if (classObject) {
        id subObj = [self dictionaryWithPropertiesOfObject:[obj valueForKey:key]];
        [dict setObject:subObj forKey:key];
      }
      else
      {
        id value = [obj valueForKey:key];
        if(value) [dict setObject:value forKey:key];
      }
   }

   free(properties);

   return [NSDictionary dictionaryWithDictionary:dict];
}

我希望它会帮助别人。完全归功于Richard J. Ross III。

Answer 3

如果属性与用于访问字典的键具有相同的名称，那么您可以使用KVC并使用valueForKey:代替objectForKey。

例如给出这本词典

NSDictionary *annotation = [[NSDictionary alloc] initWithObjectsAndKeys:
                             @"A title", @"title", nil];

和这个对象

@interface MyAnnotation : NSObject

@property (nonatomic, copy) NSString *title;

@end

如果我有一个字典实例或MyAnnotation我可以调用

那就无所谓了

[annotation valueForKey:@"title"];

显然，这也是另一种方式，例如。

[annotation setValue:@"A title" forKey:@"title"];

Answer 4

为了完成Richard J. Ross的方法，这个方法适用于自定义对象的NSArray。

+(NSDictionary *) dictionaryWithPropertiesOfObject:(id)obj
{
    NSMutableDictionary *dict = [NSMutableDictionary dictionary];

    unsigned count;
    objc_property_t *properties = class_copyPropertyList([obj class], &count);

    for (int i = 0; i < count; i++) {
        NSString *key = [NSString stringWithUTF8String:property_getName(properties[i])];
        Class classObject = NSClassFromString([key capitalizedString]);

        id object = [obj valueForKey:key];

        if (classObject) {
            id subObj = [self dictionaryWithPropertiesOfObject:object];
            [dict setObject:subObj forKey:key];
        }
        else if([object isKindOfClass:[NSArray class]])
        {
            NSMutableArray *subObj = [NSMutableArray array];
            for (id o in object) {
                [subObj addObject:[self dictionaryWithPropertiesOfObject:o] ];
            }
            [dict setObject:subObj forKey:key];
        }
        else
        {
            if(object) [dict setObject:object forKey:key];
        }
    }

    free(properties);
    return [NSDictionary dictionaryWithDictionary:dict];
}

Answer 5

有很多解决方案，对我来说没什么用，因为我有一个复杂的嵌套对象结构。这个解决方案取决于理查德和达米恩的事情，但即兴创作，因为达米恩的解决方案与命名键作为类名有关。

这是标题

@interface NSDictionary (PropertiesOfObject)
+(NSDictionary *) dictionaryWithPropertiesOfObject:(id)obj;
@end

这是.m文件

@implementation NSDictionary (PropertiesOfObject)

static NSDateFormatter *reverseFormatter;

+ (NSDateFormatter *)getReverseDateFormatter {
if (!reverseFormatter) {
    NSLocale *locale = [[NSLocale alloc] initWithLocaleIdentifier:@"en_US_POSIX"];
    reverseFormatter = [[NSDateFormatter alloc] init];
    [reverseFormatter setDateFormat:@"yyyy-MM-dd'T'HH:mm:ss.SSS'Z'"];
    [reverseFormatter setLocale:locale];
}
return reverseFormatter;
}

 + (NSDictionary *)dictionaryWithPropertiesOfObject:(id)obj {
NSMutableDictionary *dict = [NSMutableDictionary dictionary];

unsigned count;
objc_property_t *properties = class_copyPropertyList([obj class], &count);

for (int i = 0; i < count; i++) {
    NSString *key = [NSString stringWithUTF8String:property_getName(properties[i])];
    id object = [obj valueForKey:key];

    if (object) {
        if ([object isKindOfClass:[NSArray class]]) {
            NSMutableArray *subObj = [NSMutableArray array];
            for (id o in object) {
                [subObj addObject:[self dictionaryWithPropertiesOfObject:o]];
            }
            dict[key] = subObj;
        }
        else if ([object isKindOfClass:[NSString class]]) {
            dict[key] = object;
        } else if ([object isKindOfClass:[NSDate class]]) {
            dict[key] = [[NSDictionary getReverseDateFormatter] stringFromDate:(NSDate *) object];
        } else if ([object isKindOfClass:[NSNumber class]]) {
            dict[key] = object;
        } else if ([[object class] isSubclassOfClass:[NSObject class]]) {
            dict[key] = [self dictionaryWithPropertiesOfObject:object];
        }
    }

}
return dict;
}

@end

Answer 6

您还可以使用GitHub上提供的NSObject+APObjectMapping类别：https://github.com/aperechnev/APObjectMapping

这很容易退出。只需在您的班级中描述映射规则：

#import <Foundation/Foundation.h>
#import "NSObject+APObjectMapping.h"

@interface MyCustomClass : NSObject
@property (nonatomic, strong) NSNumber * someNumber;
@property (nonatomic, strong) NSString * someString;
@end

@implementation MyCustomClass
+ (NSMutableDictionary *)objectMapping {
  NSMutableDictionary * mapping = [super objectMapping];
  if (mapping) {
    NSDictionary * objectMapping = @{ @"someNumber": @"some_number",
                                      @"someString": @"some_string" };
  }
  return mapping
}
@end

然后您可以轻松地将对象映射到字典：

MyCustomClass * myObj = [[MyCustomClass alloc] init];
myObj.someNumber = @1;
myObj.someString = @"some string";
NSDictionary * myDict = [myObj mapToDictionary];

您也可以从字典中解析对象：

NSDictionary * myDict = @{ @"some_number": @123,
                           @"some_string": @"some string" };
MyCustomClass * myObj = [[MyCustomClass alloc] initWithDictionary:myDict];

从带有属性的NSObject转换为NSDictionary的Obj-C简单方法？

以下是我的想法，感谢下面的人们......

}

更简单的修复，如下所示......

6 个答案: