Hello I a class of type NSObject:
ProductDetails *details = [[ProductDetails alloc] init];
details.name = @"Soap1";
details.color = @"Red";
details.quantity = 4;
I want to pass the "details" object to a dictionary.
I did,
NSDictionary *dict = [NSDictionary dictionaryWithObject:details forKey:@"details"];
I am passing this dict to another method which performs a check on JSONSerialization:
if(![NSJSONSerialization isValidJSONObject:dict])
And I am getting a crash on this check. Am I doing anything wrong here? I know that the details I am getting is a JSON object and I am assigning it to the properties in my ProductDetails class.
Please help me. I am a noob in Objective-C.
I now tried:
NSError* error;
NSDictionary* json = [NSJSONSerialization JSONObjectWithData:(NSData*)details options:kNilOptions error:&error];
All I need here is an easy way to convert details to NSData.
I noticed that I have an array inside my object may be thats why all the ways I tried is throwing an exception. However since this question is becoming to big, I have started an another question thread for it where I have displayed the data I am getting inside the object - https://stackoverflow.com/questions/19081104/convert-nsobject-to-nsdictionary
NSDictionary *details = {@"name":product.name,@"color":product.color,@"quantity":@(product.quantity)};
NSError *error;
NSData *jsonData = [NSJSONSerialization dataWithJSONObject:details
options:NSJSONWritingPrettyPrinted // Pass 0 if you don't care about the readability of the generated string
error:&error];
if (! jsonData) {
NSLog(@"Got an error: %@", error);
} else {
NSString *jsonString = [[NSString alloc] initWithData:jsonData encoding:NSUTF8StringEncoding];
}
Second part's source: Generate JSON string from NSDictionary in iOS
This may well be the easiest way to achieve it. Do import #import <objc/runtime.h> in your class file.
#import <objc/runtime.h>
ProductDetails *details = [[ProductDetails alloc] init];
details.name = @"Soap1";
details.color = @"Red";
details.quantity = 4;
NSDictionary *dict = [self dictionaryWithPropertiesOfObject: details];
NSLog(@"%@", dict);
//Add this utility method in your class.
- (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];
}
In .h File
#import <Foundation/Foundation.h>
@interface ContactDetail : NSObject
@property (nonatomic) NSString *firstName;
@property (nonatomic) NSString *lastName;
@property (nonatomic) NSString *fullName;
@property (nonatomic) NSMutableArray *mobileNumbers;
@property (nonatomic) NSMutableArray *Emails;
@property (assign) bool Isopen;
@property (assign) bool IsChecked;
-(NSDictionary *)dictionary;
@end
in .m file
#import "ContactDetail.h"
#import <objc/runtime.h>
@implementation ContactDetail
@synthesize firstName;
@synthesize lastName;
@synthesize fullName;
@synthesize mobileNumbers;
@synthesize Emails;
@synthesize IsChecked,Isopen;
//-(NSDictionary *)dictionary {
// return [NSDictionary dictionaryWithObjectsAndKeys:self.fullName,@"fullname",self.mobileNumbers,@"mobileNumbers",self.Emails,@"emails", nil];
//}
- (NSDictionary *)dictionary {
unsigned int count = 0;
NSMutableDictionary *dictionary = [NSMutableDictionary new];
objc_property_t *properties = class_copyPropertyList([self class], &count);
for (int i = 0; i < count; i++) {
NSString *key = [NSString stringWithUTF8String:property_getName(properties[i])];
id value = [self valueForKey:key];
if (value == nil) {
// nothing todo
}
else if ([value isKindOfClass:[NSNumber class]]
|| [value isKindOfClass:[NSString class]]
|| [value isKindOfClass:[NSDictionary class]] || [value isKindOfClass:[NSMutableArray class]]) {
// TODO: extend to other types
[dictionary setObject:value forKey:key];
}
else if ([value isKindOfClass:[NSObject class]]) {
[dictionary setObject:[value dictionary] forKey:key];
}
else {
NSLog(@"Invalid type for %@ (%@)", NSStringFromClass([self class]), key);
}
}
free(properties);
return dictionary;
}
@end
if any crash ,You check the property (NSMutableArray,NSString,etc ) in else if condition inside of for.
In Your Controller, in any func...
-(void)addItemViewController:(ConatctViewController *)controller didFinishEnteringItem:(NSMutableArray *)SelectedContact
{
NSLog(@"%@",SelectedContact);
NSMutableArray *myData = [[NSMutableArray alloc] init];
for (ContactDetail *cont in SelectedContact) {
[myData addObject:[cont dictionary]];
}
NSError *error = nil;
NSData *jsonData = [NSJSONSerialization dataWithJSONObject:myData options:NSJSONWritingPrettyPrinted error:&error];
if ([jsonData length] > 0 &&
error == nil){
// NSLog(@"Successfully serialized the dictionary into data = %@", jsonData);
NSString *jsonString = [[NSString alloc] initWithData:jsonData
encoding:NSUTF8StringEncoding];
NSLog(@"JSON String = %@", jsonString);
}
else if ([jsonData length] == 0 &&
error == nil){
NSLog(@"No data was returned after serialization.");
}
else if (error != nil){
NSLog(@"An error happened = %@", error);
}
}
As mmackh said, you want to define a custom method for your ProductDetails object that will return a simple NSDictionary of values, e.g.:
@implementation ProductDetails
- (id)jsonObject
{
return @{@"name" : self.name,
@"color" : self.color,
@"quantity" : @(self.quantity)};
}
...
Let's assume that we added manufacturer property to our ProductDetails, which referenced a ManufacturerDetails class. We'd just write a jsonObject for that class, too:
@implementation ManufacturerDetails
- (id)jsonObject
{
return @{@"name" : self.name,
@"address1" : self.address1,
@"address2" : self.address2,
@"city" : self.city,
...
@"phone" : self.phone};
}
...
And then change the jsonObject for ProductDetails to employ that, e.g.:
@implementation ProductDetails
- (id)jsonObject
{
return @{@"name" : self.name,
@"color" : self.color,
@"quantity" : @(self.quantity),
@"manufacturer" : [self.manufacturer jsonObject]};
}
...
If you have potentially nested collection objects (arrays and/or dictionaries) with custom objects that you want to encode, you could write a jsonObject method for each of those, too:
@interface NSDictionary (JsonObject)
- (id)jsonObject;
@end
@implementation NSDictionary (JsonObject)
- (id)jsonObject
{
NSMutableDictionary *dictionary = [NSMutableDictionary dictionary];
[self enumerateKeysAndObjectsUsingBlock:^(id key, id obj, BOOL *stop) {
if ([obj respondsToSelector:@selector(jsonObject)])
[dictionary setObject:[obj jsonObject] forKey:key];
else
[dictionary setObject:obj forKey:key];
}];
return [NSDictionary dictionaryWithDictionary:dictionary];
}
@end
@interface NSArray (JsonObject)
- (id)jsonObject;
@end
@implementation NSArray (JsonObject)
- (id)jsonObject
{
NSMutableArray *array = [NSMutableArray array];
[self enumerateObjectsUsingBlock:^(id obj, NSUInteger idx, BOOL *stop) {
if ([obj respondsToSelector:@selector(jsonObject)])
[array addObject:[obj jsonObject]];
else
[array addObject:obj];
}];
return [NSArray arrayWithArray:array];
}
@end
If you do something like that, you can now convert arrays or dictionaries of your custom objects object into something that can be used for generating JSON:
NSArray *products = @[[[Product alloc] initWithName:@"Prius" color:@"Green" quantity:3],
[[Product alloc] initWithName:@"Accord" color:@"Black" quantity:1],
[[Product alloc] initWithName:@"Civic" color:@"Blue" quantity:2]];
id productsJsonObject = [products jsonObject];
NSError *error = nil;
NSData *data = [NSJSONSerialization dataWithJSONObject:productsJsonObject options:0 error:&error];
If you're simply trying to save these objects in a file, I'd suggest NSKeyedArchiver and NSKeyedUnarchiver. But if you need to generate JSON objects for your own private classes, you can do something like the above might work.
Try using
NSDictionary *dict = [details valuesForAttributes:@[@"name", @"color"]];
And compare what the dictionary contains. Then try to convert it to JSON. And look at the JSON spec - what data types can go into a JSON encoded file?
The perfect way to do this is by using a library for serialization/deserialization many libraries are available but one i like is JagPropertyConverter https://github.com/jagill/JAGPropertyConverter
it can convert your Custom object into NSDictionary and vice versa
even it support to convert dictionary or array or any custom object within your object (i.e Composition)
JAGPropertyConverter *converter = [[JAGPropertyConverter alloc]init];
converter.classesToConvert = [NSSet setWithObjects:[ProductDetails class], nil];
//For Object to Dictionary
NSDictionary *dictDetail = [converter convertToDictionary:detail];
NSDictionary* json = [NSJSONSerialization JSONObjectWithData:dictDetail options:NSJSONWritingPrettyPrinted error:&error];
You also can use the NSObject+APObjectMapping category which is available on GitHub: https://github.com/aperechnev/APObjectMapping
It's a quit easy. Just describe the mapping rules in your class:
#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
And then you can easily map your object to dictionary:
MyCustomClass * myObj = [[MyCustomClass alloc] init];
myObj.someNumber = @1;
myObj.someString = @"some string";
NSDictionary * myDict = [myObj mapToDictionary];
Also you can parse your object from dictionary:
NSDictionary * myDict = @{ @"some_number": @123,
@"some_string": @"some string" };
MyCustomClass * myObj = [[MyCustomClass alloc] initWithDictionary:myDict];
You can convert object (say modelObject) to dictionary at runtime with the help of objc/runtime.h class but that has certain limitations and is not recommended.
Considering MVC, mapping logic should be implemented in Model class.
@interface ModelObject : NSObject
@property (nonatomic) NSString *p1;
@property (nonatomic) NSString *p2;
-(NSDictionary *)dictionary;
@end
#import "ModelObject.h"
@implementation ModelObject
-(NSDictionary *)dictionary
{
NSMutableDictionary *dict = [[NSMutableDictionary alloc] init];
[dict setValue:self.p1 forKey:@"p1"];// you can give different key name here if you want
[dict setValue:self.p2 forKey:@"p2" ];
return dict;
}
@end
Uses:
NSDictionary *modelObjDict = [modelObj dictionary];
Try this:
#import <objc/runtime.h>
+ (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] ? [obj valueForKey:key] : @"" forKey:key];
}
free(properties);
return [NSDictionary dictionaryWithDictionary:dict];
}
来源：https://stackoverflow.com/questions/19079862/converting-nsobject-to-nsdictionary