This question already has answers here:
How do I sort an NSMutableArray with custom objects in it?
(27 answers)
Closed 9 years ago.
I have a class like this :
#interface MyObject : NSObject
#property (nonatomic, strong) NSString *type;
#end
and I am creating an array like this:
NSMutableArray *array = [NSMutableArray array];
MyObject *obj = [[MyObject alloc] init];
obj.type = #"test1";
[array addObject:obj];
MyObject *obj2 = [[MyObject alloc] init];
obj2.type = #"test2";
[array addObject:obj2];
MyObject *obj3 = [[MyObject alloc] init];
obj3.type = #"test1";
[array addObject:obj3];
I would like to filter the array to just have only the objects which have different types, in my example just to have obj1, obj2 and remove the obj3.
Something along these lines should do the trick:
NSMutableSet * types = [NSMutableSet setWithCapacity:10];
NSPredicate * filterPredicate = [NSPredicate predicateWithBlock:^BOOL(id evaluatedObject, NSDictionary *bindings) {
if ([types containsObject:[evaluatedObject type]]) {
return NO;
}
else {
[types addObject:[evaluatedObject type]];
return YES
}
}];
NSArray * filteredArray = [detailedError filteredArrayUsingPredicate:filterPredicate];
The above code keeps the first object of each type and removes others.
I would do this by just overriding hash and isEqual:
- (BOOL) isEqual:(id)object
{
if([object isKindOfClass: [self class]])
return [_type isEqualToString: object];
return NO;
}
- (NSInteger) hash
{
return [_type hash];
}
Then taking the distinct objects array from a set created from the array:
NSArray* filteredArray= [NSSet setWithArray: array].allObjects;
Related
I have a search bar for my table view and until now I used a predicate to check if the data array contains the search bar value. But now there are objects in my data array and now I don't know how to use the predicate. Here is my code:
NSPredicate *predicate = [NSPredicate predicateWithFormat:#"SELF contains [cd] %#", self.controller.searchBar.text];
NSMutableArray *temp = [[NSMutableArray alloc] init];
for (int i = 0; i < [self.data count]; i++) {
Student *student = [[Student alloc] initWithIdentifier:[[self.data objectAtIndex:self.tableView.indexPathForSelectedRow.row] objectForKey:#"id"] name:[[self.data objectAtIndex:self.tableView.indexPathForSelectedRow.row] objectForKey:#"name"] is_public:[[self.data objectAtIndex:self.tableView.indexPathForSelectedRow.row] objectForKey:#"is_public"] password:[[self.data objectAtIndex:self.tableView.indexPathForSelectedRow.row] objectForKey:#"passwort"]];
[temp addObject:student];
}
self.results = [temp filteredArrayUsingPredicate:predicate];
Now it compares the search bar value with the object. But it should compare the search bar value with object.name. How can I do this?
EDIT:
The Student code:
#implementation Student
- (id)initWithIdentifier:(NSString *)identifier name:(NSString *)name is_public:(NSString *)is_public password:(NSString *)password {
self= [super init];
if( self ) {
self.identifier = identifier;
self.name = name;
self.is_public = is_public;
self.password = password;
}
return self;
}
- (NSDictionary*)writableRepresentation {
NSMutableDictionary *writableRepresentation= [NSMutableDictionary dictionaryWithCapacity:4];
[writableRepresentation setValue:self.identifier forKey:#"Identifier"];
[writableRepresentation setValue:self.name forKey:#"Name"];
[writableRepresentation setValue:self.is_public forKey:#"is_public"];
[writableRepresentation setValue:self.password forKey:#"password"];
return writableRepresentation;
}
+ (Student*)studentFromDictionary:(NSDictionary*)dictionaryRepresentation {
return [[Tipprunde alloc] initWithIdentifier:[dictionaryRepresentation valueForKey:#"Identifier"] name:[dictionaryRepresentation valueForKey:#"Name"] is_public:[dictionaryRepresentation valueForKey:#"is_public"] password:[dictionaryRepresentation valueForKey:#"password"]];
}
#end
It don't seem to work with SELF.name. I get the following error:
-[Student objectForKey:]: unrecognized selector sent to instance...
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
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];
}
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
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.
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);
}
}
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];
}
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 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 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?
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];
Swift
Now the swift is very popular and most of the SDK's are written in Objective C, we need to convert NSObject to NSDictionary, With the Help of #thatzprem Answer, I wrote an extension for Swift which will convert our NSObject into NSDictionary, then we can use that NSDictionary to simple Dictionary or JSON Object or other purpose. I hope so this will help out the Swift User.
extension NSObject {
func convertNSObjectToNSDictionary() -> [AnyHashable : Any]? {
var dict: [AnyHashable : Any] = [:]
var count: UInt32 = 0
let properties = class_copyPropertyList(type(of: self), UnsafeMutablePointer<UInt32>(mutating: &count)) //as? objc_property_t
for i in 0..<Int(count) {
var key: String? = nil
if let property = properties?[i] as? objc_property_t {
key = String(utf8String: property_getName(property))
}
//dict[key] = (obj as? NSObject)?.value(forKey: key ?? "")
dict[key] = (self).value(forKey: key ?? "")
}
free(properties)
return dict
}
}
I ran across something that I eventually figured out, but think that there's probably a much more efficient way to accomplish it.
I had an object (an NSObject which adopted the MKAnnotation protocol) that had a number of properties (title, subtitle,latitude,longitude, info, etc.). I needed to be able to pass this object to another object, which wanted to extract info from it using objectForKey methods, as an NSDictionary (because that's what it was getting from another view controller).
What I ended up doing was create a new NSMutableDictionary and use setObject: forKey on it to transfer each piece of vital info, and then I just passed on the newly created dictionary.
Was there an easier way to do this?
Here's the relevant code:
// 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;
}
}
Thanks in advance for your collective wisdom.
Here's what I came up with, thanks to the folks, below...
- (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;
}
}
And a even simpler fix, as seen below...
Using valueForKey instead of object for key to retrieve the information.
Sure thing! Use the objc-runtime and 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
And you would use like this:
MyObj *obj = [MyObj new];
NSDictionary *dict = [NSDictionary dictionaryWithPropertiesOfObject:obj];
NSLog(#"%#", dict);
This is an old post and Richard J. Ross III's answer is really helpful, but in case of custom objects (an custom class has another custom object in it). However, sometimes properties are other objects and so forth, making the serialization a bit complicated.
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;
For converting these type of objects (multiple custom objects) into dictionary, I had to modify Richard J. Ross III's Answer a little bit.
+(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];
}
I hope it will help someone. Full credit goes to Richard J. Ross III.
If the properties had the same names as the keys used to access the dictionary then you could have just used KVC and had valueForKey: instead of objectForKey.
For example given this dictionary
NSDictionary *annotation = [[NSDictionary alloc] initWithObjectsAndKeys:
#"A title", #"title", nil];
and this Object
#interface MyAnnotation : NSObject
#property (nonatomic, copy) NSString *title;
#end
it wouldn't matter if I had an instance of the dictionary or MyAnnotation I could call
[annotation valueForKey:#"title"];
Obviously that works the other way as well e.g.
[annotation setValue:#"A title" forKey:#"title"];
To complete the method of Richard J. Ross, this one works with NSArray of custom object.
+(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];
}
There are so many solutions and nothing worked for me as I had a complex nested object structure. This solution takes things from Richard and Damien but improvises as Damien's solution is tied to naming keys as class names.
Here is the header
#interface NSDictionary (PropertiesOfObject)
+(NSDictionary *) dictionaryWithPropertiesOfObject:(id)obj;
#end
Here is the .m file
#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
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];
I'm creating UILabels dynamically in a for each loop. Every loop that is run creates 1-4 UILabels.
What I want is that I put these UILabels into my NSMutableArray and being able later to easy retrieve the data.
My original thought was to put these UILabels into a NSDictionary and use [dictGroupLabels setValue:uiLabel1 forKey:#"uiLabel1"] and then [dictGroupLabels setValue:uiLabel2 forKey:#"uiLabel2"] and so on. And then put this dictionary into my NSMutableArray for each loop. Later on I could access the values like UILabel *label = [[myArray objectAtIndex:0] valueForKey:#"uiLabel1"] BUT that unfortunately doesn't work since UILabels don't conform to the NSCopying protocol.
So with this in mind how would you solve this?
this question provided more information on what you are trying to accomplish. Since you know for a fact, the possible set of labels you are trying to create in each case, I would highly recommend using mutable dictionaries instead of arrays.
To illustrate, given the following hypothetical class definition:
#interface MyClass: NSObject {
NSMutableDictionary * _labelDict;
}
#property (nonatomic, retain) NSMutableDictionary * labelDict;
- ( void )methodA;
- ( void )methodB;
- (NSMutableDictionary *) labelsForRunLoop: (NSUInteger) loopIdx;
#end
You would have the following, hypothetical, class implementation:
#implementation MyClass
#synthesize labelDict = _labelDict;
- ( id ) init {
if( ( self = [ super init ] ) ) {
[self setLabelDict: [NSMutableDictionary dictionaryWithCapacity: 8]];
}
}
- ( void ) dealloc {
[ self.labelDict release ];
[ super dealloc ];
}
- ( void ) methodA {
for(NSUInteger i = 0; i < some index; i++) {
[self.labelDict setObject: [self labelsForRunLoop: i] forKey: [NSString stringWithFormat: #"%d", i]];
}
}
- ( void ) methodB {
// Locate the label you need to work with. Example based on this crude pseudo code
NSMutableDictionary * subDict = (NSMutableDictionary *) [self.labelDict objectForKey: #"0"];
UILabel * theLabel = (UILabel * ) [subDict objectForKey: #"UILabel.Z"];
theLabel.text = #"Label 1";
}
- (NSMutableDictionary *) labelsForRunLoop: (NSUInteger) loopIdx {
NSMutableDictionary * dictionary = [NSMutableDictionary dictionaryWithCapacity: 4] ;
[dictionary setObject: create-w-label forKey: #"UILabel.W"];
[dictionary setObject: create-x-label forKey: #"UILabel.X"];
[dictionary setObject: create-y-label forKey: #"UILabel.Y"];
[dictionary setObject: create-z-label forKey: #"UILabel.Z"];
return [dictionary retain];
}
#end
This is basically pseudo code and will not successfully compile. However it will serve as a good starting point. You probably want to store each label dictionary under some key that makes sense, instead of just using the loop's index. Hope this helps.
They don’t need to adhere to NSCopying to be added to an array. It sounds like you just need to do something like this:
NSMutableArray *mainArray = [NSMutableArray array];
for(int i = 0; i < 5; i++)
{
NSMutableArray *subArray = [[NSMutableArray alloc] initWithCapacity:5];
for(int j = 0; j < 4; j++)
{
UILabel *label = [[UILabel alloc] init];
// etc.
[subArray addObject:label];
[label release];
}
[mainArray addObject:subArray];
[subArray release];
}
// then, to get one of the labels:
UILabel *someSpecificLabel = [[mainArray objectAtIndex:2] objectAtIndex:1];
Given a basic key/value array, I'm wanting to store two sorted arrays based on the original array: one array will be sorted by name, and the other by age.
The arrays seem to be sorting correctly when I output them to the log; however, when I try to access them elsewhere in the code, I'm receiving a EXC_BAD_ACCESS error.
Here's what I have so far:
// MyController.h
#interface MyController : UIViewController {
NSMutableArray *originalArray;
NSMutableArray *nameArray;
NSMutableArray *ageArray;
}
#property (nonatomic, retain) NSMutableArray *originalArray;
#property (nonatomic, retain) NSMutableArray *nameArray;
#property (nonatomic, retain) NSMutableArray *ageArray;
-(void)someRandomMethod;
#end
// MyController.m
#import "MyController.h"
#implementation MyController
#synthesize originalArray;
#synthesize nameArray;
#synthesize ageArray;
-(void)viewDidLoad {
// originalArray = (
// {
// "name" = "Sally";
// "age" = 18;
// },
// {
// "name" = "Chad";
// "age" = 26;
// },
// {
// "name" = "Carla";
// "age" = 24;
// },
// )
// sort by name
NSSortDescriptor *sortByNameDescriptor;
sortByNameDescriptor = [[[NSSortDescriptor alloc]
initWithKey:#"name"
ascending:NO] autorelease];
NSArray *sortByNameDescriptors = [NSArray arrayWithObject:sortByNameDescriptor];
nameArray = [originalArray sortedArrayUsingDescriptors:sortByNameDescriptors];
// sort by age
NSSortDescriptor *sortByAgeDescriptor;
sortByAgeDescriptor = [[[NSSortDescriptor alloc]
initWithKey:#"age"
ascending:NO] autorelease];
NSArray *sortAgeDescriptors = [NSArray arrayWithObject:sortByAgeDescriptor];
ageArray = [originalArray sortedArrayUsingDescriptors:sortByAgeDescriptors];
[super viewDidLoad];
}
-(void)someRandomMethod {
// whenever I try to access the sorted arrays, I receive the EXC_BAD_ACCESS error
[[nameArray objectAtIndex:0] valueForKey:#"name"];
[[ageArray objectAtIndex:0] valueForKey:#"age"];
}
-(void)viewDidUnload {
self.originalArray = nil;
self.nameArray = nil;
self.ageArray = nil;
[super viewDidUnload];
}
- (void)dealloc {
[originalArray release];
[nameArray release];
[ageArray release];
[super dealloc];
}
#end
Any ideas?
UPDATE: Thanks to #robin, by changing the code above to the code below, everything works great:
// sort by name
NSSortDescriptor *sortByNameDescriptor;
sortByNameDescriptor = [[[NSSortDescriptor alloc]
initWithKey:#"name"
ascending:NO] autorelease];
NSArray *sortByNameDescriptors = [NSArray arrayWithObject:sortByNameDescriptor];
nameArray = [[NSMutableArray alloc] initWithArray:[originalArray sortedArrayUsingDescriptors:sortByNameDescriptors]];
// sort by age
NSSortDescriptor *sortByAgeDescriptor;
sortByAgeDescriptor = [[[NSSortDescriptor alloc]
initWithKey:#"age"
ascending:NO] autorelease];
NSArray *sortAgeDescriptors = [NSArray arrayWithObject:sortByAgeDescriptor];
ageArray = [[NSMutableArray alloc] initWithArray:[originalArray sortedArrayUsingDescriptors:sortByAgeDescriptors]];
I dont think you know about this or not but when ever you create an object like string or array or dictionary, with init methods then the retain count gets incremented by 1
and if you create them like this
NSArray *anarray = [NSArray arrayWithArray:temp];
this will create an autorelease objects that will be released automatically after sometime.
So my advice don't use this type of code if you want to use the objects in more than 1 function. Always use init methods first to get the work done.
and if you are sure that the objects are not needed for the rest of the program than release them using release methode.