I am new to Objective C, I'm trying to add objects to NSMutableArray that I can use multiple times on my project. I have a Model class as
History.h
@interface History : NSObject
@property (nonatomic) NSString *itemName;
@property (nonatomic) int quantity;
@property (nonatomic) double total;
@property (nonatomic) NSDate *purchaseDate;
- (instancetype)initWithName: (NSString*)itemName withQuantity:(int)quantity withTotal:(double) total withPurchaseDate:(NSDate*) purchaseDate;
@end
History.m
#import "History.h"
@implementation History
-(instancetype)initWithName: (NSString*)iName withQuantity:(int)iQuantity withTotal:(double) iTotal withPurchaseDate:(NSDate*) iPdate {
self = [super init];
if(self) {
self.itemName = iName;
self.quantity = iQuantity;
self.quantity = iQuantity;
self.purchaseDate = iPdate;
}
return self;
}
@end
Repository.h
#import <Foundation/Foundation.h>
@interface Repository : NSObject
@property (nonatomic) NSMutableArray *itemHistory;
-(void) pushToArray:(NSString *)name withQuantity:(int)qty withTotal:(double) total withPurchaseDate:(NSDate*) pDate;
@end
Repository.m
#import "Repository.h"
#import "History.h"
@interface Repository()
//@property (nonatomic) NSMutableArray *itemHistory;
@end
@implementation Repository
-(NSMutableArray *) itemHistory {
if(_itemHistory == nil) {
_itemHistory = [[NSMutableArray alloc] init];
}
return _itemHistory;
}
This is my method that I want to use to add objects to the MutableArray.
-(void) pushToArray:(NSString *)name withQuantity:(int)qty withTotal:(double) total withPurchaseDate:(NSDate*) pDate {
self.itemHistory = [[NSMutableArray alloc] init];
History *obj = [[History alloc] init];
obj.itemName = name;
obj.quantity = qty;
obj.total = total;
obj.purchaseDate = pDate;
[self.itemHistory addObject:obj];
}
@end
Thank you for your help in advance.
Every time you call pushToArray:...
you are replacing the existing itemHistory
with a new, empty, mutable array. You'll only ever see the last item to be pushed in that array.
However, you also don't need to lazily initialize _itemHistory
. Just create an instance in your init
method and be done with it. Saves confusion and refactoring hell.
In your Repository class, simply implement the designated initializer:
- (instancetype) init
{
if (self=[super init]) {
_itemHistory = [[NSMutableArray alloc] init];
}
return self;
}
Uncomment the property:
@interface Repository()
@property (nonatomic) NSMutableArray *itemHistory;
@end
And remove this from the -pushToArry:... method:
//self.itemHistory = [[NSMutableArray alloc] init];
If it still doesn't work, you need to show how you are logging the failure.
The technical post webpages of this site follow the CC BY-SA 4.0 protocol. If you need to reprint, please indicate the site URL or the original address.Any question please contact:yoyou2525@163.com.