我有这个方法来保存一个名为 myWallet 的可变数组，其中包含 Class Card 的实例。
- (void)saveMyWallet
{
NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];
[defaults setObject:[NSKeyedArchiver archivedDataWithRootObject:self.myWallet] forKey:@"myWalletArray"];
[defaults synchronize];
}
我拥有的 Card 类具有三个实例变量：名称、引脚和点。到目前为止，在 UserDefaults 中保存 Card 的新实例是可以的。我只想知道一些关于如何覆盖点值的建议，因为当我继续计算点时，我想更新它。
这是我的卡类
卡片.h
#import <Foundation/Foundation.h>
@interface Card : NSObject <NSCoding>
@property (nonatomic, strong) NSString *name;
@property (nonatomic, strong) NSString *pin;
@property (nonatomic, strong) NSNumber *points;
@property (nonatomic, strong) NSMutableArray *pointsToDeduct;
- (double) subtractPoints: (double) requiredPoints;
- (void) encodeWithCoder:(NSCoder *)coder;
- (id) initWithCoder: (NSCoder *)coder;
@end
卡.m
#import "Card.h"
@implementation Card
@synthesize name = _name;
@synthesize pin = _pin;
@synthesize points = _points;
@synthesize pointsToDeduct = _pointsToDeduct;
- (id)initWithCoder:(NSCoder *)coder
{
self = [[Card alloc] init];
if(self != nil) {
self.name = [coder decodeObjectForKey:@"name"];
self.pin = [coder decodeObjectForKey:@"pin"];
self.points = [coder decodeObjectForKey:@"points"];
}
return self;
}
- (void)encodeWithCoder:(NSCoder *)coder
{
[coder encodeObject:self.name forKey:@"name"];
[coder encodeObject:self.pin forKey:@"pin"];
[coder encodeObject:self.points forKey:@"points"];
}
- (double) subtractPoints:(double) requiredPoints
{
double latestPoints;
latestPoints = ([self.points doubleValue] - requiredPoints);
return latestPoints;
}
@end
最后，这里是点的新值（名为 resultsPoints）应该来自的委托方法。
- (void)perksDetailsViewController:(PerksDetailsViewController *)sender didPassRequiredPoints:(NSNumber *)requiredPoints withCard:(Card *)selectedCard
{
double perksPoints = [requiredPoints doubleValue];
self.resultingPoints = [NSNumber numberWithDouble:[selectedCard subtractPoints:perksPoints] ];
NSLog(@"points remaining %@", self.resultingPoints);
}
用建议轰炸我:)提前谢谢！