iphone - 单例更改不会保存到下一个 View IOS

Question

我有一个单例类，我打算在整个应用程序中共享它。 它看起来像这样:

.m

    @implementation PersonalGlobal

@synthesize firstName;
@synthesize lastName;
@synthesize SSN;
@synthesize customerNo;
@synthesize email;
@synthesize address;
@synthesize city;
@synthesize postalCode;
@synthesize telNo;
@synthesize mobileNo;

#pragma mark Singleton Methods

+ (id)sharedPersonal {
    static PersonalGlobal *sharedPersonalGlobal = nil;
    static dispatch_once_t onceToken;
    dispatch_once(&onceToken, ^{
        sharedPersonalGlobal = [[self alloc] init];
    });
    return sharedPersonalGlobal;
}


- (void)dealloc {
    [super dealloc];
    // Should never be called
}

@end

.h

#import <foundation/Foundation.h>

@interface PersonalGlobal : NSObject {
    NSString *firstName;
    NSString *lastName;
    NSString *SSN;
    NSString *customerNo;
    NSString *email;
    NSString *address;
    NSString *city;
    NSString *postalCode;
    NSString *telNo;
    NSString *mobileNo;    
}

@property (nonatomic, retain) NSString *firstName;
@property (nonatomic, retain) NSString *lastName;
@property (nonatomic, retain) NSString *SSN;
@property (nonatomic, retain) NSString *customerNo;
@property (nonatomic, retain) NSString *email;
@property (nonatomic, retain) NSString *address;
@property (nonatomic, retain) NSString *city;
@property (nonatomic, retain) NSString *postalCode;
@property (nonatomic, retain) NSString *telNo;
@property (nonatomic, retain) NSString *mobileNo;

+ (id)sharedPersonal;

@end

在代码中我像这样保存字符串:

PersonalGlobal *sharedPersonal = [PersonalGlobal sharedPersonal];
sharedPersonal.firstName = @"Some string";

但是当我改变 View 并尝试像这样访问字符串时:

   PersonalGlobal *sharedPersonal = [PersonalGlobal sharedPersonal];
   //Setting some textfield    
   sometextfield.text = sharedPersonal.firstName;

我一无所获。我在所有文件中都做了一个#import "PersonalGlobal.h"。 我可以以任何方式将更改提交给单例类吗？

谁能看出我在这里做错了什么？ 谢谢!

Answer 1

您的实现看起来不错。如果您的单例返回唯一的一个实例，这应该有效。所以在你的 sharedPersonal 方法中存在疑问。试着在这个方法中添加断点，看看它是否每次都在创建一个新实例。作为我得到的引用 this所以问题。

如果没有那么你也可以试试这个:

+(SingleTon *)getSharedInstance
{
    static PersonalGlobal *sharedPersonalGlobal = nil;
    if (sharedPersonalGlobal==nil)
    {
        sharedPersonalGlobal=[[PersonalGlobal alloc]init];
    }
    return sharedPersonalGlobal;
}

这是适合我的工作代码。