Question

我在NSMutableArray中看到了一些关于如何根据NSUserDefaults保存对象的帖子，但有一种方法可以使用[NSKeyedArchiver]进行编码并对其进行编码与NSCoder虽然我很难理解如何做，并希望有人可以提供帮助。

Student *student1 = [Student studentWithImage:[UIImage imageNamed:@"default"] withForename:@"John" withSurname:@"Smith" withAddress:@"3 Fake Road, Faketown, FA31 KEE" withDateOfBirth:[dateFormatter dateFromString:@"17-Jul-93"] withAge:24];
[studentArray addObject:student1];

我希望将此内容和其他一些类似的Students保存到我的NSMutableArray studentArray。我想将此数组保存到NSUserDefaults并重新加载它。

I have seen this post here看起来是我问题的正确答案，但我需要帮助将其实现到我的代码中，因为我很难理解它！谢谢

Answer 1

首先在Student类

中添加此内容

- (void)encodeWithCoder:(NSCoder *)coder;
{
    [coder encodeObject:self.Forename forKey:@"keyForename"];
    // do same for all property
}

- (id)initWithCoder:(NSCoder *)coder;
{
    self = [[Student alloc] init];
    if (self != nil)
    {
        self.Forename = [coder decodeObjectForKey:@"keyForename"];
        // do same other property here
    }   
    return self;
}

存储阵列

[studentArray addObject:student1];
[[NSUserDefaults standardUserDefaults] setObject:[NSKeyedArchiver archivedDataWithRootObject:studentArray] forKey:@"mySavedArray"];

检索数组

NSUserDefaults *currentDefaults = [NSUserDefaults standardUserDefaults];
NSData *savedArray = [currentDefaults objectForKey:@"mySavedArray"];
if (savedArray != nil)
{
        NSArray *oldArray = [NSKeyedUnarchiver unarchiveObjectWithData:savedArray];
        if (oldArray != nil) {
                customObjectArray = [[NSMutableArray alloc] initWithArray:oldArray];
        } else {
                customObjectArray = [[NSMutableArray alloc] init];
        }
}

如何在NSUserDefaults中保存NSMutableArray的“自定义类对象”？

1 个答案: