ios - 在 iOS 中使用 RMapper 库从对象文件中获取值

Question

我用过RMMapper库

导入文件

#import "NSUserDefaults+RMSaveCustomObject.h"

MyCart *cart = [[MyCart alloc]init];
cart.ProdCode = code;
cart.ProdName = s;
cart.Price = [NSString stringWithFormat:@"%f",tot];
cart.Quantity = quantity.text;
cart.Image = _imageProd;
NSMutableArray *array = [[NSUserDefaults standardUserDefaults] rm_customObjectForKey:@"cart"];
[array addObject:cart];

在其他页面上，我想检索存储在对象文件中的值。

我如何获得该值？

谁能帮我解决这个问题？

Answer 1

由于您要将自定义模型对象数据保存为用户默认值，因此您需要在自定义对象中实现 encodeWithCoder 和 initWithCoder 方法。同样，在保存时使用 archivedDataWithRootObject，在获取时使用 unarchiveObjectWithData。

只需将这两个方法(encodeWithCoder 和 initWithCoder)放入您的 MyCart.m

- (void)encodeWithCoder:(NSCoder *)encoder {
    //Encode properties, other class variables, etc
    [encoder encodeObject:self.ProdCode forKey:@"ProdCode"];
    [encoder encodeObject:self.ProdName forKey:@"ProdName"];
    [encoder encodeObject:self.Price forKey:@"Price"];
    [encoder encodeObject:self.Quantity forKey:@"Quantity"];
    [encoder encodeObject:self.ImageName forKey:@"ImageName"];
}

- (id)initWithCoder:(NSCoder *)decoder {
    if((self = [super init])) {
        //decode properties, other class vars
        self.ProdCode = [decoder decodeObjectForKey:@"ProdCode"];
        self.ProdName = [decoder decodeObjectForKey:@"ProdName"];
        self.Price = [decoder decodeObjectForKey:@"Price"];
        self.Quantity = [decoder decodeObjectForKey:@"Quantity"];
        self.ImageName = [decoder decodeObjectForKey:@"ImageName"];
    }
    return self;
}

然后以下代码将展示如何从 NSUserDefault 保存和获取数据

我要保存的代码:

- (void)saveCart
{
    MyCart *cart = [[MyCart alloc]init];
    cart.ProdCode = @"123";
    cart.ProdName = @"Name";
    cart.Price = [NSString stringWithFormat:@"%f",100.0];
    cart.Quantity = @"20";
    cart.ImageName = @"image url";

    NSArray *arrayTemp = [[NSUserDefaults standardUserDefaults] objectForKey:@"cart"];

   // You can not use the arrayTemp to add object as the return type from `NSUserDefault` is `NSArray` which is immutable, so use another mutable array and add the object like this
    NSMutableArray *array = [NSMutableArray array];

    if([arrayTemp count])
    {
        [array addObjectsFromArray:arrayTemp];
    }

    NSData *encodedObject = [NSKeyedArchiver archivedDataWithRootObject:cart];
    [array addObject:encodedObject];
    [[NSUserDefaults standardUserDefaults] setObject:array forKey:@"cart"];
    [[NSUserDefaults standardUserDefaults] synchronize];

}

我要获取的代码:

- (void)getCart
{
    NSMutableArray *array = [[NSUserDefaults standardUserDefaults] objectForKey:@"cart"];

    for (NSData *encodedObject in array) {

        MyCart *object = [NSKeyedUnarchiver unarchiveObjectWithData:encodedObject];

        NSLog(@"cart ImageName %@", object.ImageName);
    }
}

希望对您有所帮助。

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