Ios NSUserdefaults不使用NSKeyedArchiver

我有一个NSMutableArray，里面装满了我想保存的电影类的对象，但它不起作用，我不知道为什么

电影h:

@interface Movie : NSObject <NSCoding>{
    NSString *name;
    int year;
    int length;
    NSString *file_size;
    int rating;
    NSArray *genre;
    NSString *plot;
}

@property (nonatomic, retain) NSString *name;
@property (nonatomic, assign) int year;
@property (nonatomic, assign) int length;
@property (nonatomic, retain, retain) NSString *file_size;
@property (nonatomic, assign) int rating;
@property (nonatomic, retain) NSArray *genre;
@property (nonatomic, retain) NSString *plot;

-(id) initWithName:(NSString*)newName year:(int)newYear length:(int)newLength filesize:(NSString*)newFileSize rating:(int)newRating genre:(NSArray*)newGenre plot:(NSString*)newPlot;
- (void) encodeWithCoder : (NSCoder *)encode ;
- (id) initWithCoder : (NSCoder *)decode;

@end

保存操作（Movies是包含我的对象的NSMutableArray）：

荷载作用：

NSData *decodedData = [userDefault objectForKey: [NSString stringWithFormat:@"MOVIES"]];
    NSArray *decodedArray =[NSKeyedUnarchiver unarchiveObjectWithData: decodedData];

返回的数组始终为（null）。。。我不知道

---

我尝试了在internet和/或stackoverflow上找到的几种不同类型的代码片段。一个快速测试是查看可变数组本身是否不是nil。在

userDefaults

中设置可变数组之前，请尝试输出该数组

在尝试向可变数组添加对象之前，请确保该数组已初始化

movies = [[NSMutableArray alloc] init];

---

您的

Movie initWithName…

方法不正确。它需要：

- (instancetype)initWithName:(NSString *)newName year:(int)newYear length:(int)newLength filesize:(NSString *)newFileSize rating:(int)newRating genre:(NSArray *)newGenre plot:(NSString *)newPlot {
    self = [super init];
    if (self) {
        self.name = newName;
        self.year = newYear;
        self.length = newLength;
        self.file_size = newFileSize;
        self.rating = newRating;
        self.genre = newGenre;
        self.plot = newPlot;
    }

    return self;
}

此外，您似乎正在遵循一个非常过时的教程

您不需要为您的属性声明IVAR

您不需要调用

@synthesis

您应该使用ARC而不是MRC，因此您的

retain

属性应该是

strong

（虽然

NSString

属性应该是

copy

）

您的

init

方法应该返回

instancetype

，而不是

id

记住所有这些，你的

电影

课程应该如下：

Movie.h

@interface Movie : NSObject <NSCoding>

@property (nonatomic, copy) NSString *name;
@property (nonatomic, assign) int year;
@property (nonatomic, assign) int length;
@property (nonatomic, copy) NSString *file_size;
@property (nonatomic, assign) int rating;
@property (nonatomic, strong) NSArray *genre;
@property (nonatomic, copy) NSString *plot;

- (instancetype)initWithName:(NSString *)newName year:(int)newYear length:(int)newLength filesize:(NSString *)newFileSize rating:(int)newRating genre:(NSArray *)newGenre plot:(NSString *)newPlot;

@end

您不会显示如何创建和填充

Movies

变量（该变量应命名为

Movies

，而不是

Movies

。请确保它不是

nil

另外，不要不必要地使用

stringWithFormat

您的保存代码应为：

NSUserDefaults *userDefault=[NSUserDefaults standardUserDefaults];
NSData *encodedData = [NSKeyedArchiver archivedDataWithRootObject:movies];
[userDefault setObject:encodedData forKey:@"MOVIES"];

NSData *decodedData = [userDefault objectForKey:@"MOVIES"];
NSArray *decodedArray = [NSKeyedUnarchiver unarchiveObjectWithData: decodedData];

您的加载代码应为：

NSUserDefaults *userDefault=[NSUserDefaults standardUserDefaults];
NSData *encodedData = [NSKeyedArchiver archivedDataWithRootObject:movies];
[userDefault setObject:encodedData forKey:@"MOVIES"];

NSData *decodedData = [userDefault objectForKey:@"MOVIES"];
NSArray *decodedArray = [NSKeyedUnarchiver unarchiveObjectWithData: decodedData];

---

谢谢@rmaddy！这帮我做到了！：）顺便说一句，电影不是问题，一定是解码/编码选择器

NSData *decodedData = [userDefault objectForKey:@"MOVIES"];
NSArray *decodedArray = [NSKeyedUnarchiver unarchiveObjectWithData: decodedData];