NSKeyedArchiver archiveRootObject 总是返回 NO

Posted 2023-02-15

【中文标题】NSKeyedArchiver archiveRootObject 总是返回 NO

【英文标题】：NSKeyedArchiver archiveRootObject always returns NO

【发布时间】：2014-10-07 15:29:35

【问题描述】：

我是 Objective C 的新手，正在编写一些简单的程序来熟悉自己。

尝试使用 NSKeyedArchiver 保存/读取信息，但每次我都无法创建 .plist 文件。我环顾四周，无法找到答案。谁能帮我理解为什么“出了问题……”总是最终输出？

谢谢！

// main.m
#import <Foundation/Foundation.h>
#import "Domicile.h"

void CreateAndArchive(NSMutableArray* objs, NSURL *saveLocation)

    NSLog(@"Creating DOMICILE objects...");

    Domicile *now = [[Domicile alloc] init];
    Domicile *then = [[Domicile alloc] init];

    now.HouseName = @"place1;
    now.Address = @"506 99th street";
    now.Residents = [[NSMutableArray alloc] initWithObjects: @"Erik", @"Jeremiah", @"Alex", @"Ryan", @"Kyle", @"Connor", nil];
    now.City = @"aCity";
    now.State = @"CA";
    now.Zip = @"12345";

    then.HouseName = @"place2";
    then.Address = @"1011 E Fairmont street";
    then.Residents = [[NSMutableArray alloc] initWithObjects: @"Erik", @"Asa", @"Ryan", @"Gabe", @"Josh", nil];
    then.City = @"anotherCity";
    then.State = @"VA";
    then.Zip = @"54321";

    NSMutableArray *saveThis = [[NSMutableArray alloc] initWithObjects: now, then, nil];

    NSLog(@"saving to %@", [saveLocation absoluteString]);
    if ([NSKeyedArchiver archiveRootObject:saveThis toFile:[saveLocation absoluteString]])
    
        NSLog(@"SAVED!");
    
    else
        NSLog(@"Something went wrong...");
    


NSMutableArray* Load(NSURL *location)
    NSLog(@"Loading data from %@", [location absoluteString]);

    return [NSKeyedUnarchiver unarchiveObjectWithFile: [location absoluteString]];



int main(int argc, const char * argv[])

    @autoreleasepool 

        NSURL *dir = [[NSFileManager defaultManager] URLForDirectory:NSDesktopDirectory inDomain:NSUserDomainMask appropriateForURL:nil create:NO error:nil];
        NSURL *file = [dir URLByAppendingPathComponent:@"data.plist"];

        NSMutableArray *domiciles = [[NSMutableArray alloc] init];

        if ([[NSFileManager defaultManager] fileExistsAtPath:[file absoluteString]])
        
            domiciles = Load(file);
            NSLog(@"data loaded!");
            NSLog(@"displaying for your convenience:");

            for (Domicile *dom in domiciles) 
                NSLog(@"\n\n%@", dom);
            
        
        else
        
            CreateAndArchive(domiciles, file);
        

    
    return 0;

---

//  Domicile.m
#import "Domicile.h"

@implementation Domicile

-(instancetype)initWithCoder:(NSCoder *)coder

    self = [super init];
    if (self) 
        _HouseName = [coder decodeObjectForKey:@"name"];
        _Residents = [coder decodeObjectForKey:@"residents"];
        _Address = [coder decodeObjectForKey:@"address"];
        _City = [coder decodeObjectForKey:@"city"];
        _State = [coder decodeObjectForKey:@"state"];
        _Zip = [coder decodeObjectForKey:@"zip"];
    
    return self;


-(void) encodeWithCoder:(NSCoder *)aCoder
    [aCoder encodeObject:self.HouseName forKey:@"name"];
    [aCoder encodeObject:self.Residents forKey:@"residents"];
    [aCoder encodeObject:self.Address forKey:@"address"];
    [aCoder encodeObject:self.City forKey:@"city"];
    [aCoder encodeObject:self.State forKey:@"state"];
    [aCoder encodeObject:self.Zip forKey:@"zip"];



-(NSString *) description
    NSString *desc = [[NSString alloc] initWithFormat: @"House : %@\n%@\n%@, %@\n%@\n", self.HouseName, self.Address, self.City, self.State, self.Zip];
    return desc;

@end

【问题讨论】：

查看***.com/questions/14326533/…

【参考方案1】：

当您想要转换文件NSURL 以用于需要路径的方法时，您应该使用path 方法，而不是absoluteString 方法。正如path 方法文档所说：

如果 URL 对象包含文件或文件引用 URL（由 isFileURL 确定），则此方法的返回值 [path] 适合输入到 NSFileManager 或 NSPathUtilities 的方法中。如果路径有尾部斜杠，则将其剥离。

absoluteString 方法返回一个看起来像 file:///Users/... 的字符串，但您不希望在这些正在寻找某些资源的路径的方法中使用 file:// 方案前缀。 path 方法返回您的文件路径，不受 file:// 前缀的影响。