objective-c - NSKeyedArchiver archiveRootObject 总是返回 NO

Question

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，但每次我这样做都无法创建 .plist 文件。我环顾四周，一直找不到答案。谁能帮我理解为什么“出了点问题……”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

Answer 1

当你想转换文件 NSURL 用于需要路径的方法时，你应该使用 path 方法，而不是 absoluteString方法。正如 path 方法文档所说:

If the URL object contains a file or file reference URL (as determined with isFileURL), the return value of this method [path] is suitable for input into methods of NSFileManager or NSPathUtilities. If the path has a trailing slash, it is stripped.

absoluteString 方法返回一个看起来像 file:///Users/... 的字符串，但您不需要那个 file:// 这些方法中的方案前缀正在寻找某些资源的路径。 path 方法返回您的文件路径，不受 file:// 前缀的影响。