Question

如何保存/读取填充了我为其创建类的对象的NSMutableArray？

这就是我到目前为止......（其中'ObjectA'代表我的类，'objects'是一个包含许多'ObjectA'实例的数组）

//Creating a file
    //1) Search for the app's documents directory
    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
    NSString *documentsDirectory = [paths objectAtIndex:0];
    //2) Create the full file path by appending the desired file name
    NSString *documentFileName = [documentsDirectory stringByAppendingPathComponent:@"save.dat"];


    //Load the array
    objects = [[NSMutableArray alloc] initWithContentsOfFile: _documentFileName];
    if(objects == nil)
    {
        //Array file didn't exist... create a new one
        objects = [[NSMutableArray alloc]init];
        NSLog(@"Did not find saved list, Created new list.");
    }
    else
    {
        NSLog(@"Found saved list, Loading list.");
    }

这将加载一个数组（如果存在）。如果数组填充了像NSNumbers这样的属性类型对象，我就可以使用它。如果我用自己的对象填充它，它会崩溃！这是错误:(其中'objectAInt'是属于'ObjectA'的私有int）

-[__NSCFNumber objectAInt]: unrecognized selector sent to instance 0x15d417f02013-11-19 17:28:58.645 My Project[1791:60b] *** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[__NSCFNumber objectAInt]: unrecognized selector sent to instance 0x15d417f0'

我需要做什么才能让我的类'ObjectA'使用保存/读取过程，就像使用NSNumbers和其他类型（id）的NS对象一样？

谢谢！

P.S。我的类实现并符合NSCoding。如果需要更多信息，请不要犹豫！：）

编辑 - 这是我的ObjectA（每个请求）（它是NSObject的子类）

//
//  ObjectA.m
//  My Project
//
//  Created by Will Battel on 8/8/13.
//
//

#import "ObjectA.h"

@implementation ObjectA
@synthesize objectAString, objectAString2, objectAString3, objectAInt;

-(id)initWithName:(NSString *)_objectAString{
    self = [super init];

    objectAString = _objectAString;
    objectAInt = 2;
    objectAString3 = @"$0.00";

    return self;
}

-(id)initWithCoder:(NSCoder *)decoder {
    self = [super init];
    if (self) {
        NSLog(@"Decoding");
        [self setObjectAString:[decoder decodeObjectForKey:@"objectAStringKey"]];
        [self setObjectAString2:[decoder decodeObjectForKey:@"objectAString2Key"]];
        [self setObjectAString3Price:[decoder decodeObjectForKey:@"objectAString3Key"]];
        [self setobjectAInt:[decoder decodeIntForKey:@"objectAIntKey"]];
    }
    return self;
}

-(void)encodeWithCoder:(NSCoder *)encoder {
    NSLog(@"Encoding");
    [encoder encodeObject:objectAString forKey:@"objectAStringKey"];
    [encoder encodeObject:objectAString2 forKey:@"objectAString2Key"];
    [encoder encodeObject:objectAString3 forKey:@"objectAString3Key"];
    [encoder encodeInt:objectAInt forKey:@"objectAIntKey"];
}

@end

Answer 1

由于数组包含符合NSCoding的对象，您可以使用编码方法，例如......

- (NSMutableArray *)instancesFromArchive {

    // compute documentFileName using your original code

    if ([[NSFileManager defaultManager] fileExistsAtPath:documentFileName]) {
        return [NSKeyedUnarchiver unarchiveObjectWithFile:documentFileName];
    } else {
        return [NSMutableArray array];
    }
}

// archives my array of objects
- (BOOL)archiveInstances {

    // compute documentFileName using your original code

    return [NSKeyedArchiver archiveRootObject:self.objects toFile:documentFileName];
}

Answer 2

NSNumber类符合NSCoding标准。你自己的对象符合NSCoding吗？

保存一个填充了自定义对象的NSMutableArray

2 个答案: