Question

我一直在努力实施is it possible to save NSMutableArray or NSDictionary data as file in iOS?给出的答案，但他们并没有为我工作。有人请告诉我我做错了什么吗？我的NSArray是一个自定义对象，比如Cat。猫本身由字符串和数字组成。这是我的代码

-(void)saveArrayToFile:(NSArray *)response;
{
//    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
//    NSString *documentsDirectory = [paths objectAtIndex:0];
//    NSString *filePath = [documentsDirectory stringByAppendingPathComponent:PERSISTENT_FILENAME];
//    
//    [response writeToFile:filePath atomically:YES];
    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory,NSUserDomainMask, YES);
    if ([paths count] > 0)
    {
        // Path to save array data
        NSString  *arrayPath = [[paths objectAtIndex:0] stringByAppendingPathComponent:@"array.out"];
        // Write array
        [response writeToFile:arrayPath atomically:YES];


    }else NSLog(@"NO paths");
}

-(NSArray *)getArrayFromFile
{
//    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
//    NSString *documentsDirectory = [paths objectAtIndex:0];
//    NSString *filePath = [documentsDirectory stringByAppendingPathComponent:PERSISTENT_FILENAME];
//    return [NSArray arrayWithContentsOfFile:filePath];
    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory,NSUserDomainMask, YES);
    if ([paths count] > 0)
    {
        // Path to save array data
        NSString  *arrayPath = [[paths objectAtIndex:0] stringByAppendingPathComponent:@"array.out"];
        NSArray *arrayFromFile = [NSArray arrayWithContentsOfFile:arrayPath];
        return arrayFromFile;
    }else NSLog(@"No file to retrieve");
    return nil;
}

首先我尝试了注释代码。然后我尝试了另一个。到目前为止的问题是文件没有被保存。

Answer 1

保存时[response writeToFile：arrayPath atomically：YES]返回false。所以它没有成功保存。尝试使用

Bool result = [NSKeyedArchiver archiveRootObject:response toFile:arrayPath];
NSArray *arrayFromFile = [NSKeyedUnarchiver unarchiveObjectWithFile:arrayPath];

在你的cat文件中：

@property(nonatomic, strong)NSString* score;
@property(nonatomic, assign)BOOL bGenuine;
@property(nonatomic, assign)NSInteger errorCode;

@synthesize score,bGenuine,errorCode;

- (void)encodeWithCoder:(NSCoder *)encoder {
    [encoder encodeObject:score forKey:@"score"];
    [encoder encodeObject:[NSNumber numberWithBool:bGenuine] forKey:@"bGenuine"];
    [encoder encodeObject:[NSNumber numberWithInt:errorCode] forKey:@"errorCode"];
}

- (id)initWithCoder:(NSCoder *)decoder {
    score = [decoder decodeObjectForKey:@"score"];
    bGenuine = [[decoder decodeObjectForKey:@"bGenuine"] boolValue];
    errorCode = [[decoder decodeObjectForKey:@"errorCode"] integerValue];
    return self;
}

Answer 2

如果数组的内容都是属性列表对象（NSString，NSData，NSArray或NSDictionary对象），则此方法编写的文件可用于使用类方法arrayWithContentsOfFile：或实例方法initWithContentsOfFile初始化新数组：。

如果您的数组包含自定义对象

，这可能就是您无法读取文件的原因

或者尝试使用NSKeyedArchiver

如何从文件中保存NSArray并从中检索NSArray

2 个答案: