Question

我想将NSMutableArray * allRedItems保存到文件中。它包含自定义对象，Itemz：

@interface Itemz : NSObject <NSCoding>
@property double price;
@property double quality;
@property double style;


@property double overallAverage;

到目前为止，我已经完成了所有正确的步骤：

@implementation Itemz

- (void)encodeWithCoder:(NSCoder *)encoder {


[encoder encodeDouble:self.price forKey:@"price"];
[encoder encodeDouble:self.style forKey:@"style"];
[encoder encodeDouble:self.quality forKey:@"quality"];
[encoder encodeDouble:self.overallAverage forKey:@"overallAverage"];

[encoder encodeBool: self.isClicked forKey:@"isClicked"];
}

- (id)initWithCoder:(NSCoder *)decoder {
if((self = [super init])) {
    //decode properties, other class vars
    self.price = [decoder decodeDoubleForKey:@"price"];

    self.style = [decoder decodeDoubleForKey:@"style"];
    self.quality = [decoder decodeDoubleForKey:@"quality"];
    self.overallAverage = [decoder decodeDoubleForKey:@"overallAverage"];
    self.isClicked = [decoder decodeBoolForKey:@"isClicked"];


}
return self;
}
@end

这是我保存数组* allRedItems

的地方

@implementation AllRedItems
NSData *data = [NSKeyedArchiver archivedDataWithRootObject:self.allRedItems];

NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentationDirectory, NSUserDomainMask, YES);

NSString *documentsDirectory = [paths objectAtIndex:0];

NSString *allItemsRed = [documentsDirectory  stringByAppendingPathComponent:@"allItemsRed"];

[data writeToFile:allItemsRed atomically:YES];
 @end

当我检索它时，它会给我这个错误 - [NSKeyedUnarchiver initForReadingWithData：]：data is NULL

@implementation ItemSuggestion
NSArray * paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString * documentsDirectory = [paths objectAtIndex:0];
NSString * path = [documentsDirectory stringByAppendingPathComponent:@"allItemsRed"];
NSData * data = [NSData dataWithContentsOfFile:path];
NSMutableArray *allRedItems = [NSKeyedUnarchiver unarchiveObjectWithData:data];
@end

我错过了什么吗？或者我需要添加一些东西吗？

Answer 1

您可以将其保存在NSDocumentationDirectory

中

NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentationDirectory, NSUserDomainMask, YES);

但是从NSDocumentDirectory检索它，所以你无法得到它。

NSArray * paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);

在两种方法中使用NSDocumentDirectory。

错误消息说我的数据是NULL - NSKeyedUnArchiver - 我已经按照所有步骤 - 仍然无法正常工作

1 个答案: