[英]How to save NSArray to and retrieve NSArray from file
我一直在尝试实现给出的答案, 是否可以将NSMutableArray或NSDictionary数据另存为iOS中的文件? 他们还没有为我工作。 有人可以告诉我我做错了什么吗? 我的NSArray是一个自定义对象,例如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,我尝试了注释的代码。 然后我尝试了另一个。 到目前为止的问题是该文件没有被保存。
保存时[以原子方式响应writeToFile:arrayPath:YES]返回false。 因此无法成功保存。 尝试使用
Bool result = [NSKeyedArchiver archiveRootObject:response toFile:arrayPath];
NSArray *arrayFromFile = [NSKeyedUnarchiver unarchiveObjectWithFile:arrayPath];
在您的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;
}
如果数组的内容都是所有属性列表对象(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。
这可能是为什么如果数组包含自定义对象则无法读取文件的原因
或者尝试使用NSKeyedArchiver
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