我如何保存在NSFileManager中？

Question

我有一個應用程序使用json服務，我想保存在NSFileManager這個度量，可以有至多？大小有限制？

Answer 1

爲了節省：

UIImage *pickedImage = [UIImage imageNamed:@"anyImageName"]; 
NSData *pngData = UIImagePNGRepresentation(pickedImage); 
NSString *withFullPathName = @"yourFullPathFileName"; 
[pngData writeToFile:withFullPathName atomically:YES]; 

一旦你保存你的數據（想象中的照片），所以你可以使用的NSFileManager閱讀：

NSData* data; 
NSString *fullPathName = @"yourFullPathFileName"; 
if ([[NSFileManager defaultManager] fileExistsAtPath:fullPathName]) { 

    data = [[NSData alloc] initWithContentsOfFile:fullPathName]; 
    UIImage *image = [UIImage imageWithData:data]; 
} else { 
    NSLog(@"file does not exist."); 
} 

// When you set your fullPathName try make sure it is unique for each file. 

編輯

// Considering your JSON is a NSString: 

// 1. Convert the nsstring to nsdata 
NSString* str = @"yourJsonAsString:{...}"; 
NSData* data = [str dataUsingEncoding:NSUTF8StringEncoding]; 

// You don't use nsfilemanager to save you use to read, you use "writeToFile:" to store your info. 
[data writeToFile:@"yourFullPathName" atomically:YES]; 

// To read your file, use the example of the code above about NSFileManager. 
// About the size, the only size limit is the amount of available space on the device. However is not a good pratice save a huge file. You should use core-data.