iphone - 将文本文件保存到 iOS 7 中的文档目录

Question

我正在尝试将纯文本文件保存到 iOS 7 中的 Documents 目录。这是我的代码:

//Saving file
NSFileManager *fileManager = [[NSFileManager alloc] init];
NSArray *urls = [fileManager URLsForDirectory:NSDocumentDirectory inDomains:NSUserDomainMask];

NSString *url = [NSString stringWithFormat:@"%@", urls[0]];

NSString *someText = @"Random Text To Be Saved";
NSString *destination = [url stringByAppendingPathComponent:@"File.txt"];

NSError *error = nil;

BOOL succeeded = [someText writeToFile:destination atomically:YES encoding:NSUTF8StringEncoding error:&error];

if (succeeded) {
    NSLog(@"Success at: %@",destination);
} else {
    NSLog(@"Failed to store. Error: %@",error);
}

这是我遇到的错误:

2013-10-13 16:09:13.848 SavingFileTest[13675:a0b] Failed to store. Error: Error Domain=NSCocoaErrorDomain Code=4 "The operation couldn’t be completed. (Cocoa error 4.)" UserInfo=0x1090895f0 {NSFilePath=file:/Users/Username/Library/Application%20Support/iPhone%20Simulator/7.0-64/Applications/F5DA3E33-80F7-439B-A9AF-E8C7FC4E1630/Documents/File.txt, NSUserStringVariant=Folder, NSUnderlyingError=0x10902aeb0 "The operation couldn’t be completed. No such file or directory"}

我不明白为什么在模拟器上运行时会出现此错误。如果我使用 NSTemporaryDirectory()，这会起作用。

Answer 1

来自 Apple 的 Xcode 模板:

/**
 Returns the URL to the application's Documents directory.
 */
- (NSURL *)applicationDocumentsDirectory {
    return [[[NSFileManager defaultManager] URLsForDirectory:NSDocumentDirectory 
         inDomains:NSUserDomainMask] lastObject];
}

你可以这样保存:

NSString *path = [[self applicationDocumentsDirectory].path 
                       stringByAppendingPathComponent:@"fileName.txt"];
[sampleText writeToFile:path atomically:YES
                       encoding:NSUTF8StringEncoding error:nil];