NSFileWrapper基础:如何提取组件

Question

如果这是显而易见的，我很抱歉，但我正在努力解决如何从NSFileWrapper和docs were not particular enlightening.中提取组件

我有两个包装纸。其中一个包含一个简单的txt文件。另一个保存pageSettings。PageSettings是一个包含多个NSStrings、BOOLs等的NSObject。这是我的包装器(基于Apple's Document-Based Application Programming Guide for iOS)，我现在再次尝试提取信息：

    if (self.fileWrapper == nil) {
    self.fileWrapper = [[NSFileWrapper alloc] initDirectoryWithFileWrappers:nil];
}

NSDictionary *fileWrappers = [self.fileWrapper fileWrappers];

if (([fileWrappers objectForKey:@"page"] == nil) && (self.text != nil)) {
    NSData *textData = [self.text dataUsingEncoding:NSUTF8StringEncoding];
    NSFileWrapper *textFileWrapper = [[NSFileWrapper alloc] initRegularFileWithContents:textData];
    [textFileWrapper setPreferredFilename:@"page"];
    [self.fileWrapper addFileWrapper:textFileWrapper];
}

if (([fileWrappers objectForKey:@"pageSettings"] == nil) && (self.pageSettings != nil)) {
    NSData *settingsData = [NSKeyedArchiver archivedDataWithRootObject:self.pageSettings];
    NSFileWrapper *settingsWrapper = [[NSFileWrapper alloc] initRegularFileWithContents:settingsData];
    [settingsWrapper setPreferredFilename:@"pageSettings"];
    [self.fileWrapper addFileWrapper:settingsWrapper];
}

所以我的问题是如何将txt文件和pageSettings重新加载到self.text和self.pageSettings中？

我要使用- (NSData *)serializedRepresentation吗？如果是这样的话，是怎么做的？或者我简单地像这样颠倒它：

NSDictionary *fileWrappers = [self.fileWrapper fileWrappers];
self.text = [fileWrappers objectForKey:@"page"];
self.pageSettings = [fileWrappers objectForKey:@"pageSettings"];

如有任何解释，我将不胜感激。非常感谢。

Answer 1

NSDictionary *fileWrappers = [self.fileWrapper fileWrappers];

NSFileWrapper *pageWrapper = [fileWrappers objectForKey:@"page"];
NSData *pageData = pageWrapper.regularFileContents;
self.text = [[NSString alloc] initWithData:pageData encoding:NSUTF8StringEncoding];

NSFileWrapper *pageSettingsWrapper = [fileWrappers objectForKey:@"pageSettings"];
NSData *pageSettingsData = pageSettingsData.regularFileContents;
self.pageSettings = [NSKeyedUnarchiver unarchiveObjectWithData:pageSettingsData];