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嗨，我正在为我的应用程序使用 iCloud 支持并UIDocument用于存储。我能够将数据保存到 iCloud 并第一次获取相同的数据。但是当我在设备上删除并重新安装该应用程序时，似乎EXC BAD ACCESS在尝试使用NSKeyUnarchiver.

代码。

BuyerDocument.m // UIDocument Subclass

// Accessor for BuyerData

- (BuyerData *)data {
if (_data == nil) {
    if (self.fileWrapper != nil) {
        self.data = [self decodeObjectFromWrapperWithPreferredFilename:BUYER_FILENAME];  // BUYER_FILENAME = @"buyer.data"
    } else {
        self.data = [[BuyerData alloc] init];
    }
}
return _data;
}

- (id)decodeObjectFromWrapperWithPreferredFilename:(NSString *)preferredFilename {

NSFileWrapper * fileWrapper = [self.fileWrapper.fileWrappers objectForKey:preferredFilename];
if (!fileWrapper) {
    NSLog(@"Unexpected error: Couldn't find %@ in file wrapper!", preferredFilename);
    return nil;
}
if([fileWrapper isRegularFile]){
    NSLog(@"is regular wrapper");
}
NSData * data = [fileWrapper regularFileContents];

NSLog(@"data %@",data);         // This logs successfully
//    NSLog(@"data bytes %@",[data bytes])     // This also causes app to crash.
NSKeyedUnarchiver *unarchiver = [[NSKeyedUnarchiver alloc] initForReadingWithData:data];       // App will crash here

return [unarchiver decodeObjectForKey:@"data"];
}

在此处加载买方文档。

- (void)loadDocAtURL:(NSURL *)fileURL {

// Open doc so we can read metadata
BuyerDocument * doc = [[BuyerDocument alloc] initWithFileURL:fileURL];
[doc openWithCompletionHandler:^(BOOL success) {
.......
    BuyerData * data = doc.data;

    ....
    [doc closeWithCompletionHandler:^(BOOL success) {

       .....          
}];
}


 BuyerData.m

#define kVersionKey @"Version"
#define kNameKey @"Name"

- (void)encodeWithCoder:(NSCoder *)encoder {
   [encoder encodeInt:1 forKey:kVersionKey];
   [encoder encodeObject:self.name forKey:kNameKey];
}

- (id)initWithCoder:(NSCoder *)decoder {
[decoder decodeIntForKey:kVersionKey];
NSString *nameData = [decoder decodeObjectForKey:kNameKey];
//    NSLog(@">>>>>>>>>>>>>>>>>>> %@",name);   // This logs for first 2-3 files and then crash occurs
return [self initWithName:nameData];
}

正如我所说，当我第一次添加数据时一切都运行良好，只是在删除并重新安装之后才开始发生崩溃。在此崩溃发生之前，还会获取前 3-4 个名称并将其显示在 tableview 中。试过这个但没有帮助我对UIDocumentand还很陌生NSCoding。所以不能多说他们。但我猜一些问题可能与在NSData那里迷路或损坏有关。我在这里错过了一些基本和重要的东西吗？我究竟做错了什么？

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