简单的文档应用程序，在Mac OS X 10.7中引发“恢复保存”异常Lion

Question

我有一个简单的文档应用程序，基于文档模板，当“恢复保存 - >上次打开时引发异常版本“菜单项在Mac OS X 10.7上被选中。

这个异常不在我的代码中，它在可可里面。它也似乎与我正在做的任何事情有关。我的应用程序非常简单（在此阶段），基于最新稳定版本的Xcode附带的模板，几乎是基于可可文档的可可基于文本的应用程序。

我意识到这可能是Lion中的一个错误，但我需要找到一种解决方法。

查看下面的例外，以及我的NSDocument子类的整个内容（非常小）。

步骤来重现

• 打开任何文件
• 类型的单个字符在文本视图
• 选择文件 - >恢复到保存
• 点击最后开业版本

异常

2011-09-04 07:10:29.182 myapp[15433:707] *** -[NSPathStore2 stringByAppendingPathExtension:]: nil argument 
2011-09-04 07:10:29.191 myapp[15433:707] (
    0 CoreFoundation      0x00007fff89c2b986 __exceptionPreprocess + 198 
    1 libobjc.A.dylib      0x00007fff90c6ed5e objc_exception_throw + 43 
    2 CoreFoundation      0x00007fff89c2b7ba +[NSException raise:format:arguments:] + 106 
    3 CoreFoundation      0x00007fff89c2b744 +[NSException raise:format:] + 116 
    4 Foundation       0x00007fff86d2b172 -[NSPathStore2 stringByAppendingPathExtension:] + 112 
    5 AppKit        0x00007fff9148f8c3 -[NSDocument _preserveCurrentVersionForReason:error:] + 579 
    6 AppKit        0x00007fff9147655b __-[NSDocument _revertToVersion:preservingFirst:error:]_block_invoke_3 + 99 
    7 Foundation       0x00007fff86ef28c3 __-[NSFileCoordinator coordinateReadingItemAtURL:options:error:byAccessor:]_block_invoke_1 + 113 
    8 Foundation       0x00007fff86ef2f34 -[NSFileCoordinator(NSPrivate) _invokeAccessor:orDont:thenRelinquishAccessClaimForID:] + 202 
    9 Foundation       0x00007fff86d98a28 -[NSFileCoordinator(NSPrivate) _coordinateReadingItemAtURL:options:error:byAccessor:] + 663 
    10 Foundation       0x00007fff86ef284c -[NSFileCoordinator coordinateReadingItemAtURL:options:error:byAccessor:] + 79 
    11 AppKit        0x00007fff91484b41 __-[NSDocument _revertToVersion:preservingFirst:error:]_block_invoke_1 + 347 
    12 AppKit        0x00007fff914901e3 -[NSDocument performSynchronousFileAccessUsingBlock:] + 42 
    13 AppKit        0x00007fff9148fc90 -[NSDocument _revertToVersion:preservingFirst:error:] + 125 
    14 AppKit        0x00007fff91476cf9 -[NSDocument _revertToDiscardRecentChangesPreservingFirst:error:] + 43 
    15 AppKit        0x00007fff91477094 __-[NSDocument _revertToDiscardRecentChangesThenContinue:]_block_invoke_3 + 164 
    16 AppKit        0x00007fff91474851 __-[NSDocument performSynchronousFileAccessUsingBlock:]_block_invoke_1 + 19 
    17 AppKit        0x00007fff91475bda -[NSDocument continueFileAccessUsingBlock:] + 227 
    18 AppKit        0x00007fff91490413 -[NSDocument _performFileAccessOnMainThread:usingBlock:] + 466 
    19 AppKit        0x00007fff9149023f -[NSDocument performSynchronousFileAccessUsingBlock:] + 134 
    20 AppKit        0x00007fff91495891 __-[NSDocument _revertToDiscardRecentChangesThenContinue:]_block_invoke_2 + 301 
    21 AppKit        0x00007fff914909a9 -[NSDocument _something:wasPresentedWithResult:soContinue:] + 21 
    22 AppKit        0x00007fff91381bee -[NSAlert didEndAlert:returnCode:contextInfo:] + 93 
    23 AppKit        0x00007fff9138e356 -[NSApplication endSheet:returnCode:] + 275 
    24 AppKit        0x00007fff91381ab4 -[NSAlert buttonPressed:] + 265 
    25 CoreFoundation      0x00007fff89c1b11d -[NSObject performSelector:withObject:] + 61 
    26 AppKit        0x00007fff911dd852 -[NSApplication sendAction:to:from:] + 139 
    27 AppKit        0x00007fff911dd784 -[NSControl sendAction:to:] + 88 
    28 AppKit        0x00007fff911dd6af -[NSCell _sendActionFrom:] + 137 
    29 AppKit        0x00007fff911dcb7a -[NSCell trackMouse:inRect:ofView:untilMouseUp:] + 2014 
    30 AppKit        0x00007fff9125c57c -[NSButtonCell trackMouse:inRect:ofView:untilMouseUp:] + 489 
    31 AppKit        0x00007fff911db786 -[NSControl mouseDown:] + 786 
    32 AppKit        0x00007fff911a666e -[NSWindow sendEvent:] + 6280 
    33 AppKit        0x00007fff9113ef19 -[NSApplication sendEvent:] + 5665 
    34 AppKit        0x00007fff910d542b -[NSApplication run] + 548 
    35 AppKit        0x00007fff9135352a NSApplicationMain + 867 
    36 myapp        0x00000001000018d2 main + 34 
    37 myapp        0x00000001000018a4 start + 52 
) 

NSDocument子类

@implementation MyTextDocument 

@synthesize textStorage; 
@synthesize textView; 

+ (BOOL)autosavesInPlace 
{ 
    return YES; 
} 

- (id)init 
{ 
    self = [super init]; 
    if (self) { 
     self.textStorage = nil; 
     self.textView = nil; 

     textContentToLoad = [@"" retain]; 
    } 
    return self; 
} 

- (NSString *)windowNibName 
{ 
    return @"MyTextDocument"; 
} 

- (void)windowControllerDidLoadNib:(NSWindowController *)aController 
{ 
    [super windowControllerDidLoadNib:aController]; 

    self.textStorage = self.textView.textStorage; 
    [self loadTextContentIntoStorage]; 
} 

- (NSData *)dataOfType:(NSString *)typeName error:(NSError **)outError 
{ 
    return [self.textStorage.string dataUsingEncoding:NSUTF8StringEncoding]; 
} 

- (BOOL)readFromData:(NSData *)data ofType:(NSString *)typeName error:(NSError **)outError 
{ 
    textContentToLoad = [[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding]; 
    if (!textContentToLoad) { 
    *outError = [NSError errorWithDomain:NSCocoaErrorDomain code:NSFileReadUnknownError userInfo:nil]; 
    return NO; 
    } 

    [self loadTextContentIntoStorage]; 

    return YES; 
} 

- (void)loadTextContentIntoStorage 
{ 
    if (!self.textStorage || !textContentToLoad) 
    return; 

    [self.textStorage beginEditing]; 
    [self.textStorage replaceCharactersInRange:NSMakeRange(0, self.textStorage.length) withString:textContentToLoad]; 

    [textContentToLoad release], textContentToLoad = nil; 
} 

@end 

Answer 1

是您的plist中正确设置，当涉及到的类型？

看来，NSDocument将[self fileNameExtensionForType:[self autosavingFileType] saveOperation:NSAutosaveElsewhereOperation]的结果传递给stringByAppendingPathExtension:（此处引发异常的方法）。如果您的应用程序针对此表达式返回nil，则可能导致此异常。

您应该为Apple提交一个bug，但同时请确保您的应用程序返回非nil。

Answer 2

粘贴此为您的文档类（例如Document.m）：

-(NSString*)fileNameExtensionForType:(NSString *)typeName saveOperation: (NSSaveOperationType)saveOperation 
{ 
    return @"yourAutosaveExtension"; 
} 

之前，像kperryua说，这种方法没有得到执行，并返回零。