我试图创建一个核心数据,基于文档的应用程序,但有限制,一次只能查看一个文档(这是一个音频应用程序,wouldn'对于许多文档来说,立即产生噪音是有意义的)。如何子类NSDocumentController一次只允许一个文档
我的计划是以一种不需要将它链接到任何菜单的动作的方式来继承NSDocumentController。这一直合理,但我遇到了一个问题,让我质疑我的方法一点。
下面的代码工作在大多数情况下,除非用户执行以下操作: - 试图打开一个文档与现有的“脏”文档打开 - 点击取消保存/不保存/取消警报(此工作好) - 然后尝试再次打开文档。出于某种原因,即使打开对话框出现,openDocumentWithContentsOfURL方法也不会再次被调用。
任何人都可以帮我找出原因吗?或者,也许可以指出我如何做到这一点的一个例子?这感觉就像一些人必须实施的东西,但我一直没能找到10.7+的例子。
- (BOOL)presentError:(NSError *)error
{
if([error.domain isEqualToString:DOCS_ERROR_DOMAIN] && error.code == MULTIPLE_DOCS_ERROR_CODE)
return NO;
else
return [super presentError:error];
}
- (id)openUntitledDocumentAndDisplay:(BOOL)displayDocument error:(NSError **)outError
{
if(self.currentDocument) {
[self closeAllDocumentsWithDelegate:self
didCloseAllSelector:@selector(openUntitledDocumentAndDisplayIfClosedAll: didCloseAll: contextInfo:)
contextInfo:nil];
NSMutableDictionary* details = [NSMutableDictionary dictionary];
[details setValue:@"Suppressed multiple documents" forKey:NSLocalizedDescriptionKey];
*outError = [NSError errorWithDomain:DOCS_ERROR_DOMAIN code:MULTIPLE_DOCS_ERROR_CODE userInfo:details];
return nil;
}
return [super openUntitledDocumentAndDisplay:displayDocument error:outError];
}
- (void)openUntitledDocumentAndDisplayIfClosedAll:(NSDocumentController *)docController
didCloseAll: (BOOL)didCloseAll
contextInfo:(void *)contextInfo
{
if(self.currentDocument == nil)
[super openUntitledDocumentAndDisplay:YES error:nil];
}
- (void)openDocumentWithContentsOfURL:(NSURL *)url
display:(BOOL)displayDocument
completionHandler:(void (^)(NSDocument *document, BOOL documentWasAlreadyOpen, NSError *error))completionHandler NS_AVAILABLE_MAC(10_7)
{
NSLog(@"%s", __func__);
if(self.currentDocument) {
NSDictionary *info = [NSDictionary dictionaryWithObjectsAndKeys:[url copy], @"url",
[completionHandler copy], @"completionHandler",
nil];
[self closeAllDocumentsWithDelegate:self
didCloseAllSelector:@selector(openDocumentWithContentsOfURLIfClosedAll:didCloseAll:contextInfo:)
contextInfo:(__bridge_retained void *)(info)];
} else {
[super openDocumentWithContentsOfURL:url display:displayDocument completionHandler:completionHandler];
}
}
- (void)openDocumentWithContentsOfURLIfClosedAll:(NSDocumentController *)docController
didCloseAll: (BOOL)didCloseAll
contextInfo:(void *)contextInfo
{
NSDictionary *info = (__bridge NSDictionary *)contextInfo;
if(self.currentDocument == nil)
[super openDocumentWithContentsOfURL:[info objectForKey:@"url"] display:YES completionHandler:[info objectForKey:@"completionHandler"]];
}