也许这个答案太晚了，没有用，但是......在我的一个应用程序中，我在我的 NSApplication 派生类中实现了 -(IBAction)terminate:(id)sender ，它会有条件地调用 [super terminate] 以仅在以下情况下实际关闭应用程序所有打开的文档都被干净地保存了。我可能在 Apple 文档或其他示例中找到了其中的一些内容。
终止覆盖将遍历每个文档并关闭它（因为它已保存），或者在 NSDocument 派生类中调用文档的 canCloseDocumentWithDelegate 方法，将“self”和“terminate”作为 didSaveSelector。由于 terminate 方法失败并且除了使文档呈现 NSAlert 之外什么都不做，如果用户单击“是”或“否”，文档类中的警报将回调并重新运行终止例程。如果所有文档都是干净的，则应用程序将终止，因为 [super terminate] 将被调用。如果存在更多脏文档，则重复该过程。
例如：
@interface MyApplication : NSApplication
@end
@implementation MyApplication
- (IBAction)terminate:(id)sender
{
//Loop through and find any unsaved document to warn the user about.
//Close any saved documents along the way.
NSDocument *docWarn = NULL;
NSArray *documents = [[NSDocumentController sharedDocumentController] documents];
for(int i = 0; i < [documents count]; i++)
{
NSDocument *doc = [documents objectAtIndex:i];
if([doc isDocumentEdited])
{
if(docWarn == NULL || [[doc windowForSheet] isKeyWindow])
docWarn = doc;
}
else
{
//close any document that doesn't need saving. this will
//also close anything that was dirty that the user answered
//NO to on the previous call to this routine which triggered
//a save prompt.
[doc close];
}
}
if(docWarn != NULL)
{
[[docWarn windowForSheet] orderFront:self];
[[docWarn windowForSheet] becomeFirstResponder];
[docWarn canCloseDocumentWithDelegate:self shouldCloseSelector:@selector(terminate:) contextInfo:NULL];
}
else
{
[super terminate:sender];
}
}
@end
稍后在文档派生类中：
typedef struct {
void * delegate;
SEL shouldCloseSelector;
void *contextInfo;
} CanCloseAlertContext;
@interface MyDocument : NSDocument
@end
@implementation MyDocument
- (void)canCloseDocumentWithDelegate:(id)inDelegate shouldCloseSelector:(SEL)inShouldCloseSelector contextInfo:(void *)inContextInfo
{
// This method may or may not have to actually present the alert sheet.
if (![self isDocumentEdited])
{
// There's nothing to do. Tell the delegate to continue with the close.
if (inShouldCloseSelector)
{
void (*callback)(id, SEL, NSDocument *, BOOL, void *) = (void (*)(id, SEL, NSDocument *, BOOL, void *))objc_msgSend;
(callback)(inDelegate, inShouldCloseSelector, self, YES, inContextInfo);
}
}
else
{
NSWindow *documentWindow = [self windowForSheet];
// Create a record of the context in which the panel is being
// shown, so we can finish up when it's dismissed.
CanCloseAlertContext *closeAlertContext = malloc(sizeof(CanCloseAlertContext));
closeAlertContext->delegate = (__bridge void *)inDelegate;
closeAlertContext->shouldCloseSelector = inShouldCloseSelector;
closeAlertContext->contextInfo = inContextInfo;
// Present a "save changes?" alert as a document-modal sheet.
[documentWindow makeKeyAndOrderFront:nil];
NSBeginAlertSheet(@"Would you like to save your changes?", @"Yes", @"Cancel", @"No", documentWindow, self,
@selector(canCloseAlertSheet:didEndAndReturn:withContextInfo:), NULL, closeAlertContext, @"%");
}
}
- (void)canCloseAlertSheet:(NSWindow *)inAlertSheet didEndAndReturn:(int)inReturnCode withContextInfo:(void *)inContextInfo
{
CanCloseAlertContext *canCloseAlertContext = inContextInfo;
void (*callback)(id, SEL, NSDocument *, BOOL, void* ) = (void (*)(id, SEL, NSDocument *, BOOL, void* ))objc_msgSend;
if (inAlertSheet) [inAlertSheet orderOut:self];
// The user's dismissed our "save changes?" alert sheet. What happens next depends on how the dismissal was done.
if (inReturnCode==NSAlertAlternateReturn)
{
//Cancel - do nothing.
}
else if (inReturnCode==NSAlertDefaultReturn)
{
//Yes - save the current document
[self saveDocumentWithDelegate:(__bridge id)canCloseAlertContext->delegate
didSaveSelector:canCloseAlertContext->shouldCloseSelector contextInfo:canCloseAlertContext->contextInfo];
}
else
{
// No - just clear the dirty flag and post a message to
// re-call the shouldCloseSelector. This should be
// the app:terminate routine.
[self clearDirtyFlag];
if (canCloseAlertContext->shouldCloseSelector)
{
(callback)((__bridge id)canCloseAlertContext->delegate,
canCloseAlertContext->shouldCloseSelector, self, YES, canCloseAlertContext->contextInfo);
}
}
// Free up the memory that was allocated in -canCloseDocumentWithDelegate:shouldCloseSelector:contextInfo:.
free(canCloseAlertContext);
}
@end
应该这样做 - 没有循环......没有等待......