Cocoa: Displaying an error after NSApp beginSheet results the main window hiding

Question

I have broken this down into a very small project. Using the following code in the application delegate:

- (void)applicationDidFinishLaunching:(NSNotification *)aNotification
{
    TestingWindowController * testingWindowController = [[TestingWindowController alloc] initWithWindowNibName: @"TestingWindowController"];

    // Begin our sheet
    [NSApp beginSheet: testingWindowController.window
       modalForWindow: self.window
        modalDelegate: self
       didEndSelector: @selector(windowDidEnd:returnCode:contextInfo:)
          contextInfo: NULL];
}

- (void)windowDidEnd:(id)alert returnCode:(NSInteger)returnCode contextInfo:(id) contextInfo
{
    // If the user did not accept, then we really don't care what else they did!
    if (returnCode != NSOKButton) return;

    // We have had an error. Display it.
    [[NSApplication sharedApplication] presentError: nil
                                     modalForWindow: self.window
                                           delegate: nil
                                 didPresentSelector: nil
                                        contextInfo: NULL];
}

And the following action tied to button on the windows nib. (Note that the nib's window is also set to not be visible on launch).

- (IBAction) onClose: (id) sender
{
    [[NSApplication sharedApplication] endSheet: self.window
                                     returnCode: NSOKButton];

    [self.window orderOut: nil];    
} // End of onClose

What ends up happening is, once I the onClose runs, all of the windows disappear and I am left with nothing but the error dialog (the main window has disappeared).

Is there something wrong with my code? Why does my main window go away?

NOTE: I know that I am not passing an error to the presentError method. I purposely left this null as I only had a short time to write the sample code. Passing an actual error results in the same behaviour.

Sample project is available here.

Answer 1

Looks like you are still using the old api, try the new one

(deselect Always visible at launch for the UserLoginWindowController window)

- (IBAction)userButtonPressed:(id)sender {

    UserLoginWindowController * wc = [UserLoginWindowController new];
    // we keep a reference, so the WC doesn't deallocate
    self.modalWindowController = wc;

    [[self window] beginSheet:[wc window] completionHandler:^(NSModalResponse returnCode) {
        self.modalWindowController = nil;
    }];

}

in the UserLoginWindowController

- (IBAction)cancelButtonPressed:(id)sender {

    [[[self window] sheetParent] endSheet:[self window] returnCode:NSModalResponseCancel];

}

Answer 2

You are using 2 methods to open your window, beginSheet:....., and runModalForWindow:. You only need one of those. If you want a sheet attached to your window, use the first method, if you want a stand alone window, use the second. Likewise, in your onClose method, you should use endSheet:returnCode: if you're closing a sheet (the argument for that method should be testingWindowController.window not self.window) , and stopModalWithCode: if you're closing a modal window, you shouldn't have both.