Cocoa:在 NSApp beginSheet 后显示错误导致主窗口隐藏

Question

我已将其分解为一个非常小的项目。在应用程序委托(delegate)中使用以下代码:

- (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];
}

以下操作与 Windows Nib 上的按钮相关。 (请注意， Nib 的窗口也设置为在启动时不可见)。

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

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

最终发生的事情是，一旦我运行了onClose，所有窗口都会消失，除了错误对话框之外什么也没有(主窗口已经消失)。

我的代码有问题吗？为什么我的主窗口消失了？

注意:我知道我没有将错误传递给presentError 方法。我故意将这个值留为空，因为我只有很短的时间来编写示例代码。传递实际错误会导致相同的行为。

示例项目已可用 here .

Answer 1

看来您仍在使用旧的 API，请尝试新的

(取消选择 UserLoginWindowController 窗口启动时始终可见)

- (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;
    }];

}

在 UserLoginWindowController 中

- (IBAction)cancelButtonPressed:(id)sender {

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

}