NSAlert beginSheetModalForWindow does not display alert

Question

I have the following code in a ViewController in my OS X app:

   NSAlert *alert = [NSAlert new];
   alert.messageText = @"Connection error";
   alert.informativeText = @"You do not appear to be connected to the internet";
   [alert addButtonWithTitle:@"Third button"];
   [alert addButtonWithTitle:@"Second button"];
   [alert addButtonWithTitle:@"Ok"];

   [alert beginSheetModalForWindow:[[self view] window] completionHandler:^(NSInteger result) {
       NSLog(@"Success");
   }];
// [alert runModal];

When this code executes nothing happens. If I comment out the beginSheetModalForWindow line, and uncomment [alert runModal], then the alert is displayed as expected.

What am I doing wrong here that it doesn't display as a sheet?

Answer 1

I imagine you are trying to show the NSAlert too early (while the window is setting up) try adding a perfromselector with a delay to see if this is the case

[self performSelector:@selector(delayed) withObject:nil afterDelay:1.0];


-(void)delayed {
    NSAlert *alert = [NSAlert new];
    alert.messageText = @"Connection error";
    alert.informativeText = @"You do not appear to be connected to the internet";
    [alert addButtonWithTitle:@"Third button"];
    [alert addButtonWithTitle:@"Second button"];
    [alert addButtonWithTitle:@"Ok"];

    [alert beginSheetModalForWindow:[self.view window] completionHandler:^(NSInteger result) {
        NSLog(@"Success");
    }];
}

If so, try showing it once the window has loaded, for example in

- (void)windowDidLoad {
    //code here
}