How to show a presentModalView inside another presentModalView?

How do I show a presentModalView inside another presentModalView?

I wanna call this:

[button addTarget:self action:@selector(settingsTapped) forControlEvents:UIControlEventTouchUpInside];

IN HERE

UINavigationController *_nc = [[[开发者_C百科UINavigationController alloc] initWithRootViewController:scannerVC] autorelease]; //Put our SKScannerViewController into a UINavigationController. (So it looks nice).
        [scannerVC release];

[self presentModalViewController:_nc animated:YES]; //Slide it up onto the screen.

then

//another screen pop up in _nc
qrcode_info *otherVC = [[qrcode_info alloc] initWithNibName:@"qrcode_info" bundle:Nil  ];

//  [self presentModalViewController: otherVC animated:YES];

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Just call -presentModalViewController:animated: from within the view controller that is being shown modally.