问题
How do you launch a second MainWindow.xib in an iPad application?
回答1:
You load the nib, most likely using NSBundle, and then call makeKeyAndVisible on the window in the nib. The best way to get the window is to use an outlet in the object loading the nib.
[[NSBundle mainBundle] loadNibNamed:@"SecondWindow" owner:self options:nil];
[self.secondWindow makeKeyAndVisible]; //assuming the window was connected to a property named secondWindow
回答2:
Usually you don't. Instead, you transition to the new top level modal view controller (either in a xib or programmatically created) that would have been in your second MainWindow.
来源：https://stackoverflow.com/questions/5161016/how-do-you-launch-a-second-mainwindow-xib-in-an-ipad-application