presentModalViewController from app delegate

Question

How can I present a modal view controller from the app delegate\'s view, the top most? Trying to present a modal view controller from a UIView, which made me confused.

Answer 1

The best way to do this is to create a new UIWindow, set it's windowLevel property, and present your UIViewController in that window.

This is how UIAlertViews work.

Interface

@interface MyAppDelegate : NSObject 

@property (nonatomic, strong) UIWindow * alertWindow;

...

- (void)presentCustomAlert;

@end

Implementation:

@implementation MyAppDelegate

@synthesize alertWindow = _alertWindow;

...

- (void)presentCustomAlert
{
    if (self.alertWindow == nil)
    {
        CGRect screenBounds = [[UIScreen mainScreen] bounds];
        UIWindow * alertWindow = [[UIWindow alloc] initWithFrame:screenBounds];
        alertWindow.windowLevel = UIWindowLevelAlert;
    }

    SomeViewController * myAlert = [[SomeViewController alloc] init];
    alertWindow.rootViewController = myAlert;

    [alertWindow makeKeyAndVisible];
}

@end