UIApplication keyWindow example ios

[UIApplication keyWindow]

The application's key window. (read-only)

@property(nonatomic, readonly) UIWindow *keyWindow

Discussion of [UIApplication keyWindow]

This property holds the UIWindow object in the windows array that is most recently sent the makeKeyAndVisible message.

Example of [UIApplication keyWindow]

id rootVC = [[[[[UIApplication sharedApplication] keyWindow] subviews] objectAtIndex:0] nextResponder];

Example of [UIApplication keyWindow]

UIWindow* window = [UIApplication sharedApplication].keyWindow;
if (!window) 
    window = [[UIApplication sharedApplication].windows objectAtIndex:0];
[[[window subviews] objectAtIndex:0] addSubview:myView];    

Example of [UIApplication keyWindow]

#import "UIApplication+WindowOverlay.h"

@implementation UIApplication(WindowOverlay)

    -(UIView *)baseWindowView{
        if (self.keyWindow.subviews.count > 0){
            return [self.keyWindow.subviews objectAtIndex:0];
        }
        return nil;
    }

    -(void)addWindowOverlay:(UIView *)view{
        [self.baseWindowView addSubview:view];
    }
@end