UIAlertController+Window.m

//
//  UIAlertController+Window.m
//  FFM
//
//  Created by Eric Larson on 6/17/15.
//  Copyright (c) 2015 ForeFlight, LLC. All rights reserved.
//

#import "UIAlertController+Window.h"
#import <objc/runtime.h>

@interface UIAlertController (Private)

@property (nonatomic, strong) UIWindow *alertWindow;

@end

@implementation UIAlertController (Private)

@dynamic alertWindow;

- (void)setAlertWindow:(UIWindow *)alertWindow {
  objc_setAssociatedObject(self, @selector(alertWindow), alertWindow, OBJC_ASSOCIATION_RETAIN_NONATOMIC);
}

- (UIWindow *)alertWindow {
  return objc_getAssociatedObject(self, @selector(alertWindow));
}

@end

@implementation UIAlertController (Window)

- (void)show {
  [self show:YES];
}

- (void)show:(BOOL)animated {
  self.alertWindow = [[UIWindow alloc] initWithFrame:[UIScreen mainScreen].bounds];
  self.alertWindow.rootViewController = [[UIViewController alloc] init];
  self.alertWindow.windowLevel = UIWindowLevelAlert + 1;
  [self.alertWindow makeKeyAndVisible];
  [self.alertWindow.rootViewController presentViewController:self animated:animated completion:nil];
}

- (void)viewDidDisappear:(BOOL)animated {
  [super viewDidDisappear:animated];

  // precaution to insure window gets destroyed
  self.alertWindow.hidden = YES;
  self.alertWindow = nil;
}

@end