public
Created

UIViewController+Alerts Category for presenting a view controller with a transparency above another view controller

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UIViewController+Alerts.h
Objective-C
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//
// UIViewController+Alerts.h
//
// Created by Dave Wood on 2012-01-17.
//
// Simplified BSD License
// Copyright (c) 2012, Cerebral Gardens
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are met:
//
// 1. Redistributions of source code must retain the above copyright notice, this
// list of conditions and the following disclaimer.
// 2. Redistributions in binary form must reproduce the above copyright notice,
// this list of conditions and the following disclaimer in the documentation
// and/or other materials provided with the distribution.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
// ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
// WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
// DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
// ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
// (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
// LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
// ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
// SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
//
// The views and conclusions contained in the software and documentation are those
// of the authors and should not be interpreted as representing official policies,
// either expressed or implied, of the FreeBSD Project.
//
 
#import <UIKit/UIKit.h>
 
@interface UIViewController (Alerts)
 
- (void)presentAlertViewController:(UIViewController *)alertViewController named:(NSString *)key animated:(BOOL)animated;
- (void)dismissAlertViewControllerNamed:(NSString *)key animated:(BOOL)animated;
 
@end
UIViewController+Alerts.m
Objective-C
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//
// UIViewController+Alerts.m
//
// Created by Dave Wood on 2012-01-17.
//
// Simplified BSD License
// Copyright (c) 2012, Cerebral Gardens
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are met:
//
// 1. Redistributions of source code must retain the above copyright notice, this
// list of conditions and the following disclaimer.
// 2. Redistributions in binary form must reproduce the above copyright notice,
// this list of conditions and the following disclaimer in the documentation
// and/or other materials provided with the distribution.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
// ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
// WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
// DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
// ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
// (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
// LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
// ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
// SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
//
// The views and conclusions contained in the software and documentation are those
// of the authors and should not be interpreted as representing official policies,
// either expressed or implied, of the FreeBSD Project.
//
 
#import "UIViewController+Alerts.h"
#import <objc/runtime.h>
 
static const char *alertViewControllersKey = "alertViewControllersKey";
 
@implementation UIViewController (Alerts)
 
- (void)presentAlertViewController:(UIViewController *)alertViewController named:(NSString *)key animated:(BOOL)animated
{
NSMutableDictionary *alertViewControllers = objc_getAssociatedObject(self, alertViewControllersKey);
if (!alertViewControllers)
{
alertViewControllers = [[NSMutableDictionary alloc] init];
objc_setAssociatedObject(self, alertViewControllersKey, alertViewControllers, OBJC_ASSOCIATION_RETAIN_NONATOMIC);
}
// Check for an existing object with the same key
UIViewController *oldViewController = [alertViewControllers objectForKey:key];
if (oldViewController)
{
[self dismissAlertViewControllerNamed:key animated:YES];
}
// store the alertViewController in our array
[alertViewControllers setObject:alertViewController forKey:key];
[self addChildViewController:alertViewController];
 
// Add new view to our view stack
CGFloat originalAlpha = alertViewController.view.alpha;
alertViewController.view.alpha = 0;
[self.view addSubview:alertViewController.view];
 
[UIView animateWithDuration:(animated ? 0.3 : 0.0) animations:^{
alertViewController.view.alpha = originalAlpha;
}];
}
 
- (void)dismissAlertViewControllerNamed:(NSString *)key animated:(BOOL)animated
{
NSMutableDictionary *alertViewControllers = objc_getAssociatedObject(self, alertViewControllersKey);
if (alertViewControllers)
{
UIViewController *alertViewController = [alertViewControllers objectForKey:key];
 
if (alertViewController)
{
// animate out of position
CGFloat originalAlpha = alertViewController.view.alpha;
[UIView animateWithDuration:(animated ? 0.3 : 0.0) animations:^{
alertViewController.view.alpha = 0;
} completion:^(BOOL finished) {
// remove the view controller from the list
[alertViewController.view removeFromSuperview];
alertViewController.view.alpha = originalAlpha;
[alertViewController removeFromParentViewController];
[alertViewControllers removeObjectForKey:key];
}];
}
}
}
 
@end

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