How to dismiss UIAlertView when home button is pressed? - ios

Question

I am making an app that should support iOS versions from iOS5 onwards. It uses a UIAlertView, and if it's visible when the user presses the home button, I would like it to be dismissed before the user returns to the app (i.e. it's gone when the app is re-opened using multitasking). All methods in the app delegate show it as not visible (isVisible=NO) even if it is still visible when reopened. Is there a way to do this?
Thanks.

Answer 1

Or you inherit your class from UIAlertView and add NSNotification observer for UIApplicationWillResignActiveNotification and when notification occurs call to alertview method dismissWithClickedButtonIndex:
Example:
.h file
#import <UIKit/UIKit.h>
#interface ADAlertView : UIAlertView
#end
.m file
#import "ADAlertView.h"
#implementation ADAlertView
- (void) dealloc {
[[NSNotificationCenter defaultCenter] removeObserver:self];
}
- (id) initWithTitle:(NSString *)title
message:(NSString *)message
delegate:(id)delegate
cancelButtonTitle:(NSString *)cancelButtonTitle
otherButtonTitles:(NSString *)otherButtonTitles, ... {
self = [super initWithTitle:title
message:message
delegate:delegate
cancelButtonTitle:cancelButtonTitle
otherButtonTitles:otherButtonTitles, nil];
if (self) {
[[NSNotificationCenter defaultCenter] addObserver:self
selector:#selector(dismiss:)
name:UIApplicationDidEnterBackgroundNotification
object:nil];
}
return self;
}
- (void) dismiss:(NSNotification *)notication {
[self dismissWithClickedButtonIndex:[self cancelButtonIndex] animated:YES];
}
#end
With your own class inherited from UIAlertView you are need not to store link to alertview or something else, only one thing that you must do its replace UIAlertView to ADAlertView (or any other class name).
Feel free to use this code example (if you are not using ARC, you should add to the dealloc method [super dealloc] after [[NSNotificatioCenter defaultCenter] removeObserver:self])

Answer 2

Keep a reference to the displayed UIAlertView in your app delegate. When you show the alert, set the reference; when the alert is dismissed, nil out the reference.
In your app delegate's applicationWillResignActive: or applicationDidEnterBackground: method, call the dismissWithClickedButtonIndex:animated: method on the reference to the alert view. This would take care of dismissing it on pressing the "home" button.
Keep in mind that applicationWillResignActive: will be called for things such as phone calls, so you need to decide if you'd like to dismiss the alert in cases like that or if you should keep it up through the phone call.