I'm looking for a way, to automatically dismiss an alert view after some time or after a task is done.
Is there a possibility? (or another way to show a message for some time?)
You can call the -dismissWithClickedButtonIndex:animated: method to dismiss the alert view.
To dismiss it automatically, create an NSInvocation and then use -performSelector:withObject:afterDelay: to -invoke it.
UIAlertView has a method called:
- ( void )dismissWithClickedButtonIndex: ( NSInteger )buttonIndex animated:( BOOL )animated
You can call it on your UIAlertView object to simulate a button press.
To dismiss it automatically after some time, you will need something like an NSTimer, to check if the alert view is still displayed, and in such a case, dismiss it.
Related
In my interface file I said I conform to the UIAlertViewProtocol and I implemented the alertView:clickedButtonAtIndex: method in my implementation file, and normally whenever the alertview button is pressed (the button that makes the alert go away)that method gets called. Well, it gets called most of the time, but for one of my alert views it doesn't get called after I press the cancel button on it, what would be a reason for this?
Oh Its because in one of my alert views for the delegate parameter i passed in nil instead of self, thats embarassing.
I want Button action done automatically when a view load. Is it possible?
The other answers are correct in that setting the action that your button is tied to, then in your viewDidLoad:, call that function will work. I will just chime in with another method for others info.
You can send it a control event telling it that the button should act as if it has been pressed:
[button sendActionsForControlEvents:UIControlEventTouchUpInside];
This is useful when you do not have an outlet to the button. For instance, I created an app where the user can press on a web view and launch a youtube video. It was also required that if the user presses a "video" button, then the same youtube video would launch. Basically, I had to fire a press event on the web view. So i searched through its views and found the button, from there I called the above line, and the webview pushes a video view controller for the youtube video.
Certainly Yes. Call your method as
assuming your method declaration as
-(IBAction)yourButtonTapEvent:(id)sender;
[self yourButtonTapEvent:nil];
Yes, in your viewDidAppear method, just call the action you are providing for that specific button.
- (void)viewDidAppear:(BOOL)animated
{
[self yourButtonAction:nil];
[super viewDidAppear:animated];
}
In my timer application,
My timer runs on oneViewController.
When I switch to another view without any efforts it runs in background of another view
as I press the back button I can see the results..
But,
I want to put an alert message on second view controllerwhen my time is Up.....
How could I do this...
**Should I use
-Delegate
-Notification
-Local Notifications**
Or else.....Thanks
EDIT: Answer:
Answer is in first comment...**
You can make your timer call a method on your view controller. Inside that method, you can check whether time is up. If so, create an UIAlertView instance and -show; it as it will be shown/seen from any view controller.
I have a UIAlert that pops up 3 times every time it is called. It appears and then disappears before I can click on it. Could it be that the viewDidLoad itself is being called 3 times?
I implemented an UIAlert in the viewDidLoad of my app:
UIAlertView *alert = [[UIAlertView alloc] initWithTitle:title message:alertMessage delegate:self cancelButtonTitle:ok otherButtonTitles:nil];
This is the viewDidLoad in the rootViewController, that manages the views:
- (void)viewDidLoad {
Kundenkarte *kartenAnsicht = [[Kundenkarte alloc]
initWithNibName:#"Kundenkarte" bundle:nil];
kartenAnsicht.rootViewController = self;
kartenAnsicht.viewDidLoad;
self.map = kartenAnsicht;
[self.view addSubview:kartenAnsicht.view];
[kartenAnsicht release];
// [super viewDidLoad];
}
The viewDidLoad that evokes the UIAlert is in the kartenAnsicht view controller.
I hope someone can help me because I'm out of ideas.
You don't need to call -viewDidLoad yourself, it's run automatically by the NIB-loading mechanism. That means you get extra invocations of -viewDidLoad: one by design, and extras whenever you call it.
First of all, you should never put any type of display in viewDidLoad. That method is intended for behind the scenes configuration after the view is first read from nib. There is no certainty that it will be called every time the view displays because after the first time it loads, the view maybe held in memory and not reloaded from nib.
Instead, put the call to evoke the NSAlert in viewWillDisplay or viewDidDisplay. This will display the alert each time the view appears.
I doubt that viewDidLoad is called three times but to check for that just put an NSLog in the method to see how many times it is called.
When you say that:
i implemented an NSAlert in the
viewDidLoad() of my app:
... what does that mean? What object exactly has the method? If it is the application delegate, this will not work because the application delegate protocol does not respond to viewDidLoad. It has to be in a UIViewController.
Edit01:
See this post that had the same problem: UIAlertView Pops Up Three Times per Call Instead of Just Once
Short answer: You kill the alert by releasing it. Either retain it as a property of the view controller or better yet, display the alert with runModal instead of show and capture the button number returned immediately.
It would be helpful to see the code around the alert call.
I am using an alert whenever the reachability changes. Since reachability is checked repeatedly, the alert could get called repeatedly. To alleviate that, I wrap the alert code like so:
if (!myAlert) { /* set up and show myAlert */ }
However, one problem with this is that when you click the Cancel button, the alert will remain non-nil, and therefore can never show again because of that conditional. If someone could add to this response with a fix for that, that would be great. I assume I can add a handler for the cancel button that will destroy myAlert.
The UIAlertViewDelegate protocol defines two methods, alertView:clickedButtonAtIndex: and alertView:didDismissWithButtonIndex:, which seem to me to be identical in usefulness.
Why is there a clickedButtonAtIndex and a didDismissButtonWithIndex when they both do the same thing? I realize there is also a willDismissButtonWithIndex that happens before the alert view is dismissed, but is there any reason to use clickedButtonAtIndex instead of didDismissButtonWithIndex?
I found a more useful difference between the two:
When showing a UIAlertView, and the device goes to sleep, alertView:didDismissWithButtonAtIndex: gets called, even though the alert view is not actually dismissed. It is shown again once the device wakes up. alertView:clickedButtonAtIndex: is only called when the user clicks one of the buttons.
The alertView:clickedButtonAtIndex: is called when the user clicks a button on an alert view whereas the alertView:didDismissWithButtonIndex: is called after an alert view is dismissed from the screen. (See the UIAlertViewDelegate Protocol Reference.)
The difference is minimal but it allows you to do something before or after animation.
If the alert view disappears for any reason (including being covered by another UIAlertView, going to sleep, etc.), didDismissWithButtonAtIndex: is called. This can mean that the method can be called even without the user clicking on anything. This can lead to unexpected behaviour if you depend on this delegate callback to be called in response to the user actually clicking on a button. In this case clickedButtonAtIndex: is more useful.
I couldn't reproduce Ed's behaviour by locking my device with the alert view present on iOS 7.
However, the most important difference between alertView:clickedButtonAtIndex:, alertView:didDismissWithButtonIndex: and alertView:willDismissWithButtonIndex: is that the first method (clickedButtonAtIndex:) is only called when the user explicitly taps on a button on your alert view (hence 'clicked').
Is it possible that an alert view is dismissed without clicking on a button? Yes, you could programmatically hide an alert view using the UIAlertView method dismissWithClickedButtonIndex:animated:.
So, if you need some behavior to be always triggered upon the dismissal of the alert view—whether it was triggered by the user tapping on a button or triggered programmatically—then using the didDismissWithButtonIndex: and willDismissWithButtonIndex: makes more sense.