I have activity indicator in alert view that I use until my app gets the server response. The app send data to server and the alert view shows, how to close it when the server sends me the response. Here is code from my alert
UIAlertView *alert = [[UIAlertView alloc] initWithTitle:#"Canceling reservation" message:#"please wait" delegate:self cancelButtonTitle:nil otherButtonTitles: nil];
[alert show];
UIActivityIndicatorView *indicator = [[UIActivityIndicatorView alloc] initWithActivityIndicatorStyle:UIActivityIndicatorViewStyleWhiteLarge];
// Adjust the indicator to place at the bottom of the dialog window.
indicator.center = CGPointMake(alert.bounds.size.width / 2, alert.bounds.size.height-50);
[indicator startAnimating];
[alert addSubview:indicator];
[alert dismissWithClickedButtonIndex:0 animated:YES];
You can use MBProgressHUD instead of standart UIAlertView for something like that.
You can use the dismissWithClickedButtonIndex: delegate method for dismissing the alertView.
[alert dismissWithClickedButtonIndex:0 animated:YES];
Make sure that alert is declared on the #Interface.
dismissWithClickedButtonIndex:animated:
Dismisses the receiver, optionally with animation.
- (void)dismissWithClickedButtonIndex:(NSInteger)buttonIndex animated:(BOOL)animated Parameters
buttonIndex
The index of the button that was clicked just before invoking this method. The button indices start at 0.
animated
YES if the receiver should be removed by animating it first; otherwise, NO if it should be removed immediately with no animation.
Discussion
In iOS 4.0, you may want to call this method whenever your application
moves to the background. An alert view is not dismissed automatically
when an application moves to the background. This behavior differs
from previous versions of the operating system, where they were
canceled automatically when the application was terminated. Dismissing
the alert view gives your application a chance to save changes or
abort the operation and perform any necessary cleanup in case your
application is terminated later. Availability
Available in iOS 2.0 and later.
Declared In UIAlertView.h
Please refer UIAlertView
Related
I've got an alert:
UIAlertView *connectionError = [[UIAlertView alloc] initWithTitle:#"Error" message:#"Connection Failed" delegate:self cancelButtonTitle:#"OK" otherButtonTitles:nil, nil];
I want to know how I can programatically close an alert view when I hit a certain event in my code. I know there is no distinct call to just close out an alert, and I've seen people make calls straight to buttons, however, I'm not sure how to call the cancel button on an alert.
Is this even the right way to go about it? Or is there a better path?
You can use -dismissWithClickedButtonIndex:animated: method for dismissing alert view:
[connectionError dismissWithClickedButtonIndex: connectionError.cancelButtonIndex
animated: YES];
That's the only public API for dismissing alerts, so you should use it.
Declare you alert view in .h file
then call this function
[connectionError dismissWithClickedButtonIndex:0 animated:YES];
Hope it helps..
I need to run some database processing when my app first starts once a day.
I elected to do this in my first view and showed an alertview with an activity indicator. I tried using NSThread detachNewThreadSelector to run the db processing. At the end of the function I used dismissWithClickedButtonIndex to dismiss the alert view.
I then called the view controller from applicationWillEnterForeground if the date permitted.
However, I'm getting an error Tried to obtain the web lock from a thread other than the main thread or the web thread. Crashing now, on the dismissWithClickedButtonIndex line.
I believe this is occurring due to a flaw in using an object like an alertview with a thread.
I need this to be iOS 4 compatible.
Can anyone point me at an alternative approach ?
You won't be able to create and work directly with the UIAlertView in a background thread.
Here's a skeletal idea of what you could do:
UIAlertView *alertView = [[UIAlertView alloc] initWithTitle:#"Title" message:#"Message" delegate:self cancelButtonTitle:#"OK" otherButtonTitles:nil];
// create your progress indicator in your alert view
[alertView show];
dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
// do your db update
dispatch_async(dispatch_get_main_queue(), ^{
// update your alert view here.
});
});
The idea is to do your processing on a background queue and message back to the main queue for objects that are main-thread only (like UIAlertView.)
I display a UIAlertView above my cocos2d layer.
I release it after I how it.
Is it really gone? Do I have to somehow remove it from my UIView?
If you just do
UIAlertView* alert = [[UIAlertView alloc] initWithTitle...];
[alert show];
[alert release];
then there's no need to worry about it. However, if you set the alert's delegate to some object, make sure that object still exists when the user taps a button in the alert - otherwise your app will crash when the alert will try to call alertView:didDismissWithButtonIndex: delegate method.
I have a working application
before the first view is loaded, i put an alert in the viewWillAppear method:
- (void)viewWillAppear
{
UIAlertView *alert = [[UIAlertView alloc] initWithTitle:#"MyAppp" message:#"Application will connect to Internet. Continue?"
delegate:self cancelButtonTitle:nil otherButtonTitles:#"No, quit", #"Yes", nil];
[alert show];
[alert release];
}
I can get the clicks on the two button (Yes/No) correctly...
But...I would like code execution to stop and wait for an answer, but instead the code goes on, connects to the internet and retrieves data...
How do I prevent a view to load, based on a user input?
The viewWillAppear is a notification which allows you to complete some stuff before the view is shown, you can't avoid the appearing of the view here. You have to review your implementation.
Just break your one viewWillAppear method into two methods. Don't try to do it all in one chunk of sequential code.
The first method will launch the alert and then just exit/quit/return.
The second method can be called by the alert button response handler, and then finish loading the view only after it's been called by the alert handler, after the user has responded.
You may or may not have to save extra state information (in extra properties or instance variables instead of method locals) between the first and second methods.
the below can be used, i know its little old question but might be useful for others
..
[alert show];
while ((!alert.hidden) && (alert.superview != nil))
{
[[NSRunLoop currentRunLoop] limitDateForMode:NSDefaultRunLoopMode];
}
I solved it by showing the answer in the "ViewDidLoad", got a delegate to get which button was pressed and then processing the data ONLY if the user pressed "Yes"
I write a piece of code to "do something->show alert1->do something->show alert2".
//do something
UIAlertView *alert = [[UIAlertView alloc]
initWithTitle:#"Alert 1"
message:nil
delegate:nil
cancelButtonTitle:#"OK"
otherButtonTitles:nil];
[alert show];
[alert release];
//do something
UIAlertView *alert2 = [[UIAlertView alloc]
initWithTitle:#"Alert 2"
message:nil
delegate:nil
cancelButtonTitle:#"OK"
otherButtonTitles:nil];
[alert2 show];
[alert2 release];
And suddenly a strange thing happened to multiple AlertViews: It shows "Alert 1"->"Alert 2"(Press 'OK')->"Alert 1". Why "Alert 1" shows again? I haven't written any delegate method yet. Maybe a bug?(Thanks to cobbal, alert1 is still there when alert2 appears.)
I find -(void)alertView:(UIAlertView *)alertView clickedButtonAtIndex:(NSInteger)buttonIndex works well. Is the delegate method a common way to show multiple alertViews?
I would guess that alert 1 is shown and then covered by alert 2 since show isn't modal. When alert 2 is closed, alert 1 is still open.
To your second question, alertView:didDismissWithButtonIndex: may work better, but I haven't actually tested that.
The delegate is so that you can be notified when the alert is dismissed, and which button was used to dismiss it. It doesn't impact whether the alert is dismissed at all.
The alert will remain visible until it is dismissed either by you tapping a button (if any - they are not required) or you call either [UIAlertView dismissWithClickedButtonIndex:animated] or the (undocumented) dismiss method of the alert instance.
It looks like (as Cobbal suggested), alert 2 is popping up over alert 1, you dismiss alert 2, and alert 1 remains there (until it itself is dismissed).
Is there a particular reason you want to show a new alert while another is still showing? Perhaps some more context would help us to get to the root of the issue, which I suspect may be a design issue.
[edit] coming back to this and reading again, I wonder if what you are asking about with the delegate method is whether you should be showing alert 2 from there? In which case that's probably what you want - whether directly or indirectly. By indirectly I mean that you may have some state set elsewhere that determines whether alert 2 should be shown (or the circumstances that lead to it). That state (a flag, perhaps) could be set when you show the first alert, and cleared when the alert is dismissed (from the delegate method).
The reason this happens is because UIAlertView doesn't block while it's showing. Any code written after showing an alertview will run straight after the alert is shown.
What you should have is two different methods. One that does something and then shows an alert, and then another that does something and shows another alert.
Kick off the first method to do something and show an alert, and then hook into the alert's delegate method, and when you get the callback from the alertview, run the other method.
This way, the second part of the process won't happen until the user has pressed OK on the alert in first part of the process.