I am getting this warning sometimes " wait_fences: failed to receive reply: 10004003 ", do not know why this is coming,
I do not have viewdidiappear method in my code, i have a UIAlert in my view, the code is
UIAlertView *alert = [[UIAlertView alloc] initWithTitle:#"Start" message:[NSString stringWithFormat:#"Hi %#,",[user objectAtIndex:0] ] delegate:self cancelButtonTitle:#"OK" otherButtonTitles: nil];
[alert show];
[alert release];
this is due to UI actions on a view controller on which you are not currently,i.e. the screen of which you are accessing UI, not visible currently.
if you read my answer in the comment you would understand, but what you need to do is add the above code in the -viewDidAppear method and make sure you add [super viewDidAppear:YES]; and if you want to keep it in your init method you'll have to add a delay like so
[self performSelector:#selector(next) withObject:nil afterDelay:0.5];
Related
I've implemented the Reachability function in a method that handles all the server requests. I can see through NSLogs that the function works perfectly. However there is never a "pause" within the method which means I can't use the UIAlertView without crashing the program.
I might be going at this the completely wrong way, but I can't find anything else...
Does anybody have an idea of how to get a notification to show somehow?
Thanks in advance
CODE:
-(id) getJson:(NSString *)stringurl{
Reachability * reach = [Reachability reachabilityWithHostname:#"www.google.com"];
NSLog(#"reached %d", reach.isReachable);
if (reach.isReachable == NO) {
UIAlertView *alert = [[UIAlertView alloc] initWithTitle:#"Passwords don't match."
message:#"The passwords did not match. Please try again."
delegate:nil
cancelButtonTitle:#"OK"
otherButtonTitles:nil];
[alert show];
}else{
id x =[self getJsonFromHttp:stringurl];
return x;
}
return nil;
}
After moving the discussion to a chat, we discovered that your UIAlertView was being called from a background thread. Never do anything related to updating the UI (User-Interface) in a background thread. The UIAlertView updates the UI by adding a little pop-up dialog, so it should be done on the main thread. Fix by making these changes:
// (1) Create a new method in your .m/.h and move your UIAlertView code to it
-(void)showMyAlert{
UIAlertView *alert = [[UIAlertView alloc] initWithTitle:#"Passwords don't match."
message:#"The passwords did not match. Please try again."
delegate:nil
cancelButtonTitle:#"OK"
otherButtonTitles:nil];
[alert show];
}
// (2) In -(id)getJson replace your original UI-related code with a call to your new method
[self performSelectorOnMainThread:#selector(showMyAlert)
withObject:nil
waitUntilDone:YES];
I need help on dismissing a UIAlertView programmatically. Currently I have this
UIAlertView *alert1 = [[UIAlertView alloc]initWithTitle:#"title" message:#"message" delegate:nil cancelButtonTitle:nil otherButtonTitles:nil];
then later on I call this
[alert1 dismissWithClickedButtonIndex:0 animated:NO];
but nothing happens.
You need to set two things.
1. include your .h file : <UIAlertViewDelegate>
2. please follow below implementation...
UIAlertView *alert1 = [[UIAlertView alloc]initWithTitle:#"title" message:#"message" delegate:nil cancelButtonTitle:nil otherButtonTitles:nil];
[alert1 show];
[self performSelector:#selector(dismiss:) withObject:alert1 afterDelay:1.0];
the dismiss method will be...
-(void)dismiss:(UIAlertView*)alert
{
[alert dismissWithClickedButtonIndex:0 animated:YES];
}
I hope this will help you.
I encountered this problem too.
In my case, for some reason calling:
[alert dismissWithClickedButtonIndex:0 animated:NO];
didn't work always (yes, even calling it on UI thread and yes, alert != nil), instead simply setting the animated flag to YES it worked:
[alert dismissWithClickedButtonIndex:0 animated:YES];
Maybe it's an Apple bug...
you should display it first:
UIAlertView *alert1 = [[UIAlertView alloc]initWithTitle:#"title" message:#"message" delegate:self cancelButtonTitle:#"Cancel" otherButtonTitles:nil];
[alert1 show];
then in delegate method
- (void)alertView:(UIAlertView *)alertView willDismissWithButtonIndex:(NSInteger)buttonIndex{
if(buttonIndex==0){
// do something
}
}
The methods you called is correct.
I guess the alert1 is nil when your call the method dismissWithClickedButtonIndex:animated:
Try to check your variable alert1.
You can use the delegate method -alertView:didDismissWithButtonIndex: instead—it gets called once the alert view’s been removed from the screen, OR better approach is , use a background thread, e.g. with -performSelectorInBackground:withObject:, to handle whatever processing you need to do.
in my Alert View, there is two button, OK and Cancel. When the user click the OK button, the delegate method dismissWithClickedButtonIndex:animated get called, and if the index is 0, then i get called to a method to execute some code:
UIAlertView *alert = [[UIAlertView alloc] initWithTitle:#"Alert"
message:#"Are you sure you want to exit"
delegate:self cancelButtonTitle: #"OK"
otherButtonTitles: #"Cancel",nil];
[alert show];
[alert release];//release the reference
Delegate method:
- (void)alertView:(UIAlertView *)alertView didDismissWithButtonIndex:(NSInteger)buttonIndex{
if (buttonIndex==0) {
[self aMethod];
}
}
-(void)aMethod{
//Some useful code
}
Now, what i want to instead of all this, is to execute the code of the aMethod method in the AlertView directly, without referring to A delegate method and a method which get called, something like that:
UIAlertView *alert = [[UIAlertView alloc] initWithTitle:#"Alert"
message:#"Are you sure you want to exit"
delegate:self cancelButtonTitle: #"OK" //Put here some useful code
otherButtonTitles: #"Cancel",nil];
Is it possible?
Unfortunately this is not possible at this time (iOS 5.1). The AlertView class does not support blocks.
I made a pair of UIAlertView and UIActionSheet subclasses that do exactly that. Grab them here:
https://github.com/rydermackay/RMActionSheet
Use them like this:
RMAlertView *alertView = [RMAlertView alertViewWithTitle:#"Alert!" message:nil];
[alertView addButtonWithTitle:#"OK"
action:^{
NSLog(#"OK");
}];
[alertView addCancelButtonWithTitle:#"Cancel"
action:nil];
[alertView show];
EDIT:
From your comments it sounds like you're not familiar with blocks. Read this now. Seriously.
http://developer.apple.com/library/ios/#documentation/cocoa/Conceptual/Blocks/Articles/00_Introduction.html
This is a good one too:
http://www.mikeash.com/pyblog/friday-qa-2009-08-14-practical-blocks.html
I use the following code to handle failed requests.
- (void)requestFailed:(ASIHTTPRequest *)request {
[self.alertView dismissWithClickedButtonIndex:0 animated:YES];
UIAlertView *alert = [[UIAlertView alloc] initWithTitle:#"Request failed." message:requestFailMessage delegate:self cancelButtonTitle:#"OK" otherButtonTitles:nil];
[alert show];
[self.navigationController popViewControllerAnimated:YES];
}
To simulate, I turn on "Airplane Mode." I try the request, and it fails. After I press the "OK" button, I am greeted with this error:
2012-03-28 02:23:56.048 Obfuscated[40835:207] Finishing up a navigation transition in an unexpected state. Navigation Bar subview tree might get corrupted.
Basically, I just want the navigationController to go back to the previous view controller when the request fails. However, this does not seem to work.
What can I do to fix this?
I think you use popViewControllerAnimated twice once below the alert code and once in you delegate for alert method.
Sice your navigation stack not having view to pop so it gives you this problem.
Do like this
- (void)requestFailed:(ASIHTTPRequest *)request {
UIAlertView *alert = [[UIAlertView alloc] initWithTitle:#"Request failed." message:requestFailMessage delegate:self cancelButtonTitle:#"OK" otherButtonTitles:nil];
[alert show];
}
- (void)alertView:(UIAlertView *)alertView clickedButtonAtIndex:(NSInteger)buttonIndex{
[self.navigationController popViewControllerAnimated:YES];
}
I load data from a webservice in a background thread. Is it safe to show an UIAlertView in the background thread when anything goes wrong or should I show the alert view in the mainthread ?
thanks for the advice
Frank
Never do anything with the GUI except from the main thread. It can cause very weird issues and or crashes you don't want to deal with. Usually the backtraces are also very unhelpful so try to avoid such issues by default.
Therefore use this:
[self performSelectorOnMainThread:#selector(showAlert:) withObject:alertString waitUntilDone:NO];
If you are using grand Central dispatch you could do something like:
dispatch_async(dispatch_get_main_queue(), ^{ /* show alert view */ });
Update:
Swift (3.0+):
DispatchQueue.main.async { // code }
It is sometimes helpful to do this with Notifications you receive as well, I have had instances where they were fired from a different thread.
Update 2:
It looks like apple has added some new tools coming in iOS11/Xcode9 to help debug issues where stuff is called on the incorrect thread.
dispatch_async(dispatch_get_main_queue(), ^{
UIAlertView *alert = [[UIAlertView alloc] initWithTitle:#"Title" message:#"Message" delegate:self cancelButtonTitle:#"OK" otherButtonTitles:nil];
[alert show];
});
this code works for me
You could try showing the alert on the main thread by:
UIAlertView *alert = [
[[UIAlertView alloc] initWithTitle:#"the title"
message:#"the message"
delegate:self
cancelButtonTitle:#"OK"
otherButtonTitles: nil] autorelease];
[alert performSelector:#selector(show)
onThread:[NSThread mainThread]
withObject:nil
waitUntilDone:NO];
[alert release];