performSegueWithIdentifier crashes randomly - ios

I have never had this problem before or heard of it happening. I am using a Master-Detail Application (splitview) for the ipad. I have a dynamic tableview for my MVC and am trying to transition each cell to a custom view controller.
Currently I only have two items in my table. When the program boots I can select either of them and it will transition to the correct view controller without any problems. But most of the time when I click on something a second time the program crashes. Sometimes it takes four or five clicks but it always eventually crashes.
Here is the code snippet:
- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
{
NSString *segueName = [self.tableObjects objectAtIndex:indexPath.row];
[self performSegueWithIdentifier:segueName sender:self];
}
tableObjects is an NSArray that I use to create the table items. If I throw a print statement in before the segue call it does print the correct segue name.
The error is always being thrown on the actual performSegueWithIdentifier call. I checked it with the debugger. The exception I keep getting is: EXC_BAD_ACCESS.
Again both of the segues work initially so I do not think it is a problem with this. Does this method sometimes get called randomly? Is there a way to double check that the method call is safe? Do I need to override performSegueWithIdentifier and do something there?
I attempted to put it into a try catch:
#try {
[self performSegueWithIdentifier:segueName sender:self];
}
#catch (NSException *exception) {
NSLog(#"%#", exception);
}
#finally {
NSLog(#"finally");
}
and it still pointed to the method call inside of the #try. It does not seem to be throwing the error like an exception?

FYI, I was running into this exact same issue, and I found the answer on another SO thread: iOS - UISplitViewController with storyboard - multiple master views and multiple detail views
Basically, the uisplitviewcontroller delegate needed to be set again when making the segue. Hope this helps someone in the future.

Related

How can to come back to my view when I confirm form?

I’m I downloaded MZFormSheetController library for my app.
I’ve got a problem on my popup. When I am on my TableViewController, I tap on a row to get popup to open up so that I can change the name. The popup opens, I set the name and when I tap on the button to correct the name, I call the button method but i can’t close my popup while reload my list.
- (IBAction)modifierTournoi:(id)sender {
//code to update database
//this method close the popup but don't call method viewWillAppear to reload database
//I don't know what method i can use..?
[self dismissFormSheetControllerAnimated:YES completionHandler:^(MZFormSheetController *formSheetController) {
}];
}
Before that, I used the method popViewControllerAnimated to come back to my list while recharging my list.
- (IBAction)modifierJoueur:(id)sender {
//code to update database
[self.navigationController popViewControllerAnimated:true];
}
Can you help me please ?
Thank you very much.
It looks like there is a specific completion handler for this purpose built into the library you are using:
- (IBAction)modifierTournoi:(id)sender {
//code to update database
//this method close the popup but don't call method viewWillAppear to reload database
//I don't know what method i can use..?
[self dismissFormSheetControllerAnimated:YES completionHandler:^(MZFormSheetController *formSheetController) {
// Reloading your database should work in here.
}];
}
The reason viewWillAppear will not be being called is because rather than placing a viewController modally above your window, I imagine MZFormSheetController will be adding a UIView above all presented UIViews, so viewWillAppear will never be called. But as I said above, you should be able to reload in the completion handler block.

[CustomViewController respondsToSelector:]: message sent to deallocated instance

This is used to work fine for my pre-ARC code, but since refactoring all the project to be ARC compatible, I start getting this crash:
[CustomViewController respondsToSelector:]: message sent to deallocated instance
My project is an iPad app with a split view, but contrary to apple documentation, previous developer has put another view controller to be visible on app launch before split view. So I know this is not the right way to do, but as I said it used to work before ARC integration so I need to get a workaround with this.
The root view controller which contain a menu of items, each item display a detail form to be filled, then a click on next button move to the next detail screen, etc.
The issue starts when I click on home button put on root view to get back to the home view, here is the relevant code that move the user to the home screen:
//this method is in the appdelegate, and it gets called when clikc on home button located on the root view
- (void) showHome
{
homeController.delegate = self;
self.window.rootViewController = homeController;
[self.window makeKeyAndVisible];
}
Then when I click on a button to get back to the split view (where are the root/details view), the app crashes with the above description. I profiled the app with instruments and the line of code responsible of that is located in the RootViewController, in the didSelectRowAtIndexPath method, here is the relevant code:
if(indexPath.row == MenuCustomViewController){
self.customVC=[[CustomViewController alloc] initWithNibName:#"CustomVC"
bundle:nil];
[viewControllerArray addObject:self.customVC];
self.appDelegate.splitViewController.delegate = self.customVC;
}
customVC is a strong property, I tried to allocate directly and assign to the instance variable but that didn't help to fix the crash. Any thoughts ?
EDIT:
Here is the stack trace given by instruments:
[self.appDelegate.splitViewController setViewControllers:viewControllerArray];//this line caused the crash
[viewControllerArray addObject:self.appDescVC];//this statement is called before the above one
self.custinfoVC=[[CustInfoViewController alloc] initWithNibName:#"CustInfo" bundle:nil];//this statement is called before the above one
self.appDelegate.splitViewController.delegate = self.appDescVC;//this statement is called before the above one
custinfoVC and appDescVC are strong properties.
I solved this problem by setting my delegates and datasources to nil in the dealloc method. Not sure if it'll help you but its worth a try.
- (void)dealloc
{
homeController.delegate = nil;
//if you have any table views these would also need to be set to nil
self.tableView.delegate = nil;
self.tableView.dataSource = nil;
}
You may want to setup the CustomViewController during app launch, and display the other views modally on top if necessary. The error message you're getting is because something is getting released by ARC prematurely. It might have not manifested before because pre-arc stuff wasn't always deallocated immediately. ARC is pretty serious about releasing stuff when it leaves scope
Hard to tell without seeing a lot more of the code involved, and what line it breaks on, etc.
This:
- (void) showHome {
//THIS: where is homeController allocated?
homeController.delegate = self;
self.window.rootViewController = homeController;
[self.window makeKeyAndVisible];
}
EDIT:
Add this line right above the line that causes your crash
for (id object in viewControllerArray) {
NSLog(#"Object: %#",object);
}
I had the same Problem.If you are not using "dealloc" method then use "viewWillDisappear" to set nil.
It was difficult to find which delegate cause issue, because it does not indicate any line or code statement for my App So I have try some way to identify delegate, Maybe it becomes helpful to you.
1.Open xib file and from file's owner, Select "show the connections inspector" right hand side menu. Delegates are listed, set them to nil which are suspected.
(Same as my case)Property Object like Textfield can create issue, So set its delegate to nil.
-(void) viewWillDisappear:(BOOL) animated{
[super viewWillDisappear:animated];
if ([self isMovingFromParentViewController]){
self.countryTextField.delegate = nil;
self.stateTextField.delegate = nil;
}
}

Get images from internet CollectionView

This is my first question so excuse me for being a newbie.
I am working with a CollectionView that shows images downloaded from the internet. The problem appears when I try to do it asynchronously.
#interface myViewController
{
NSArray *ArrayOfSections
}
#end
-(void)viewDidLoad{
[self performSelectorInBackground:#selector(refreshImages) withObject:nil];
}
-(void)refreshImages{
... //Get information from the net
NSArray internetInfo = ...;
[self performSelectorOnMainThread:#selector(refreshCollectionView:) withObject:internetInfo waitUntilDone:NO];
}
-(void)refreshCollectionView:(NSArray tempArray){
ArrayOfSections = tempArray;
}
This code is not working. It shows an empty CollectionView, although I have double checked that the information stored on ArrayOfSections is correct.
Moreover, if I do it synchronously (I change only viewDidLoad).
-(void)viewDidLoad{
[self refreshImage];
}
Everything works fine. I am going bananas. Please help
I think it's because you're not telling the collection view to reload. Your refresh method updates the model but not the view.
If you're fetching the data on a background thread, the main thread can continue it's lifecycle, which involves querying the collection view datasource and delegate methods then updating the view, but it will be doing this too soon in your case, as the model isn't ready. That's why you need to tell it to do that again, when the model is ready, at the end of your data fetch. Since you block the thread when doing it synchronously, it won't reach the collection view methods until the model is ready, which is why it works that way.

UIActivity activityViewController not dismissing on iPad

I have a UIActivity subclass that creates its own activityViewController:
- (UIViewController *)activityViewController {
WSLInProgressViewController* progressView = [[[WSLInProgressViewController alloc] init] autorelease];
progressView.message = [NSString stringWithFormat:NSLocalizedString(#"Posting to %#...",#"Posting to..."),
self.activityType];
return progressView;
}
I've add a full repro on GitHub.
According to the documentation, you aren't supposed to dismiss this manually. Instead, the OS does that when you call activityDidFinish:. This works fine when ran on an iPhone.
When I say "works," this is the sequence of events that I'm expecting (and see on the iPhone):
Display the UIActivityViewController
User presses my custom activity
My view controller appears
I call activityDidFinish:
My custom view controller is dismissed
The UIActivityViewController is also dismissed
However, when I run this same code on the iPad Simulator -- the only difference being that I put the UIActivityViewController in a popup, as the documentation says you should -- the activityViewController never dismisses.
As I say, this is code wo/the popUP works on the iPhone and I have stepped through the code so I know that activityDidFinish: is getting called.
I found this Radar talking about the same problem in iOS6 beta 3, but it seems such fundamental functionality that I suspect a bug in my code rather than OS (also note that it works correctly with the Twitter and Facebook functionality!).
Am I missing something? Do I need to do something special in the activityViewController when it's run in a UIPopoverViewController? Is the "flow" supposed to be different on the iPad?
The automatic dismissal only appears to happen when your 'activity' controller is directly presented, not wrapped in anything. So just before showing the popup it's wrapped in, add a completion handler
activity.completionHandler = ^(NSString *activityType, BOOL completed){
[self.popup dismissPopoverAnimated:YES];
};
and you'll be good.
I see the question is quite old, but we've been debugging the same view-controller-not-dismissing issue here and I hope my answer will provide some additional details and a better solution than calling up -dismissPopoverAnimated: manually.
The documentation on the UIActivity is quite sparse and while it hints on the way an implementation should be structured, the question shows it's not so obvious as it could be.
The first thing you should notice is the documentation states you should not be dismissing the view controller manually in anyway. This actually holds true.
What the documentation doesn't say, and what comes as an observable thing when you come across debugging the non-dissmissing-view-controller issue, is iOS will call your -activityViewController method when it needs a reference to the subject view controller. As it turns out, probably only on iPad, iOS doesn't actually store the returned view controller instance anywhere in it's structures and then, when it wants to dismiss the view controller, it merely asks your -activityViewController for the object and then dismisses it. The view controller instantiated in the first call to the method (when it was shown) is thus never dismissed. Ouch. This is the cause of the issue.
How do we properly fix this?
Skimming the UIActivity docs further one may stumble accross the -prepareWithActivityItems: method. The particular hint lies along the following text:
If the implementation of your service requires displaying additional UI to the user, you can use this method to prepare your view controller object and make it available from the activityViewController method.
So, the idea is to instantiate your view controller in the -prepareWithActivityItems: method and tackle it into an instance variable. Then merely return the same instance from your -activityViewController method.
Given this, the view controller will be properly hidden after you call the -activityDidFinish: method w/o any further manual intervention.
Bingo.
NB! Digging this a bit further, the -prepareWithActivityItems: should not instantiate a new view controller each time it's called. If you have previously created one, you should merely re-use it. In our case it happily crashed if we didn't.
I hope this helps someone. :)
I had the same problem. It solved for me saving activityViewController as member and return stored controller. Activity return new object and dismiss invoked on new one.
- (UIViewController *)activityViewController {
if (!self.detaisController) {
// create detailsController
}
return self.detailsController;
}
I pass through the UIActivity to another view then call the following...
[myActivity activityDidFinish:YES];
This works on my device as well as in the simulator. Make sure you're not overriding the activityDidFinish method in your UIActivity .m file as I was doing previously. You can see the code i'm using here.
a workaround is to ask the calling ViewController to perform segue to your destination ViewController via - (void)performActivity although Apple does not recommend to do so.
For example:
- (void)performActivity
{
if (UI_USER_INTERFACE_IDIOM() == UIUserInterfaceIdiomPad)
{
[self.delegate performSomething]; // (delegate is the calling VC)
[self activityDidFinish: YES];
}
}
- (UIViewController *)activityViewController
{
if (UI_USER_INTERFACE_IDIOM() == UIUserInterfaceIdiomPhone)
{
UIViewController* vc=XXX;
return vc;
}
else
{
return nil;
}
}
Do you use storyboards? Maybe in your iPad storyboard, the UIActivityIndicatorView doesn't have a check on "Hides When Stopped"?
Hope it helps!
So I had the same problem, I had a custom UIActivity with a custom activityViewController and when it was presented modally it would not dismiss not matter what I tried. The work around I choose to go with so that the experience remained the same to the user was to still use a custom UIActivity but give that activity a delegate. So in my UIActiviy subclass I have the following:
- (void)performActivity
{
if ([self.delegate respondsToSelector:#selector(showViewController)]) {
[self.delegate showViewController];
}
[self activityDidFinish:YES];
}
- (UIViewController *)activityViewController
{
return nil;
}
Then I make the view controller that shows the UIActivityViewController the delegate and it shows the view controller that you would otherwise show in activityViewController in the delegate method.
what about releasing at the end? Using non-arc project!
[progressView release];
Many Users have the same problem as u do! Another solution is:
UIActivityIndicatorView *progress= [[UIActivityIndicatorView alloc] initWithFrame:CGRectMake(125, 50, 30, 30)];
progress.activityIndicatorViewStyle = UIActivityIndicatorViewStyleWhiteLarge;
[alert addSubview:progress];
[progress startAnimating];
If you are using storyboard be sure that when u click on the activityind. "Hides When Stopped" is clicked!
Hope that helped...

in the main view after i am trying to wrote first name in another view it not apears in the main view

the app are not work i am trying to enter a first name but it isnt appears in the main view
#pragma IBAaction
-(IBAction)DoneButton:(id)sender;
{
Customer *newCustomer=[[Customer alloc]init];
newCustomer.firstName=self.firstNameTextField.text;
newCustomer.LastName=self.LastNameTextField.text;
[self.delegate addCustomerViewControllerDidSave:self newCustomer:newCustomer];
[self.tableView reloadData];
}
-(IBAction)CancelButton:(id)sender
{
[self dismissModalViewControllerAnimated:YES];
}
I'm just taking a stab in the dark here given the little information given. But either your Done button isn't wired to the DoneButton: method in interface builder, or self.delegate isn't set like you think it if.
Either way, the debugger or a couple of NSLog statements should help shed some light on the issue.

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