I have a modal view controller which fetches a password. Since I don't want the password written to disk if my application is interrupted, I want to cear the password on applicationWillResignActive. (For those who may comment, I know the secure text field does not properly zeroize).
I've tried the following code, and my view controller is never located. For the first set of code (UIView) I believe its because I'm mixing and matching views and view controllers. I'm not sure why the second set of code (UIViewController) is not working since a few folks have suggested it.
How does one enumerate view controllers and locate a controller of interest? I simply want to send clearPassworAndPin to PasswordPromptController if present (since viewWillDisappear is not always sent when the view disappears).
Modified 7KV7 and Jhaliya answer is below (it worked). The 'if' statement using viewController.modalViewController was executed 5 times (once for each controller in the tab view). So the single modal controller of interest was sent the clearPasswords message 5 times.
for (UIViewController * viewController in viewsControllers)
{
if ([viewController isKindOfClass:passwordPromptClass])
{
[(PasswordPromptController *)viewController clearPassworAndPin];
}
else
{
if(viewController.modalViewController)
[self clearPasswords:[NSArray arrayWithObjects:viewController.modalViewController, nil]];
}
}
Using UIViews (no joy)
- (void)applicationWillResignActive:(UIApplication *)application
{
if(application.windows != nil)
[self clearPasswords:application.windows];
}
- (void)clearPasswords:(NSArray *)subviews
{
Class passwordPromptClass = [PasswordPromptController class];
for (UIView * subview in subviews)
{
if ([subview isKindOfClass:passwordPromptClass])
[(PasswordPromptController *)subview clearPassworAndPin];
}
}
Using UIViewController (no joy)
- (void)applicationWillResignActive:(UIApplication *)application
{
if(tabBarController.viewControllers != nil)
[self clearPasswords:tabBarController.viewControllers];
}
- (void)clearPasswords:(NSArray *)viewsControllers
{
Class passwordPromptClass = [PasswordPromptController class];
for (UIViewController * viewController in viewsControllers)
{
if ([viewController isKindOfClass:passwordPromptClass])
[(PasswordPromptController *)viewController clearPassworAndPin];
}
}
NSArray *array = [self.navigationController viewControllers];
yourViewController = [array objectAtIndex:yourChoiceOfIndex];
Hope it helps.
At the point where you present the PasswordPromptController as a modalViewController could you not store it as an instance variable? Then, in your applicationWillResignActive: callback you will have a handle to the VC to message against.
Be sure to release and nullify your reference to the PasswordPromptController reference when it gets dismissed.
you will have to go through the navigation stack to get the controllers.
Use UINavgationController below method to get all viewController in your navigation stack.
#property(nonatomic, copy) NSArray *viewControllers
hmm..., I have to say I like to give alternative suggestions/solutions as many folks have tried to answer you question specifically.
If you found it's not easy to find the PasswordPromptController by enumerating view controllers, you can just declare (alloc/init) that controller in your app delegate, whenever you need to use it in other controllers, get it through app delegate, do something like presenting as a modal view.
When you want to do something against it in your app delegate, e.g. clear the pwd, it's super easy because you have the reference to it.
Related
I'm using a custom-made container view controller in my dictionary app. Basically, the container view controller contains a custom navigation bar on top (NOT a UINavigationBar--just a UIView with back and forward UIButtons, a UISearchBar, and a bookmark UIButton at the right), and a tab bar controller at the bottom.
My problem is this: I use the back and forward buttons to push and pop view controllers in one of the tabs (a UINavigationController) so the user can navigate through the dictionary browsing history. However, if I press the back or forward buttons too fast, I get this message in the log pane and some of the screens don't appear at all:
Unbalanced calls to begin/end appearance transitions for
<DefinitionViewController: 0x8e5d230>.
Looking around StackOverflow, I understood that this is because clicking on the back or forward buttons too fast calls the push/pop methods of the UINavigatonController in the active tab, but it does not let the animation finish. https://stackoverflow.com/a/17440074/855680
Pushing or popping view controllers without the animations solves the problem, but I do want to keep the animations. How can I approach this problem? I looked at the UINavigationController class reference to see if there are any delegate methods or properties that indicate that it's in the middle of an animation, but there doesn't seem to be any.
Fixed it myself. The solution was to create a property in my container view controller which indicates whether the UINavigationController transition animations are still happening:
#property (nonatomic, getter = isStillAnimatingTransition) BOOL stillAnimatingTransition;
Now, for all the UIViewController classes that I push into the UINavigationController, I set this flag to YES or NO in each of the view controllers' viewWillDisappear and viewDidAppear methods, like this:
- (void)viewDidAppear:(BOOL)animated
{
[super viewDidAppear:animated];
self.containerViewController.stillAnimatingTransition = NO;
}
- (void)viewWillDisappear:(BOOL)animated
{
self.containerViewController.stillAnimatingTransition = YES;
[super viewWillDisappear:animated];
}
And my container view controller only ever allows the execution of the back and forward buttons if the animation flag is set to NO, like this:
- (void)backButtonClicked
{
if (!self.isStillAnimatingTransition) {
// Do whatever.
}
}
- (void)forwardButtonClicked
{
if (!self.isStillAnimatingTransition) {
// Do whatever.
}
}
Maybe you can take advantage of the UINavigationControllerDelegate class and handle the events there.
In your main class that holds the navigation controller, set the delegate to yourself and handle the interactions there.
i.e. in the .h file:
#interface yourClass : UIViewController <UINavigationControllerDelegate> {
UINavigationController *content;
}
and then in the .m file:
content = [[UINavigationController alloc] initWithRootViewController:yourRootViewController];
content.delegate = self;
After that you can listen to the transition events via the following functions, and set your animation flags accordingly.
- (void)navigationController:(UINavigationController *)navigationController didShowViewController:(UIViewController *)viewController animated:(BOOL)animated {
stillAnimatingTransition = NO;
}
- (void)navigationController:(UINavigationController *)navigationController willShowViewController:(UIViewController *)viewController animated:(BOOL)animated {
stillAnimatingTransition = YES;
}
You can find more references about the delegate protocol from apple
https://developer.apple.com/library/ios/documentation/uikit/reference/UINavigationControllerDelegate_Protocol/Reference/Reference.html#//apple_ref/occ/intfm/UINavigationControllerDelegate/navigationController:willShowViewController:animated:
Is their any Possibilty to Check which viewController is running in IPhone application Programmatically in Appdelegate
There is no easy answer to this. You need to walk the view controller hierarchy starting with the main window's root view controller. If you encounter a UINavigationController you need to look at the topViewController. Once you get to a UIViewController, you need to look at the modalViewController, if any. If you have any tab bar controllers then you need to look at the currently selected tab.
Things like UISplitViewController complicates things since this can show two view controllers at once.
Here is the start of a category method you could add to UIViewController. This only handles regular view controllers and navigation controllers.
- (UIViewController *)topMostController {
if (self.modalViewController) {
return [self.modalViewController topMostController];
} else {
if ([self isKindOfClass:[UINavigationController class]]) {
UINavigationController *nc = (UINavigationController *)self;
return [nc.topViewController topMostController];
} else {
return self;
}
}
}
Call this from your app delegate on the key window's rootViewController.
Assuming you've set the rootViewController property in your AppDelegate:
[UIApplication sharedApplication].keyWindow.rootViewController;
For view controller it is not possible to get the curent running viewcontroller name.
for that you write one following method in your app delegate file & then call getCurentViewController method in each viewcontroller view did load or view did appear if you are not allocating agin by passing self to it
-(void) getCurentViewController:(UIViewController*) vc
{
if([vc isMemberOfClass:NSClassFromString(#"vcName")])
{
//write your code here
}
else if([vc isMemberOfClass:NSClassFromString(#"vcName1")])
{
//write your code here
}
}
UIViewController *currentViewController = yourRootViewController;
while (currentViewController.presentedViewController) {
currentViewController = currentViewController.presentedViewController;
}
//currentViewController is now your top-most viewController
//I use this same snippet in my production code
I know there's like 3-5 similar questions here, but non of the answers solves my problem.
I have a ViewController that opens a modal (table)view controller, which opens another one. Both modal view controllers are in fact table view controllers. I'm trying to dismiss both of them from the second one. I tried every accepted answer on similar question, none of them worked for me.
I tried
[self dismissModalViewControllerAnimated:true]
[self.parentViewController dismissModalViewControllerAnimated:true]
[self.parentViewController.parentViewController dismissModalViewControllerAnimated:true]
[self.presentingViewController dismissModalViewControllerAnimated:true]
[self.presentingViewController.presentingViewController dismissModalViewControllerAnimated:true]
When I try options 2, 3 and 5, nothing happens at all. When I use options 1, and 4, I see dismiss modal view animation and the underlying view itself for a moment, and then everything goes back to the second modal view (this time without animation).
I'm starting to think that this have something with the fact that I use tableViewControllers for modal views.
Btw, I'm dismissing modal views in didSelectRowAtIndexPath.
Try this:-
When you dismiss your SecondView set a BOOL flag variable in app delegate file and check that variable in your FirstView's viewWillAppear method whether SecondView was open and close or not. If so, then [self dismissModalViewControllerAnimated:true]
typical model view controller behavior would suggest that you dismiss the modal view controller from the calling view controller rather than from self. not a hard and fast rule, but good practice.
to accomplish this, create a protocol:
#protocol MyModalViewControllerDelegate
- (void)modalViewControllerDidFinish;
#end
and make both the parentViewController and FirstModalViewController be implemntors of this protocol.
#interface FirstModalViewController <MyModalViewControllerDelegate>
then in both FirstModalViewController.h and SecondModalViewController.h, add:
#property id<MyModalViewControllerDelegate> modalViewControllerDelegate
in both parentViewController and FirstModalViewController, right before calling presentModalViewController:... , set the following:
modalViewControllerAboutToAppear.modalViewControllerDelegate = self;
[self presentModalViewController:modalViewControllerAboutToAppear animated:YES];
next, in the SecondModalViewController, in the code where you determine that the item needs to be dismissed, call
[self.modalViewControllerDelegate modalViewControllerDidFinish];
now, in FirstModalViewController, implement the following:
- (void)modalViewControllerDidFinish:(MyModalViewController*)controller {
[self dismissModalViewControllerAnimated:YES]
[self.modalViewControllerDelegate modalViewControllerDidFinish];
}
and finally, in the parent view controller, you should be able to perform:
- (void)modalViewControllerDidFinish:(MyModalViewController*)controller {
[self dismissModalViewControllerAnimated:YES]
}
Since I don't use delegate files, I did the following:
To FirstView add field
BOOL mClose;
To FirstView add method
- (void)close
{
mClose = YES;
}
To FirstView method viewDidAppear add
if (mClose)
{
[self dismissModalViewControllerAnimated:YES];
}
To FirstView method which opens SecondView add
[secondView closeWhenDone:self];
To SecondView add field
FirstView *mParent;
To SecondView add method
- (void)closeWhenDone:(FirstView*)parent
{
mParent = parent;
}
To SecondView method which closes it add
[mParent close];
I'm writing an iPhone app. Starting from a view controller in a navigation stack [called EditCreatorController], I am presenting a custom modal view controller [called BMSStringPickerController]. I have created a delegate protocol, etc. per the Apple guidelines for passing data back to the first view and using that view to dismiss the modal view. I even get the expected data back from the modal controller and am able to dismiss it just fine. The problem is, at that point, almost any action I take on the original view controller leads to debugger errors like
-[EditCreatorController performSelector:withObject:withObject:]: message sent to deallocated instance 0x3a647f0
or
-[EditCreatorController tableView:willSelectRowAtIndexPath:]: message sent to deallocated instance 0x3c12c40
In other words, it seems like the original view controller has evaporated while the modal view was showing. This is true no matter which of the two delegate callbacks is invoked.
Here is the code from the parent controller that invokes the modal view:
- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath {
if (indexPath.row == 1) { // selection on creator type row
// create a string picker to choose new creator type from list
BMSStringPickerController *picker = [[BMSStringPickerController alloc] initWithNibName:#"BMSStringPickerController" bundle:nil];
picker.delegate = self;
picker.stringChoices = [NSArray arrayWithObjects:#"composer", #"lyricist", #"arranger", #"original artist", #"other", nil];
picker.currentChoice = creator.type;
picker.title = #"Creator Type";
// wrap it in a nav controller so we can get tile bar etc. (from VC prog guide p. 93)
UINavigationController *newNavigationController = [[UINavigationController alloc]
initWithRootViewController:picker];
[self.navigationController presentModalViewController:newNavigationController animated:YES];
[newNavigationController release];
[picker release];
}
}
And here are the delegate callbacks:
- (void)stringPickerController:(BMSStringPickerController *)picker didPickString:(NSString *)string {
NSLog(#"received string back: %#", string);
typeLabel.text = string; // only change the label for now; object only changes if done button pressed
[self.tableView reloadData];
[self dismissModalViewControllerAnimated:YES];
}
- (void)stringPickerControllerDidCancel:(BMSStringPickerController *)picker {
NSLog(#"picker cancelled");
[self dismissModalViewControllerAnimated:YES];
}
Another weird thing (perhaps a clue) is that although I get the "received string back" NSLog message, and assign it to typeLabel.text (typeLabel is an IBOutlet to a label in my table view), it never appears there, even with the table reload.
Anyone have some ideas?
Maybe you release the delegate in dealloc of BMSStringPickerController?
It may not solve your problem, but I suggest telling the picker to dismiss itself (in the delegate methods), allowing the responder chain to correctly handle the dismiss:
[picker dismissModalViewControllerAnimated:YES];
The default behavior when there is a memory warning is the release the view of all view controllers that are not visible. So if there was a memory warning while in your modal view controller, its parent view controller could have its view unloaded.
When this happens, viewDidUnload is called on the view controller so that you can release any references you hold into the view. If you have references that you didn't retain they will become invalid when the view is unloaded. Maybe this is happening in your case?
See the UIViewController reference Memory Management section for details. The UIViewController method didReceiveMemoryWarning: releases the view if the view is not currently visible and then calls viewDidUnload.
I have a button inside the content of a UIPopoverController. This button runs a method called myAction.
MyAction has the form
- (void) myAction:(id)sender
so, myAction receives the id of the caller button.
Now, inside this method I would like to dismiss the UIPopoverController, but the only thing I have is the ID of the caller button. Remember that the button is inside the UIPopoverController.
Is there a way to discover the ID of the UIPopoverController, given the button ID I already have?
thanks.
Unfortunately no. At least, not within the standard practices. You might be able to travel up the responder stack to find it, but it's a hack, it's buggy, and it's really, really messy.
If you want to dismiss a popover by pushing a button, some place relevant should keep a reference to the popover. Usually that would be the owner of the popover (not the controller showed within the popover). When the button is pressed, it can send a message to the owner controller, which can then dismiss the popover.
You might be tempted to have the controller displayed inside of the popover be the owner of its own popover, but coding this way is brittle, can get messy (again), and may result in retain loops so that neither ever gets released.
You can access the presenting popoverController by accessing "popoverController" with KVC.
[[self valueForKey:#"popoverController"] dismissPopoverAnimated:YES]
I have this working, and I do not think it is a hack. I have a standard split view iPad app. I then added a method on my detail controller (the owner of the pop over) to handle the dismissal.
On the standard split view architechture, both the root and detail view controllers are available via the app delegate. So I bound a button click inside the pop over to call a method which gets the app delegate. From there I call the method on the detail controller to dismiss the pop over.
This is the code for the method on the View Controller that is displayed inside the popover:
- (void) exitView: (id)sender {
MyAppDelegate *appDelegate = (MyAppDelegate *)[[UIApplication sharedApplication] delegate];
[appDelegate.detailViewController exitDrill];
}
Then the simple method to dismiss on the Detail View Controller:
- (void) exitDrill {
if(dtController != nil){
[dtController dismissPopoverAnimated: YES];
[dtController release];
}
}
I like the ability to do this because it give me a way to show a user how they can exit a pop over. This may not be necessary in future versions of the app; for right now, while this paradigm is still new to the platform, I prefer to let the users gexit a display in a couple fo different ways to make sure I minimize frustration.
As Ed Marty already wrote
If you want to dismiss a popover by pushing a button, some place relevant should keep a reference to the popover
This is very true; however, when showing a UIPopoverController, the class opening the popovercontroller keeps this resource already. So, what you could do is to use this class as the delegate class for your Popover Controller.
To do so, you could do the following, which I use in my code.
In the class opening the popover, this is my code:
- (void)showInformationForView:(Booking*)booking frame:(CGRect)rect
{
BookingDetailsViewController *bookingView = [[BookingDetailsViewController alloc] initWithStyle:UITableViewStyleGrouped booking:booking];
[bookingView setDelegate:self];
UINavigationController *navController = [[UINavigationController alloc] initWithRootViewController:bookingView];
self.popController = [[UIPopoverController alloc] initWithContentViewController:navController];
[self.popController setDelegate:self];
[self.popController setPopoverContentSize:CGSizeMake(320, 320)];
rect.size.width = 0;
[self.popController presentPopoverFromRect:rect inView:self.view permittedArrowDirections:UIPopoverArrowDirectionLeft animated:YES];
}
- (void)dismissPopoverAnimated:(BOOL)animated
{
[self.popController dismissPopoverAnimated:animated];
}
So what I am doing here is creating a UINavigationController and setting a BookingDetailsViewController as its rootViewController. Then I am also adding the current class as delegate to this BookingDetailsViewController.
The second thing I added is a dismissal method called dismissPopoverAnimated:animated.
In my BookingDetailsViewController.h I added the following code:
[...]
#property (nonatomic, strong) id delegate;
[...]
And in my BookingDetailsViewController.m I added this code:
[...]
#synthesize delegate = _delegate;
- (void)viewDidLoad
{
UIBarButtonItem *closeButton = [[UIBarButtonItem alloc] initWithTitle:#"Close" style:UIBarButtonItemStylePlain target:self action:#selector(closeView)];
[self.navigationItem setRightBarButtonItem:closeButton];
[super viewDidLoad];
}
- (void)closeView
{
if ([self.delegate respondsToSelector:#selector(dismissPopoverAnimated:)]) {
[self.delegate dismissPopoverAnimated:YES];
}
else {
NSLog(#"Cannot close the view, nu such dismiss method");
}
}
[...]
What happens is that when the "Close" button in the UINavigationController is pressed, the method closeView is called. This method check if the delegate responds to dismissPopoverAnimated:animated and if so, it calls it. If it does not respond to this method it will show a log message and do nothing more (so it wont crash).
I have written my code using ARC, hence there is no memory management.
I hope this helped you.