I have a viewcontroller which contains a tableview. I call another view via pushViewController. When I get back to my original viewController I hope to redraw the table, but viewWillAppear is never called.
Any other ideas?
I've used this in my own projects with success.
-(void)viewWillAppear:(BOOL)animated {
[super viewWillAppear:animated];
[[self tableView] reloadData];
}
Double check the spelling of the method.
I had two classes competing for messages, UITabbarcontroller and UINavigationController. I had a UITabBar from a previous experiment. It was created but not used. The messages where getting to UITabBarController, and UINavigationController was never told.
Hope this solution will help someome someday
Related
I have a splitViewController that has a master and detail view controllers. The code below is from the master and it creates the new view in the detail:
UIViewController *controller = [self.storyboard instantiateViewControllerWithIdentifier:[NSString stringWithFormat:#"%#",[self.defaultSettingsMenuItems objectAtIndex:indexPath.row]]];
[self.detailViewController.view addSubview:controller.view];
detailViewController is a global instance of DetailViewController. In the detailViewController, I have many textFields and need to utilize the UITExtFieldDelegate. However, I think that the detailViewController isn't self at that point, and that's why I'm getting EXC_BAD_ACCESS errors on using the TextFieldDelegate methods in detailViewController.
EDIT: I have now found that the subView delegate methods only work for the viewController I setup as the rootViewCOntroller relationship from within Storyboard. Ex. If I have 6 views in the default menu settings above, whichever one I have setup as the first and root view in storyboard will work correctly. Any and all other subviews shown (from making a new selection in the master view) will not work properly. I think this will help diagnose the problem.
I am not familiar with storyboards, but I don't see you setting the detailViewController's delegate anywhere. You probably need to have something like self.detailViewController.delegate = self; somewhere before you yield control over to the subview.
This all I needed, the second line:
UIViewController *viewController= [self.detailViewController.storyboard instantiateViewControllerWithIdentifier:[NSString stringWithFormat:#"%#",[self.defaultSettingsMenuItems objectAtIndex:indexPath.row]]];
if (self.detailViewController.childViewControllers.count >= 1) {
NSLog(#"childViewControllers: %#",self.detailViewController.childViewControllers);
[[self.detailViewController.childViewControllers objectAtIndex:0] removeFromParentViewController];
}
[self.detailViewController addChildViewController:viewController];
[self.detailViewController.view addSubview:viewController.view];
EDIT: I've updated my answer with the if look to remove viewControllers from the stack. Slightly hacky, but functional.
When i call presentModalViewController
[self presentModalViewController:iPSPvc animated:NO];
is there a method i can implement in the target viewController (iPSPvc) that gets called every time this happens?
I need to make sure some updating of the view is done.
viewDidLoad gets called when i create an instance of iPSPvc so I need a method where I can do sometime similar.
Many Thanks
-Code
Try viewWillAppear method
-(void)viewWillAppear:(BOOL)animated
{
//your code goes here
}
what's with viewWillAppear and viewDidAppear?
- (void)viewWillAppear:(BOOL)animated
If I've understood your question aright, the above method (or one its close cousins) in your target viewController. This gets called every time the controller's view is about to appear, not just when the view is first loaded.
In a UIViewController subclass, I have the following methods:
-(void)viewWillAppear:(BOOL)animated {
[super viewWillAppear:animated];
// do something
myTextField.text = #"Default";
}
- (void)viewDidAppear:(BOOL)animated {
[super viewDidAppear:animated];
// do something
[myTextField selectAll:self];
[myTextField becomeFirstResponder];
}
- (void)viewDidLoad {
[super viewDidLoad];
// do something
myTextField.delegate = self;
}
The NIB has been created using Interface Builder. The corresponding view controller object is pushed by the navigation controller through pushViewController.
The inteded behavior is to show a default text entry in a text field, to select the entire text and to set the text field as first responder. [Edit: I've noticed that selecting all and making first responder makes no sense as the selection would dissapear; still, I wonder why the methods behave as described next.]
However, while methods viewDidLoad and viewWillAppear are called, the method viewDidAppear is not called. Can anybody tell me why? Most questions I found on the web and here deal with both viewWillAppear/viewDidAppear are not working; I also understood that in subviews or programmatically created views these methods are not evoked; but this does not apply in case and also I wonder why one of these "lifecycle" methods is evoked and the other not.
Any idea? Thanks!
I had this issue happen to me: viewWillAppear was being called but viewDidAppear was not!
I finally figured out that this was because I had a tabBarController where I overloaded it's own viewDidAppear and forgot the [super viewDidAppear:animated];
It threw off every VC in every tab! adding that line back in fixed it for my other VC's.
Hope this helps someone!
There is one case when viewWillAppear will be called but viewDidAppear will not.
Suppose you have two viewControllers and you push from the first to the second controller. Then, using the swipe, you want to go back to the first one, both controllers are displayed at the same time and at that moment viewWillAppear will be called from the first controller.
This way, you do not finish the swipe and stay on the second controller and viewDidAppear will not be called from the first controller.
I had the same problem.
I had copy/pasted viewDidAppear to create viewWillAppear but had forgotten to change the super.viewDidAppear() call. This then seemed to stop viewDidAppear from being called.
It sounds like somewhere in your code you have missed or messed-up a call to the superclass.
The call to viewDidAppear: should always follow viewWillAppear: unless you are doing something custom, which you say you don't. I don't know why it doesn't work but here are a few ideas:
Could it be that you are doing something strange in one of the delegate methods for UITextFieldDelegate? It's unlikely that it would affect viewDidAppear: being called but it could be a culprit.
Have you loaded a lot of stuff into memory before pushing the view? I'm not sure what would happen if you got a memory warning between viewWillAppear: and viewDidAppear:.
Have you tried to do a Clean? Sometimes that can help.
In cases like these when it should work I usually create a new class and the introduce the functionality one at a the time to see if I can get it work that way. I tried your code in a new Navigation Based project where I added a new UIViewController with an outlet to the text field. Then I pasted the code from the question and it did work as expected.
This can be because you added a child view controller to your parent VC in viewDidLoad or viewWillAppear. The child's appearance prevents the call to viewDidAppear.
This is a crazy thing to do, and I only know because this was a bug in my code. I meant to add the child VC to this VC, not the parent VC.
I'm trying to detect a shake on the iPhone device, so for what i've read I need to set my view controller as first responder on the viewDidAppear method. This method is supposed to be called automatically, but for some reason this method is never called. Only viewDidLoad is called.
this is my code (I put only the relevant parts):
BuildHouseViewController.h:
#interface BuildHouseViewController : UIViewController {
BuildHouseViewController.m:
- (void)viewDidLoad {
[super viewDidLoad];
[self.view becomeFirstResponder];}
-(void)viewDidAppear:(BOOL)animated{
[self becomeFirstResponder];
[super viewDidAppear:animated];}
-(BOOL)canBecomeFirstResponder {
return YES;}
- (void)motionEnded:(UIEventSubtype)motion withEvent:(UIEvent *)event{
NSLog(#"shake");
if ( event.subtype == UIEventSubtypeMotionShake )
{ }
if ( [super respondsToSelector:#selector(motionEnded:withEvent:)] )
[super motionEnded:motion withEvent:event];
}
I added breakpoints on the viewDidAppear method and it is never called. Shakes are never detected, I suppose it is because as this methods are never called, so the view controller can never become first responder. I don't understand why this is happening.
Any help will be appreciated.
Edit:
I call the view from another view using:
[self.view addSubview:nextScreen.view];
The view is displayed on screen
Thanks for the quick answers.
I've found something interesting. I tried loading the same view I'm having problems with in different ways and I'm getting different results
-As I said before if I call it from another view using:
[self.view addSubview:nextScreen.view];
viewDidLoad is never called and I cannot detect shakes.
-Now if I call it from the AppDelegate using:
[window addSubview:nextScreen.view];
viewDidLoad is called!! and I am able to detect shakes, however this solution is not possible, I should be able to call it from another view
-If I call it from another view using:
[self presentModalViewController:nextScreen animated:YES];
viewDidLoad is called!! However I don't want to use a modal view controller, but it appears to be the only solution to my problem, shakes are detected.
It is strange that the first method doesn't load the view correctly, is it a bug??
The [self becomeFirstResponder] and the like don't actually make that become the first responder. The method gets called when the view is going to become the first responder. So that's not doing what you think it is.
Secondly, the viewDidAppear will only be called when the view, well, did appear. Is it showing up on the screen? Where are you telling it to be displayed? You need to either add the view controller's view as a subview of another view, or pushed onto a navigation controller stack, or pushed as a modal view.
viewDidAppear:(BOOL)animated only gets called when the view is shown by UINavigationController or UITabBarController. If you add a view controller's view to a subview (such as a scrollview or what have you), it won't get called. You would think it would but you'd be wrong. Just got bit by this myself.
Further to #Genericrich's comments, you can manually call viewDidAppear after you put the subview in yourself.
[self.view addSubview:theViewController.view];
[theViewController viewDidAppear:FALSE];
This worked for me. Hope it helps someone else.
Being new to Cocoa, I'm having a few issues with Interface Builder, UIViewController and friends.
I have a UIViewController subclass with a UIView defined in a xib, and with the controller's view outlet connected to the view. The xib's "file's owner" is set as myViewcontroller subclass.
In this one instance, the following code to load the controller/view (from the main view controller) doesn't work as expected:
if ( self.myViewController == nil )
{
self.myViewController = [[MyViewController alloc]
initWithNibName:#"MyViewController" bundle:nil];
}
[self.navigationController
pushViewController:self.myViewController animated:YES];
In MyViewController's methods, I have placed breakpoints and log messages to see what is going on:
-(id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil {
if (self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil]) {
NSLog(#"initWithNibName\n");
}
return self;
}
-(void)viewDidLoad {
[super viewDidLoad];
NSLog(#"viewDidLoad\n");
}
Expected result
Both -initWithNibName and -viewDidLoad methods are called, and myViewController's view is displayed.
Observed result
Only -initWithNibName is called, the view is not displayed.
Have I missed something? Can anyone recommend anything to check? (Particularly in the wondrously opaque Interface Builder tool).
RE: SOLUTION FOUND!!!!!
Indeed that seems to be a working solution, however the real trick is not in setting the view.hidden property to NO, what makes the view load from the nib file is the calling of the UIViewController's view method, the view only actually gets loaded from the nib when the view method is called for the first time.
In that sense, a simple [viewController view] message would force the view to load from the nib file.
Ok, I have a partial answer - maybe the gurus can explain some more. The problem is:
[self.navigationController pushViewController:myViewController animated:YES];
Looking more closely, in this case self.navigationController is nil - so the push message is going no-where.
Instead, if I send:
[self.view addSubview:self.myViewController.view];
Then the view appears and -viewDidLoad is called.
I'm not entirely sure why self.navigationController is not set in this instance - the only thing I can think of is that self is a subclass of UIViewController rather than UITableViewController (where the pushViewController code came from).
Also, silently allowing messages to go to nil seems like a bad idea, although these answers say otherwise. See also my question here.
Final edit:
Answers in comments below, I've realised the display function that I was actually after (given myViewController is modal) is:
[self presentModalViewController:myViewController animated:YES];
Thanks everyone for their helpful responses.
SOLUTION FOUND!!!!!
Even something as innocuous as this makes the viewDidLoad method call happen.
Insert this right after alloc initWithNibName
viewController.view.hidden = NO; //calls viewDidLoad
make sure that the view outlet in File's Owner (your viewController subclass) is connected to the actual view (i.e. the 480X320 canvas you see on your screen that you use to build your UI)
Chances are that you might not have linked the supposed ViewController in main.storyboard from the Identity Inspector to the custom class you created. You might be able to navigate to that controller from other view controllers via segues but any of viewDidLoad(), viewWillAppear() etc. won't be executed.
Simply use
- (void)viewDidAppear:(BOOL)animated{
[super viewDidAppear:animated];
//Your Code here
}
instead of the viewDidLoad method.
Another reason, somewhat obvious in retrospect: if viewController.view is set in code, then the viewDidLoad event will not trigger.
It looks like a capitalization problem to me. You're referencing the class MyViewController instead of the property myViewController in the call to pushViewController.
Check your run log for errors. Almost certainly, the NIB is not loading, and there should be an error to that effect. The most likely cause for that is failure to put it in the bundle. Look in your "Copy Resources" build phase and make sure that the XIB is actually being copied. Build for the simulator, and go down into the build directory and make sure that the NIB is in the .app bundle.
Apart from other answers here,
It often happens when the identifier with which you instantiate your ViewController from the storyboard is incorrect. For e.g.
[[self getStoryboard] instantiateViewControllerWithIdentifier:MyVC];
If MyVC is the identifier of some other ViewController, this might happen.
OP is using nib instead of storyboard here. But the answer applies.
The page has been presented but not visible in Debug view hierarchy & in device(simulator also), issue happens based on and
i found the fix:
func viewWillLayoutSubviews{
if day == true{
self.view.backgroundColor = .clear
}else{
self.view.backgroundColor = .blue
}
}
Don't try to implement the self.view (viewcontrollers view) in function of layoutsubviews. So better use self.view in viewwillappear or viewdidload. This issue happens starts from v-14 devices.
Hope it works for you too.