-(void)Complete{
CM(#"complete");
[BNUtilitiesQuick UtilitiesQuick].startForm=0;
[self.view removeFromSuperview]; //This remove superView and the new view will be listNewController
[self setSearchLocationWhenChangeSearchBar];
if([self.searchListTemp isEqualToString:[cachedProperties singleton].searchList] && [self.searchLocationTemp isEqualToString:[cachedProperties singleton].searchLocation]){
CLog(#"Don't do anything");
}
else{
...
//Blablabla
//[Timer searchCriteriaChanged];
}
[[BNUtilitiesQuick ListController] viewWillAppear:true];//It's not called if I don't do this
}
Part of me feel that it should be called automatically. Somehow I must have done something wrong when it's not called.
Obviously I don't want things to get called twice either.
So I ended up calling them explicitly. Somehow it feels wrong. Am I wrong?
viewWillAppear is declared in UIViewController.h , it gets called automatically every time the view is about to appear. at some point you have to use super in your implementation.that could be the reason why its not called automatically, because your BNUtilitiesQuick is not a class of UIViewController
If you want some action to happen just before your view disappears, you can write your code in the viewWillDisappear method. This method notifies the view controller that its view is about to be removed from a view hierarchy.
- (void)viewWillDisappear:(BOOL)animated{}
Related
I perform a segue which is defined in the Storyboard to open a new view controller. I need to configure the destination view controller of the segue in a special state where some of it's buttons does not needed to be displayed.
I know that I can do this by setting a variable on this controller in my source view controller's -prepareForSegue:sender:. The problem with this is, that firstly it instantiates the controller, so it's -viewDidLoad: will run, then only after can I set anything on it.
I can't create the controller entirely from code, because it's user interface is in Storyboard. -instantiateViewControllerWithIdentifier: also calls -viewDidLoad first obviously.
I could probably use a semaphore and add the initialization code into my destination controller's -viewWillAppear, but that's ugly, it has to be some more elegant way to do this than doing a check every time the view appears. (My settings need to be done only once.)
Is there some way to pass variables into the controller before it's -viewDidLoad runs?
EDIT: It looks like this happens only if I trigger the segue from code using -performSegueWithIdentifier:.
On my machine and on iOS 8.0 and iOS 9.0, viewDidLoad is called after prepareForSegue. So, something like the following worked for my test case of your answer.
In your source controller:
- (void) prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender
{
TimViewController * controller = segue.destinationViewController;
if( [controller isKindOfClass:[TimViewController class]] )
controller.name = #"tim";
}
In your destination controller (TimViewController):
- (void)viewDidLoad
{
[super viewDidLoad];
// Do view setup here.
NSLog( #"view did load %#", self.name );
}
Add a segue (a show segue) from your source control to the destination view controller.
Output:
2015-09-17 19:09:04.351 Test[51471:7984717] view did load tim
I think there is some confusion here. -prepareForSegue:sender: gets called before -viewDidLoad gets called. Please double check your implementation.
Edit:
May be this thread will help you understand this and one of the mentioned cases fall in your case.
In a project I'm writing I get this error when I present a new view controller:
Attempt to present.... while a presentation is in progress!
I think it happens because I first present a new view controller, and then in that view I present another view controller.
- (void)loadLabelSettings {
LabelSettingsViewController *labelSettings =
[[LabelSettingsViewController alloc] init];
labelSettings.modalTransitionStyle = UIModalTransitionStyleFlipHorizontal;
[self presentViewController:labelSettings animated:YES completion:nil];
}
The program doesn't crash or anything it runs just fine, and there is no errors or warnings in my code. So my question is: Is it something I should be concerned with and if yes how do I solve it?
Thanks in advance :)
It is, like you said, probably caused by presenting two view controllers at the same time. Wait with presenting the second view controller until the first one has been fully presented. A good location would be to do this in viewDidAppear.
In my case, I connected a UIViewControllers UIButton with a second UIViewController by a UIStoryboardSegue. Inside my code a called it a second time programmatically. So pressing the UIButton caused presenting the specified view two times.
I figured out my problem, as Scott wrote it was because I was presenting 2 view controllers at the same time. It happened because I had a button that had a UILongPressGestureRecognizer, that showed the new view controller. The problem was that when using a UILongPressGestureRecognizer, the method that is being called, is called twice. First when the long press is detected and when your finger is released from the screen. So the presentViewController method of the same view, was called twice. I fixed this by only reacting to the first detection. Here is the code :
- (void)loadButtonSettings:(UILongPressGestureRecognizer *)recognizer {
if (recognizer.state == UIGestureRecognizerStateBegan) {
}
}
Okay so I feel like there's something obvious I'm missing in this question. I've used makeFirstResponder throughout my code to move from textField 1 to 2, 2 to 3, etc. That seems to work as I want it to, yet when the new view is loaded, I want the cursor to be in textField1, and yet the following code does not place the cursor in textField1 upon load.
- (void) awakeFromNib{
[[[self view] window] makeFirstResponder:textField1];
}
I also tried setInitialFirstResponder, and that didn't have any effect either (I don't even think that would be right.) So, is it because it is in the awakeFromNib method? Can anyone tell me what I'm missing? Thanks in advance.
EDIT - My solution was differed slightly from the accepted answer so I thought I'd post my implementation. Because the view I wanted to set the first responder for was a subview added later (think the second screen of an application wizard), I simply added a setCursorToFirstTextField method:
- (void) setCursorToFirstTextField {
[[[self view] window] makeFirstResponder:textField1];
}
And made sure to call it after I had added the subview to the custom view on the original window.
Yes, you're right about the problem being the location of the method in awakeFromNib. If you log [self.view window] in your awakeFromNib, you'll see that it's NULL. I don't know how exactly you have things set up, but I'm guessing (if this relates to your WizardController question) that you're doing an alloc initWithNibName:bundle: in another class to create your view controller and then adding that controller's view to the view hierarchy. If you throw some logs in there, it will show you that awakeFromNib in the controller class is called after the alloc init, but before the view is added as a subview, so there is no window at that time. The way I got around this problem was to create a setup method in the view controller class (with the makeFirstResponder code in it), and call it from the class where you create the controller after you add it as a subview.
- (void)applicationDidFinishLaunching:(NSNotification *)aNotification {
self.wizard = [[WizardController alloc] initWithNibName:#"WizardController" bundle:nil];
[self.window.contentView addSubview:wizard.view];
[self.wizard doSetup];
}
I have a UIView class which I am currently removing from my view by using from inside the class [self removeFromSuperview]. Hopefully that's the correct thing to do.
However, now from my view controller (of which I add this view to) I need to know when it has removed itself so that I can call a method when this happens.
Generally speaking, the view shouldn't be doing things like removing itself. That's the job of the view controller.
If a UIView subclass can produce events that require the view hierarchy to be changed, I would define a delegate property for that view, and when an event occurs, call a method on that delegate. Then, when your view controller adds the view, it would set itself as the delegate and define the relevant method to handle the event.
If you have removed the UIView
view.removeFromSuperview()
you can check if it exists with the following code:
if !(view.superview != nil) {
//no superview means not in the view hierarchy
}
You could have a delegate callback setting the controller as the view's delegate. When you're about to remove the view, make the delegate callback and implement the callback method in your controller.
The 'removeFromSuperview' has always seemed backwards to me… :(
I'm assuming you are making the remove call after some sort of action, like a button press or something. if that is the case, set the buttons delegate to be the view controller, not the view class, and inside the action method in the view controller, call
[yourCustomView removeFromSuperview];
The best choice would be to let the controller remove the view
[self.view removeFromSuperview];
and to know if the view was removed (or never added) you can ask
if(![self.view superview]) {
//no superview means not in the view hierarchy
}
Not sure what sdk you are using - but I am using iOS 5 and I just use the following method in the superview:
-(void)willRemoveSubview:(UIView *)subview{
if([subview isEqual:someView]){
//do stuff
}
//you could do some stuff here too
}
This should be straight forward for a guru. I don't have any code really written out, just a couple of controllers and a custom UIView. All connected through nibs. The app loads without crashing, yet I can't see my NSLog() hit from my custom UIView.
My application delegate has default template code which calls for a class of mine called TabAnimationController. TabAnimationViewController has its view set to TabView. I made sure that in TabAnimationViewController's NIB that File's owner is set to TabAnimationViewController and that my instance of UIView has its class set to TabView.
In TabView.m I'm trying to see how NSLog is going to hit, and it's not showing up at all.
- (void)loadView {
NSLog(#"calling loadView");
}
- (id)initWithFrame:(CGRect)frame {
NSLog(#"Calling initWithFrame:");
return self;
}
Strange. I'm not sure why even after proper IB connections that my NSLog will not show up. Only anything put into drawRect: will invoke. Why isn't initWithFrame or loadView ever get hit? What if I want to customize this view programmatically?
First of all, when a view is dehydrated from nib file, instead of initWithFrame, initWithCoder is invoked. So you need to implement your initialization in initWithCoder as well. (It may be a good idea to keep the initWithFrame initialization as well, if you anticipate programmatically creating your TabView instead of hooking up in the IB. Just refactor your initialization to another method and call it from both implementations.)
Also in your initialization code above you must always call the super class's initialization. There is a boiler plate pattern all custom classes use in their init implementation for that:
if (self = [super initXXX]) { do your initialization }
return self;
Second, loadView which is actually a UIViewController method and not a UIView method is invoked only if the view outlet of the controller is nil.
Unless you are composing your view yourself programmatically using your controller, you do not need to override loadView. Instead you should override viewDidLoad, which is called after the view is loaded, to do additional initialization.
The simplest way to get this up and running is simply to use the "View based Application" template when you create a new project. It sets up everything you need to start with.
But, in short, you're looking at the wrong methods. First, you shouldn't override loadView unless you're creating your view programatically. If it's loading from a XIB file look at the initWithNibName method.
You might also want to look at the viewDidLoad, viewWillAppear and viewDidAppear methods that are triggered, well, it's fairly obvious when!