I have a project where I have set up a protocol to pass information back from one TableViewController to a ViewController. Everything worked fine and as expected, but I decided to embed in a Navigation Controller to the TableViewController so I could add a "DONE" barButtonItem to dismiss the Controller when the user is done. Since embedding in the navigation controller, the button works well, the TablieViewController looks identical, but none of its features and methods that use the Protocol and Delegate work, and if I remove the NavigationController everything works. Could someone explain how I can fix this issue? I am fairly new to iOS and objective c.
Here is the prepareForSegue method in the NoteViewController
- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender {
if ([segue.destinationViewController isKindOfClass:[ToolTableViewController class]]) {
ToolTableViewController *targetVC = segue.destinationViewController;
targetVC.toolDelegate = self;
targetVC.autoCorrectIsOn = self.autoCorrectIsOn;
targetVC.undoAvailable = self.undoAvailable;
targetVC.redoAvailable = self.redoAvailable;
}
}
ToolTableViewController.h
#protocol ToolTableViewControllerDelegate <NSObject>
#property (weak, nonatomic) id <ToolTableViewControllerDelegate> toolDelegate;
ToolTableViewController.m - example of a method called
-(void)clearInputText{
// NSLog(#"Clear Method Selected");
[self.toolDelegate didClearInputText];
}
NoteViewController.m
-(void)didClearInputText{
self.noteTextView.text = #"";
[self dismissViewControllerAnimated:YES completion:nil];
}
Since your table view controller is embedded in a navigation controller, it's the navigation controller that will be the destination view controller of the segue. Also, it would be better to use the identifier of the segue for the if statement, rather than the class of the destination view controller (I'm using "SegueToTable" as the identifier, change that to whatever you put for the identifier). Therefore, prepareForSegue should look like this,
- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender {
if ([segue.identifier isEqualToString:#"SegueToTable"]) {
UINavigationController *nav = segue.destinationViewController;
ToolTableViewController *targetVC = nav.topViewController;
targetVC.toolDelegate = self;
targetVC.autoCorrectIsOn = self.autoCorrectIsOn;
targetVC.undoAvailable = self.undoAvailable;
targetVC.redoAvailable = self.redoAvailable;
}
}
Your delegate methods are called just fine (based on the sample you pasted).
Since your controllers are embedded in a navigation controller now, you should use:
[self.navigationController popViewControllerAnimated:YES]
Before, you were presenting your controllers modally, that's why dismissViewController worked fine then but not now ( in the context of a nav controller).
Related
The relevant part of my storyboard appears as follows:
You can see the custom "Container Controller" view houses two Container Views, one which links to a Navigation Controller via embedded segue, and another that links to a custom "Master View Controller" (which implements a Table View Controller) via embedded segue. The Navigation Controller component further has a relationship with a custom "Location Filter Controller."
I need to implement delegation such that when one of the UISteppers in the Location Filter Controller is incr./decr., the table view in the Master View Controller knows to update the data it displays accordingly.
I am not unaccustomed to working with protocols/delegates, but this unique situation of talking between views housed in segues is really tricking me! For the most part I have had success following the example here: Passing Data between View Controllers. In this case however, I am not able to directly link instantiated views as he indicates to do in 'Passing Data Back' step 6.
I had considered using a singleton object from which each of these views could get/set the necessary data, but the issue here is that the table view would not necessarily know when to update its contents, despite having data with which it could/should update.
Here is a code snippet from ContainerController.m where I setup the embedded segues to function:
- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender
{
DataHold *data = [[DataHold alloc] init]; // <-- this actually is a singleton object
if([segue.identifier isEqualToString:#"locationEmbedSegue"])
{
}
else if([segue.identifier isEqualToString:#"tableEmbedSegue"])
{
[[segue destinationViewController] setDelegate:data.detailTableViewController];
// ^ This part actually sets up a delegate so that the table view (Master View Controller)
// delegates to the detail view controller of the overarching split view controller
// and tells it what to display when a row is pressed.
}
}
Thanks for any help!
I think you are on the right track setting the table view delegate to your Location Filter Controller.
I found that a simple way to work with embeded view controller is to add "placeholders" property for them, and set these property when the segue is "performed".
// MyContainerController.h
#property (strong, nonatomic) MyLocationFilterController *detailViewController;
#property (strong, nonatomic) UITableViewController *masterViewController;
// MyContainerController.m
- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender
{
if([segue.identifier isEqualToString:#"locationEmbedSegue"])
{
UINavigationViewController *dest = (UINavigationViewController *)segue.destinationViewController;
self.detailViewController = dest.topViewController;
}
else if([segue.identifier isEqualToString:#"tableEmbedSegue"])
{
self.masterViewController = (UITableViewController *)segue.destinationViewController;
[self.masterViewController.tableView setDelegate:self.detailViewController];
}
}
I came to this question recently and found there may be one problem with the answer above.
Move the setDelete: method out. This makes sure no controller is nil.
Then code becomes:
// MyContainerController.h
#property (strong, nonatomic) MyLocationFilterController *detailViewController;
#property (strong, nonatomic) UITableViewController *masterViewController;
// MyContainerController.m
- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender
{
if([segue.identifier isEqualToString:#"locationEmbedSegue"])
{
UINavigationViewController *dest = (UINavigationViewController *)segue.destinationViewController;
self.detailViewController = dest.topViewController;
} else if([segue.identifier isEqualToString:#"tableEmbedSegue"])
{
self.masterViewController = (UITableViewController *)segue.destinationViewController;
}
[self.masterViewController.tableView setDelegate:self.detailViewController];
}
I have an UISplitViewController with the master having an UIViewController embedded in an UINavigationController. A toolbar button is responsible for bringing an UIPopoverController up, via segue. Such popover controller wraps an UIViewController also embedded in an UINavigationController, called SettingsViewController.
I can get a pointer to the UIPopoverController from the UIStoryboardPopoverSegue:
- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(UITableViewCell *)sender
{
if ([segue.identifier isEqualToString:#"Settings"]) {
UIStoryboardPopoverSegue *popoverSegue = (UIStoryboardPopoverSegue*) segue;
SettingsViewController *settingsViewController = ... // TODO
settingsViewController.popoverController = popoverSegue.popoverController;
}
}
But I can't find a way to get a reference to the inner SettingsViewController. I don't want to use a static field accessible via class method, it would be a terrible workaround.
What am I missing to get it right?
Thanks for your help!
UIPopoverSegue contains a UIPopoverController
UIPopoverController *popoverController = popoverSegue.popoverController;
With this you can easily get the contentViewController (view displayed in the popover)
UINavigationController *contentNC = (UINavigationController *) popoverController.contentViewController;
And from the content navigation controller, you get the actual view controller:
SettingsViewController *settingsVC = [contentNC.viewControllers lastObject];
Does this solve your problem?
I have a very similar setup in my app as described at the beginning of the question.
In my prepareForSegue (and inside where I check the segue.identifier) I grab and set things on the popover's view controller like so:
settingsViewController *settingsPop = segue.destinationViewController;
settingsPop.someVar = self.var;
segue.destinationViewController makes it simple and easy.
When doing a modal segue, does the originating ViewController get discarded after the segue is performed? I am setting the destination controller's delegate to the source ViewController, but when the destination ViewController.viewDidLoad, the self.delegate is nil...
The following code will produce the log message "ListViewController.viewDidLoad: My delegate is nil :("
[Source] MapViewController:
- (void) prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender{
if([segue.identifier isEqualToString:#"mapToList"]){
NSLog(#"MapViewController.prepareForSegue: Segue mapToList being called, setting LisViewController's delegate to myself");
[segue.destinationViewController setDelegate:self];
if(!self){
NSLog(#"MapViewController.prepareForSegue: I am nil.");
} else {
NSLog(#"MapViewController.prepareForSegue: I am NOT nil.");
}
}
}
[Destination] ListViewController:
- (void)viewDidLoad
{
[super viewDidLoad];
if(!self.delegate){
NSLog(#"ListViewController.viewDidLoad: My delegate is nil :(");
} else {
NSLog(#"ListViewController.viewDidLoad: My delegate populated");
}
}
Your code seems correct, the only thing I have done differently is test this in a skeleton framework I have that is a tableviewcontroller nested in a navigationcontroller. I just tested with the following code and it works fine for me:
RootViewController .h:
#interface RootTableViewController : UITableViewController <newTest>
Prepare for Segue (in rootViewController):
-(void) prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender{
if ([segue.identifier isEqualToString:#"segueToModalView"]){
[segue.destinationViewController setDelegate:self];
}
}
Top of Modal View Controller .h:
#protocol newTest <NSObject>
-(void) hello;
#end
Property Declaration in Modal View:
#property (nonatomic, strong) id <newTest> delegate;
ViewDidLoad in Modal View:
- (void)viewDidLoad
{
[super viewDidLoad];
NSLog(#"%#", self.delegate);
}
My NSLog of self.delegate properly prints out and my code appears to be more or less the same as yours. Is your property declared correctly?
This is an old question but I came upon it when running into the same issue myself. Couple of things here:
To the guy who didn't understand why someone would want to use a Nav controller with a modal display - its to get the benefit of the nav bar without having to embed a UINavigationBar into your own view controller like tw airball did.
To solve the problem without resorting to what tw airball did remember that the destination view controller for the segue in this case is the navigation controller...not the view controller embedded in the nav.
So the fix is in your prepareForSeque:
UINavigationController *navController = segue.destinationViewController;
MyRealDestViewController *myRealDestViewController = (MyRealDestViewController)navController.topViewController;
myRealDestViewController.delegate = self;
If the segue is to a NavigationController then the destinationViewController loses the delegate.
I got around this problem by having the modal segue into the destinationViewController, and then adding NavigationBar and Bar Buttons to simulate the navigation controller (I assume you wrapped the destinationViewController in a NavigationController for the "done" and "cancel" buttons).
Set the delegate as normal in the rootViewController:
-(void) prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender{
if ([segue.identifier isEqualToString:#"segueToModalView"]){
[segue.destinationViewController setDelegate:self];
}
}
Hope that helps
I was wondering how to properly use the storyboard to put up a view controller modally. Personally I prefer working with xibs, but it seems that the storyboard is gaining popularity and will be the way to go in the future.
The way I would normally put up a view controller modally would be like this: let's say we have ViewControllerA (A for short) and ViewControllerB (B for short).
I would then normally put a protocol in B.h specifying the delegate method when B wants to be dismissed and add the id<theProtocol> delegate field as an assign property. Assuming i'm busy in A and I want to present B modally, I would write:
B* b = [[B alloc] initWithNibName:#"B" bundle:nil];
b.delegate = self;
[self presentModalViewController:B animated:YES];
Using the storyboard, I know it's possible to put up a different view controller in a modal way by ctrl-dragging from a button to a viewcontroller and selecting modal as transition type. I'm just wondering though; where do I set the delegate of the new view controller? What's the correct practice of passing things to your modal view controller? I don't really know what the whole deal with Segues is...
Take a look at this tutorial
According to it, you should set the delegate as follows:
- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender
{
if ([segue.identifier isEqualToString:#"AddPlayer"])
{
UINavigationController *navigationController =
segue.destinationViewController;
PlayerDetailsViewController
*playerDetailsViewController =
[[navigationController viewControllers]
objectAtIndex:0];
playerDetailsViewController.delegate = self;
}
}
Where #"AddPlayer" is the name of your 'modal' segue
Instead of using the navigation controller you could directly use the UIStoryboardSegue object passed in prepareForSegue. It has a property called destinationViewController which is the view controller that is being instantiated. I find that a lot cleaner.
This is an example.
- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender
{
if ([segue.identifier isEqualToString:#"AddPlayer"])
{
PlayerDetailsViewController
*playerDetailsViewController =
(PlayerDetailsViewController *) segue.destinationViewController;
playerDetailsViewController.delegate = self;
}
}
IMO I think that storyboards are great because they function like a blueprint of your application. Also I've never liked nibs. =D
I'm using storyboard in my ipad application and successfully able to do transitions, use segues etc.
Currently I am showing pop over view controller on click of a button. I want to detect when the pop over dismisses.
How can I do it?
Here is what I did:
- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender
{
if ([[segue identifier] isEqualToString:#"popover"])
{
UIStoryboardPopoverSegue *pop = (UIStoryboardPopoverSegue*)segue;
pop.popoverController.delegate = self;
}
}
UIPopoverController
Now with my revelation that you're talking about a UIPopoverController, here are the steps:
Setup the UIPopoverController with an appropriate delegate (I'm assuming the "sender" view controller)
Have your "sender" conform to the UIPopoverControllerDelegate
Implement the – popoverControllerDidDismissPopover: message and have any detection logic here
Implement - prepareForSegue:sender: and use the segue's destinationController to both get a reference and set the delegate, something like below:
((MyViewController*)segue.destinationController).delegate = self;
Modal View Controller
Add a delegate to the view controller that is being presented
Name your segue if you haven't already
Have your base view controller implement - prepareForSegue:sender: (refer to the UIViewController documentation)
Assign the sending view controller as the modal view controller's delegate in prepareForSegue:sender:
Call a desired method on the delegate immediately before or after you call dismissModalViewControllerAnimated:
That is how I would approach this. I would also recommend having a formal protocol to conform your sending view controller with.
Create a segue in view controller:
#property (strong, nonatomic) UIStoryboardPopoverSegue* popSegue;
In XIB, create an identifier called "popover" for the view.
In Interface, write the following code:
- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender
{
if( [[segue identifier] isEqualToString:#"popover"] )
{
//[[segue destinationViewController] setDelegate:self];
NSLog(#"%#",[[segue destinationViewController] viewControllers]);
self.popSegue = (UIStoryboardPopoverSegue*)segue;
.
.
.
}
Write the following code to dismiss the pop over by coding:
[self.popSegue.popoverController dismissPopoverAnimated:YES];
Since UIStoryboardPopoverSegueis deprecated in iOS 9, you can use a UIStoryboardPopoverPresentationSegue.
Then in prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?)you can set the delegate like this:
Swift:
if let identifier = segue.identifier where identifier == "showPopover" {
let destVC = segue.destinationViewController as! UIViewController
destVC.popoverPresentationController?.delegate = self
}
An Objective-C code for the question is below.
if ([segue.identifier isEqualToString:#"home_login"])
{
UIViewController *dest = segue.destinationViewController;
dest.popoverPresentationController.delegate = self;
}
- (BOOL) popoverPresentationControllerShouldDismissPopover:(UIPopoverPresentationController *)popoverPresentationController
{
return NO;
}