Update Text Label From Another View - ios

I have an NSTimer that runs every 10 seconds and is kicked off from LandingController.m. It continues to run as you go to other views in the application. I want to be able to (when a certain condition is met within that timer) update a label field from another view GuardMenu.m The label I want to update is called CurrentZone.text and I want to update it from value "N" to value "Y."
Here's my timer on LandingController.m
self.messageTimer = [NSTimer scheduledTimerWithTimeInterval:10.0
target:self
selector:#selector(checkForMessages)
userInfo:nil
repeats:YES];
Which calls this on LandingController.m
- (void)checkForMessages
{
if ( //some condition here ){
//update CurrentZone.text label in GuardMenu view and set equal to "Y"
} else {
//no need to update label in GuardMenu as it's currently equal to "N"
}
}

First create a NSNotification in your init method of GuardMenu class
- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil {
self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
if (self) {
[[NSNotificationCenter defaultCenter] addObserver:self selector:#selector(receiveNotification:) name:#"TextChangeNotification" object:nil];
}
return self;
}
Then implement the notification's selector, this is where you will be changing your CurrentZone label text.
- (void)receiveNotification:(NSNotification *) notification {
if ([[notification name] isEqualToString:#"TextChangeNotification"]) {
NSLog (#"Change you label here");
self.lblCurrentZone.text = #"Y";
}
}
Now in your LandingViewController.m -viewDidLoad Method
Start the timer.
self->msgTimer = [NSTimer scheduledTimerWithTimeInterval:10.0 target:self selector:#selector(checkForMessages) userInfo:nil repeats:YES];
Now implement the #selector for the NSTimer, this is where you will be sending the notification back to the GuardMenu class
- (void)checkForMessages {
NSString *strText = #"test";
if ([strText isEqualToString:#"test"]){
[[NSNotificationCenter defaultCenter] postNotificationName:#"TextChangeNotification" object:nil];
}
else {
}
}
NOTE: the NotificationName should be the same.
Sample Project Code Dropbox Link

You can use the prepareForSegue method to pass objects between view controllers in the storyboard. For example, to pass a string from the GreyViewController to the OrangeViewController, in GreyViewController.m you have:
- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender {
OrangeViewController *orange = [segue destinationViewController];
orange.self.orangeString = #"text for orangeView";
}
Then in the viewDidLoad of the other view controller, in the OrangeViewController.m, you can set the text of the label by doing the following:
self.orangeLabel.text = self.orangeString;

Maybe you should describe which error you're getting. Is your checkForMessages method (not) firing? Use an NSLog() message to check. Otherwise, check if the UILabel you want to change is actually loaded into memory (i.e. is not nil). Please also let us know if the currentZone.text is part of the view hierarchy of the LandingController or of another view controller.

You can make use of notifications.
In GuardMenu class init register for custom notification
[[NSNotificationCenter defaultCenter] addObserver:self
selector:#selector(receiveNotification:)
name:#"MessageChangeNotification"
object:nil];
In LandingController->checkForMessages method post the notification when condition is satisfied.
[[NSNotificationCenter defaultCenter] postNotificationName:#"MessageChangeNotification"
object:nil];
In GuardMenu class implement the notification callback selector
- (void) receiveNotification:(NSNotification *) notification
{
if ([[notification name] isEqualToString:#"MessageChangeNotification"]) {
NSLog (#"Successfully received the notification");
//Change the label text here..
}
}
Hope it helps!
Amar.

Make sure that the label you are trying to edit is declared as a property in the appropriate view and properly synthesised. Also make sure it is connected in Interface Builder.
In GuardMenu.h
#property (strong, nonatomic) IBOutlet UILabel *CurrentZone;
Also, in LandingController.h, import GuardMenu.h:
#import "GuardMenu.h"
You will now be able to access the label and its text property from LandingController.h using
-(void)checkForMessages
{
GuardMenu *guardMenu = [[GuardMenu alloc]init];
if (/* some condition here */) {
//update CurrentZone.text label in GuardMenu view and set equal to "Y"
guardMenu.CurrentZone.text = #"Y";
} else {
//no need to update label in GuardMenu as it's currently equal to "N"
}
}

For this you should use KVO(Key Value Observing). There are lot of ways to pass notifications, but KVO is potentially much simpler. I suspect that Notification is used more often because you can do a ‘chain of responsibility’ for an event as opposed to just assigning an observer. However, just having an observer in a controller that can watch a particular property in another object and get notified of changes is a powerful and simple way to solve a whole class of problems.
Firstly set a public property in LandingController like "lablelText" .
Then add the observer once, when you create the LandingController view. Once you've added the observer, the observeValueForKeyPath:ofObject:change:context: method will be executed in GuardMenu, so you can do the update to the GuardMenu UI from there. You shouldn't need to do anything every time GuardMenu is about to appear.
In GuardMenu, you should probably create LandingController just before you are going to push LandingController onto the controller stack, presumably in the event handler for some action the user took. Immediately after you create LandingController, add the observer in GuardMenu with the correct NSKeyValueObservingOption value.
If you just want to be notified whenever the public property "lablelText" in LandingController is changed, then try this:
LandingController
#interface LandingController : UIViewController {
}
#property (strong, nonatomic) NSString* lablelText;
- (void)checkForMessages;
#end
#implementation LandingController
#synthesize lablelText;
- (void)checkForMessages
{
if ( //some condition here ){
//update CurrentZone.text label in GuardMenu view and set equal to "Y"
self.lablelText = #"Y";
} else {
//no need to update label in GuardMenu as it's currently equal to "N"
self.lablelText = #"N";
}
}
#end
GuardMenu
#interface GuardMenu : UIViewController {
}
#property (strong, nonatomic) IBOutlet UILabel* nameLabel;
- (IBAction) methodToHandleEvent:(id)sender;
#end
#implementation GuardMenu
- (IBAction) methodToHandleEvent:(id)sender{
LandingController* tempVC = [[LandingController alloc]init];
[tempVC addObserver:self forKeyPath:#"lablelText" options:NSKeyValueObservingOptionNew context:NULL];
[self.navigationController pushViewController:tempVC animated:YES];
}
- (void) observeValueForKeyPath:(NSString*)keyPath ofObject:(id)object change:(NSDictionary*)change context:(void*)context {
// Here you will be notified everytime lablelText changes
if ([keyPath isEqual:#"lablelText"]) {
NSString* changedName = [change objectForKey:NSKeyValueChangeNewKey];
// do something with the changedName - call a method or update the UI here
self.nameLabel.text = changedName;
}
}
#end
As an alternative for this you can use NSNotificationCeneter to pass notifications from one class to another for some event.
For this you can check my detailed answer How to pass Notifications from one class to another for some event.
Hope it helps you.

Create a notification in the init of GuardMenu class
[[NSNotificationCenter defaultCenter] addObserver:self
selector:#selector(receiveNotification:)
name:#"UpdateCurrentZoneNotification"
object:nil];
In the LandingController,
(void)checkForMessages
{
if ( //some condition here ){
[[NSNotificationCenter defaultCenter] postNotificationName:#"UpdateCurrentZoneNotification"
object:nil];
//update CurrentZone.text label in GuardMenu view and set equal to "Y"
} else {
//no need to update label in GuardMenu as it's currently equal to "N"
}
}

Related

ios - Action from UITableView to a UIViewController

I have MainController which is the (UIViewController) main view in the app, and MenuController which is a UITableView.
In the MainController.h
- (void) menu1:(NSInteger ) row;
In the MainController.m
- (void) menu1:(NSInteger ) row{
switch(row){
case 0:
//DO SOMETHING.......
break;
default:
break;
}
}
I want "menu1" to make action when I click a cell in the MenuController.
I made this: (in MenuController.m)
- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath {
if(indexPath.section == 0){
[menu1:indexPath.row]; //<=== What should I do to make it work ?
}
}
You can access the method using your UINavigationController.
So in your MainController.h, add this:
- (void) menu1:(NSInteger)row;
Now in your MenuController.m:
#import "MainController.h";
and change didSelectRowAtIndexPathto:
- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath {
if(indexPath.section == 0){
MainController *mC = [self.navigationController.viewControllers objectAtIndex:0]; // Change the objectAtIndex number to the number of your MainController in the navigationController view hierarchy
[mC menu1:indexPath.row];
}
}
Your menu1 method is an instance method on the MainController, so you'll want to send the message to an instance of that class. Like so:
MainController *mainVC = [[MainController alloc] init];
[mainVC menu1:indexPath.row];
Or, if you were to define your menu1 method as a class method, you could just send the message to the MainController without initializing. Use plusses instead of minuses when defining your menu1 method, then call like this:
[MainController menu1:indexPath.row];
However, this probably isn't the best way for you to pass data back and forth between View Controllers. You'll likely want to at the very least set a property on your MenuController, and then send the message to that (of course, setting the property wherever it makes sense).
[self.mainController menu1:indexPath.row];
But another really good method for calling a method on another View Controller is the delegate pattern, but I'll leave that up to you to research on your own.
https://developer.apple.com/library/ios/documentation/General/Conceptual/DevPedia-CocoaCore/Delegation.html
in your MenuController.h
You get back to your previous view like this.
[[self navigationController] popToViewController:yourController animated:YES];
or
[self.navigationController popToRootViewControllerAnimated:animated];
and use UINotificationCenter or Delegate pattern.
If you have no idea about them UINoitifcation is easier but Delegate pattern is better in this situation. I ll explain how to use UINotificationCenter.
Throw notification from your menuController like this.
[[NSNotificationCenter defaultCenter]
postNotificationName:#"yourNotificationName"
object:nil ];
This code is for catch notification write it down to your viewappear method.
[[NSNotificationCenter defaultCenter] addObserver:self
selector:#selector(yourMethodAboutWhatYouWantToDoAfterCatchNotification:)
name:#"yourNotificationName"
object:nil ];
Do what you want to do after catch it
- (void) yourMethodAboutWhatYouWantToDoAfterCatchNotification:(NSNotification *) notification
{
// do your job.
}
And in viewDidDisappear remove it. Or you can catch it multiple times after time.
[[NSNotificationCenter defaultCenter] removeObserver:self name:#"yourNOtificationName" object:nil];
There are two ways to achieve this.
Implement a protocol, whose implementation should be there in MainController.m
In that implementation, you should call the method which you have in MainController.m.
Set the table views delegate to MainController instead of setting it as self (MenuController)
This will help to implement the delegate methods directly in the MainController.m, from which the menu1 method can be called.
Provided code below for the first way:
Create a protocol file, which will help to make a callback, and create a method.
//
// utilProtocol.h
// tempProject
//
#protocol utilProtocol <NSObject>
#optional
-(void)captureCellSelectForRow:(int)rowNumber;
#end
Now Import this file inside in MenuController.
#import "utilProtocol.h" // Inside MenuController
And create a variable for the protocol.
#property(readwrite,assign)id<utilProtocol>utilDelegate;
In MainController.h, Import the utilProtocol.h and have its delegate into it.
Don't forget to add utilProtocol
#import <UIKit/UIKit.h>
#import "utilProtocol.h"
#interface ViewController : UIViewController <utilProtocol>
#end
Now Implement the method in MainController.m
-(void)captureCellSelectForRow:(int)rowNumber
{
[menu1:rowNumber];
}
Also set the delegate for it when the tableVIew's object is created in MainController.m
[tableViewObject setUtilDelegate:self];
Now when ever didSelectRowAtIndexPath is called in MenuController, just call the method using protocol.
- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath {
if(indexPath.section == 0){
[utilDelegate captureCellSelectedForRow:indexPath.row];
}
}
Using this, the method inside MainController can be called.

how to update a persistent UILabel spanning all views from the subsequent views

I'm trying to test some ideas on a Tabbed Application preset - what I want to do is have the main view 90% container for subsequent views (which is working fine so far) and have a persistent status bar at the top showing a UILabel that can be updated from the subsequent views, however am having trouble updating the label.
In seeking a solution I have attempted both a global variable and protocol approach.
Whilst I can set the label text to be that of the global variable when the main view is loaded, I cannot figure out how to refresh the label once the global variable has been changed in a subsequent view. Similarly with the protocol approach, trying to create a global function in the main view that will update the instance UILabel's properties when called from a subsequent view is not allowed.
If someone could point me in the right direction I would be very grateful.
EDIT
I have tried creating a public function that can be called from subsequent views:
GlobalContainerViewController.h
#interface GlobalContainerViewController : UIViewController
#property (weak, nonatomic) IBOutlet UILabel *statusLabel;
+ (void) updateLabel;
#end
GlobalContainerViewController.m
...
+ (void) updateLabel
{
_statusLabel.text = [NSString stringWithFormat:#"updated"];
}
However get the error "Instance variable '_statusLabel' accessed in class method.
I have also tried using a global variable to store the status text:
AppDelegate.h
NSString * statusVar;
AppDelegate.m
- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
statusVar = [NSString stringWithFormat:#"initialStatus"];
return YES;
}
GlobalContainerViewController.m (with AppDelegate.h imported into .h)
- (void)viewDidLoad
{
[super viewDidLoad];
_statusLabel.text = statusVar;
}
SecondViewController.m (with AppDelegate.h imported into .h)
- (IBAction)updateStatusPressed:(id)sender {
statusVar = [NSString stringWithFormat:#"Update"];
}
However am not sure how to get the label to refresh with this updated data.
To anyone else that comes across the same problem, I've solved using notifications (Send and receive messages through NSNotificationCenter in Objective-C?) - not sure if that's the best way but is working for my needs at this stage:
GlobalContainerViewController.m
- (void)viewDidLoad
...
[[NSNotificationCenter defaultCenter] addObserver:self
selector:#selector(receiveTestNotification:)
name:#"TestNotification"
object:nil];
}
- (void) receiveTestNotification:(NSNotification *) notification
{
if ([[notification name] isEqualToString:#"TestNotification"])
NSLog (#"Successfully received the test notification!");
NSDictionary * info = notification.userInfo;
NSString *statusString=info[#"status"];
NSLog(#"Name = '%#;",statusString);
_statusLabel.text = statusString;
}
SecondViewController.m
- (IBAction)updateStatusPressed:(id)sender {
statusVar = [NSString stringWithFormat:#"Update from 2nd view"];
NSDictionary * dict =[NSDictionary dictionaryWithObject:statusVar forKey:#"status"];
[[NSNotificationCenter defaultCenter]
postNotificationName:#"TestNotification"
object:self userInfo:dict];
}

Execute function to call performSegueWithIdentifier from another class

I've spent a few hours on this trying to work it out myself but I give up!
I have a master-detail arrangement where the user input screen needs to call a function on another class to post to a web service. Upon completion of the asynchronous call, the class will then call a specified function. In this case, I'm just testing and all I want to do is go back to the main screen after the user input is accepted by the web service.
When the uses taps a button on the input screen (SetLocationViewController), the asynchronous operation is called in the class APIPostClass. After it is complete, I want SetLocationViewController to segue back to MasterViewController.
In APIPostClass.m in (called after the asynchronous op finishes)
-(void)callWhenDone {
NSLog(#"callWhenDone loaded.");
SetLocationViewController *SLVClassInstance = [[SetLocationViewController alloc] init];
[SLVClassInstance doSegue];
}
In SetLocationViewController.m
-(void) doSegue {
NSLog(#"doSegue loaded");
[self performSegueWithIdentifier:#"SetLocationViewControllerManualUnwind" sender:self];
}
Calling doSegue from an action on SetLocationViewController.m does work so I know my segue is ok but the above doesn't work. I get the error reason: 'Receiver () has no segue with identifier 'SetLocationViewControllerManualUnwind''
I'm guessing the reason is because of the alloc init way of initialising of the VC, but I don't know any better. Thus, how can I call a function on another class as if it was being called by it's own class?
Create a delegate it would be much more reliable and fast than Notifications.
#protocol APIPostDelegate <NSObject>
#required
-(void)OnRequestSucess;
#end
In your APIPost add new property for delegate
#interface APIPost : NSObject
#property (weak) id<APIPostDelegate> delegate;
In SetLocationViewController implement APIPostDelegate
SetLocationViewController.h
SetLocationViewController :NSObject<APIPostDelegate>
SetLocationViewController.m
-(void)OnRequestSucess
{
[self doSegue];
}
before you make call to method on APIPost, assign self to delegate property.
APIPost *apipost=[[APIPost alloc]init];
apipost.delegate=self;
[apipost <your api method>];
APIPost.m
[self.delegate OnRequestSucess];
Hope this helps.
There are a few methods to make it happens:-
Use Delegate
Use NSNotification.
The way described by Artur above (For SplitViewController Only - iPad)
You should use delegate whenever it is possible but it might not be too straight forward. NSNotification is more straight forward but it is not a good practice and not a good programming style.
I will only share the NSNotification method as it is easier to implement.
In SetLocationViewController.m
-(void)viewWillAppear:(BOOL)animated{
[super viewWillAppear:animated];
[[NSNotificationCenter defaultCenter] addObserver:self selector:#selector(doSegue) name:#"calldoSegue" object:nil];
}
-(void)viewWillDisappear:(BOOL)animated{
[super viewWillDisappear:animated];
[[NSNotificationCenter defaultCenter]removeObserver:self name:#"calldoSegue" object:nil];
}
-(void) doSegue {
NSLog(#"doSegue loaded");
[self performSegueWithIdentifier:#"SetLocationViewControllerManualUnwind" sender:self];
}
In APIPostClass.m
-(void)callWhenDone {
NSLog(#"callWhenDone loaded.");
[[NSNotificationCenter defaultCenter]postNotificationName:#"calldoSegue" object:nil];
}
The above code should work but again, this is not a good practice. You should try to learn the Delegate method.
The answer is here: Performing segue from another class
In my APIPostClass.h, I setup the view controller:
#interface APIPostClass : NSObject {
SetLocationViewController *setLocationViewController;
}
#property(nonatomic, strong) SetLocationViewController *setLocationViewController;
#end
In my APIPostClass.m, I synthesize it:
#synthesize setLocationViewController;
then, instead of this (as in my question):
-(void)callWhenDone {
NSLog(#"callWhenDone loaded.");
SetLocationViewController *SLVClassInstance = [[SetLocationViewController alloc] init];
[SLVClassInstance doSegue];
}
I have:
-(void)callWhenDone {
NSLog(#"callWhenDone loaded");
[self.setLocationViewController doSegue];
}
Over in SetLocationViewController.m, the segue method remains unchanged:
-(void) doSegue {
NSLog(#"doSegue loaded");
[self performSegueWithIdentifier:#"SetLocationViewControllerManualUnwind" sender:self];
}
But when I call my API, I need to "attach" (forgive my terminology) the view controller to it. This is what I had:
- (IBAction)btnTestAPICall:(id)sender {
NSLog(#"User tapped API button");
APIPostClass *APIPostClassInstance = [[APIPostClass alloc] init];
[APIPostClassInstance APICall: ... ....
}
But this is what works after bringing all of the above:
- (IBAction)btnTestAPICall:(id)sender {
NSLog(#"User tapped API button");
APIPostClass *APIPostClassInstance= [[APIPostClass alloc] init];
UIViewController *currentVC=self;
APIPostClassInstance.setLocationViewController = currentVC;
[APIPostClassInstance APICall: ... ...
I hope this will help someone else!

Can't programmatically change UILabel text after viewWillAppear

I have a routine in my iOS program that imports and manipulates a file from Dropbox. This can take some time (5-10 seconds) and it doesn't make sense to return the user to the normal UI while it's doing it, so I want to present a view letting the user know what the progress is.
From one VC, I use Dropbox's drop-in file picker, then load up a presented (modal VC) thus:
ZSImportVC *importVC = [[ZSImportVC alloc] init];
importVC.results = results;
[importVC setModalPresentationStyle:UIModalPresentationFormSheet];
[self presentViewController:importVC animated:YES completion:^{
[self performFetch];
}];
The VC (a bog-standard UIViewController), has a UILabel property:
#property (weak, nonatomic) IBOutlet UILabel *statusMessage;
In viewWillAppear: I can set the text of this label without any problem. The thing is, I want to keep changing this text as the process of manipulating the file continues.
The method that manipulates the file is called from viewDidAppear:
- (void)viewDidAppear:(BOOL)animated
{
[super viewDidAppear:animated];
[self processImport];
}
However, within the processImport method, the following has no effect:
self.statusMessage.text = #"Some text to update the user.";
So I created a method:
- (IBAction)updateStatus:(NSString *)message
{
[self.statusMessage setText:message];
NSLog(#"%#", message);
}
just to check what's going on. The NSLog shows that the method is being called okay, but the label text doesn't change. I tried adding:
[self.statusMessage setNeedsDisplay];
to the method, but that didn't help. I'm not using any private queues or background threads. I read somewhere that using NSNotification helps, so I tried adding this to viewDidLoad:
[[NSNotificationCenter defaultCenter] addObserver:self selector:#selector(updateStatus:) name:#"updateStatus" object:nil];
Then changed the called method to:
- (void)updateStatus:(NSNotification *)message
{
[self.statusMessage setText:message.object];
NSLog(#"%#", message.object);
}
and called this from the main method with:
[[NSNotificationCenter defaultCenter] postNotificationName:#"updateStatus" object:#"Retrieving file from Dropbox" userInfo:nil];
I could see from the console messages that the updateStatus method is getting called, but still the text doesn't change. Clearly I'm missing something here. Any thoughts?
Check your ZSImportVC instances on Debug perspective.
I think u are sending [self.statusMessage setText:message.object];
to another instance, that it is not shown on the screen.
I mean,
put a debug point here:
- (void)viewDidAppear:(BOOL)animated
{
[super viewDidAppear:animated];
[self processImport]; /* Debug point here*/
}
and check what´s the hexadecimal direction for self.
Now , do the same here:
- (void)updateStatus:(NSNotification *)message
{
[self.statusMessage setText:message.object]; /* Debug point here*/
NSLog(#"%#", message.object);
}
Btw, I had some problems with
[[NSNotificationCenter defaultCenter] postNotificationName:#"updateStatus" object:#"Retrieving file from Dropbox" userInfo:nil];
because the instance that receive this notification was not the correct.
I fixed that calling a normal method, but u maybe could not do that.
Sorry for my english :S

How to make UIbutton only appear when text is written?

I'm making a word game, and ive called my custom keyboards textfield _textbox
Ive put a x button that represents "clear written text" and I only need it to appear when the user types letters into the textfield!
Then disappear after the letters were cleared!
code:
- (IBAction)btnclear:(id)sender {
NSString *oldString = _textbox.text;
NSString *newString;
newString = [oldString substringFromIndex: _textbox.text.length];
[_textbox setText:newString];
}
The image is on the button!
If you're using a UITextField you can use the standard clear button with:
_textbox.clearButtonMode = UITextFieldViewModeWhileEditing;
If you're wanting a custom appearance to the button you can use rightView and rightViewMode to manage the state for you.
Use the following code, it uses UITextFieldTextDidChangeNotification notification,which is called every time you change text in your textfield, and hides or shows your button depending on input text.
- (void) viewDidLoad
{
[super viewDidLoad];
[[NSNotificationCenter defaultCenter] addObserver:self selector:#selector(textDidChange:) name:UITextFieldTextDidChangeNotification object: _textbox];
}
- (void) textDidChange:(NSNotification *)notification
{
UITextField *tf = (UITextField*)notification.object;
_button.hidden = (tf.text.length == 0);
}
- (void)dealloc
{
[[NSNotificationCenter defaultCenter] removeObserver:self name:UITextFieldTextDidChangeNotification object: _textbox];
}
With the property "hidden" of the UIButton you can hide it
Check if there is text on your textView, and then hide your button
Use UITextFielDelegate method
- (void)textFieldDidEndEditing:(UITextField *)textField
{
if(textField.text.length==0){
textXclear.hidden = NO;
}else{
textXclear.hidden = YES;
}
}
There are two ways, and by hidden do you mean not visible or just disabled?
For not visible, use the button.hidden property. For disabled (meaning it can't be touched), use the button.enabled property.
As for the textfield you could do something like this:
if ([textfield.text length] > 0) {...} else {...}
//extra stuff and suggestions
Also if you are using the text in the textfield to be added to some other view (say its an add item screen), you have to create a #property regarding the added item. And then you could, rather than the aforementioned mention write the code like in the .m:
if (self.aProperty != nil) {
button.hidden = NO;
} else {
button.hidden = YES;
And you'd have to declare the property in the .h file:
#property (nonatomic, strong) ObjectYouAreUsing *aProperty;
And this may be the reason it's not working but create a new file with the NSObject subclass. This will be the ObjectYouAreUsing.
This way you can access the pure object you are using and just import it where ever you need it. Also with this, if the user were to close the screen you could then write the initWithCoder method.

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