Currently I have a BOOL in runtime attributes for my view controller that I use to see if my view controller should add a button to the navigation bar programmatically. I was told that to access the attribute in the code, you add a property with the same name like this:
#interface MyViewController
#property (nonatomic, assign) BOOL showButton;
#end
#implementation
#synthesize showButton = _showButton;
-(void)viewDidLoad {
[super viewDidLoad];
if (_showButton) {
//show button
}
}
#end
And this does work in iOS 8 and 9, but for some reason in the simulator, iOS 7 does not read the Boolean and it's always set to false.
I feel like this is a serious enough problem that someone should have an answer but Google or the search results on SO didn't seem to have results for this.
I really appreciate the help!
UPDATE: I set the value in the Storyboard.
Related
I am working on an iOS project and wanted to include a UIView that is reused on multiple screens in the application (appearing at the bottom of different UIViews). I am using a storyboard for the UI work so far but created an .xib file to be used by the reusable view (playerView in code below).
The view gets added but the button I have added to the View is unresponsive, also my background color cannot be changed on the view. I have tried to set background color programmatically and in the .xib with no luck. Very weird symptoms and I tried to instantiate the view from #5 of this article and probably did something wrong. I dont fully understand everything in the article which makes me nervous - for instance my showSubclassedView method returns IBAction but I just call the function name in code and dont use a button (I did hook up the buttons in the view as the article described though).
Here is the code:
EventViewController.m (where I trry and add PlayerView)
#import "EventViewController.h"
#import "PlayerView.h"
#interface EventViewController ()
-(IBAction)showSubclassedView;
#end
#implementation EventViewController
-(IBAction)showSubclassedView
{
[PlayerView presentInViewController:self];
}
PlayerView.h (.h for reusable view)
#import <UIKit/UIKit.h>
#import "Utils.h"
#class PlayerView;
#protocol PlayerViewDelegate
-(void)playerViewTouchedUp:(PlayerView*) playerView;
-(void)playerViewDidDismiss:(PlayerView*) playerView;
#end
#interface PlayerView : UIView
+(void)presentInViewController:(UIViewController<PlayerViewDelegate>*) playerView;
-(IBAction)viewTouchedUp;
-(IBAction)dismiss;
#end
PlayerView.m (.m for reusable view)
#import "PlayerView.h"
#interface PlayerViewOwner : NSObject
#property(nonatomic,weak) IBOutlet PlayerView *playerView;
#end
#implementation PlayerViewOwner
#end
#interface PlayerView ()
#property (nonatomic, weak) UIViewController <PlayerViewDelegate> *delegateViewController;
#end
#implementation PlayerView
+(void)presentInViewController:(UIViewController<PlayerViewDelegate> *)viewController
{
PlayerViewOwner *owner = [PlayerViewOwner new];
[[NSBundle mainBundle] loadNibNamed:NSStringFromClass(self) owner:owner options:nil];
owner.playerView.delegateViewController = viewController;
[viewController.view addSubview:owner.playerView];
}
-(IBAction)viewTouchedUp
{
//forward to delegate
NSLog(#"you clicked a button");
[self.delegateViewController playerViewTouchedUp:self];
}
-(IBAction)dismiss
{
[self removeFromSuperview];
// Forward to delegate
[self.delegateViewController playerViewDidDismiss:self];
}
#end
PlayerView.xib has a UIbutton on it that connects it to viewTouchedUp method in PLayerView.m
Is there anything I did wrong in the code above? Is this the best way to do a reusable view to display on other views?
Thank you!
Here's a workaround I found after not being able to solve this.
New implementation is from this article
I reverted my changes from my initial question and implemented this. It lacks the nice protocol separation for talking back and forth and I might need something like this later but I think now I can still implement a protocol to solve this.
At least with this solution I have usable items in my view and a background that changes!
I am trying to do the following, and not able to find a straightforward answer.. It is related to this :Passing uitextfield from one view to another. But not exactly.
I have a Firstview.m, from which I push to a Secondview.m. The Secondview.m has a UITextView. I allow the user to edit the UITextView on Secondview.m. Now I want to store this text value in a variable in Firstview.m. One way to to do this is as follows
in Firstview.h
#property (nonatomic) Secondview *secondView;
That is keep a secondView variable in Firstview itself. But this doesn't seem efficient. Ideally I should only have 1 NSString text field in FirstView. What is the right way to do this ? Thanks
You can achieve this by using Delegation in Objective-C.
In your SecondView.h add following right after Header Inclusion
#protocol YourDelegateName <NSObject>
-(void)setText:(NSString *)strData;
#end
Also add delegate property to your header for accessing them in calling class, like below (This goes with other properties declaration in SecondView.h file):
#property (nonatomic, weak) id<YourDelegateName> delegate;
Now, Comes the calling the delegate part. Say, you want to save the text value of UITextView of SeconView in strTextViewData of FirstView class, when the following event occurs:
- (IBAction)save:(id)sender
{
[self.delegate setText:self.txtView.text]; // Assuming txtView is name for UITextView object
}
Now, In FirstView.h add YourDelegateName in delegate list like below:
#interface FisrtView : ViewController <YourDelegateName>
#property (nonatomic, reatin) NSString *strTextViewData;
#end
And then in FisrtView.m file when you create instance of SecondView class, set delegate to self like below:
SecondView *obj = [[SecondView alloc] initWithNibName:#"SeconView" bundle:nil];
obj.delegate = self; // THIS IS THE IMPORTANT PART. DON'T MISS THIS.
Now, Implement the delegate method:
-(void)setText:(NSString *)strData
{
self.strTextViewData = strData;
}
Applying this to your code will do what you want. Also, Delegation is one of the most important feature of Objective-C language, which - by doing this - you will get to learn.
Let me know, if you face any issue with this implementation.
When the views are simple, their IBActions and IBoutlets are in viewcontroller, viewcontrollers assigns respective models to be loaded and viewcontroller get notified when models are prepared.
As My project contains lot of custom views for each viewcontroller, I want to implement actions in custom view itself and set data from controller (ViewController).
I should be able to use the same controllers and models for both iPhone and iPad where only UI changes.
I am concerned about how to pass data from view to viewcontroller and displaying data back on view when model changes?
Can anyone please suggest me to pass data between views <---> viewcontroller (controller) <---> model?
To do this I use Delegate design-pattern. It looks like this :
MyView.h
#protocol MyViewDelegate <NSObject>
- (void)customViewDidSomething;
#end
#interface MyView : UIView
#property (nonatomic, assign) id<MyViewDelegate> delegate
#end
MyView.m
- (void)userDidSomething {
[_delegate customViewDidSomething];
}
MyViewController.h
#import "MyView.h"
// ViewController has to implement the protocol
#interface MyViewController <MyViewDelegate>
#property (nonatomic, retain) IBOutlet MyView myView;
MyViewController.m
- (void)viewDidLoad { // Set the delegate somewhere
_myView.delegate = self
}
- (void)customViewDidSomething {
// Ok VC is aware that something happened
// Do something (tell subview to do something ?)
}
Instead of using different custom views, try using a UIViewController and then use the viewcontroller's view to display your UI. Also, this will also ensure that you will be able to communicate between the views and controller efficiently without confusion.
I am struggling to make a simple thing (at least I think it's simple) but I just can't do it!
I will try to explain a little bit.
It's an app which displays information. When the user is inside a view, he can click on a button, which displays a popoverview, where he can choose which information he wants to know.
Actually, I can't create an action that changes the UILabel text I created in the main view when the user clicks on the popoverview's buttons.
Anyone has any idea?
Just for you to know: the main view I created a class for it, and also for the popoverview. Although, the popover view I created its design in a XIB file (I don't know if this is important, that's why I am putting this).
Well, I hope you guys were able to understand my question.
Thanks in advance.
Fernando.
Just create a property from the viewcontroller and access it from the consumer (other viewcontroller )
You will have to use delegation in order to see changes in the main view when you are making different actions inside the popover. First, you need to create a protocol inside your popover controller header file:
#import <Foundation/Foundation.h>
#class MyPopoverController;
#protocol MyPopoverDelegate
- (void)valueChanged:(NSString*) newVal;
#end
#interface MyPopoverController: UIPopoverController
#property (weak) id<MyPopoverDelegate> delegate;
#end
Then in .m you implement it like this:
- (void) someActionOccured
{
if([self.delegate respondsToSelector:#selector(valueChanged:)]){
[self.delegate valueChanged:valueYouWantToSendBack];
}
}
Remember that in your main class you have to implement MyPopoverDelegate protocol:
#interface MainViewController: UIViewController <MyPopoverDelegate>
And when you instantiate your popover controller:
/*
** inside MainViewController.m
*/
// remember to assign it's delegate
MyPopoverController *popoverController = [MyPopoverController alloc] init];
popoverController.delegate = self;
Also, you'll have to implement the protocol's method:
/*
** inside MainViewController.m
*/
- (void)valueChanged:(NSString*) newVal
{
// process the string and display it where you need it
}
The Problem
An IBOutlet is released before I have a chance to use it.
What I Want
I want to access a navigation controller from my app delegate so I can reload a table view.
My Setup
I have:
A Main.xib that's set as my main interface in target settings
An IBOutlet to the navigation controller as an ivar on my app delegate
This IBOutlet hooked up to the correct navigation controller in Main.xib
App Delegate is instantiated in the xib but not set as File's Owner
I'm using ARC, Xcode 4.3.2 and iOS5.1
What I've Tried
Changing deployment target
Putting a break point on dealloc for the navigation controller, app delegate - they're never called
Reading everything I can find on ARC and IBOutlets - nothing seems to contradict what I'm doing
Creating a fresh project with just a the minimum classes required - I see exactly the same problem
Code
KPAppDelegate.h
#interface KPAppDelegate : UIResponder <UIApplicationDelegate> {
IBOutlet KPBrowseExpensesNavigationController *nc;
}
#property (strong) IBOutlet KPBrowseExpensesNavigationController *nc;
KPAppDelegate.m
#implementation KPAppDelegate
#synthesize nc;
-(void)setNc:(KPBrowseExpensesNavigationController *)nc_ {
nc = nc_; // This gets called on view load and nc gets set.
}
...snip...
// This is called about 5 seconds after app startup
-(void)objectLoader:(RKObjectLoader *)objectLoader didLoadObjects:(NSArray *)objects {
// By the time we get here, nc is nil.
UITableViewController *tvc = [[nc viewControllers] objectAtIndex:0];
[[tvc tableView] reloadData];
}
#end
UPDATE
I must be doing something really silly here. Even an incredibly simple project still shows this problem. See link below.
Download a simple test project that shows the problem.
In Window nib, set the FilesOwner Class as UIApplication and then point it's delegate from Outlets to the AppDelegate object. This is what is wrong in your project example.
is your outlet from the Interface Builder set as an KPBrowseExpensesNavigationController type?
If not it is not going to create the connection between your nib and ViewController.
You should set its Custom Class as KPBrowseExpensesNavigationController in the Identity Inspector
I am not sure why you declare it as a property & a non-property. I should do something like this:
#interface KPAppDelegate : UIResponder <UIApplicationDelegate>
#property (nonatomic, strong) IBOutlet KPBrowseExpensesNavigationController *nc;
And in your implementation:
#implementation KPAppDelegate
#synthesize nc = _nc; // So you don't accidentally use nc
...snip...
// This is called about 5 seconds after app startup
-(void)objectLoader:(RKObjectLoader *)objectLoader didLoadObjects:(NSArray *)objects {
// By the time we get here, nc is nil.
UITableViewController *tvc = [[**self.nc** viewControllers] objectAtIndex:0];
[[tvc tableView] reloadData];
}
#end
Hope this helps!
I didn't see where you alloc your nav controller. Just declaring the property won't assign any value to it, so it would be nil. In you -didFinishLaunchingWithOptions in the app delegate, set your alloc/init statement. Everything else looks fine.
KPBrowseExpensesNavigationController *nc = [[KPBrowseExpensesNavigationController alloc] init];
If you have a custom init, you can use that too, but just make sure to set it up before you try and use it.