how to connect IBOutlet from a class to another class - ios

I have Class A which contains a xib with some buttons and a UITextField and Class B which contains a tableView
I want to add Class A to the table view header.
I am importing the xib from class A into class B using [[[NSBundle mainBundle] loadNibName: owner:self options:nil] objectAtIndex:0];
I just want to reflect the button and textview actions inside classB. In ClassB I do have some UITextfield Delegate methods which i expect to be called when typing some text in uitextfield defined and declared in ClassA (xib + property definition in .h file).
Class A .h:
//properties are set from xib file ClassA.xib
#interface ClassA : UIView
#property (unsafe_unretained, nonatomic) IBOutlet UIButton *addC;
#property(strong, nonatomic) IBOutlet UITextField *nText;
#end
Class B.h
#import "ClassA"
#interface ClassB : UIViewController <UITextFieldDelegate, UITableViewDataSource,...>
#property (strong, nonatomic) IBOutlet UITableView *mTableView; //property set from ClassB.xib
#property(strong, nonatomic) IBOutlet UITextField *nText_B;
#property (unsafe_unretained, nonatomic) IBOutlet UIButton *addC_B;
- (IBAction)addC:(UIButton *)sender;
#end
I don't know how to make the link ClassB button and textfield to ClassA
In ClassB viewDidLoad method i;ve tried this:
getHeader = [[ClassA alloc]init];
_addC_B = [getHeader addC];
_nText_B = [getHeader nText];
_nText_B.delegate =self;
_nText_B.text=#"";
but it's not working
I am new to iOS on this side area.
Thank you for your help

You haven't explained your problem well. Classes do not "contain xibs".
If your objective is to create a piece of user interface in XIB and reuse it, you can achieve this with [NSBundle loadNibNamed:owner:options:]. The best way to reference parts of it is through properties like Noval explained in his answer. Another possibility is to attach views to "File's Owner" outlet's properties.

you can't connecting IBOutlet that placed outside your XIB class. but if you just want to access the outlet from other class, it's possible by creating instance of ClassA in ClassB. and then accessing the property like instanceOfClassA.outletObject

Related

Xcode Property Not Retaining Value

I have a view controller called LoginWindowViewController.h that declared a property called usernameTextField:
#property (strong, nonatomic) IBOutlet UITextField *usernameTextField;
A string called James is associated to this TextField.
I then import another view controller,FirstViewController.h into my LoginWindowViewController.m and I also imported LoginWindowViewController.h into FirstViewController.m . In my FirstViewController.h there is a property called username.
#property (strong, nonatomic) IBOutlet NSString *userName;
Then i assign usernameTextField to username(In my FirstViewController.m). But when i NSlog the property username in my FirstViewController.m, it gives a null value.How do i fix this?
When you import classes you do not actually import any values. When you set the value of a property it is only set on that instance of the class. You will need to explicitly reference the property of your current instance to get the value you have set.
One note: IBOutlet stands for Interface Builder Outlet and is how you create a link from a storyboard or xib file UI element to a class property. So, no need to use IBOutlet if you are not linking to something in interface builder.
String should be declared
#property (nonatomic, strong) NSString *userName;
Then when you instantiate your login view controller from first view controller you can set the property like this
LoginWindowViewController *loginVC = [[LoginWindowViewController alloc] init];
[loginVC.usernameTextField setText:self.userName];

iOS custom UIView access properties in code

So I've created a custom UIView subclass and have it assigned to a UIView in my main storyboard. When the view loads everything is displayed properly.
The issue I'm having is that I need to be able to access properties of said custom UIView since the view is data driven.
JSON_table.h:
#import <UIKit/UIKit.h>
#interface JSON_table : UIView
#property (strong, nonatomic) IBOutlet UIView *view;
#property (weak, nonatomic) IBOutlet UISearchBar *searchbar;
#property (weak, nonatomic) IBOutlet UITableView *table_view;
#property (weak, nonatomic) NSString *data_header;
#property (weak, nonatomic) NSString *data_list;
#end
JSON_table.m:
#import "JSON_table.h"
#implementation JSON_table
- (id) initWithCoder:(NSCoder *)aDecoder{
self = [super initWithCoder:aDecoder];
if (self) {
[[NSBundle mainBundle] loadNibNamed:#"JSON_table" owner:self options:nil];
[self addSubview:self.view];
}
return self;
}
#end
(I know I'm missing delegates for tableview, ill be adding these later)
The issue I'm having is when I right click on my UIView on my storyboard I get:
The problem is when I try to connect "view" to my header file "
ViewController.h" it doesn't let me create a IBOutlet, so I cannot reference my view and its properties in code.
This is what I am trying to accomplish:
"Table" is of type UIView
Idea:
Would this have anything to do with the UIView being on the second view in my storyboard? I noticed that I don't seem to have any problem attaching to anything on the first page, but the second one I can't.
You can only connect the outlets of a view to it's class object. You are trying to connect outlets of JSON_table object to UIViewController object.
If you need to access those properties in UIViewController object. You need to import
JSON_table.h
in your view controller. And create and instantiate a object of it.
JSON_table * customView = [[JSON_table alloc]init];
Now you can access all the properties of it as:
customView.searchbar, customView.view etc.
Added by theshadow124:
Thanks to everyone who attempted to help me solve my problem. Due to being fairly new to coding for iOS I didn't realize I had to assign a custom class to every UIViewController in my storyboard(I thought they they would inherit from the base if I didn't specify). simply creating a new subclass of UIViewController and assigning it under the Identity inspector fixed my problem and now I can properly assign outlets.
Im going to accept this answer because it was one of the issues I ran into after fixing the subclass on the storyboard issue.
Please make sure that in assistant editor your are opening the same class that your custom class is contained in .

Cannot talk to elements inside xib

I am still learning interface builder.
I created a xib containing a button, a progress bar and a spinner. Lets call this xib MyToolbar.xib. I created classes for that xib (MyToolbar.h and .m). Inside the xib, I set the toolbar’s class to MyToolbar. Inside the xib I set File’s Owner to MyToolbar. I connected outlets to all elements and put them on the header.
The class header is this:
#import <UIKit/UIKit.h>
#interface MyToolbar : UIToolbar
#property (weak, nonatomic) IBOutlet UIButton *button;
#property (weak, nonatomic) IBOutlet UIActivityIndicatorView *spinner;
#property (weak, nonatomic) IBOutlet UIProgressView *progressBar;
#end
this is the implementation
#import “MyToolbar.h"
#implementation MyToolbar
- (id)init {
self = [super init];
if (self) {
self = [[[NSBundle mainBundle] loadNibNamed:#"MyToolbar"
owner:self
options:nil]
objectAtIndex:0];
}
return self;
}
Now I create the object on the main class
MyToolbar *toolbar = [[MyToolbar alloc] init];
at this point, toolbar is not nil but toolbar.button, toolbar.progessBar and toolbar.spinner are all nil.
I know the elements are not instantiated unless you display them.
Is there a way to make this work without displaying the object?
Did you connect the views to File's owner outlet? Try to remove the File's owner or connections and connect the views to MyToolbar.h outlets. I tried and it's working.

Should I make my ivars properties in iOS?

Just when you think you understand something, you don't! :)
I understand that if I make a variable a property, I can access it anywhere in the Class and even set it from outside that class.
I thought if I didnt need it I could just make it an ivar. So I have a viewcontroller with about 5 UILabels. So in its viewDidLoad I say:
pharmacyName.text = self.receivedLocation.name;
pharmacyTel1.text = #"556-7843";
pharmacyTel2.text = #"991-2345";
pharmacyTel3.text = #"800-0001";
When I have declared them like so in the .h file:
#interface DetailViewController : UIViewController{
IBOutlet UILabel *pharmacyName;
IBOutlet UILabel *pharmacyTel1;
IBOutlet UILabel *pharmacyTel2;
IBOutlet UILabel *pharmacyTel3;
}
#property (nonatomic,strong) MyLocation *receivedLocation;
#end
No. Its not mandatory to create ivar as property. If you don't want to access it outside of class just use as it is. In ARC you can also declare your IBOutlet as below:
#interface DetailViewController : UIViewController{
__weak IBOutlet UILabel *pharmacyName;
__weak IBOutlet UILabel *pharmacyTel1;
__weak IBOutlet UILabel *pharmacyTel2;
__weak IBOutlet UILabel *pharmacyTel3;
}
This will keep a week reference of outlets. Here is detail of __weak and strong
There are always many ways you can approach programming tasks and standards. Our group has started using a few coding standards. We like to put our instance variables that are NOT accessed from outside the class (and protocol statements) in the private interface in the .m file like this:
#interface DetailViewController() {
NSString *value_;
}
#end
We also like to use #property for our instance ivars and declare those in the private interface as well like this:
#interface DetailViewController() {
}
#property (nonatomic, strong) IBOutlet UIlabel *pharmacyName;
#end
and then in your code, you would refer to this as self.pharmacyName. It seems to work pretty well with autocomplete, and with getting and setting. Also when you have thread safety issues, the nonatomic, strong behavior comes in handy.

Changing outlet object properties

I have a view controller alertForNeedsClassification as a property in another class, as such:
#interface SCAAppDelegate()
{
HomeScreenViewController * _homeScreenViewController;
NSInteger SCAStatus;
}
#property (strong, nonatomic) PromptClassifyViewController * alertForNeedsClassification;
#end
#implementation SCAAppDelegate
#synthesize alertForNeedsClassification;
#synthesize window = _window;
PromptClassifyViewController's interface looks like this:
#interface PromptClassifyViewController : UIViewController
#property (weak, nonatomic) IBOutlet UILabel *headerTitle;
#property (weak, nonatomic) IBOutlet UITextView *message;
#property (weak, nonatomic) IBOutlet UIButton *notNowButton;
#property (weak, nonatomic) IBOutlet UIButton *classifyButton;
#property (weak, nonatomic) IBOutlet UIImageView *backgroundImageView;
#property (weak, nonatomic) IBOutlet UIView *alertView;
#property NSUInteger tag;
#property (weak, nonatomic) IBOutlet id<PromptClassifyViewControllerDelegate> delegate;
- (void)show;
- (void)showFromView:(UIView *)view;
- (IBAction)show:(id)sender;
- (IBAction)dismiss:(id)sender;
- (IBAction)buttonWasPressed:(id)sender;
- (void)setHeaderTitleWithText:(NSString *)text;
#end
I am trying to change the values of IBOutlets message and headerTitle text, like this:
alertForNeedsClassification = [[PromptClassifyViewController alloc] initWithNibName:#"PromptClassifyViewController" bundle:nil];
//[alertForNeedsClassification setDelegate:self];
self.alertForNeedsClassification.headerTitle.text = #"A title";
alertForNeedsClassification.message.text = #"A message";
Then I show alertForNeedsClassification calling a show method (it's like a custom uialertview, but it doesn't subclass from uialertview).
Thing is, no matter how I change it, the text on alertForNeedsClassification.view is always that which is defined in the nib, ie. I can't change it programmatically.
My custom alert view is based on Jeff LaMarche's design: http://iphonedevelopment.blogspot.com/2010/05/custom-alert-views.html
Any ideas what might be going on?
Please be careful when you allocate and initialize the UIView object, especially if you trying to mix using Nib and dynamically generating objects. The best place is within -(void)awakeFromNib or -(void)viewDidLoad
Also, make sure these methods are called. By using -(id)initWithNibName:bundle: only cannot make sure your view to be loaded. Try -(void)addChildViewController and -(void)addSubview: on parentViewController's view to make sure view is loaded after being initialized.
If the text had to be prepared before being loaded, assign it to separate NSString property within PromptClassifyViewController class. Since this property is independent from view being loaded, you can change it's value BEFORE view is appeared. Make sure this text is used and applied to the headerTitle within -(void)show method.
Since you allocate PromptClassifyViewController and access weak referenced headerTitle from self. alertForNeedsClassification, make sure it's not deallocated right afterward.
Usually, weak option is not used for IBOutlet properties. Though it is used when generating outlet connection code by dragging objects from Interface Builder. Try testing your code using strong.
I was assigning values to the IBOutlets before they were alloc'd/initialized. The solution I implemented was to set the values I needed to non-IBOutlet properties (NSStrings in this case) and assign those where needed, in Prompt...Controller's viewDidLoad;

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