I am setting the parent property for a window and when I check the property in windowDidLoad, everything is good. But when I check it in IBAction, it is nil. What am I missing here?
AppController.m
loginController = [[LoginController alloc] initWithWindowNibName:#"Login" owner:self];
loginController.parent = self;
[[loginController window] makeKeyAndOrderFront:self];
LoginController.h
#property (nonatomic, weak) AppController *parent;
LoginController.m
#synthesize parent;
- (void)windowDidLoad
{
[super windowDidLoad];
NSLog(#"Parent: %#", self.parent); //<--- Parent: <AppController: 0xblahblah>
}
- (IBAction)login:(id)sender
{
NSLog(#"Parent: %#", self.parent); //<--- nil
}
I think that your problem is just that you have set the wrong file owner, is login controller that holds the xib file, thus it has all the IBOutlets and IBActions bound.
Call initWithWindowNibName: instead of initWithWindowNibName:owner: , so that the file owner will be the newly created login controller, and not the app controller:
loginController = [[LoginController alloc] initWithWindowNibName:#"Login"];
Edit
Like I suspected, you have two separate instances of login controller and you think to have only one. See the xib file:
That object "Login Controller" in the xib file, creates another instance of login controller. It's not the same instance that you allocate in app controller.
The solution is to make parent be an IBOutlet:
#property (nonatomic, weak) IBOutlet AppController *parent;
And to don't allocate it in app controller, it will be load from the xib file automatically. All you have to do is to bind it to the instance of login controller in the xib file (if the file owner is app controller you should ctrl-drag the parent propert to the object icon, tell me if you meet some problem doing it). So that's why it prints null: the action is handled by another object, which hasn't the parent property initialized.
In viewDidLoad you access an iVar called parent.
In login: you access the property self.parent.
That can be the same or it can be different.
Did you #synthesize the property? If so, without any additional options? Then you should be fine. parent and self.parent should be the same thing.
Did you autosynthesize it? That is ok. But then the corresponding iVar is called _parent. Meaning then you must have an additional ivar parent which is not the same ivar.
Add all the declarations to your question for more details.
Related
I have an xib for the main window, and I created a custom view in the following steps:
Create a new class which inherits from NSView.
MyView.h:
#import <Cocoa/Cocoa.h>
IB_DESIGNABLE
#interface MyView : NSTableCellView
#end
MyView.m:
#import "MyView.h"
#implementation MyView
- (void)awakeFromNib {
NSLog(#"Post view awaking from nib.");
}
#end
Create a new xib, and set the root view's class to the class created above. And design in that xib.
Set outlets from the xib to the class.
And I tried to use this custom view in the main window in the following steps:
Drag a custom view to the main window's xib.
Set the class of that custom view to the class created above.
But nothing renders. From the log, I can see that code in awakeFromNib from the custom view class is executed. When I set the class to be IB_DESIGNABLE, the view gets empty in the main window's xib, different from what I designed.
I tried to set the file owner of the custom view's xib to the custom class, but nothing changed.
I guess the problem is that, the custom view's xib file is not actually loaded. When I googled it, there seem to be few references on this exact topic. So, how should I actually achieve this goal? I.e., design a view in IB, implement its methods in a class, associate these two, and expose it just like a system view for use in other xibs?
UPDATE:
I found a tutorial and realized what I lack (for correctly rendering the view when built). I have to add an outlet from the view in the xib to the view class:
#property (nonatomic, strong) IBOutlet NSView *view;
, and then load it in the (id)initWithCoder:(NSCoder *)coder method.
[[NSBundle mainBundle] loadNibNamed:#"MyView" owner:self topLevelObjects:nil];
[self addSubview:self.view];
But the view still won't render in the interface builder.
Your guess is correct: the xib is not being loaded. The nib loader doesn't know about your custom view's nib. The nib framework doesn't provide a facility for defining that connection, so you need to write code to load the xib.
Here's what I'd do. Add a contentView property to your custom view:
#interface MyView ()
#property (nonatomic, strong, readwrite) IBOutlet NSView *contentView;
#end
In your custom view's nib, set the custom class of the root view back to NSView and disconnect all the (no-longer-valid) outlet connections from it. Set the custom class of File's Owner to your custom class name (e.g. MyView). Connect the root view to File's Owner's contentView outlet, and connect all the other outlets from File's Owner to the appropriate objects in the nib.
Then implement awakeFromNib in your custom view subclass to load the nib and add the content view as a subview:
#implementation MyView {
BOOL hasLoadedOwnNib: 1;
}
- (void)awakeFromNib {
[super awakeFromNib];
[self loadOwnNibIfNeeded];
}
- (void)loadOwnNibIfNeeded {
if (hasLoadedOwnNib) {
return;
}
hasLoadedOwnNib = YES;
[[NSBundle bundleForClass:self.class] loadNibNamed:NSStringFromClass(self.class) owner:self topLevelObjects:nil];
self.contentView.frame = self.bounds;
self.contentView.autoresizingMask = NSViewWidthSizable | NSViewHeightSizable;
[self addSubview:self.contentView];
}
#end
Note that you have to be careful not to allow infinite recursion. When your app loads the main window's nib, it will create an instance of MyView and (eventually) send it awakeFromNib. Then, in awakeFromNib, MyView loads its own nib, where it is the File's Owner. The nib loader sends awakeFromNib to File's Owner, and this will happen while you're already in -[MyView awakeFromNib]. If you don't check for this, you get a stack overflow due to unbounded recursion.
You aren't providing any code, but here are some sanity checks:
Are you specifying the nib name correctly? In iOS its caps sensitive, but I don't think it is for you.
Check the package, is the nib actually there? Make sure it is part of the target you are building.
Could also be a frame issue. Make sure your auto-resizing parameters are set up correctly and that everything is in frame.
Another check you can do is set your IBOutlets to the actual frame of a UIView (or other) that you are interested in. Then in awakeFromNib, you can make sure their frame exists, or that they exist at all.
Simple problem, I have defined a UIImageView, called bigImageView in a UIViewController using the storyboard,
It's declared in the h file of that UIViewController as follows:
#property (retain, nonatomic) IBOutlet UIImageView *bigImageView;
on my appDelegate I init the UIViewController as follows:
imageViewController = [storyboard instantiateViewControllerWithIdentifier:#"chosenImageController"];
this calls initWithCoder on my UIViewController m file:
-(id)initWithCoder:(NSCoder *)aDecoder
{
self = [super initWithCoder:aDecoder];
if (self) {
// Custom initialization
}
return self;
}
This function is only called once so there's no double init.
However, later, when I check my bigImageView pointer, it's still nil.
Isn't the init supposed to allocate memory to it?
I think that's why when I try to set this UIImageview to hold a UIImage it doesn't display the image
Thanks
It's all working how it's meant to. First every object in the nib/storyboard gets alloc/init called on them, then all the connections are made, and then viewDidLoad is called.
You need to wait for - (void)viewDidLoad to be called on your controller, and then bigImageView should be set. If it's not set then you did something wrong in the storyboard.
init methods are not responsible for allocating any memory. All memory is allocated by the alloc method which is always called before init. Alloc will fill all your instance variables with nil/NULL/0 values, and then init gives the chance to assign initial values to each one (based on the contents of the NSCoder object usually, but it's up to you to decide what should be done).
For IB outlets however, those are setup by the nib loading process after init.
EDIT:
// ViewControllerA.m:
imageViewController = [storyboard instantiateViewControllerWithIdentifier:#"chosenImageController"];
imageViewController.image = imageToShow;
// ViewControllerB.h
#property (retain) NSImage *image;
#property (retain, nonatomic) IBOutlet UIImageView *bigImageView;
// ViewControllerB.m
- (void)viewDidLoad
{
self.bigImageView.image = self.image;
[super viewDidLoad];
}
You don't need to define initWithCoder, since you have no custom logic in there. I would delete that boilerplate code.
Here is what I would check:
In the storyboard, ensure that the class of the view controller is set properly.
Ensure that the outlet is hooked up properly in the storyboard by looking for a circle near your #property. It should be a filled in circle, not an outline of a circle.
Make sure you are reading the value only after viewDidLoad is called. Apple's only guarantee is that the outlet is set after this method call.
Update: It sounds like you want to access the image view before the view is loaded. There is no way to do this. One hack is to call viewController.view which will force the view to load, but there are many reasons why you should not do this.
A better approach would be to implement properties on your view controller which work for both when the view is not loaded and when the view is loaded. You can see an example of an elegant solution in this question. Notice how if the view is loaded, the photographerLabel will get set via the didSet method. On the other hand, if the view is not loaded, it will get set via the viewDidLoad method. For an Objective-C version of that code or for more details, see the linked video in that question.
I have a trouble.
There is viewConntroller and an object inside this viewController. This object tries to get information via NSURLConnection later it has to notify viewController to run method. If i try to create object of viewController inside I catch problem: new viewController makes the same thing that first one do, so new viewController makes NSURLConnection, creates third viewController and so on.
You can pass reference to this object. But first create new property with assign attribute.
//property in your class
#property(nonatomic, assign) id myViewController;
//set reference to your UIViewController
[myClassInstance setMyViewController: self]; //self is MyViewController instance
//call UIViewController's method from your class
MyViewController *controller = (MyViewController *)self.myViewController;
[controller myMethodInUIViewController];
How about passing on a reference of the viewController to the object you´re making inside that viewController?
So something along the lines of:
Object *obj = [[Object alloc]init];
obj.viewController = self;
Obviously, you'd have to create an attribute to hold the viewController on the object class.
Then, when you need to call methods on the viewController, you could use:
[self.viewController performSelector:#selector(methodName:)];
I'm new to objective-c and, maybe I haven't grassped the concept of delegation very clearly yet, but i hope to do it by using it. I'm trying to implement a delegation in my app.
Idea is that i have class TableViewController which has NSMutableArray used for TableView initialization. I need to reinitialize this Array from my DropDown class. I'v tried to do that using delegation but failed to do it yet, maybe there is something wrong with it. I could pass TableViewController to DropDown class and edit the table via object. But i'd like to get it done using delegation.
Here is my TableViewController.h
#protocol TableViewControllerdelegate;
#interface TableViewController : UIViewController<UITableViewDataSource,UITableViewDelegate,MFMessageComposeViewControllerDelegate>
{
ControllerType controllerType;
}
#property (retain, nonatomic) IBOutlet UITableView *tableView;
#property (retain, nonatomic) NSMutableArray *dataArray;
#property (retain, nonatomic) NSArray *imageArray;
- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil andType:(ControllerType)type;
- (void)sendSMS: (NSString *) sms;
#end;
Here is my DropDown.h
#import "TableViewController.h"
#interface DropDownExample : UITableViewController <VPPDropDownDelegate, UIActionSheetDelegate> {
#private
VPPDropDown *_dropDownSelection;
VPPDropDown *_dropDownSelection1;
VPPDropDown *_dropDownSelection2;
VPPDropDown *_dropDownSelection3;
VPPDropDown *_dropDownSelection4;
VPPDropDown *_dropDownDisclosure;
VPPDropDown *_msg;
VPPDropDown *_dropDownCustom;
NSIndexPath *_ipToDeselect;
}
+ (bool) uncheck:(UITableViewCell *) cell andData:(NSString *) data;
- (void)reloadData;
#end
And this is how i try to edit my tableview object array
TableViewController *newControll = (TableViewController*)[UIApplication sharedApplication].delegate;
NSMutableArray *arrayWithInfo = [[NSMutableArray alloc] initWithObjects:AMLocalizedString(#"Status", nil),AMLocalizedString(#"Call", nil),AMLocalizedString(#"Location", nil),AMLocalizedString(#"Control", nil),AMLocalizedString(#"Sim", nil),AMLocalizedString(#"Object", nil),AMLocalizedString(#"Info", nil),nil];
newControll.dataArray = arrayWithInfo;
[arrayWithInfo release];
[newControll.tableView reloadData];
I get it running, but it get's '-[AppDelegate setDataArray:]: unrecognized selector sent to instance after reaching this code.
OK, I am not sure if I got this right but it finally clicked for me what delegation is and why I need it. Hopefully you'll understand too once you read through my scenario.
History
Previously, in my UITabBar app, I wanted to show a custom form view overlaid on top of my view controller to enter name and email.
Later I also needed to show the same custom overlay on top of another view controller on another tab.
At the time I didn't really know what delegation was for, so the first method I used to tackle this problem was NSNotificationCenter. I duplicated the same code to my second view controller and hooked it up to a button press event.
On pressing a button on the second view controller on another tab, it certainly showed my custom overlay, just like my first view controller.
However, this is where the problem starts.
The Problem
I needed to close my custom form view. So using NSNotificationCenter, I posted a notification and the listener callback method for the notification was told to close my custom view.
The problem was, using NSNotificationCenter, all listeners both in my first tab and my second tab responded to the posted notification and as a result, instead of closing just the custom form view overlaid on top of my second view controller, it closed ALL my custom view, regardless of where the custom view was opened from.
What I wanted was when I tap on the "X" button to close my custom form view, I only want it to close it for that single instance of the custom view, not all the other ones I had opened.
The Solution: Delegation
This is where it finally clicked for me - delegation.
With delegation, I tell each instance of my custom form view who the delegate was, and if I was to tap on the "X" button to close my custom view, it only close it for that single instance that was opened, all the other view controllers were untouched.
Some Code
Right, down to some code.
Not sure if this is the best way to do it (correct me if I am wrong) but this is how I do it:
// ------------------------------------------------------------
// Custom Form class .h file
// ------------------------------------------------------------
#protocol MyCustomFormDelegate <NSObject>
// if you don't put a #optional before any method, then they become required
// in other words, you must implement these methods
-(void)sendButtonPressed;
-(void)closeButtonPressed;
// example: these two methods here does not need to be implemented
#optional
-(void)optionalMethod1;
-(void)optioinalMethod2;
#end
#interface MyCustomFormView : UIView
{
...
id<MyCustomFormDelegate> delegate;
}
...
#property (nonatomic, retain) id<MyCustomFormDelegate> delegate;
#end
// ------------------------------------------------------------
// Custom Form class .m file
// ------------------------------------------------------------
...
#implementation TruckPickerView
#synthesize delegate;
-(id)initWithFrame:(CGRect)frame
{
self = [super initWithFrame:frame];
if(self)
{
...
[btnSend addTarget:self selector:#selector(sendEmail) forControlEvent:UIControlEventTouchUpInside];
...
[btnClose addTarget:self selector:#selector(closeForm) forControlEvent:UIControlEventTouchUpInside];
}
return self;
}
-(void)sendEmail
{
// code sends email
...
// ------------------------------------------------------------
// tell the delegate to execute the delegate callback method
//
// note: the implementation will be defined in the
// view controller (see below)
// ------------------------------------------------------------
[delegate sendButtonPressed];
}
-(void)closeForm
{
// ------------------------------------------------------------
// tell the delegate to execute the delgate callback method
//
// note: the implementation will be defined in the
// view controller (see below)
// ------------------------------------------------------------
[delegate closeButtonPressed];
}
// ------------------------------------------------------------
// view controller .h file
// ------------------------------------------------------------
#import "MyCustomFormView.h"
// conform to our delegate protocol
#interface MyViewController <MyCustomFormDelegate>
{
...
// create a single instance of our custom view
MyCustomFormView *customForm;
}
#property (nonatomic, retain) MyCustomFormView *customForm;
// ------------------------------------------------------------
// view controller .m file
// ------------------------------------------------------------
#synthesize customForm;
-(void)viewDidLoad
{
customForm = [[MyCustomFormView alloc] initWithFrame:....];
// tell our custom form this view controller is the delegate
customForm.delegate = self;
// only show the custom form when user tap on the designated button
customForm.hidden = YES;
[self.view addSubview:customForm];
}
-(void)dealloc
{
...
[customForm release];
[super dealloc];
}
// helper method to show and hide the custom form
-(void)showForm
{
customForm.hidden = NO;
}
-(void)hideForm
{
customForm.hidden = YES;
}
// ------------------------------------------------------------
// implement the two defined required delegate methods
// ------------------------------------------------------------
-(void)sendButtonPressed
{
...
// email has been sent, do something then close
// the custom form view afterwards
...
[self hideForm];
}
-(void)closeButtonPressed
{
// Don't send email, just close the custom form view
[self hideForm];
}
You get that error, because (as the error says) you're sending a setDataArray: message to your app delegate (the AppDelegate class).
[UIApplication sharedApplication].delegate;
This will return the delegate of you app. There are a couple of ways to find out which class is your app's delegate, but usually it's called AppDelegate (as in your case) and it's implementing the UIApplicationDelegate protocol too.
You can't simply cast that to a completely different class. If your app delegate has an ivar or property of type TableViewController you have to use accessors to get it. If it's a property, you can use the dot notation. If it's an ivar, you can either implement a getter method that returns the ivar, or make it a property instead.
// assuming your app delegate has a TableViewController property called myTableViewController.
AppDelegate *appDelegate = (AppDelegate *)[UIApplication sharedApplication].delegate;
TableViewController *tableViewController = appDelegate.myTableViewController;
This will fix the error, but your use of the delegate pattern is wrong too. I don't see where you're using any custom delegates. You forward declare a TableViewControllerdelegate protocol, but I don't see any declaration of it, or I don't see where you're trying to use it.
Looking at some of the other questions, this is the code I implemented in the .m of the view implementing the custom keyboard.
- (id)initWithCoder:(NSCoder *)coder {
self = [super initWithCoder:coder];
if (self) {
self.userInteractionEnabled = YES;
[self addGestureRecognizer:
[[UITapGestureRecognizer alloc] initWithTarget:self
action:#selector(becomeFirstResponder)]];
NSArray *bundle = [[NSBundle mainBundle] loadNibNamed:#"FormulaKeyboard" owner:self options:nil];
for (id object in bundle) {
if ([object isKindOfClass:[FormulaKeyboard class]])
keyboard = (FormulaKeyboard *)object;
}
self.inputView = keyboard;
}
return self;
}
Below is the error that showed up.
* Terminating app due to uncaught exception 'NSUnknownKeyException', reason: '[ setValue:forUndefinedKey:]: this class is not key value coding-compliant for the key view.'
When I load the nib in an actual view controller, it works fine. However, as evidenced above, it doesn't work when I try loading it inside another view.
Also, in the nib, I set the file owner's class to UIViewController and attached it to the main view, since this was what another SO question instructed. I'm not sure if I need to modify this since I'm adding the custom view inside another view and not a viewc controller.
Thanks
EDIT:
.h of view implementing keyboard
#interface EquationTextField : UIView <KeyInput> {
FormulaKeyboard *keyboard;
}
#property (readwrite, retain) UIView *inputView;
#end
Inside the xib if you ctrl + click the File's Owner you will most likely see that you have a view outlet that is connected to the top level view object in the xib.
Refers to an IBOutlet in your code
Refers to an object in Interface Builder
The reason this works inside a UIViewController is that a UIViewController has a property view which gets connected up when loading the xib.
A UIView subclass does not normally have a property called view therefore you get an exception.
Seems as you are grabbing the item from the top level objects array returned by the loadNibNamed:owner:options: method you do not need this connection in the xib. Therefore you can disconnect this connection in the xib file.
Alternatively
You could:
Change the File's Owner class to the class of your custom view.
Make inputView an IBOutlet
Connect inputView to your custom keyboard in the xib
Then just use
[[NSBundle mainBundle] loadNibNamed:#"FormulaKeyboard" owner:self options:nil];
It seems like your view does not have a property called 'inputView', hence when you set the property on self, you get the exception.