im on OSX, XCode9, Objective C.
I have a viewController layouted in IB. The view contains a button connected to the corresponding viewController
SHTourViewController.h
#property (weak) IBOutlet SHStandardButton *closeButton;
// SHStandardButton is a subclass from NSBUtton.
The view controller gets instantinated by code in another class (i need to instantinate this viewController from other classes cause i need it more than once).
// Get instance of viewController
SHTourViewController* tourViewController = [storyBoard instantiateControllerWithIdentifier:#"tourViewController"];
Now in viewDidLoad method of my viewController, i like to connect the buttons action and target:
SHTourViewController.m
- (void)viewDidLoad {
[super viewDidLoad];
[self.closeButton setAction:#selector(closeButtonClicked:)];
[self.closeButton setTarget:self];
}
- (void)closeButtonClicked:(id)sender {
NSLog(#"CLOSE!");
}
}
When i click the button, the app crashes (Thread 1: EXC_BAD_ACCESS). I can't find the mistake i am doing here.
Any help appreciated.
You are not supplying enough information about what you're doing. But, as it stands, the fact that fact that you are getting a Bad Access would suggest that some important object has vanished prematurely in a puff of smoke. My guess is that that object is self, and that the problem has to do with code after this line:
SHTourViewController* tourViewController =
[storyBoard instantiateControllerWithIdentifier:#"tourViewController"];
You are obtaining a completely new instance of this view controller but then you are not getting its view correctly into the view hierarchy and the view controller itself into the view controller hierarchy, so the view controller (I'm guessing) is released.
But you didn't show us the relevant code, so that's just a guess.
Related
Apologies if this has been replied already, I've been searching and I quiet cannot find what I am looking for.
I am trying to make a multiple view application (based on the single view template) and I want to have an object linked to each of the views.
So my intention is to have the same I have coming from the single view template: 1 view on the storyboard which is linked to the ViewController class.
I found some tutorials by using Navigation Controllers, Page View controllers, etc... but I don't want to use that functionality, I prefer to create my own buttons and link them to those pages.
I have a few questions, if you can help:
1 - Should I have an array of view objects?
I've seen an old tutorial where the guy creates a new view object when a button is pressed and then set the view as modal (which leads to the other class) and afterwards it destroys it immediately (I guess when the code come back once the modal view is closed).
In my case I would like to have an array of views and initialize all of them at the beginning of the app and just swap from one to the other depending on the user actions.
Which one is a better approach?
2 - How I create the class linked to the other view?
Can I create a normal class and make it subclass of UIViewController, is that enough or I need something else?
3 - Once I have the class created, how can I 'link' it to a view on the storyboard?
Basically I would like to have the outlets of each view in its correspondent class (and actions, etc...).
I am not sure if what I am trying to do is actually the correct way, any comments or help is more than appreciated :)
EDIT: I´ve managed to create a class, link it to a view of the storyboard and lunch it when the user press a button, but the new view appears completely black - any ideas?
Here is my code:
TestView.h:
#import <UIKit/UIKit.h>
#interface TestView : UIViewController
#end
TestView.m:
#import "TestView.h"
#interface TestView ()
#end
#implementation TestView
- (id) init
{
self = [super init];
return self;
}
- (void)viewDidLoad {
[super viewDidLoad];
// Do any additional setup after loading the view, typically from a nib.
}
#end
Then in the storyboard, I dragged in a new View, and in the "Identity Inspector" in the field "Class" I selected the TestView.
The in the file ViewController (the one created by default by the single view wizard), I added an action when a button is pressed:
- (IBAction)goToView1:(id)sender
{
[self presentViewController:view1 animated:YES completion:nil];
}
Also in the ViewController, function 'ViewDidLoad' I initialize the TestView class:
- (void)viewDidLoad {
[super viewDidLoad];
// Do any additional setup after loading the view, typically from a nib.
view1 = [[TestView alloc] init];
}
So when I pressed the button it seems is doing something right or attempting to move to a different view, but the whole screen appears black - Am I missing something?
Thanks a lot in advance!!
I am creating some sample applications to understand the concepts of view navigation, binding etc in cocoa.
Here is the scenario:
I have a window that has a tab view(2 tabs) in MainMenu.Xib.
I have a text field in the first tab and label in the second tab. I want both of them to reflect the same value and I want to do this using binding. Also, I don't want to use the views provided to me along with the tab view.
These are the steps I have done.
The view of each tab view item is set separately in the applicationDidFinishLaunching: method using the following code:
- (void)applicationDidFinishLaunching:(NSNotification *)aNotification
{
// Insert code here to initialize your application
//initialize view controllers
view1=[[ViewTab1 alloc] initWithNibName:#"ViewTab1" bundle:nil];
view2=[[ViewTab2 alloc] initWithNibName:#"ViewTab2" bundle:nil];
//set views
[[[myTabView tabViewItems] objectAtIndex:0]setView:view1.view];
[[[myTabView tabViewItems] objectAtIndex:1]setView:view2.view];
}
myTabView is the outlet reference of the tab view from MainMenu.xib in AppDelegate.
ViewTab1 is the name of the first view controller (and the xib).
ViewTab2 is the name of the second view controller (and the xib).
ViewTab1 has one single text field (and an associated label). I have bound this to a variable(name) declared in AppDelegate.
ViewTab2 has a label. I have bound this also to the same variable in AppDelegate.
The variable, 'name' is initialized in the init method of AppDelegate.
AppDelegate.h
....
NSString *name;
....
#property(strong) ViewTab1 *view1;
#property(strong) ViewTab2 *view2;
#property (assign) IBOutlet NSTabView *myTabView;
#property (strong) NSString *name;
....
AppDelegate.m
....
#synthesize myTabView;
#synthesize view1,view2;
#synthesize name;
....
- (id)init {
self = [super init];
if (self) {
name=#"dummy";
}
return self;
....
Apart from this I haven't done any coding in my program.
In the ViewTab1.xib I got an object and made it an instance of AppDelegate and then connected the delegate reference of the Application object(NSApplication) to the same object. (I hope this is the right way of getting the AppDelegate object.)
I did the same in ViewTab2.xib
Then I bound the text field in ViewTab1 and label in ViewTab2 to this variable in AppDelegate.
When I run the program both the text field and label shows "dummy". But when I change the value in the text field, its not reflected in the label in the second tab( i.e. ViewTab2).
Please tell me what I'm doing wrong.
How to establish binding to the same App delegate object from any loaded Nib?
Yes, I know this frustrated situation as described in question... after many weeks and hundreds pages of documentation for KVO - Notifications - Bindings I think there is one very simple solution for that.
As we can find in some information sources the nib-loading process produce new instances of members... and we need to use binding connection to the old one.
Note that bindings made in InterfaceBuilder are redirect to these new instances automatically after loading nib
Why not redirect the pointer of App delegate to the old instance?
In method where you loads your nib you can test which object is app delegate before and just after nib load.
If the new one isn’t the same as the previous one you can redirect it as you want.
This simple example works for me in Xcode3 under 10.5.8 with target to OSX10.5 / i386:
// ***** SOMEWHERE IN DEFAULT APP-DELEGATE.m IMPLEMENTATION
- (IBAction) createOtherWindowFromNib: (id)sender
{
// ensure that app delegate is set as you want...
[NSApp setDelegate:self];
NSLog(#"APP-DELEGAT **** CREATE-TEST-WINDOW ***** WHO IS APP-DELEGATE BEFORE NIB LOAD: %# ", [[NSApp delegate] description]);
// we can bind members of the nib to this controller over proxy object named "File’s Owner"
NSWindowController *otherWinCapo = [[NSWindowController alloc] initWithWindowNibName: #"OtherTestWindow"];
NSLog(#"APP-DELEGAT **** CREATE-TEST-WINDOW ***** WHO IS APP-DELEGATE AFTER NIB LOAD: %# ", [[NSApp delegate] description]);
// make some test for delegates before/after here if you need ...
// usually your bindings made inside "OtherTestWindow.xib" by IB doesn’t works in this moment
// ... and some redirection if needed
[NSApp setDelegate:self];
// afer that the bind made in IB inside "OtherTestWindow.xib"
// referred to (proxy object) "Application.delegate.myBOOL" (Bind to:Application, Model Key Path:delegate.myBOOL)
// react to changes of myBOOL placed in default app delegate object as expected
// simultaneously in every open instance of "OtherTestWindow.xib"
[otherWinCapo showWindow: otherWinCapo.window]; // we need populate the window instance on screen to see it
}
I think the problem is that the objects in your xibs that you set to the app delegate class create 2 different instances of the app delegate, so changing the value of the text field changes the value of name in one instance but not in the other. That's what you're doing wrong, unfortunately, I can't think of a solution at this time.
Have you turned on 'Continuously Updates Value' in the NSTextField controls?
See this example.
I have a simple test app (in OSX) that has a view controller with a button in its view. The button's action method is in the view controller's class, and that IBAction is connected in IB (through File's Owner). When the button is clicked, I get an EXC_BAD_Access error (except occasionally I get -[NSRunLoop buttonClick:] instead). I've read a bunch of posts here on SO having to do with NSViewControllers not being in the responder chain, but also that specifically hooking the action method up in IB should work. The only code I have is this:
In the app delegate:
- (void)applicationDidFinishLaunching:(NSNotification *)aNotification {
TestController *controller = [[TestController alloc] initWithNibName:#"TestController" bundle:nil];
[self.window.contentView addSubview:controller.view];
}
And, in the TestController class, just this:
-(IBAction)buttonClick:(id)sender {
NSLog(#"%#",sender);
}
I have 2 questions. Why is this happening, and where is the correct mvc place to put IBActions for button methods (shouldn't controller classes handle these)?
First off, I believe in the App Delegate there is already a property called viewController already defined for you. You should use this code self.viewController = [[TestController alloc] initWithNibName:#"TestController" bundle:nil]; instead of TestController *controller = [[TestController alloc] initWithNibName:#"TestController" bundle:nil];. If that doesn't fix it, then I'm not sure what's wrong. Your code should return the attributes of the button you clicked. I created my own sample project and tested out your code (although my app delegate looked different than yours) and it worked fine.
Second, you should elaborate on your second question "Why is this happening, and where is the correct mvc place to put IBActions for button methods (shouldn't controller classes handle these)?". It's not very clear what you mean.
Hope this helps a little.
NSViewController will not respond to IBActions on mac os x on iPhone It is the correct place to put your IBAction as the view should only draw its content (data) not change it. But on Mac os x the NSViewController is for setting up the NSView it's no ment to respond to IBActions you have two choices one is to put your IBAction in your NSView or is create a NSWindowController .
On mac osx you have plenty of screen space and you will alway have views within a window you'll use NSViewController to add them to your window and to setup your view but the window is first in your responder chain then your NSWindowController . eg: you may have one window and two view controller showing the same view which may have 5 test fields in it and view controller one loads that with data but you can not edit the data then view controller two loads the same view with the same data but enable editing for the text fields so. but all action methods will go to the WindowController .
I recommend you to check your viewController's identity inspector.
It may indicate wrong custom class.
viewController created basically usually has name ViewController on the section.
I am trying to open a ViewController from within another ViewController if certain conditions are met. The code seems to run without error but the view is never shown. I am new to xcode 4 /ios 5 so I must be missing something.
Here is the code responsible for opening the second viewcontroller:
CreateUserViewController *createUserController = [[CreateUserViewController alloc] initWithNibName:#"CreateUserView" bundle:[NSBundle mainBundle] keyWrapper:keyChainWrapper];
[self presentViewController:createUserController animated:YES completion:nil];
In my project I have a xib called, "CreateUserView". I have added a view controller to this xib and assigned it to, "CreateUserViewController".
Also I noticed in the apple documentation that is shows setting the delegate of the viewcontroller to be presented. But it seems that no property called, "delegate" is on the viewcontroller object. Is this documentation old? This is the document I am trying to use (section 9-1):
View Controller Programming
Can someone give me a hint? Thanks..
edit Adding Custom Constructor
-(id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil keyWrapper:(KeychainItemWrapper *)keyWrapper
{
self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
if(self){
[self setKeyChainWrapper:keyWrapper];
}
return self;
}
Regarding CreateUserView.xib: you don't want to put a CreateUserViewController object in the nib. You want to set the custom class of the File's Owner placeholder to CreateUserViewController. Then you need to connect the view outlet of File's Owner to the top-level view in the nib.
Regarding the delegate property: The UIViewController class doesn't have its own delegate property. The idea is that you add a delegate property to your subclass of UIViewController. The delegate provides a way for your presented view controller to pass custom information back to the presenting view controller.
Why would you want to do that? Let's consider the code you posted. I'll assume you have a UserListViewController that shows a list of User objects, and has a "Create new user" button. When the user touches the "Create new user" button, you create a CreateUserViewController and present it.
The user interacts with the CreateUserViewController to set the attributes of the new User object - name, rank, hairstyle, etc. Then he touches a "Done" button. Your CreateUserViewController creates the new User object and puts it in the database. Then it needs to dismiss itself, so the UserListViewController's list of User objects will appear again.
But you want the User list to include the newly created User object and you want to scroll the list so that the new User is on the screen. So you need a way to have your CreateUserViewController tell the UserListViewController about the newly created User object. This is where the delegate comes in.
You define a protocol like this:
#protocol CreateUserViewControllerDelegate
- (void)didCreateUser:(User *)user;
#end
and you give your CreateUserViewController a delegate property:
#interface CreateUserViewController
#property (weak, nonatomic) id<CreateUserViewControllerDelegate> delegate;
// ...
When your CreateUserViewController's "Done" button is touched, you notify your delegate of the new User:
- (IBAction)doneButtonWasTouched:(id)sender {
User *user = [self createUser];
[self.delegate didCreateUser:user];
[self dismissViewControllerAnimated:YES completion:nil];
}
In your UserListViewController, you adopt and implement the protocol:
#interface UserListViewController <CreateUserViewControllerDelegate, UITableViewDelegate, UITableViewDataSource>
// ...
#end
#implementation UserListViewController
- (void)didCreateUser:(User *)user {
NSIndexPath *indexPath = [NSIndexPath indexPathForRow:[self.users count] inSection:0];
[self.users addObject:user];
[self.tableView insertRowsAtIndexPaths:[NSArray arrayWithObject:indexPath] withRowAnimation: UITableViewRowAnimationAutomatic];
[self.tableView scrollToRowAtIndexPath:indexPath atScrollPosition: UITableViewScrollPositionNone animated:YES];
}
and when you need to present a CreateUserViewController, you set the new controller's delegate to the UserListViewController:
- (IBAction)createUserButtonWasTouched:(id)sender {
CreateUserViewController *createUserController = [[CreateUserViewController alloc] initWithNibName:#"CreateUserView" bundle:[NSBundle mainBundle] keyWrapper:keyChainWrapper];
createUserController.delegate = self;
[self presentViewController:createUserController animated:YES completion:nil];
}
In iOS5 the method for pushing new view controllers was really changed around quite a bit from iOS4 and Xcode 3. In summary, storyboards are now used to create your application view controller flow. Even though you may use standalone .xib files to build an application it is much less common in iOS5.
Anyway, the main method for pushing new view controllers onto the screen is done using segues. Check out this tutorial for an introduction: http://www.raywenderlich.com/5138/beginning-storyboards-in-ios-5-part-1
It does a good job on explaining how to create a storyboard and use segues. You can still present view controllers in code "the old way" but it is much much less common now with the introduction of these new technologies. There are also some absolutely awesome tutorials on iTunes U - search for CS193P. It's the Stanford Introductory class to Objective-C and programming for iOS. This should get you started and maybe help you think of a way to push your createUserController in a way more up to speed with iOS5.
UPDATE
I just wanted to add. If you configure your program to use storyboards and segues you can use the method performSegueWithIdentifier:sender: to perform the segue to your createUserController view if the proper conditions are met. See the Apple API for UIViewController for information on how to use this method.
I have a view based app (not navigation or tab based...)
My main view controller is called from the app delegate and initiated from a xib.
Then I use presentModalViewController to bring another view on the screen with it's own xib and view controller.
I have no problems passing data to that view controller.
However, when I dismiss the second view controller, I want to send data back to the main view controller for my app, but I just can't figure out how to reference it. Actually, I'd like to call a method in the main view controller if possible.
I've been struggling with this a bit and have found suggestions online but I just can't seem to get it to work. I'm hoping someone can provide the sample code to do this.
P.s. is this "main view controller" still referred to as a "root view controller" or is that term only used when dealing with a view controller stack (i.e. navigation or tab view controller)
EDIT:
I'm sure Bryan's solution would work so I have accepted as answer. However I ended up using NSNotificationCenter to get this to work and I find it a bit simpler to understand as a beginner
You can use the delegation pattern. In your modal view controller's header file, create an interface for a new delegate protocol...
#protocol ModalViewControllerDelegate <NSObject>
- (void)sendData:(Data *)someData;
#end
...and give your ModalViewController a new instance variable that implements this protocol:
#property (nonatomic, assign) id<ModalViewControllerDelegate> delegate;
Your main view controller should implement this protocol...
#interface MainViewController : UIViewController <ModalViewControllerDelegate> {
...and set itself as the delegate before it presents the modal view controller:
ModalViewController *modalViewController = [[[ModalViewController alloc] init] autorelease];
[modalViewController setDelegate:self];
// Present modal view controller
The main view controller should implement the delegate protocol's method:
- (void)sendData:(Data *)someData {
NSLog("I have just received some data: %#", someData);
}
Then inside your modal view controller, you can simply call the following method whenever you want to send data back to the main view controller:
[delegate sendData:someData];