Sorry - this may be an easy question, I'm new to iPhone development and still wrapping my head around Views vs ViewControllers.
I have a NavigationViewController and I can push Views using the following method in the RootViewController which is connected to a Bar Button Item:
- (IBAction)switch:(id)sender {
NSLog(#"Swith...");
LibraryViewController *varLibraryViewController = [[LibraryViewController alloc] initWithNibName:#"LibraryViewController" bundle:nil];
[[self navigationController] pushViewController:varLibraryViewController animated:YES];
}
I want to call this same method from a button on the same view that is currently loaded. Basically I want to have the Bar Button at the top call the same method as a button on the view. I was wondering how to call a method in the ViewController from the view loaded from that viewController. Hopefully that makes sense.
Do I need to create an instance of the RootViewController? I would think that would already be instantiated. Thank you.
BTW, the code you have pasted there is leaking your LibraryViewController. You need to either explicitly release it after pushing it, or autorelease it when it's created.
Your RootViewController should have its own xib file. In this xib, the RootViewController is represented by the object named "File's Owner". You can link buttons on the view to File's Owner the same way you can link things to RootViewController in MainMenu.xib.
You'll want to declare your method as an IBAction in your header file:
- (IBAction) myMethod: (id) sender;
Save your header, then switch to Interface Builder. Right click on the Bar Button, and drag from the selector tag to your view controller object (probably the File Owner). When you release, you should be given a popup menu of available actions, and myMethod should be selectable.
If you don't get this popup, you may need to make sure your File Owner class is set properly: select the File Owner in the file window, then select "Tools" > "Identity Inspector" from the menu. In the inspector, type your view controller's class into the Class field.
Related
I programmatically instantiate a UIViewController from a xib, add it as a child VC to an existing main view, then add the child VC's view (which contains a button) to my main view. The view with the button displays just fine, but when I press the button, the app crashes with an "unrecognized selector" message.
I created the XIB by creating a custom subclass of a UIViewController ( File - New - Cocoa Touch class, selecting a subclass of UIViewController, and asking Xcode to also generate the XIB file). I then placed a button on that XIB, and hooked it up to the newly created UIViewController subclass. The XIB file's owner is set to the name of the new class.
So it looks to me like the ButtonPushed action message doesn't get send to my custom UIVC, and is going instead to the generic UIViewController - which rightly doesn't understand the ButtonPushed message.
How do I make sure that the action message sent when the button is pressed in fact goes to my custom UIViewController?
This is the code in my awakeFromNib method for the main view (main view is from Main.storyboard):
UIViewController *vc2 = [[UIViewController alloc] initWithNibName:#"ButtonVC" bundle:nil];
vc2.view.frame = CGRectMake(90, 140, 50, 200); //dont obscure the main view completely.
[self addChildViewController:vc2];
[self.view addSubview:vc2.view]; //vc2.view has a button, which shows up fine
[vc2 didMoveToParentViewController:self];
I've managed to get the equivalent functionality by creating a storyboard just with the button, and programmatically loading that, then instantiating my buttonViewController, adding it and its view as a child VC to my main view. That works just fine, but it seems to me like I should be able to achieve this with "only" a XIB.
Try this:
UIViewController *vc2 = [[ButtonVC alloc] initWithNibName:#"ButtonVC" bundle:nil];
And also make sure that the class in your xib for the view controller is set properly (see my answer here)
I have a UIButton that I create in my sub class ViewController, and add it to my MainViewController.
Now, I added a target method to this button that should push another view controller to my Navigation controller (the one that in the MainViewController).
I know that the method did call when I push the button, but the view wasn't push to the Navigation Controller.
I scanned this drawing - this is the drawing (I also added part of my code):
This is the code I'm using in my button:
(remember it's in a deferent ViewController).
- (void)buttonPressed:(UIButton *)sender
{
Photo_ScreenGlobalView *photo = [[Photo_ScreenGlobalView alloc] init];
[self.navigationController pushViewController:photo animated:YES];
}
Usually I solve these situations with delegation. If there is a view controller which is subordinate to another (i.e. a "sub" view controller) but should have the ability to trigger navigation changes, etc... then it should have a weak pointer back to it's 'parent'. Then the parent VC should implement an appropriately named protocol with a callback for the child to use. The names of these things can be generic, such as #property navigationDelegate and requestNavigationToViewController: or they can be more semantic, such as #property userFormDelegate and userFormDoneButtonPressed:
Generally speaking, a subordinate view controller should not be able to directly modify navigation at it's parent's level; but it can trigger it via more loosely-coupoled interfaces like these.
i came back to let you all know how i actually did it.
after googling a lot found this nice and quick guide how to make DELEGATE
and working with delegate solved all my problems. if you need any help don't hesitate to send me PM.
this is the guide:
http://css.dzone.com/articles/do-not-publishcreating-your
I have a UISplitViewController with the master view set up like this:
UITabBarController
Tab1:
UINavigationController -> UIViewController -> UIViewController
Tab2:
UINavigationController -> UIViewController
Each of the UIViewControllers is a table view, and when the user chooses a row in the last one, an image is shown in the detail view, which contains a UIScrollView.
The tab bar Controller is the UISplitViewControllerDelegate and handles putting up the button on a toolbar at the top of the scroll view.
The problem is, I want to add code to dismiss the popover when the user makes their choice. The pointer to the popover has to be saved in the tab bar controller when the button goes up, and then used to dismiss the popover several view controllers down the line when the user makes their final selection. There doesn't seem to be any way for the view controller that needs that pointer to get at it, without doing something gross like storing it in the App Delegate.
I don't see other people asking this question, which leads me to believe that I've once again overlooked something simple. Please enlighten me!
It sounds like your tab bar controller is already a subclass of UITabBarController, which means that you've already got some custom code in there. I would suggest that the tab bar controller is the primary owner of the popover, and it is the table view controller's responsibility to simply notify the tab bar controller that a selection has been made. The tab bar controller can respond to that message by dismissing the popover. You can take advantage of the fact that UIViewController already has a method for accessing the tab bar controller that contains a given controller.
So it would look something like this:
#interface MyTabBarController : UITabBarController
- (void)itemWasSelected;
#end
#implementation MyTabBarController {
UIPopoverController *popover;
}
- (void)itemWasSelected {
[popover dismissPopoverControllerAnimated:YES];
}
#end
//////////////
#implementation TableController
- (void)tableView:(UITableView *)tv didSelectRowAtIndexPath:(NSIndexPath *)path {
// Do whatever else you want to do
MyTabBarController *tabController = (MyTabBarController *)self.tabBarController;
[tabController itemWasSelected];
}
With this solution, the table controller doesn't have to know anything about the popover; it just has to know that it's going to be presented inside a MyTabBarController, which seems a reasonable thing for it to know.
You could create a singleton class to track your popover status and then make it available to all classes equally and easily. That way it could easily be updated and accessed from any code without having to go straight to overburdening the app delegate even though thats basically the same idea but a bit cleaner in its own singleton.
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 must be doing stupid, but I can't see what: my UITableViewController subclass is never called when the edit button of my navigation is pressed.
What could be causing that?
My view hierarchy is loaded from a Nib file and put inside a popover. The [+] button is connected to the insertNewObject action of my UITableViewController subclass. It works fine.
The [Edit] button however has no action to connect to. The doc says it will automatically call the setEditing:animated: method of the view controller, which I override.
The nib file is set up pretty much as usual AFAICT. And in fact, I'm not sure what additional detail I can give that would suggest my mistake.
What is the control flow from the click on the [Edit] button to the call of the setEditing:animated method?
I feel like we must be missing the same thing.
Whatever the case, I made it work by doing the following.
IBOutlet UIBarButtonItem *editButton;
-(IBAction)editButtonPressed:(id)sender {
[self setEditing:YES animated:YES];
}
- (void)setEditing:(BOOL)editing animated:(BOOL)animate
{
if(self.tableView.isEditing)
{
self.editButton.style = UIBarButtonItemStylePlain;
self.editButton.title = #"Edit";
}
else
{
//self.editButton.style = UIBarButtonSystemItemDone;
self.editButton.style = UIBarButtonSystemItemEdit;
self.editButton.title = #"Done";
}
// Toggle table view state
[super setEditing:!self.tableView.isEditing animated:animate];
}
I hooked the editButton up to the button I added to the nav bar and it's action to the editButtonPressed IBAction. After doing that my setEditing: is called (obviously) and the super call toggles the table view's editing state.
I'd like to use the system defined button styles, but the appropriate one is commented out because while it did change style I couldn't figure out how to change the text from "Edit" to "Done" so I had to do it all manually (that only worked if I left the button as Custom and set the style generically). This has the downside of not being localized (for free), etc.