in my Xcode project I have a button, that does two things.
First: call an IBAction
Second: go to another view (segue)
In the action linked to the button I set a variable to YES (global var), but in the viewDidLoad method in the linked view, its still NO. Its YES in viewDidAppear though. I wonder why the action is not called first. Can I change that? I'd prefer to use the viewDidLoad method, since it seems to load quicker.
You can use the prepareForSegue method to pass whatever data to the destination view before the segue assigned to the button is performed. This data will be available in the destination view viewDidLoad
Related
I have a view controller contains a table view that displays list of items. Each item could contains list of items (or could be a leaf).
To drilldow the list items, I would like to create a show/push segue, kinda in recursively way, but I seem not able to draw the manual segue to the view controller itself?
Is it supported?
I was playing around with it just after leaving that first comment - I don't think you can have a manual segue to the same view controller!
The best thing to do would be to give that view controller a storyboard identifier (e.g Selection and then create an instance of that view controller with (in Swift):
let subCategoryVC = storyboard.instantiateViewControllerWithIdentifier("Selection") as! SelectionViewController
or in Objective-C:
SelectionViewController *subCategoryVC = (SelectionViewController *) [self.storyboard instantiateViewControllerWithIdentifier:#"Selection"];
(Docs for UIStoryboard.instantiateViewControllerWithIdentifier:)
You could put that in your table view section method along with a manual segue to the leaf view controller.
(The code above assumes the view controller with the table view is called SelectionViewController!)
As Rich mentioned, this is probably not doable as for today. There are two workaround/solutions I can think of:
Instaniate the vc programatically from storyboard and programatically
use navigationController to push it. (I think this is what Rich was
talking about.)
Embed the View Controller in another Navigation Controller and draw
the manual segue to the Navigation Controller.
I choose the 2nd one just because it is very easy and more visual in storyboard. The first one should just work, too.
I have an NSArrayController bound to CoreData in my application. It is also bound to a TableView that displays the data. Two buttons are bound to the ArrayController that add and remove lines. All of this is working as expected. I can add, edit, save, and remove CoreData Entries.
There is a section of my app that is to accept drag and drop operations from files (working). It takes the data from the files, looks for various information, and is to insert this information into the Core Data database via the NSArray Controller.
I have added the class handling the parsing/adding of the file to the database as an object in IB. I created an IBOutlet for the array controller in the class, and bound the controller to the class' referencing outlet.
If I add a button to the interface to directly call the method that adds a custom record to the database, everything works. If the method is called via the drag and drop operation, nothing works, even logging a simple [arrayController className] returns null (though returns NSArrayController as expected when the method is called from the button click).
The only difference I can see is that when accessed through the button click, the method is called directly, while the other way passes through my drag and drop class before loading the parsing class, but I'm completely stuck on how to remedy this situation. I'll be happy to provide code, just not sure which code you'll need.
Any help is appreciated. Thanks!
==================
UPDATE
turns out I was connecting the IBOutlet to a class (a subclass of a view) object in IB instead of to the view itself handling the drops. Connecting these up made things work. Well, not work, I have other issues to iron out now, but the Array controller is now instantiated.
Moved from comment to answer: The array controller you are trying to add stuff is not instantiated. I assume you are not referring to your original NSArrayControllerinstance but maybe a new created one? Probably a problem of communication between your class instances.
Debugging this should be straightforward ... using the debugger. Set a few breakpoints (one at each action the button(s) call, and one at each point where your class instances are meant to talk to each other (your importer and your main controller)). Run, test, step through the code when the debugger breaks at each breakpoint.
My guess: An outlet is not hooked up (is nil) in IB or is not yet reconnected at runtime (see -awakeFromNib and make sure you're not trying to touch an outlet or action that hasn't been fully reconnected from the nib at runtime by the time you're trying to use it).
Something’s not hooked up right, BUT you don’t want to do it this way anyways. There’s no advantage to inserting via an NSArrayController. Just create new objects with NSEntityDescriptions:
+ (id)insertNewObjectForEntityForName:(NSString *)entityName inManagedObjectContext:(NSManagedObjectContext *)context;
And you’re done. If your NSArrayController is hooked up correctly it’ll auto-fetch the new objects at the end of the event so the user will see them “immediately.”
i am working on storyboards which has couple of views on first view a condition is placed i want if the condition satisfies then only navigation should happen
For this i have used Custom segue but no matter my condition satisfies or not it navigates to new view.
I have created method in custom segue class
- (void) perform{
NSLog(#"source %#",self.sourceViewController);
NSLog(#"dest %#",self.destinationViewController);
UIViewController *sVC=self.sourceViewController;
UIViewController *dVC=self.destinationViewController;
[sVC.navigationController pushViewController:dVC animated:YES];
}
I want to set condition if result is 1 then only it should navigate. Woul prepareforsegue or initwithsegue provide me any help
Are you saying that you only want to perform the segue if a condition is true?
If so, instead of creating the segue directly from a control or table cell, create a triggerless segue. A triggerless segue has the view controller as its source, and it won't ever fire automatically. Instead you can fire it programmatically any time you like, including from an IBAction.
To create a triggerless segue, start control+dragging the segue from the containing view controller icon in the scene dock at the bottom of the scene. Drag to the destination scene like normal, and pick the segue type. Select the segue, and in the inspector, choose a segue identifier.
At runtime, when you want to perform the segue, invoke -[UIViewController performSegueWithIdentifier:sender:]. You can pass any object you'd like for the sender, including nil. If the sender has no use to you, pass nil.
So, in summary:
Create a triggerless segue from the view controller to the destination scene
Set an identifier for the segue in the inspector
At runtime, and form code, call -[UIViewController performSegueWithIdentifier:sender:] when you want to trigger the segue.
I have an NSView (we'll call it view1) that is from an NSViewController. The Super view (which we'll call view2) is located inside an NSWindowController. The problem is, I can add view1 to view2, but I can't remove it.
From your comment I'd guess one of your instance variables to the view controller or the view itself isn't being set correctly, so you're calling removeFromSuperView on nil. Use the debugger to explicitly see the state of the objects involved.
I created a view Called ProgrammaView that appears when a row of a table is clicked.
This view has a UILabel, a UIImageView and a UITextView.
Now.
ProgrammaView's Outlets have to be changed by the parameter passed to a method of the view called iniz.
in this
image there is first the ProgrammaView.h and then the method iniz.
The problem is that the label and other stuff doesn't change!
I checked 3 million times that everything between the xib file and the controller is linked.
The trick to call iniz in the other viewcontrollers works well in other part of the program so i think is not that the problem.
Thank you in advance!
You need to call setNeedsDisplay to indicate that the view should be redrawn.
My understanding is that you start up and show view after that you update the values and expect the view to display new values.
You need to call setNeedsDisplay to indicate that the view should be redrawn. Try to add it at the end of your iniz method.
See apple doc.