View Controller value passing

Question

I have an iOS application that has Controller A, which uses a tableview that adopts the 3D touch protocol. Each cell actually adopts this 3D touch so when selecting a cell, it will bring a modal view controller (Controller B).

This controller B is basically used to fill information that is then added to the tableview on Controller A.

So in applying the DRY principle, I am reusing Controller B for adding and editing data.

Problem:

Controller B has a property

var didPresentVia3dTouch : Bool = false

and a method:

public func setPreference(editMode: Bool) {
   self.didPresentVia3dTouch = editMode
}

So this method is supposed to set the value of didPresentVia3dTouch to true from false when the tablecell in Controller A is forced touch, rather than being presented thru the navigation item button as a general 'Add' call.

in Controller A, i've kept a reference to Controller B like so:

var controllerBref = AddEditViewController()

so in the method

func previewingContext(previewingContext: UIViewControllerPreviewing, commitViewController viewControllerToCommit: UIViewController)

I call the method setPreference from Controller B like so:

controllerBRef.setPreference(true)

in order to invoke Controller B to act as an Edit view for data on that cell.

One issue that i've noticed is that when I print the value of Controller B's method setPreference(editMode: Bool), the editMode constant, it prints out true, but in the viewWillAppear, viewDidAppear, viewDidLoad, and all other methods, the value for didPresentVia3dTouch still reads false, so therefore not allowing me to change the title of the navigation bar whether its on Edit mode or Add new mode.

Is there something I am missing or not understanding here? I tried delegation but could not figure it out.

What I would do is just use two different view controller classes. I think your use of DRY is misplaced here. One view controller can be the subclass of the other except that one is intended for the 3D "peek" context. — matt, May 22 '18 at 22:25

score 1 · Accepted Answer · answered May 22 '18 at 22:27

1

You need to set the property on the view controller instance that will be presented, not some random instance that you have instantiated and stored in a property.

Use:

func previewingContext(previewingContext: UIViewControllerPreviewing, commitViewController viewControllerToCommit: UIViewController) {
    if let destVC = viewControllerToCommit as? AddEditViewController {
        destVC.setPreference(editMode:true)
    }
}

answered May 22 '18 at 22:27

Paulw11

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Thank you mate, it worked. I did however, used the title in the viewDidAppear method, so upon testing it, somehow when making the view false, the title takes 1 second to load and display the name of the viewController. Any thoughts? – Samarey May 23 '18 at 14:23
Sorry, no, not from what is shown here. but you could ask another question w the relevant code there – Paulw11 May 23 '18 at 20:56

score 0 · Answer 2 · answered May 22 '18 at 22:24

0

The problem is that this line

var controllerBref = AddEditViewController()

has no relation the currently presented VC , i mean it's a separate instance , so when you present B set it to controllerBref

answered May 22 '18 at 22:24

Shehata Gamal

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View Controller value passing

2 Answers2