如何在同一ViewController中初始化两个NSObject实例-Swift

Question

Please bear with me. I'm new to programming and new to StackOverflow. I hope that my question will grant me a warm response for entering the programming community. An acquaintance, whose opinion I trust, told me to post this email to him on StackOverflow.

What do I have to do to get two instances of NSObject to work in the same ViewController? I've initialized an NSObject subclass called SideBar and RightSideBar. They both draw from NSObject. The cells in the menu are called created by a TableViewController I created programatically. I followed a tutorial that did everything programmatically because I didn't know that Storyboard is better for building things.

Below is the code base.

EDITED: Sorry for being long winded. I don't know how to make this any shorter and as complete

===========

****Note the SideBar subclass is the left menu. The RightSideBar class has the same initializer setup and is the right menu. I want to be able to make them both appear on the same ViewController in the same instance of the same ViewController if possible.****

This is the left TableViewController:

import UIKit
//this protocol of the sidebar delegate manages the selection of the item in the row.
protocol SidebarTableViewControllerDelegate {

     func sidebarControlDidSelectRow(indexPath: NSIndexPath)

}

class SidebarTableViewController: UITableViewController {

    //setting up the delegate and array of menu items.
    var delegate:SidebarTableViewControllerDelegate?
    var tableData:Array <String> = []
    var imageData:[UIImage] = []


    // MARK: - Table view data source

    //Setting up the number of sections in the menu
    override func numberOfSectionsInTableView(tableView: UITableView) -> Int {

        return 1
    }
    //Setting up the number of items in the menu
    override func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {

        return tableData.count
    }

    //Setting up the menu look for the main screen after login.
    override func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
        var cell:UITableViewCell? = tableView.dequeueReusableCellWithIdentifier("Cell") as? UITableViewCell

        if cell == nil {

            cell = UITableViewCell(style: UITableViewCellStyle.Default, reuseIdentifier: "Cell")
            //configure the cell...

            cell!.backgroundColor = UIColor.clearColor()
            cell!.textLabel?.textColor = UIColor.darkTextColor()

            let selectedView:UIView = UIView(frame: CGRect(x: 0, y: 0, width: cell!.frame.size.width, height: cell!.frame.size.height))
            selectedView.backgroundColor = UIColor.blackColor().colorWithAlphaComponent(0.3)

            cell!.selectedBackgroundView = selectedView

        }

            cell!.textLabel!.text = tableData[indexPath.row]
            cell!.imageView!.image = imageData[indexPath.row]


            return cell!

    }

    //Setting up the height for each cell of the table
    override func tableView(tableView: UITableView, heightForRowAtIndexPath indexPath: NSIndexPath) -> CGFloat {

        return 45.0

    }

    //Setting up the selection of the item in the cell.
    override func tableView(tableView: UITableView, didSelectRowAtIndexPath indexPath: NSIndexPath) {

        delegate?.sidebarControlDidSelectRow(indexPath)
    }

    override func viewDidLoad() {

    }

    override func didReceiveMemoryWarning() {

    }

}

This is the right table view controller:

//setting up the RightSidebarControllerDelegate
protocol RightSidebarTableViewControllerDelegate {

    func rightSidebarControlDidSelectRow(indexPath: NSIndexPath)

}

class RightSidebarTableViewController: UITableViewController {

    //setting up the delegate and array of menu items.
    var delegate:RightSidebarTableViewControllerDelegate?
    var rightTableData:Array <String> = []
    var rightImageData:[UIImage] = []


    // MARK: - Table view data source

    //Setting up the number of sections in the menu
    override func numberOfSectionsInTableView(tableView: UITableView) -> Int {

        return 1
    }
    //Setting up the number of items in the menu
    override func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {

        return rightTableData.count
    }

    //Setting up the menu look for the main screen after login.
    override func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
        var cell:UITableViewCell? = tableView.dequeueReusableCellWithIdentifier("Cell") as? UITableViewCell

        if cell == nil {

            cell = UITableViewCell(style: UITableViewCellStyle.Default, reuseIdentifier: "Cell")
            //configure the cell...

            cell!.backgroundColor = UIColor.clearColor()
            cell!.textLabel?.textColor = UIColor.darkTextColor()

            let selectedView:UIView = UIView(frame: CGRect(x: 0, y: 0, width: cell!.frame.size.width, height: cell!.frame.size.height))
            selectedView.backgroundColor = UIColor.blackColor().colorWithAlphaComponent(0.3)

            cell!.selectedBackgroundView = selectedView

        }

        cell!.textLabel!.text = rightTableData[indexPath.row]
        cell!.imageView!.image = rightImageData[indexPath.row]


        return cell!

    }

    //Setting up the height for each cell of the table
    override func tableView(tableView: UITableView, heightForRowAtIndexPath indexPath: NSIndexPath) -> CGFloat {

        return 45.0

    }

    //Setting up the selection of the item in the cell.
    override func tableView(tableView: UITableView, didSelectRowAtIndexPath indexPath: NSIndexPath) {

        delegate?.rightSidebarControlDidSelectRow(indexPath)
    }

    override func viewDidLoad() {

    }

    override func didReceiveMemoryWarning() {

    }

}

Here is where my problems may start with SideBar:NSObject. This is the left SideBar to be initialized:

import UIKit

@objc protocol SideBarDelegate {

    func sideBarDidSelectButtonAtIndex (index: Int)
    optional func sideBarWillClose()
    optional func sideBarWillOpen()
    optional func sideBarWillDeinitialize()

}

//this class sets up the actual sidebar.
class SideBar: NSObject, SidebarTableViewControllerDelegate {

    //width of the bar, tableview setup, and views for the sidebar
    let barWidth:CGFloat = 175.0
    let sideBarTableViewTopInset:CGFloat = 25.0
    let sideBarContainerView:UIView = UIView()
    let sideBarTableViewController:SidebarTableViewController = SidebarTableViewController()
    var originView:UIView!

    //var for dynamic effect and controlling the sidebar
    var animator:UIDynamicAnimator!
    var delegate:SideBarDelegate?
    var isSideBarOpen:Bool = false


    //initializer for the "SideBar" class.
    override init() {
        super.init()

    }

    //initializer for the tableView of menu items.
    init(sourceView: UIView, menuItems: Array<String>, menuImages: [UIImage]){
        super.init()

        //initializing the views and animation for the menu.
        originView = sourceView
        sideBarTableViewController.tableData = menuItems
        sideBarTableViewController.imageData = menuImages
        setupSideBar()
        animator = UIDynamicAnimator(referenceView: originView)

    }

    //function for setting up the sidebar.
    func setupSideBar () {

        //setting up the frame/outline of the side bar.
        sideBarContainerView.frame = CGRectMake(-barWidth, originView.frame.origin.y + 45, barWidth, originView.frame.size.height)

        //setting up the color of the sidebar.
        sideBarContainerView.backgroundColor = UIColor.clearColor()

        //disables subviews from being confined to the sidebar.
        sideBarContainerView.clipsToBounds = false

        //placing the sidebar in the UIView
        originView.addSubview(sideBarContainerView)

        //adding blur to the menu.
        let blurView:UIVisualEffectView = UIVisualEffectView(effect: UIBlurEffect(style: UIBlurEffectStyle.Light))
        blurView.frame = sideBarContainerView.bounds
        sideBarContainerView.addSubview(blurView)


        //setting up controls for the sidebar
        sideBarTableViewController.delegate = self
        sideBarTableViewController.tableView.frame = sideBarContainerView.bounds
        sideBarTableViewController.tableView.clipsToBounds = false

        //disabling the scroll feature. Delete to keep the scroll feature.
        sideBarTableViewController.tableView.scrollsToTop = false

        //This will remove separators in the UITableCell. Delete to keep separators.
        sideBarTableViewController.tableView.separatorStyle = UITableViewCellSeparatorStyle.None

        //This sets the background color of the sidebar and creates the inset.
        sideBarTableViewController.tableView.backgroundColor = UIColor.clearColor()
        sideBarTableViewController.tableView.contentInset = UIEdgeInsets(top: sideBarTableViewTopInset, left: 0, bottom: 0, right: 0)

        //reloads the sidebar and adds the container view to the sideBarTableViewController.
        sideBarTableViewController.tableView.reloadData()
        sideBarContainerView.addSubview(sideBarTableViewController.tableView)
    }

    func showSideBar(shouldOpen: Bool){
        animator.removeAllBehaviors()
        isSideBarOpen = shouldOpen

        //simple if and else statements to define the direction of animation and intensity of animation
        let gravityX:CGFloat = (shouldOpen) ? 0.5 : -0.5
        let magnitude:CGFloat = (shouldOpen) ? 20 : -20
        let boundaryX:CGFloat = (shouldOpen) ? barWidth : -barWidth

        //controls the behavior of the animation.
        let gravityBehavior: UIGravityBehavior = UIGravityBehavior(items: [sideBarContainerView])
        gravityBehavior.gravityDirection = CGVectorMake(gravityX, 0)
        animator.addBehavior(gravityBehavior)

        let collisionBehavior: UICollisionBehavior = UICollisionBehavior(items: [sideBarContainerView])
        collisionBehavior.addBoundaryWithIdentifier("sideBarBoundary", fromPoint: CGPointMake(boundaryX, 20), toPoint: CGPointMake(boundaryX, originView.frame.size.height))
        animator.addBehavior(collisionBehavior)

        let pushBehavior:UIPushBehavior = UIPushBehavior(items: [sideBarContainerView], mode: UIPushBehaviorMode.Instantaneous)
        pushBehavior.magnitude = magnitude
        animator.addBehavior(pushBehavior)

        let sideBarBehavior:UIDynamicItemBehavior = UIDynamicItemBehavior(items: [sideBarContainerView])
        sideBarBehavior.elasticity = 0.3
        animator.addBehavior(sideBarBehavior)
    }
    func sidebarControlDidSelectRow(indexPath: NSIndexPath) {
        delegate?.sideBarDidSelectButtonAtIndex(indexPath.row)
    }

}

This is the right SideBar:NSObject that will eventually initialize the right menu.

import UIKit
@objc protocol RightSideBarDelegate {

    func rightSideBarDidSelectButtonAtIndex (index: Int)
    optional func sideBarWillClose()
    optional func sideBarWillOpen()

}

class RightSideBar: NSObject, RightSidebarTableViewControllerDelegate {

    //width of the bar, tableview setup, and views for the sidebar
    let barWidth:CGFloat = 175.0
    let rightSideBarTableViewTopInset:CGFloat = 25.0
    let rightSideBarContainerView:UIView = UIView()
    let rightSideBarTableViewController:RightSidebarTableViewController = RightSidebarTableViewController()
    var rightOriginView:UIView!

    //var for dynamic effect and controlling the sidebar
    var animator:UIDynamicAnimator!
    var delegate:RightSideBarDelegate?
    var isSideBarOpen:Bool = false


    //initializer for the "SideBar" class.
    override init() {
        super.init()

    }

    //initializer for the tableView of menu items.
    init(rightSourceView: UIView, rightMenuItems: Array<String>, rightMenuImages: [UIImage]){
        super.init()

        //initializing the views and animation for the menu.
        rightOriginView = rightSourceView
        rightSideBarTableViewController.rightTableData = rightMenuItems
        rightSideBarTableViewController.rightImageData = rightMenuImages
        setupSideBar()
        animator = UIDynamicAnimator(referenceView: rightOriginView)

    }

    //function for setting up the sidebar.
    func setupSideBar () {

        //setting up the frame/outline of the side bar.
        rightSideBarContainerView.frame = CGRectMake(rightOriginView.frame.size.width + barWidth , rightOriginView.frame.origin.y + 45, barWidth, rightOriginView.frame.size.height)

        //setting up the color of the sidebar.
        rightSideBarContainerView.backgroundColor = UIColor.clearColor()

        //disables subviews from being confined to the sidebar.
        rightSideBarContainerView.clipsToBounds = false

        //placing the sidebar in the UIView
        rightOriginView.addSubview(rightSideBarContainerView)

        //adding blur to the menu.
        let blurView:UIVisualEffectView = UIVisualEffectView(effect: UIBlurEffect(style: UIBlurEffectStyle.Light))
        blurView.frame = rightSideBarContainerView.bounds
        rightSideBarContainerView.addSubview(blurView)


        //setting up controls for the sidebar
        rightSideBarTableViewController.delegate = self
        rightSideBarTableViewController.tableView.frame = rightSideBarContainerView.bounds
        rightSideBarTableViewController.tableView.clipsToBounds = false

        //disabling the scroll feature. Delete to keep the scroll feature.
        rightSideBarTableViewController.tableView.scrollsToTop = false

        //This will remove separators in the UITableCell. Delete to keep separators.
        rightSideBarTableViewController.tableView.separatorStyle = UITableViewCellSeparatorStyle.None

        //This sets the background color of the sidebar and creates the inset.
        rightSideBarTableViewController.tableView.backgroundColor = UIColor.clearColor()
        rightSideBarTableViewController.tableView.contentInset = UIEdgeInsets(top: rightSideBarTableViewTopInset, left: 0, bottom: 0, right: 0)

        //reloads the sidebar and adds the container view to the rightSideBarTableViewController.
        rightSideBarTableViewController.tableView.reloadData()
        rightSideBarContainerView.addSubview(rightSideBarTableViewController.tableView)

    }

    func showSideBar(shouldOpen: Bool){
        animator.removeAllBehaviors()
        isSideBarOpen = shouldOpen

        //simple if and else statements to define the direction of animation and intensity of animation
        let gravityX:CGFloat = (shouldOpen) ? -0.5 : 0.5
        let magnitude:CGFloat = (shouldOpen) ? -20 : 20
        let boundaryX:CGFloat = (shouldOpen) ? -barWidth : barWidth

        //controls the behavior of the animation.
        let gravityBehavior: UIGravityBehavior = UIGravityBehavior(items: [rightSideBarContainerView])
        gravityBehavior.gravityDirection = CGVectorMake(gravityX, 0)
        animator.addBehavior(gravityBehavior)

        let collisionBehavior: UICollisionBehavior = UICollisionBehavior(items: [rightSideBarContainerView])
        collisionBehavior.addBoundaryWithIdentifier("sideBarBoundary", fromPoint: CGPointMake(boundaryX, 20), toPoint: CGPointMake(boundaryX, rightOriginView.frame.size.height))
        animator.addBehavior(collisionBehavior)

        let pushBehavior:UIPushBehavior = UIPushBehavior(items: [rightSideBarContainerView], mode: UIPushBehaviorMode.Instantaneous)
        pushBehavior.magnitude = magnitude
        animator.addBehavior(pushBehavior)

        let sideBarBehavior:UIDynamicItemBehavior = UIDynamicItemBehavior(items: [rightSideBarContainerView])
        sideBarBehavior.elasticity = 0.3
        animator.addBehavior(sideBarBehavior)


    }
    func rightSidebarControlDidSelectRow(indexPath: NSIndexPath) {
        delegate?.rightSideBarDidSelectButtonAtIndex(indexPath.row)
    }

}

Finally this is my current code for the DoubleMenuViewController. Something happens when I segue to the DoubleMenuViewController to break the menus. The menus won't even load. However, if I'm in a SingleMenuViewController that only calls SideBar:NSObject then the code will work so long as I'm only calling one menu. In this DoubleMenuViewController, I have the initialization section commented out for the RightSideBar class because I'm working on a solution. I know this code for this ViewController is garbled. I'm trying everything I can think of. See my remarks after the code to see what I've tried:

import UIKit

class DoubleMenuViewController: UIViewController, SideBarDelegate,       RightSideBarDelegate {

    var sideBar:SideBar?
    var ondemandSideBar:SideBar {

        get {

            if sideBar == nil {

            //setting up the menu items for the sidebar.
            sideBar = SideBar(sourceView: self.view, menuItems: ["Home", "Share", "About", "Help"], menuImages: [homeImage!, shareImage!, aboutImage!, helpImage!])
            sideBar!.delegate = self
            SideBar.new()

            }

            return sideBar!
        }
    }

    //initializes the "RightSideBar"
    var rightSideBar:RightSideBar?
    var ondemandRightSideBar:RightSideBar {

        get {

            if rightSideBar == nil {

            rightSideBar = RightSideBar(rightSourceView: self.view, rightMenuItems: [//Other items], rightMenuImages: [//Other Items])
            rightSideBar!.delegate = self
            RightSideBar.new()

            }

            return rightSideBar!
        }
    }


    var homeImage = UIImage(named: "Home")
    var shareImage = UIImage(named: "Share")
    var aboutImage = UIImage(named: "About")
    var helpImage = UIImage(named: "Help")

    @IBOutlet weak var currentMenuControl: UIBarButtonItem!

    @IBAction func currentMenuDisplay(sender: AnyObject) {

        if currentMenuControl.tag == 1 {

            ondemandSideBar.showSideBar(true)
            currentMenuControl.tag = 0

        } else {

            ondemandSideBar.showSideBar(false)
            currentMenuControl.tag = 1

        }

    }

    @IBOutlet weak var progressionMenuControl: UIBarButtonItem!

    @IBAction func progressionMenuDisplay(sender: AnyObject) {

        if progressionMenuControl.tag == 1 {

            ondemandRightSideBar.showSideBar(true)
            progressionMenuControl.tag = 0

        } else {

            ondemandRightSideBar.showSideBar(false)
            progressionMenuControl.tag = 1
        }
    }


    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view.


    }

    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
        // Dispose of any resources that can be recreated.
    }

    func sideBarDidSelectButtonAtIndex(index: Int) {

        switch index {

         //segues
        }
    }

    func rightSideBarDidSelectButtonAtIndex(index: Int) {

        switch index {

         //segues
        }
    }

}

Here's what I've tried:

1. I've tried altering the positioning of CGFloats since SubViews seem to come from the left.

2. I've renamed all the RightSideBar variables and class names everything to overcome a runtime confusion in instance variables and class names. This includes renaming the initializers that you saw in the NSObject SubClass and the target view controller.

3. I've tried using control flow in the viewDidLoad method with a button tag. I took away the swipe features to show the menu and added buttons because I thought system was struggling to deal with the Swipes.

4. I've tried deinitializing in the SideBar subclass file of NSObject. All that got me was an infinite loop that crashed the application after login.

5. Then I tried ondemand initialization in the targetViewController.....DoubleMenuViewController and SingleMenuViewController. I returned to a working menu with buttons in the SingleMenuViewController but it still won't show the left and right menu in the DoubleMenuViewController.

6. Last I tried deinitializing the SideBar (left SideBar) and the RightSideBar in the DoubleMenuViewController. However, when I add println() functions to all my sections the debugger doesn't run the print function for me to get values of objects or even show typed states like "This" . I added the print functions because I wasn't sure if I would know when deinitialization and reinitialization occurred.

It seems that my menu is initialized from the SideBar: NSObject file and the RightSideBar:NSObject file. What I mean is that my menu is being created before I hit the target view controller. This isn't a problem for me so long as I can get the compiler to initialize the SideBar and the RightSideBar in the same View Controller, but it won't do that.

I just need to be able to control both menus with swipes or button taps.

I think I have a problem with my initializers overriding each other.

However, I don't know how to fix that problem. I've read through the Swift manual and read articles on the internet. I've also searched StackOverflow.

Answer 1

You ask:

How do I Initialize two instances of NSObject in the same view controller?

Setting aside why you're dealing with NSObject at all (in Objective-C all classes have to subclass from NSObject ultimately, in Swift that's no longer the case), if you want to instantiate two objects, you simply have to have one property for each.

If these are lazily instantiated, as your code snippet suggests, then you have to identify where that lazily instantiated property is referenced (eg you might trigger it from a "swipe from edge" gesture) or what have you. Set a breakpoint in the code that references that lazily instantiated property and make sure you're getting there at all.

--

I had some observations on one of your code snippets. You say that you're instantiating your side bar like so:

var sideBar : SideBar?
var ondemandSideBar : SideBar {
    get {
        if sideBar == nil {
            sideBar = SideBar(sourceView, menuItems, menuImage etc.)
            sideBar!.delegate
            SideBar.new()
        }
    }
}

I don't think that's what you're really doing because you're not setting the delegate, you're both instantiating the SideBar as well as calling new (which you shouldn't be doing from Swift), you're not returning a value, etc.

Also, that pattern of having a stored property that is instantiated by some computed property has a certain Objective-C je ne sais quoi. I'm inferring that you want a lazily instantiated property. If that's the case, I'd be inclined to use a single lazy stored property. And I'd then set that property lazily using a closure:

I'd expect something like this pattern

protocol SideBarDelegate : class {                         // specify class so we can use `weak` reference
    func didChooseMenuItem(sender: SideBar, item: Int)
}

class SideBar {
    weak var delegate: SideBarDelegate?                    // make sure this is weak to avoid strong reference cycle
}

class ViewController: UIViewController, SideBarDelegate {

    lazy var sideBar: SideBar = {
        let _sideBar = SideBar(sourceView, menuItems, menuImage, etc.)
        _sideBar.delegate = self
        return _sideBar
    }()

    func didChooseMenuItem(sender: SideBar, item: Int) {
        // handle it here
    }

    // etc.
}

This way, the sideBar won't be instantiated until you reference sideBar somewhere in your code, but when you do, it will be instantiated with the code inside that closure.