How to code a Scroll View

What is it you do not know how to code ?

A key point for scrollView is to define a content size large enough (more than the scrollView).

In fact,scrollView is a "window" you move over the content, giving the illusion that the view is moving.

Here is my best effor to learn about NSScrollView:

In a macOS App: change viewDidLoad() to setup, add a scrollView to the storyboard, and run to show a Scrolling view?:

override func viewDidLoad() {

super.viewDidLoad()

//Create a Big documentView and fill with array of NSButtons?

let myDocView = NSView(frame: NSRect(x: 0, y: 0, width: 2000, height: 2000))

let ymax = Int(myDocView.frame.size.height)

for row in 1...9 {

for col in 1...9 {

let aButton = NSButton(frame: NSRect(x: col * 44 + 10, y: ymax - (row * 44 + 10), width: 32, height: 37))

aButton.title = row.description + "/" + col.description

myDocView.addSubview(aButton)

}

}

//then find the NSScrollView added into the View in the storyboard with?:

let arrayOfViews = self.view.subviews

print("arrayviews is \(arrayOfViews)")

let mySV = arrayOfViews[0] as! NSScrollView

print("ScrollView is \(mySV)")

mySV.scrollerStyle = .overlay

mySV.hasVerticalScroller = true

mySV.hasHorizontalScroller = true

mySV.autohidesScrollers = false

//then add my documentView?

mySV.documentView = myDocView

}

I am at a loss for understanding and any help here is appreciated

Why don't you create the scrollView in IB directly ?

I did use IB?(storyboard) to create a NSScrollView and use the code below to find the view as I usually assign a tag number to views but with NSScrollview I am unable to assign a tag number:

let arrayOfViews = self.view.subviews

print("arrayviews is \(arrayOfViews)")

let mySV = arrayOfViews[0] as! NSScrollView

print("ScrollView is \(mySV)")

Do I create a Scroll view using only IB? Does it have anything to do with the constraints; I removed most of the constraints and observed no scroll bars.

This code below worked once I changed my storyboard; I removed most of the constraints on the views and resized the Scrollview to be much smaller then the main view. ran the app and it started working. I dont know how or understand why.

class ViewController: NSViewController {

override func viewDidLoad() {

super.viewDidLoad()

let myDocView = NSView(frame: NSRect(x: 0, y: 0, width: 2000, height: 2000))

let ymax = Int(myDocView.frame.size.height)

for row in 1...9 {

for col in 1...9 {

let aButton = NSButton(frame: NSRect(x: col * 44 + 10, y: ymax - (row * 44 + 10), width: 32, height: 37))

aButton.title = row.description + "/" + col.description

myDocView.addSubview(aButton)

}

}

self.view.addSubview(myDocView)

let aButton = NSButton(frame: NSRect(x: 20, y: 20, width: 32, height: 37))

aButton.title = "aa"

self.view.addSubview(aButton)

let arrayOfViews = self.view.subviews

print("arrayviews is \(arrayOfViews)")

let mySV = arrayOfViews[0] as! NSScrollView

print("ScrollView is \(mySV)")

mySV.scrollerStyle = .overlay

mySV.hasVerticalScroller = true

mySV.hasHorizontalScroller = true

mySV.autohidesScrollers = false

mySV.documentView = myDocView

aButton.title = "BB"

mySV.addSubview(aButton)

}

Here is a simplified code for viewDidLoad():

override func viewDidLoad() {

super.viewDidLoad()

let myDocView = NSView(frame: NSRect(x: 0, y: 0, width: 2000, height: 2000))

let ymax = Int(myDocView.frame.size.height)

for row in 1...9 {

for col in 1...9 {

let aButton = NSButton(frame: NSRect(x: col * 44 + 10, y: ymax - (row * 44 + 10), width: 32, height: 37))

aButton.title = row.description + "/" + col.description

myDocView.addSubview(aButton)

}

}

let arrayOfViews = self.view.subviews

print("arrayviews is \(arrayOfViews)")

let mySV = arrayOfViews[0] as! NSScrollView

print("ScrollView is \(mySV)")

mySV.scrollerStyle = .overlay

mySV.hasVerticalScroller = true

mySV.hasHorizontalScroller = true

mySV.autohidesScrollers = false

mySV.documentView = myDocView

}

Drag an NSScrollView from the library into the view in the storyboard and play with the constraints and view size.

I played with the constraints and size of the NSScrollView and found that I can add back all constraints and expand the Scrolll view to fill the main view. It will work; I don't understand how.

Sure, the way you define constraints for a scrollView is very critical.

Inadequate constraints "freezes" the view.

May have a look at this (long) thread (iOS, but similar to MacOS)

https://forums.developer.apple.com/message/402000#402000

Or read this tutorial

Thank you for your considerations. I learned that three things are neseccary for a NSScrollView which are not documented clearly and there is absolutely no sample code anywhere I could find.

1) There needs to be another bigger NSView that hold the total display.

2) That a NSScrollView need to be added to the storyboard and the some how defined without using tag numbers.(I used view.subviews)

3) That the NSView need to be added to the NSScrollView using ScrollView.documentView = NSView(in 1)

I read the links you provided.