Problems with UIScrollView size - ios

Question

I try at the moment to resize the UIScrollView dynamically like in Android with wrap_content as attribute.
The data comes over a SQL Query that i start in the override func viewDidLoad()
I tried the freeform size variant and the version with extension
extension UIScrollView {
func resizeScrollViewContentSize() {
var contentRect = CGRect.zero
for view in self.subviews {
contentRect = contentRect.union(view.frame)
}
self.contentSize = contentRect.size
}
}
But nothing helps. Has Someone an idea?
EDIT:
#Stephen J I didn't understand your answer, sorry :(
I have a subview, too but how I can say the Scrollview that equals his size? I tried it with CTRL + Drag the mouse on the Scrollview and the same in the other direction.
So it looks at my Storyboard

Answer 1

The idea is OK, but...
Your extension is looping through the subviews of the Scroll view, but your Scroll view contains only ONE subview - your ContentView... and that view contains a bunch of subviews. (Actually, the Scroll view's subviews property also contains the scrollIndicator bars, but that doesn't really factor in here).
What you want to do is loop through the subviews of your ContentView, then change its size, and then set the .contentSize of the Scroll view based on the ContentView.
So...
// init empty rect
var contentRect = CGRect.zero
// for each subview in the ** Content ** view - NOT in the Scroll view
for view in theContentView.subviews {
// union the view's rect with the "total" rect
contentRect = contentRect.union(view.frame)
}
// set the frame size of the Content view to the "total" rect size
theContentView.frame.size = contentRect.size
// increast the size of the "total" rect by the Content view's x,y offsets
contentRect.size.width += theContentView.frame.origin.x
contentRect.size.height += theContentView.frame.origin.y
// NOW we can set the contentSize of the Scroll view
theScrollView.contentSize = contentRect.size
Personally, I've found using auto-layout and constraints to make working with Scroll views really, really easy - easier than this method, because you don't have to keep re-calculating. But, if this works for you, great :)
Edit: Here is a complete working example. It:
creates a ScrollView sized to the full view
adds a ContentView without size
adds 30 labels vertically with 16 pts spacing
then calculates and sets the size of the ContentView and the .contentSize of the Scroll view based on the ContentView's subviews
//
// ViewController.swift
// SWScrollNoAutoLayout
//
// Created by Don Mag on 6/14/17.
// Copyright © 2017 DonMag. All rights reserved.
//
import UIKit
class ViewController: UIViewController {
override func viewDidLoad() {
super.viewDidLoad()
let theScrollView = UIScrollView()
let theContentView = UIView()
theScrollView.frame = self.view.bounds
theScrollView.backgroundColor = .orange
theContentView.backgroundColor = .yellow
self.view.addSubview(theScrollView)
theScrollView.addSubview(theContentView)
var yOffset: CGFloat = 0.0
for i in 1...30 {
let lbl = UILabel()
lbl.text = "Label: \(i)"
lbl.backgroundColor = .cyan
lbl.sizeToFit()
lbl.frame.origin.y = yOffset
theContentView.addSubview(lbl)
yOffset += lbl.frame.size.height + 16
}
// init empty rect
var contentRect = CGRect.zero
// for each subview in the ** Content ** view - NOT in the Scroll view
for view in theContentView.subviews {
// union the view's rect with the "total" rect
contentRect = contentRect.union(view.frame)
}
// set the frame size of the Content view to the "total" rect size
theContentView.frame.size = contentRect.size
// increast the size of the "total" rect by the Content view's x,y offsets
contentRect.size.width += theContentView.frame.origin.x
contentRect.size.height += theContentView.frame.origin.y
// NOW we can set the contentSize of the Scroll view
theScrollView.contentSize = contentRect.size
}
}