Swift - Problem with scrollview (Need to print when dragging down) - ios

Question

I am testing the swiping controller/gesture from Jake Spracher with his SnapchatSwipeView (https://github.com/jakespracher/Snapchat-Swipe-View )
I have setup a topVC,leftVC,rightVC and middleVC(the main VC).
I manage to capture when the user swipe from the center to the rightVC or to the left VC, with this :
func scrollViewDidScroll(_ scrollView: UIScrollView) {
if delegate != nil && !delegate!.outerScrollViewShouldScroll() && !directionLockDisabled {
let newOffset = CGPoint(x: self.initialContentOffset.x, y: self.initialContentOffset.y)
self.scrollView!.setContentOffset(newOffset, animated: false)
}
if (scrollView.contentOffset) == CGPoint(x: 750.0, y: 0.0) {
print ("TEST OK LEFT!")
NotificationCenter.default.post(name: NSNotification.Name(rawValue: "loadRinkbox"), object: nil)
}
if (scrollView.contentOffset) == CGPoint(x: 0.0, y: 0.0) {
print ("TEST OK LEFT!")
}
if (scrollView.contentOffset) == CGPoint(x: -750.0, y: 0.0) {
print ("TEST OK RIGHT")
}
if (scrollView.contentOffset) == CGPoint(x: 375, y: 0.0) {
print ("TEST OK!")
}
}
But I cannot manage to capture when the user swipe from the centerVC to the topVC, and from topVC to centerVC. I have tried a lot of things but I didn't manage to do it.
My code is for swift 4.
For clarity, I put here the two full swift files. Many, million thanks for those that can help me !
ContainerViewController.swift
//
// ContainerViewController.swift
// SnapchatSwipeView
//
// Created by Jake Spracher on 8/9/15.
// Copyright (c) 2015 Jake Spracher. All rights reserved.
//
import UIKit
import AVFoundation
protocol SnapContainerViewControllerDelegate {
// print "Snapcontainerview"
func outerScrollViewShouldScroll() -> Bool
}
class SnapContainerViewController: UIViewController, UIScrollViewDelegate {
var captureSession : AVCaptureSession!
private var current: UIViewController
// print "2"
var deeplink: DeeplinkType? {
didSet {
handleDeeplink()
}
}
init() {
current = SplashViewController()
super.init(nibName: nil, bundle: nil)
}
required init?(coder aDecoder: NSCoder) {
fatalError("init(coder:) has not been implemented")
}
var topVc: UIViewController?
var leftVc: UIViewController!
var middleVc: UIViewController!
var rightVc: UIViewController!
var bottomVc: UIViewController?
var directionLockDisabled: Bool!
var horizontalViews = [UIViewController]()
var veritcalViews = [UIViewController]()
var initialContentOffset = CGPoint() // scrollView initial offset
var middleVertScrollVc: VerticalScrollViewController!
var scrollView: UIScrollView!
var delegate: SnapContainerViewControllerDelegate?
class func containerViewWith(_ leftVC: UIViewController,
middleVC: UIViewController,
rightVC: UIViewController,
topVC: UIViewController?=nil,
bottomVC: UIViewController?=nil,
directionLockDisabled: Bool?=false) -> SnapContainerViewController {
let container = SnapContainerViewController()
container.directionLockDisabled = directionLockDisabled
container.topVc = topVC
container.leftVc = leftVC
container.middleVc = middleVC
container.rightVc = rightVC
container.bottomVc = bottomVC
return container
}
var scrollOffSetClosure: ((_ offset: CGFloat) -> Void)?
// code truncated for brevity
func scrollViewDidScroll2(_ scrollView: UIScrollView) {
scrollOffSetClosure!(scrollView.contentOffset.x)
print("test here")
}
func scrollViewDidEndScrollingAnimation(_ scrollView: UIScrollView) {
print("end scroll")
}
override func viewDidLoad() {
super.viewDidLoad()
addChildViewController(current)
current.view.frame = view.bounds
view.addSubview(current.view)
current.didMove(toParentViewController: self)
}
func setupVerticalScrollView() {
middleVertScrollVc = VerticalScrollViewController.verticalScrollVcWith(middleVc: middleVc as! Camera,
topVc: topVc,
bottomVc: bottomVc)
delegate = middleVertScrollVc
}
func setupHorizontalScrollView() {
scrollView = UIScrollView()
scrollView.isPagingEnabled = true
scrollView.showsHorizontalScrollIndicator = false
scrollView.bounces = false
print ("6")
let view = (
x: self.view.bounds.origin.x,
y: self.view.bounds.origin.y,
width: self.view.bounds.width,
height: self.view.bounds.height
)
scrollView.frame = CGRect(x: view.x,
y: view.y,
width: view.width,
height: view.height
)
self.view.addSubview(scrollView)
let scrollWidth = 3 * view.width
let scrollHeight = view.height
scrollView.contentSize = CGSize(width: scrollWidth, height: scrollHeight)
leftVc.view.frame = CGRect(x: 0,
y: 0,
width: view.width,
height: view.height
)
middleVertScrollVc.view.frame = CGRect(x: view.width,
y: 0,
width: view.width,
height: view.height
)
rightVc.view.frame = CGRect(x: 2 * view.width,
y: 0,
width: view.width,
height: view.height
)
addChildViewController(leftVc)
addChildViewController(middleVertScrollVc)
addChildViewController(rightVc)
scrollView.addSubview(leftVc.view)
scrollView.addSubview(middleVertScrollVc.view)
scrollView.addSubview(rightVc.view)
leftVc.didMove(toParentViewController: self)
middleVertScrollVc.didMove(toParentViewController: self)
rightVc.didMove(toParentViewController: self)
scrollView.contentOffset.x = middleVertScrollVc.view.frame.origin.x
scrollView.delegate = self
}
func scrollViewWillBeginDragging(_ scrollView: UIScrollView) {
// print ("Scrollviewvillbegindragging scrollView.contentOffset \(scrollView.contentOffset)")
self.initialContentOffset = scrollView.contentOffset
}
func scrollViewDidScroll(_ scrollView: UIScrollView) {
if delegate != nil && !delegate!.outerScrollViewShouldScroll() && !directionLockDisabled {
let newOffset = CGPoint(x: self.initialContentOffset.x, y: self.initialContentOffset.y)
// print(newOffset.x)
//print(newOffset.y)
// Setting the new offset to the scrollView makes it behave like a proper
// directional lock, that allows you to scroll in only one direction at any given time
self.scrollView!.setContentOffset(newOffset, animated: false)
// print ("newOffset \(newOffset)")
// tell child views they have appeared / disappeared
}
if (scrollView.contentOffset) == CGPoint(x: 0.0, y: 667.0) {print ("aaa!")}
if (scrollView.contentOffset) == CGPoint(x: 0.0, y: -667.0) {print ("bbb!")}
if (scrollView.contentOffset) == CGPoint(x: 0.0, y: 375) {print ("aaccca!")}
if (scrollView.contentOffset) == CGPoint(x: 0.0, y: -375) {print ("ddddd!")}
if (scrollView.contentOffset) == CGPoint(x: 0.0, y: 0.0) {print ("eeeeeee!")}
// if (scrollView.contentOffset) == CGPoint(x: 0.0, y: 667.0) {print ("ffffff!")}
// if (scrollView.contentOffset) == CGPoint(x: 0.0, y: 667.0) {print ("aggggggggaa!")}
// print ("scrollViewDidScroll scrollView.contentOffset \(scrollView.contentOffset)")
// scrollView.contentOffset
if (scrollView.contentOffset) == CGPoint(x: 750.0, y: 0.0) {
print ("TEST OK LEFT!")
NotificationCenter.default.post(name: NSNotification.Name(rawValue: "loadRinkbox"), object: nil)
}
if (scrollView.contentOffset) == CGPoint(x: 0.0, y: 0.0) {
print ("TEST OK RIGHT!")
}
if (scrollView.contentOffset) == CGPoint(x: -750.0, y: 0.0) {
print ("TEST OK LEFT")
}
if (scrollView.contentOffset) == CGPoint(x: 375, y: 0.0) {
print ("TEST LEFT/RIGHT OK!")
}
}
private func animateFadeTransition(to new: UIViewController, completion: (() -> Void)? = nil) {
print ("Ca va dans animateFadeTransition")
current.willMove(toParentViewController: nil)
addChildViewController(new)
transition(from: current, to: new, duration: 0.3, options: [.transitionCrossDissolve, .curveEaseOut], animations: {
}) { completed in
self.current.removeFromParentViewController()
new.didMove(toParentViewController: self)
self.current = new
completion?()
}
}
private func animateDismissTransition(to new: UIViewController, completion: (() -> Void)? = nil) {
print ("Ca va dans animateDismissTransition")
let initialFrame = CGRect(x: -view.bounds.width, y: 0, width: view.bounds.width, height: view.bounds.height)
current.willMove(toParentViewController: nil)
addChildViewController(new)
new.view.frame = initialFrame
transition(from: current, to: new, duration: 0.3, options: [], animations: {
new.view.frame = self.view.bounds
}) { completed in
self.current.removeFromParentViewController()
new.didMove(toParentViewController: self)
self.current = new
completion?()
}
}
}
and VerticalScrollViewController
/ MiddleScrollViewController.swift
// SnapchatSwipeView
//
// Created by Jake Spracher on 12/14/15.
// Copyright © 2015 Jake Spracher. All rights reserved.
//
import UIKit
class VerticalScrollViewController: UIViewController, SnapContainerViewControllerDelegate {
var topVc: UIViewController!
var middleVc: UIViewController!
var bottomVc: UIViewController!
var scrollView: UIScrollView!
class func verticalScrollVcWith(middleVc: UIViewController,
topVc: UIViewController?=nil,
bottomVc: UIViewController?=nil) -> VerticalScrollViewController {
let middleScrollVc = VerticalScrollViewController()
middleScrollVc.topVc = topVc
middleScrollVc.middleVc = middleVc
middleScrollVc.bottomVc = bottomVc
return middleScrollVc
}
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view:
setupScrollView()
}
func setupScrollView() {
scrollView = UIScrollView()
scrollView.isPagingEnabled = true
scrollView.showsVerticalScrollIndicator = false
scrollView.bounces = false
let view = (
x: self.view.bounds.origin.x,
y: self.view.bounds.origin.y,
width: self.view.bounds.width,
height: self.view.bounds.height
)
scrollView.frame = CGRect(x: view.x, y: view.y, width: view.width, height: view.height)
self.view.addSubview(scrollView)
let scrollWidth: CGFloat = view.width
var scrollHeight: CGFloat
switch (topVc, bottomVc) {
case (nil, nil):
scrollHeight = view.height
middleVc.view.frame = CGRect(x: 0, y: 0, width: view.width, height: view.height)
addChildViewController(middleVc)
scrollView.addSubview(middleVc.view)
middleVc.didMove(toParentViewController: self)
case (_?, nil):
scrollHeight = 2 * view.height
topVc.view.frame = CGRect(x: 0, y: 0, width: view.width, height: view.height)
middleVc.view.frame = CGRect(x: 0, y: view.height, width: view.width, height: view.height)
addChildViewController(topVc)
addChildViewController(middleVc)
scrollView.addSubview(topVc.view)
scrollView.addSubview(middleVc.view)
topVc.didMove(toParentViewController: self)
middleVc.didMove(toParentViewController: self)
scrollView.contentOffset.y = middleVc.view.frame.origin.y
case (nil, _?):
scrollHeight = 2 * view.height
middleVc.view.frame = CGRect(x: 0, y: 0, width: view.width, height: view.height)
bottomVc.view.frame = CGRect(x: 0, y: view.height, width: view.width, height: view.height)
addChildViewController(middleVc)
addChildViewController(bottomVc)
scrollView.addSubview(middleVc.view)
scrollView.addSubview(bottomVc.view)
middleVc.didMove(toParentViewController: self)
bottomVc.didMove(toParentViewController: self)
scrollView.contentOffset.y = 0
default:
scrollHeight = 3 * view.height
topVc.view.frame = CGRect(x: 0, y: 0, width: view.width, height: view.height)
middleVc.view.frame = CGRect(x: 0, y: view.height, width: view.width, height: view.height)
bottomVc.view.frame = CGRect(x: 0, y: 2 * view.height, width: view.width, height: view.height)
addChildViewController(topVc)
addChildViewController(middleVc)
addChildViewController(bottomVc)
scrollView.addSubview(topVc.view)
scrollView.addSubview(middleVc.view)
scrollView.addSubview(bottomVc.view)
topVc.didMove(toParentViewController: self)
middleVc.didMove(toParentViewController: self)
bottomVc.didMove(toParentViewController: self)
scrollView.contentOffset.y = middleVc.view.frame.origin.y
}
scrollView.contentSize = CGSize(width: scrollWidth, height: scrollHeight)
}
// MARK: - SnapContainerViewControllerDelegate Methods
func outerScrollViewShouldScroll() -> Bool {
if scrollView.contentOffset.y < middleVc.view.frame.origin.y || scrollView.contentOffset.y > 2*middleVc.view.frame.origin.y {
return false
} else {
return true
}
}
}

Answer 1

In MiddleScrollViewController.swift, make the controller conform to UIScrollViewDelegate:
class VerticalScrollViewController: UIViewController,
SnapContainerViewControllerDelegate,
UIScrollViewDelegate {
In that class, in setupScrollView(), set the delegate:
func setupScrollView() {
scrollView = UIScrollView()
// set the delegate to self
scrollView.delegate = self
// the rest of the existing code...
Still in that class, implement didScroll (or whatever other delegate funcs you want to handle):
func scrollViewDidScroll(_ scrollView: UIScrollView) {
print("Vertical Scroll - contentOffset:", scrollView.contentOffset)
}
Now you should get lots of print lines in the debug console when you scroll vertically:
Vertical Scroll - contentOffset: (0.0, 561.0)
Vertical Scroll - contentOffset: (0.0, 560.0)
Vertical Scroll - contentOffset: (0.0, 559.0)
Vertical Scroll - contentOffset: (0.0, 558.0)
If you want your SnapContainerViewController class to be informed when vertical scrolling takes place, you'll probably want to use a new protocol/delegate so VerticalScrollViewController can send that information.