I have two view controllers, B is presented on top of A, but not full screen. I am using a UIPresentationController to custom B's frame. What I want is, when tap on A, B is dismissed and A responds to it's own tap gesture.
How to achieve this within B and the UIPresentationController, without touching A's code?
I tried to add a full screen background view for B, but don't know how to pass the tap gesture down without changing A.
Customize a background view, always return false for pointInside method to ignore the touch event and do whatever needed before return, such as dismiss B.
class BackgroundView: UIView {
override func point(inside point: CGPoint, with event: UIEvent?) -> Bool {
// anything you want
return false
}
}
Add the custom background view to the UIPresentationController. Set containerView's isUserInteractionEnabled to false, otherwise the UITransitionView will block the touch event to pass down.
class MyPresentationController: UIPresentationController {
var backgroundView: BackgroundView = BackgroundView()
var containerFrame: CGRect = UIScreen.main.bounds
override var frameOfPresentedViewInContainerView: CGRect {
return CGRect(x: 0, y: 300, width: UIScreen.main.bounds.width, height: UIScreen.main.bounds.height - 300)
}
override init(presentedViewController: UIViewController, presenting presentingViewController: UIViewController?) {
super.init(presentedViewController: presentedViewController, presenting: presentingViewController)
self.backgroundView.backgroundColor = UIColor.yellow
self.backgroundView.alpha = 0.5
self.backgroundView.translatesAutoresizingMaskIntoConstraints = false
}
override func presentationTransitionWillBegin() {
self.containerView?.addSubview(self.backgroundView)
self.containerView?.isUserInteractionEnabled = false // !!!
}
override func containerViewDidLayoutSubviews() {
super.containerViewDidLayoutSubviews()
self.containerView?.frame = self.containerFrame
self.backgroundView.frame = self.containerFrame
self.presentedView?.frame = self.frameOfPresentedViewInContainerView
}
}
I'm trying to add a child view controller to a parent view controller in a swift ios application, but when I add the child view controller, the activityIndicatorView doesn't appear. What could I be missing?
Here is a snippet that can be tried in a playground:
import PlaygroundSupport
import Alamofire
class LoadingViewController: UIViewController {
private lazy var activityIndicator = UIActivityIndicatorView(style: .gray)
override func viewDidLoad() {
super.viewDidLoad()
view.backgroundColor = .white
activityIndicator.translatesAutoresizingMaskIntoConstraints = false
view.addSubview(activityIndicator)
NSLayoutConstraint.activate([
activityIndicator.centerXAnchor.constraint(equalTo: view.centerXAnchor),
activityIndicator.centerYAnchor.constraint(equalTo: view.centerYAnchor)
])
}
override func viewWillAppear(_ animated: Bool) {
super.viewWillAppear(animated)
// We use a 0.5 second delay to not show an activity indicator
// in case our data loads very quickly.
DispatchQueue.main.asyncAfter(deadline: .now() + 0.0) { [weak self] in
self?.activityIndicator.startAnimating()
}
}
}
// methods for adding and removing child view controllers.
extension UIViewController {
func add(_ child: UIViewController, frame: CGRect? = nil) {
addChild(child)
if let frame = frame {
child.view.frame = frame
}
view.addSubview(child.view)
child.didMove(toParent: self)
}
func remove() {
// Just to be safe, we check that this view controller
// is actually added to a parent before removing it.
guard parent != nil else {
return
}
willMove(toParent: nil)
view.removeFromSuperview()
removeFromParent()
}
}
class MyViewController : UITabBarController {
override func loadView() {
let view = UIView()
view.backgroundColor = .white
let label = UILabel()
label.frame = CGRect(x: 150, y: 200, width: 200, height: 20)
label.text = "Hello World!"
label.textColor = .black
view.addSubview(label)
self.view = view
}
override func viewDidAppear(_ animated: Bool) {
super.viewDidAppear(animated)
let loadingViewController = LoadingViewController()
add(loadingViewController, frame: view.frame)
AF.request("http://www.youtube.com").response { response in
print(String(describing: response.response))
loadingViewController.remove()
}
}
}
// Present the view controller in the Live View window
PlaygroundPage.current.liveView = MyViewController()
The loadingViewController view fills the parent view, and i've tried to change the background colour at different points and that works. but activityIndicator or any other subview i try to add just doesn't appear.
Try add the line
activityIndicator.startAnimating()
in your viewDidLoad() method from your LoadingViewController class
I'm implementing in Playgound a segmented control underneath the navigation bar.
This seems to be a classic problem, which has been asked:
UISegmentedControl below UINavigationbar in iOS 7
Add segmented control to navigation bar and keep title with buttons
In the doc of UIBarPositioningDelegate, it says,
The UINavigationBarDelegate, UISearchBarDelegate, and
UIToolbarDelegate protocols extend this protocol to allow for the
positioning of those bars on the screen.
And In the doc of UIBarPosition:
case top
Specifies that the bar is at the top of its containing view.
In the doc of UIToolbar.delegate:
You may not set the delegate when the toolbar is managed by a
navigation controller. The default value is nil.
My current solution is as below (the commented-out code are kept for reference and convenience):
import UIKit
import PlaygroundSupport
class ViewController : UIViewController, UIToolbarDelegate
{
let toolbar : UIToolbar = {
let ret = UIToolbar()
let segmented = UISegmentedControl(items: ["Good", "Bad"])
let barItem = UIBarButtonItem(customView: segmented)
ret.setItems([barItem], animated: false)
return ret
}()
override func viewDidLoad() {
super.viewDidLoad()
view.addSubview(toolbar)
// toolbar.delegate = self
}
override func viewDidLayoutSubviews() {
toolbar.frame = CGRect(
x: 0,
y: navigationController?.navigationBar.frame.height ?? 0,
width: navigationController?.navigationBar.frame.width ?? 0,
height: 44
)
}
func position(for bar: UIBarPositioning) -> UIBarPosition {
return .topAttached
}
}
//class Toolbar : UIToolbar {
// override var barPosition: UIBarPosition {
// return .topAttached
// }
//}
let vc = ViewController()
vc.title = "Try"
vc.view.backgroundColor = .red
// Another way to add toolbar...
// let segmented = UISegmentedControl(items: ["Good", "Bad"])
// let barItem = UIBarButtonItem(customView: segmented)
// vc.toolbarItems = [barItem]
// Navigation Controller
let navVC = UINavigationController(navigationBarClass: UINavigationBar.self, toolbarClass: UIToolbar.self)
navVC.pushViewController(vc, animated: true)
navVC.preferredContentSize = CGSize(width: 375, height: 640)
// navVC.isToolbarHidden = false
// Page setup
PlaygroundPage.current.liveView = navVC
PlaygroundPage.current.needsIndefiniteExecution = true
As you can see, this doesn't use a UIToolbarDelegate.
How does a UIToolbarDelegate (providing the position(for:)) come into play in this situation? Since we can always position ourselves (either manually or using Auto Layout), what's the use case of a UIToolbarDelegate?
#Leo Natan's answer in the first question link above mentioned the UIToolbarDelegate, but it seems the toolbar is placed in Interface Builder.
Moreover, if we don't use UIToolbarDelegate here, why don't we just use a plain UIView instead of a UIToolbar?
Try this
UIView *containerVw = [[UIView alloc] initWithFrame:CGRectMake(0, 64, 320, 60)];
containerVw.backgroundColor = UIColorFromRGB(0xffffff);
[self.view addSubview:containerVw];
UIView *bottomView = [[UIView alloc] initWithFrame:CGRectMake(0, 124, 320, 1)];
bottomView.backgroundColor = [UIColor grayColor];
[self.view addSubview:bottomView];
UISegmentedControl *sg = [[UISegmentedControl alloc] initWithItems:#[#"Good", #"Bad"]];
sg.frame = CGRectMake(10, 10, 300, 40);
[view addSubview:sg];
for (UIView *view in self.navigationController.navigationBar.subviews) {
for (UIView *subView in view.subviews) {
[subView isKindOfClass:[UIImageView class]];
subView.hidden = YES;
}
}
By setting the toolbar's delegate and by having the delegate method return .top, you get the normal shadow at the bottom of the toolbar. If you also adjust the toolbars frame one point higher, it will cover the navbar's shadow and the final result will be what appears to be a taller navbar with a segmented control added.
class ViewController : UIViewController, UIToolbarDelegate
{
lazy var toolbar: UIToolbar = {
let ret = UIToolbar()
ret.delegate = self
let segmented = UISegmentedControl(items: ["Good", "Bad"])
let barItem = UIBarButtonItem(customView: segmented)
ret.setItems([barItem], animated: false)
return ret
}()
override func viewDidLoad() {
super.viewDidLoad()
view.addSubview(toolbar)
toolbar.delegate = self
}
override func viewDidLayoutSubviews() {
toolbar.frame = CGRect(
x: 0,
y: navigationController?.navigationBar.frame.height - 1 ?? 0,
width: navigationController?.navigationBar.frame.width ?? 0,
height: toolbar.frame.height
)
}
func position(for bar: UIBarPositioning) -> UIBarPosition {
return .top
}
}
How does a UIToolbarDelegate (providing the position(for:)) come into play in this situation? Since we can always position ourselves (either manually or using Auto Layout), what's the use case of a UIToolbarDelegate?
I sincerely do not know how the UIToolbarDelegate comes into play, if you change the UINavigationController.toolbar it will crashes with "You cannot set UIToolbar delegate managed by the UINavigationController manually", moreover the same will happen if you try to change the toolbar's constraint or its translatesAutoresizingMaskIntoConstraints property.
Moreover, if we don't use UIToolbarDelegate here, why don't we just use a plain UIView instead of a UIToolbar?
It seems to be a reasonable question. I guess the answer for this is that you have a UIView subclass which already has the behaviour of UIToolbar, so why would we create another class-like UIToolbar, unless you just want some view below the navigation bar.
There are 2 options that I'm aware of.
1) Related to Move UINavigationController's toolbar to the top to lie underneath navigation bar
The first approach might help when you have to show the toolbar in other ViewControllers that are managed by your NavigationController.
You can subclass UINavigationController and change the Y-axis position of the toolbar when the value is set.
import UIKit
private var context = 0
class NavigationController: UINavigationController {
private var inToolbarFrameChange = false
var observerBag: [NSKeyValueObservation] = []
override func awakeFromNib() {
super.awakeFromNib()
self.inToolbarFrameChange = false
}
override func viewDidLoad() {
super.viewDidLoad()
observerBag.append(
toolbar.observe(\.center, options: .new) { toolbar, _ in
if !self.inToolbarFrameChange {
self.inToolbarFrameChange = true
toolbar.frame = CGRect(
x: 0,
y: self.navigationBar.frame.height + UIApplication.shared.statusBarFrame.height,
width: toolbar.frame.width,
height: toolbar.frame.height
)
self.inToolbarFrameChange = false
}
}
)
}
override func setToolbarHidden(_ hidden: Bool, animated: Bool) {
super.setToolbarHidden(hidden, animated: false)
var rectTB = self.toolbar.frame
rectTB = .zero
}
}
2) You can create your own UIToolbar and add it to view of the UIViewController. Then, you add the constraints to the leading, trailing and the top of the safe area.
import UIKit
final class ViewController: UIViewController {
private let toolbar = UIToolbar()
private let segmentedControl: UISegmentedControl = {
let control = UISegmentedControl(items: ["Op 1", "Op 2"])
control.isEnabled = false
return control
}()
override func loadView() {
super.loadView()
setupToolbar()
}
override func viewWillAppear(_ animated: Bool) {
super.viewWillAppear(animated)
navigationController?.navigationBar.hideBorderLine()
}
private func setupToolbar() {
let barItem = UIBarButtonItem(customView: segmentedControl)
toolbar.setItems([barItem], animated: false)
toolbar.isTranslucent = false
toolbar.isOpaque = false
view.addSubview(toolbar)
toolbar.translatesAutoresizingMaskIntoConstraints = false
toolbar.leadingAnchor.constraint(equalTo: view.leadingAnchor).isActive = true
toolbar.trailingAnchor.constraint(equalTo: view.trailingAnchor).isActive = true
toolbar.topAnchor.constraint(equalTo: view.safeAreaLayoutGuide.topAnchor).isActive = true
}
}
private extension UINavigationBar {
func showBorderLine() {
findBorderLine().isHidden = false
}
func hideBorderLine() {
findBorderLine().isHidden = true
}
private func findBorderLine() -> UIImageView! {
return self.subviews
.flatMap { $0.subviews }
.compactMap { $0 as? UIImageView }
.filter { $0.bounds.size.width == self.bounds.size.width }
.filter { $0.bounds.size.height <= 2 }
.first
}
}
Here I have a simple example. im calling FirstResponder in viewDidLoad. But accessory view only shows up after tapping the screen. Why isn't it showing from the start?
class TestViewController: MainPageViewController {
private let accessoryView = UIView() //TextInputView() // MessageInputAccessoryView()
override var inputAccessoryView: UIView {
return accessoryView
}
override var canBecomeFirstResponder: Bool { return true }
override func viewDidLoad() {
super.viewDidLoad()
accessoryView.backgroundColor = .red
accessoryView.frame = CGRect(x: 0, y: 0, width: 300, height: 50)
self.becomeFirstResponder()
// Do any additional setup after loading the view.
let tap = UITapGestureRecognizer(target: self, action: #selector(tappo))
self.view.isUserInteractionEnabled = true
self.view.addGestureRecognizer(tap)
tappo()
}
func tappo() {
self.becomeFirstResponder()
}
}
viewWillAppear is a better place to put the becomesFirstResponder. Try that.
So something was resigning my first responder (as I was using UIPageViewController). So I've added this to my UIViewControler :
override var canResignFirstResponder: Bool { return false }
That's it. Cheers!
There is a Main View with subview. I need to get these subviews.
For example, I created a view:
With the Swift Code:
import UIKit
class ViewController: UIViewController {
override func viewDidLoad() {
super.viewDidLoad()
}
override func viewDidAppear(animated: Bool) {
super.viewDidAppear(animated)
// Check if has view in rect area
let rect1 = CGRect(x: 0, y: 0, width: 100, height: 100)
if CGRectContainsPoint(rect1, rect1.origin) { // return true
print("TRUE")
} else {
print("FALSE")
}
}
}
I need to get the view you are "touching" the Rect in size or origin.
In the above example, I created three subviews with different colors between them.
I need to get the view and make a print() with the backgroundColor.
Can someone help me?
This func fix the problem:
func intersectingViewWithView(panView: UIView) -> UIView? {
for view in self.view.subviews {
if view != panView {
if CGRectIntersectsRect(panView.frame, view.frame) {
return view
}
}
}
return nil
}