How to create block screen with circle loader - swift

Question

I am doing an app that does background job that can take some time
I want to show a loader in that time
I want a black screen with a simple loader in the front of it
and show it \ hide it,
when I do actions in the background
I want to do a simple half black square with loader circle
that also blocks presses to the screen
Like in this picture:
How can I achieve that and that ?

Answer 1

First create one UIView which you will put in front of your LogIn view. Then add UIActivityIndicatorView to the created UIView.
let loadingIndicatorView = UIView()
let activityIndicatorView = UIActivityIndicatorView(activityIndicatorStyle: .gray)
Now the loadingIndicatorView should have same frame size as your LogIN view. For color you can set your own color with alpha as you want to show LogIn content too. Initially keep it hidden and whenever you want to show it unhide it.
loadingIndicatorView.frame = view.frame
loadingIndicatorView.backgroundColor = .gray
loadingIndicatorView.isHidden = true
Now setup activityIndicatorView, it should be shown at centre,
activityIndicatorView.center = CGPoint(
x: UIScreen.main.bounds.size.width / 2,
y: UIScreen.main.bounds.size.height / 2
)
You can set some color to the indicator,
activityIndicatorView.color = .white
activityIndicatorView.hidesWhenStopped = true
Now add this activityIndicatorView to loadingIndicatorView and loadingIndicatorView to LogIn View.
loadingIndicatorView.addSubview(activityIndicatorView)
view.addSubview(loadingIndicatorView)
Lastly for showing do,
loadingIndicator.startAnimating()
loadingIndicatorView.isHidden = false
And for hiding,
loadingIndicator.stopAnimating()
loadingIndicatorView.isHidden = true

Answer 2

Updated Answer
Since the OP wanted an example code. Hence the updated answer. Hope everyone gets to learn something or the other out of it.
To start with, I created a subclass of UIView and named it PSOverlaySpinner and it looks something like below:
import UIKit
class PSOverlaySpinner: UIView {
//MARK: - Variables
private var isSpinning: Bool = false
private lazy var spinner : UIActivityIndicatorView = {
var spinner = UIActivityIndicatorView(style: UIActivityIndicatorView.Style.white)
spinner.translatesAutoresizingMaskIntoConstraints = false
spinner.hidesWhenStopped = true
return spinner
}()
// MARK: - View Lifecycle Functions
required init?(coder aDecoder: NSCoder) {
fatalError("init(coder:) has not been implemented")
}
init() {
super.init(frame: CGRect.zero)
self.translatesAutoresizingMaskIntoConstraints = false
self.backgroundColor = UIColor.init(white: 0.0, alpha: 0.8)
self.isSpinning = false
self.isHidden = true
createSubviews()
}
deinit {
self.removeFromSuperview()
}
func createSubviews() -> Void {
self.addSubview(spinner)
setupAutoLayout()
}
// MARK: - Private Methods
private func setupAutoLayout() {
if #available(iOS 11.0, *) {
spinner.safeAreaLayoutGuide.centerXAnchor.constraint(equalTo: safeAreaLayoutGuide.centerXAnchor).isActive = true
spinner.safeAreaLayoutGuide.centerYAnchor.constraint(equalTo: safeAreaLayoutGuide.centerYAnchor).isActive = true
} else {
// Fallback on earlier versions
spinner.centerXAnchor.constraint(equalTo: centerXAnchor).isActive = true
spinner.centerYAnchor.constraint(equalTo: centerYAnchor).isActive = true
}
}
// MARK: - Public Methods
public func show() -> Void {
DispatchQueue.main.async {
if !self.spinner.isAnimating {
self.spinner.startAnimating()
}
self.isHidden = false
}
isSpinning = true
}
public func hide() -> Void {
DispatchQueue.main.async {
if self.spinner.isAnimating {
self.spinner.stopAnimating()
}
self.isHidden = true
}
isSpinning = false
}
}
Now move onto the ViewController that you want to add this overlay view to. Since I create my views programmatically, I will show how to do it the same way, but you can easily do it via storyboard or xibs.
Step 1 : Initialize
public lazy var spinnerView : PSOverlaySpinner = {
let loadingView : PSOverlaySpinner = PSOverlaySpinner()
return loadingView
}()
Step 2 : Add as a subview
self.view.addSubview(spinnerView)
Step 3 : Set constraints
spinnerView.leadingAnchor.constraint(equalTo: self.view.leadingAnchor).isActive = true
spinnerView.trailingAnchor.constraint(equalTo: self.view.trailingAnchor).isActive = true
spinnerView.topAnchor.constraint(equalTo: self.view.topAnchor).isActive = true
spinnerView.bottomAnchor.constraint(equalTo: self.view.bottomAnchor).isActive = true
Step 4 : To show PSOverlaySpinner
spinnerView.show()
Step 5 : To hide PSOverlaySpinner
spinnerView.hide()
That is it!!
If you want you can go ahead and modify the PSOverlaySpinner as per your needs. For example, you might want to add a UILabel below the spinner indicating him of the type of action taking place and so on.
Before
After
Old Answer
If you wish to do it manually then create a UIView with the its frame matching self.view.bounds, with 0.5-0.7 alpha and black background color. Add UIActivityIndicator as its subview constrained to its center. For a spinner specific to the image you will have to use the open sourced spinners made available. A couple of them can be found here. Once done add this view as the topmost subview in self.view.

Answer 3

You need to import this library SVProgressHUD and then set few properties like as follows:
SVProgressHUD.setDefaultStyle(SVProgressHUDStyle.dark)
SVProgressHUD.setBackgroundColor(.clear)
SVProgressHUD.setForegroundColor(.white)
SVProgressHUD.setDefaultMaskType(.black)
SVProgressHUD.show()
//SVProgressHUD.show(withStatus: "Loading something, Loading something,Loading something ...")
This will produce same UI output as needed by you in OP. You can find a running sample at my repository (TestPreLoader)