How to pass different URL to webView from some buttons in swift? - swift

Question

I have some buttons in first view controller and a webView in second view controller. How to pass different url from different buttons to the webView? For example, the first button will leads to a google website and the second one is Facebook but using the same webView. Do I need to create different segues for each button or just one? If using just one, where should I start pulling that blue line (that line when you hold the control key)?
In first viewController:
class CafesView: UIViewController {
#IBOutlet weak var topBar: UIView!
#IBOutlet weak var button1: MDCFloatingButton!
#IBOutlet weak var button2: MDCRaisedButton!
#IBOutlet weak var button3: MDCRaisedButton!
#IBOutlet weak var button4: MDCRaisedButton!
#IBOutlet weak var button5: MDCRaisedButton!
#IBOutlet weak var button6: MDCRaisedButton!
#IBOutlet weak var button7: MDCRaisedButton!
#IBOutlet weak var button8: MDCRaisedButton!
#IBOutlet weak var button9: MDCRaisedButton!
let cafes = [
"Banana Joe's",
"College Eight Cafe",
"Global Village",
"Iveta",
"Oakes Cafe",
"Perk Coffee Bar",
"Stevenson Coffee House",
"Terra Fresca",
"Vivas"
]
var urlToPass: String!
override func viewDidLoad() {
super.viewDidLoad()
topBar.layer.shadowColor = UIColor.black.cgColor
topBar.layer.shadowOpacity = 0.5
topBar.layer.shadowOffset = CGSize(width: 0, height: 2)
topBar.layer.shadowRadius = 5
button1.layer.cornerRadius = 20
button2.layer.cornerRadius = 20
button3.layer.cornerRadius = 20
button4.layer.cornerRadius = 20
button5.layer.cornerRadius = 20
button6.layer.cornerRadius = 20
button7.layer.cornerRadius = 20
button8.layer.cornerRadius = 20
button9.layer.cornerRadius = 20
}
#IBAction func bananaJoes(_ sender: UIButton) {
urlToPass = "https://dining.ucsc.edu/pdf/banana-joes-menu.pdf"
}
#IBAction func collegeEightCafe(_ sender: UIButton) {
urlToPass = "https://dining.ucsc.edu/pdf/c8-menu.pdf"
}
#IBAction func globalVillage(_ sender: Any) {
urlToPass = "https://www.foodbooking.com/ordering/restaurant/menu?restaurant_uid=d368abee-3ccc-40d7-be7f-3ca5d4cbd513&glfa_cid=1263531392.1571083521&glfa_t=1571083566919"
}
#IBAction func iveta(_ sender: UIButton) {
urlToPass = "https://iveta.com/pages/iveta-ucsc-menu"
}
#IBAction func oakesCafe(_ sender: UIButton) {
urlToPass = "https://dining.ucsc.edu/pdf/oakes-menu-2019-20.pdf"
}
#IBAction func perkCoffeeBar(_ sender: UIButton) {
urlToPass = "https://google.com" //This url is just a placeholder
}
#IBAction func stevensonCoffeeHouse(_ sender: UIButton) {
urlToPass = "https://dining.ucsc.edu/pdf/stevenson-coffee-house-menu.pdf"
}
#IBAction func terraFresca(_ sender: UIButton) {
urlToPass = "https://dining.ucsc.edu/terra-fresca/pdf/terra-fresca-menu.pdf"
}
#IBAction func vivas(_ sender: UIButton) {
urlToPass = "https://dining.ucsc.edu/pdf/vivas-menu.pdf"
}
#IBAction func dismiss(_ sender: UIButton) {
self.dismiss(animated: true, completion: nil)
}
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
super.prepare(for: segue, sender: sender)
guard let destination = segue.destination as? CafesMenu else { return }
destination.detailURL = urlToPass
urlToPass = nil
}
}
In the second one:
import UIKit
import WebKit
class CafesMenu: UIViewController {
#IBOutlet weak var webView: WKWebView!
var detailURL: String?
override func viewDidLoad() {
super.viewDidLoad()
print("URL Requested: \(detailURL)")
}
override func viewWillAppear(_ animated: Bool) {
let url = URL(string: detailURL!)
let request = URLRequest(url: url!)
webView.load(request)
}
#IBAction func dismiss(_ sender: UIBarButtonItem) {
self.dismiss(animated: true, completion: nil)
}
}

Answer 1

What you need to do is use prepareForSegue:sender: to set a property in your destination view controller. prepareForSegue:sender: will be called before your initial view controller segues to any destination view controller. Within this function, we can check which button was pressed and set the appropriate URL in the destination view controller accordingly.
This approach will allow you to use any segue between your buttons and your destination view controller. This means, you simply have to drag the blue line from the buttons to the view controller you want to segue to.
1. Within your storyboard, create a segue between your first view controller and your destination view controller. This is done by holding control, clicking on the first view controller in the interface builder, and dragging over the destination view controller. Then choose a segue type:
Now, select this segue and give it the Identifier "InitialVCToDestinationVC" in the attributes inspector:
2. Make a property called urlToPass of type URL in your initial view controller:
class InitialViewController: UIViewController {
var urlToPass: URL!
#IBAction func googleButtonPressed(_ sender: Any) {
}
#IBAction func facebookButtonPressed(_ sender: Any) {
}
}
3. Make a property called receivedUrl in the destination view controller:
class DestinationViewController: UIViewController {
var receivedUrl: URL!
#IBOutlet var webView: WKWebView!
override func viewDidLoad() {
super.viewDidLoad()
let request = URLRequest(url: receivedUrl)
webView.load(request)
}
}
4. Set the urlToPass depending on which button is pressed and use the prepareForSegue:sender: function to set the destination view controller's url accordingly. Then, make use of performSegue(withIdentifier:sender:) to perform the segue with identifier InitialVCToDestinationVC.
class InitialViewController: UIViewController {
var urlToPass: URL!
#IBAction func googleButtonPressed(_ sender: Any) {
urlToPass = URL(string: "www.google.com")
performSegue(withIdentifier: "InitialVCToDestinationVC", sender: nil)
}
#IBAction func facebookButtonPressed(_ sender: Any) {
urlToPass = URL(string: "www.facebook.com")
performSegue(withIdentifier: "InitialVCToDestinationVC", sender: nil)
}
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
super.prepare(for: segue, sender: sender)
guard let destination = segue.destination as? DestinationViewController else { return }
destination.receivedUrl = urlToPass
urlToPass = nil
}
}
5. (optional) Make use of the shouldPerformSegueWithIdentifier:sender: method within InitialViewController and check whether or not urlToPass is valid. If urlToPass is valid, perform the segue, else present an alert.
class InitialViewController: UIViewController {
...
override func shouldPerformSegue(withIdentifier identifier: String, sender: Any?) -> Bool {
if let urlToPass = urlToPass {
// check if your application can open the NSURL instance
if !UIApplication.shared.canOpenURL(urlToPass) {
let alertController = UIAlertController(title: "Cannot open URL.", message: "This is an invalid URL.", preferredStyle: .alert)
let ok = UIAlertAction(title: "Okay", style: .cancel, handler: nil)
alertController.addAction(ok)
present(alertController, animated: true, completion: nil)
}
return UIApplication.shared.canOpenURL(urlToPass)
}
return false
}
}
End result:
Here's a link to the Xcode project I made the above gif from: https://github.com/ChopinDavid/PrepareForSegue

Answer 2

Try using the following code snippet to pass the urlParameter to second viewcontroller
class FirstViewController: UIViewController{
func googleActionButton() {
let vc = SecondViewController()
vc.urlToOpen = "www.google.com"
self.present(vc, animated: true, completion: nil)
}
func facebookActionButton() {
let vc = SecondViewController()
vc.urlToOpen = "www.facebook.com"
self.present(vc, animated: true, completion: nil)
}
}
class SecondViewController: UIViewController{
var urlToOpen = String()
override func viewDidLoad() {
super.viewDidLoad()
// set webview url to the 'urlToOpen' which you received from FirstViewController
}
}

Answer 3

First of all, create an enum WebURL with all the url cases that you want to open, i.e.
enum WebURL {
case google
case facebook
var url: String {
switch self {
case .google:
return "https://www.google.com"
case .facebook:
return "https://www.facebook.com"
}
}
}
Next, in FirstVC, in the UIButton's #IBAction open SecondVC using the WebURL instance corresponding to that particular button, i.e.
class FirstVC: UIViewController{
#IBAction func openGoogle(_ sender: UIButton) {
self.openSecondVC(with: WebURL.google.url)
}
#IBAction func openFacebook(_ sender: UIButton) {
self.openSecondVC(with: WebURL.facebook.url)
}
func openSecondVC(with urlString: String) {
if let vc = self.storyboard?.instantiateViewController(withIdentifier: "SecondVC") as? SecondVC {
vc.urlString = urlString
self.present(vc, animated: true, completion: nil)
}
}
}
Then, use urlString in SecondVC to configure your webView, i.e.
class SecondVC: UIViewController {
var urlString: String?
override func viewDidLoad() {
super.viewDidLoad()
//Setup your webView using urlString here...
}
}