I'm applying for a junior developer position and I've got a very specific task, that already took me 3 days to complete. Sounds easy - pass data to rootViewController.
That's what I've done:
1)
private func userDefaultsToRootController() {
let input = textField.text!
defaults.set(input, forKey: "SavedLabel")
navigationController?.popViewController(animated: true)
}
private func segueToRootViewController() {
let destinationVC = MainScreen1()
let input = textField.text!
if input == "" { self.navigationController?.popToRootViewController(animated: true) }
destinationVC.input = input
navigationController?.pushViewController(destinationVC, animated: true)
}
private func popToNavigationController() {
let input = textField.text!
if let rootVC = navigationController?.viewControllers.first as? MainScreen1 {
rootVC.input = input
}
navigationController?.popToRootViewController(animated: true)
}
I've used CoreData
But here is the difficult part - I've got an email, that all these methods are not good enough and I need to use delegate and closure. I've done delegation and closures before, but when I popToRootViewController delegate method passes nil. Could you at least point where to find info about this?
** ADDED **
There are 2 View Controllers: Initial and Second one.
That's what I have in the Initial View Controller:
var secondVC = MainScreen2()
override func viewDidLoad() {
super.viewDidLoad()
secondVC.delegate = self
}
That's how I push SecondViewController
#objc private func buttonTapped(_ sender: CustomButton) {
let nextViewController = MainScreen2()
navigationController?.pushViewController(nextViewController, animated: true)
}
In SecondViewController I've got this protocol
protocol PassData {
func transferData(text: String)
}
Also a delegate:
var delegate: PassData?
This is how I go back to initial view controller
#objc private func buttonTapped(_ sender: CustomButton) {
if let input = textField.text {
print(input)
self.delegate?.transferData(text: input)
self.navigationController?.popToRootViewController(animated: true)
}
}
Back to the Initial view controller where I've implemented delegate method
extension MainScreen1: PassData {
func transferData(text: String) {
print("delegate called")
label.text = text
}
}
Delegate doesn't get called.
BASED ON YOUR EDIT:
You must set the delegate in buttonTapped
#objc private func buttonTapped(_ sender: CustomButton) {
let nextViewController = MainScreen2()
nextViewController.delegate = self // HERE WHERE YOU SET THE DELEGATE
navigationController?.pushViewController(nextViewController, animated: true)
}
You can delete the second instance and your code in viewDidLoad. That's not the instance you push.
This should point you in the right direction to use delegation and completion handler.
protocol YourDelegateName {
func passData(data:YourDataType)
}
class SecondViewController: UIViewController {
var delegate: YourDelegateName?
func passDataFromSecondViewController(){
YourCoreDataClass.shared.getCoreData { (yourStringsArray) in
self.delegate?.passData(data: yourStringsArray)
self.navigationController?.popToRootViewController(animated: true)
}
}
class InitialViewController: UIViewController, YourDelegateName {
override func viewDidLoad() {
super.viewDidLoad()
// or whenever you instantiate your SecondViewController
let secondViewController = SecondViewController()
secondViewController.delegate = self //VERY IMPORTANT, MANY MISS THIS
self.navigationController?.pushViewController(createVC, animated: true)
}
func passData(data:YourDataType){
//user your data
}
}
class YourCoreDataClass: NSObject {
static let shared = YourCoreDataClass()
func getCoreData (completion: ([String]) -> ()){
........... your code
let yourStringsArray = [String]() // let's use as example an array of strings
//when you got the data your want to pass
completion(yourStringsArray)
}
}
I am having issues trying to pass the data back to the ViewController (from BarCodeScannerViewController to TableViewController)
SecondVC (BarCodeScannerViewController.swift):
#objc func SendDataBack(_ button:UIBarButtonItem!) {
if let presenter = self.presentingViewController as? TableViewController {
presenter.BarCode = "Test"
}
self.dismiss(animated: true, completion: nil)
}
FirstVC (TableViewController.swift):
// The result is (BarCode - )
var BarCode: String = ""
override func viewWillAppear(_ animated: Bool) {
super.viewWillAppear(animated)
print("BarCode - \(BarCode)")
}
Each time ViewWillAppear is running the value is not set, what could be causing this issue?
You should use the delegate pattern. I doubt in your code above that self.presentingViewController is actually set.
An example of using the delegate pattern for this:
// BarCodeScannerViewController.swift
protocol BarcodeScanningDelegate {
func didScan(barcode: String)
}
class BarCodeScannerViewController: UIViewController {
delegate: BarcodeScanningDelegate?
#objc func SendDataBack(_ button:UIBarButtonItem!) {
delegate?.didScan(barcode: "Test")
}
}
// TableViewController
#IBAction func scanBarcode() {
let vc = BarCodeScannerViewController()
vc.delegate = self
self.present(vc, animated: true)
}
extension TableViewController: BarcodeScanningDelegate {
func didScan(barcode: String) {
print("[DEBUG] - Barcode scanned: \(barcode)")
}
}
I have a variable by the name of email in the contact picker function. I am trying to use that variable in the IBAction function for the MFMailComposeViewController. I want to apply it to toRecipient. How would I go about using a variable from another function?
import UIKit
import Contacts
import ContactsUI
import MessageUI
class ViewController: UIViewController, CNContactPickerDelegate, MFMailComposeViewControllerDelegate, UITextFieldDelegate {
//Message Setup
#IBOutlet weak var nameTextField: UITextField!
#IBOutlet weak var companyTextField: UITextField!
#IBOutlet weak var lblDetails: UILabel!
#IBAction func btnSelectEmployee(_ sender: Any) {
let entityType = CNEntityType.contacts
let authStatus = CNContactStore.authorizationStatus(for: entityType)
if authStatus == CNAuthorizationStatus.notDetermined {
let contactStore = CNContactStore.init()
contactStore.requestAccess(for: entityType, completionHandler: { (success, nil) in
if success {
self.openContacts()
}
else {
print("Not Authorized")
}
})
}
else if authStatus == CNAuthorizationStatus.authorized {
self.openContacts()
}
}
func openContacts() {
let contactPicker = CNContactPickerViewController.init()
contactPicker.delegate = self
self.present(contactPicker, animated: true, completion: nil)
}
func contactPickerDidCancel(_ picker: CNContactPickerViewController) {
picker.dismiss(animated: true) {
}
}
func contactPicker(_ picker: CNContactPickerViewController, didSelect contact: CNContact) {
//When user select any contact
let fullName = "\(contact.givenName) \(contact.familyName)"
var email = "Not Available"
if !contact.emailAddresses.isEmpty {
let emailString = (((contact.emailAddresses[0] as AnyObject).value(forKey: "labelValuePair") as AnyObject).value(forKey: "value"))
email = emailString! as! String
self.lblDetails.text = "\(fullName)\n \(email)"
}
}
//Mail View
#IBAction func sendAction(_ sender: Any) {
let mailVC = MFMailComposeViewController()
mailVC.mailComposeDelegate = self
mailVC.setSubject("Hello. You have a visitor in the lobby.")
let mailContent = "\(nameTextField.text!) from \(companyTextField.text!) is here to see you."
mailVC.setMessageBody(mailContent, isHTML: false)
let toRecipient = "somebody5555555#gmail.com"
mailVC.setToRecipients([toRecipient])
self.present(mailVC, animated: true) {
self.nameTextField.text = ""
self.companyTextField.text = ""
}
}
func mailComposeController(_ controller: MFMailComposeViewController, didFinishWith result: MFMailComposeResult, error: Error?) {
controller.dismiss(animated: true, completion: nil)
}
func textFieldShouldReturn(_ textField: UITextField) -> Bool {
nameTextField.resignFirstResponder()
companyTextField.resignFirstResponder()
return true
}
}
Define the var outside the function
var email = "Not Available"
func contactPicker(_ picker: CNContactPickerViewController, didSelect contact: CNContact) {
//When user select any contact
let fullName = "\(contact.givenName) \(contact.familyName)"
if !contact.emailAddresses.isEmpty {
let emailString = (((contact.emailAddresses[0] as AnyObject).value(forKey: "labelValuePair") as AnyObject).value(forKey: "value"))
email = emailString! as! String
self.lblDetails.text = "\(fullName)\n \(email)"
}
}
Now you can use the variable inside your class wherever you want.
To get more basics, read documentation Apple Documentation
I am implementing a seemingly trivial and very popular use case where users select a contact, and send them a precomposed SMS.
However, the SMS ViewController dismisses itself automatically. This is easily reproducible.
How do I fix this?
Here's my code:
import UIKit
import MessageUI
import ContactsUI
class ViewController: UIViewController, MFMessageComposeViewControllerDelegate, CNContactPickerDelegate{
let contactPickerViewController = CNContactPickerViewController()
let messageVC = MFMessageComposeViewController()
override func viewDidLoad() {
super.viewDidLoad()
contactPickerViewController.delegate = self
messageVC.messageComposeDelegate = self
}
func contactPicker(picker: CNContactPickerViewController, didSelectContact contact: CNContact) {
if let phoneNumberValue = contact.phoneNumbers.first?.value as? CNPhoneNumber {
if let phoneNumber = phoneNumberValue.valueForKey("digits") as? String {
// Configure message ViewController
messageVC.recipients = [phoneNumber]
messageVC.body = "Yoyoyo"
picker.presentViewController(messageVC, animated: true, completion: nil)
}
}
}
func messageComposeViewController(controller: MFMessageComposeViewController, didFinishWithResult result: MessageComposeResult) {
self.dismissViewControllerAnimated(true, completion: nil)
}
#IBAction func invite(sender: AnyObject) {
self.presentViewController(self.contactPickerViewController, animated: true, completion: nil)
}
}
The problem is that you are asking your picker to present the message view controller. When contactPicker:picker:didSelectContact: method is called, the picker view controller is automatically being dismissed by the system. This means that the view controller is going away and you are trying to use that view controller to present your next view controller.
What you need to do is have "ViewController" in this case present the message view controller. Below is an example of the portion of your code i changed. You'll notice i have a timer there. This is because if you try to present the messageVC right away, nothing will happen because the contacts view controller isn't done dismissing itself yet.
func contactPicker(picker: CNContactPickerViewController, didSelectContact contact: CNContact) {
if let phoneNumberValue = contact.phoneNumbers.first?.value as? CNPhoneNumber {
if let phoneNumber = phoneNumberValue.valueForKey("digits") as? String {
// Configure message ViewController
messageVC.recipients = [phoneNumber]
messageVC.body = "Yoyoyo"
dispatch_async(dispatch_get_main_queue(), { () -> Void in
self.presentViewController(self.messageVC, animated: true, completion: nil)
})
}
}
}
First of all, I'm really surprised that this is not a duplicate, because there are TONS of stackoverflow questions that solve this in Objective-C, but I have yet to see a good answer that used Swift.
What I'm looking for is a code snippet in Swift that sends an arbitrary string as a the body of a text message to given phone number. Essentially, I'd like something like this from Apple's official documentation, but in Swift instead of Objective-C.
I imagine this isn't too difficult, as it can be done in just a couple of lines of code in Android.
EDIT: What I'm looking for is 5-20 lines of Swift code, I do not agree that this is too broad. In Java (for Android), the solution looks like this:
package com.company.appname;
import android.app.Activity;
import android.telephony.SmsManager;
public class MainActivity extends Activity {
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
public static final mPhoneNumber = "1111111111";
public static final mMessage = "hello phone";
SmsManager.getDefault().sendTextMessage(mPhoneNumber, null, mMessage, null, null);
}
}
Now this is the android solution, and it's only 11 lines. Java tends to be much more verbose than Swift, so I doubt what I'm asking is "too broad", it is more likely that I don't know how to use the Objective-C MessageComposer object, because the documentation that I linked to above is unclear with regard to usage in Swift.
Not sure if you really got the answer. I was in a similar hunt and came across this solution and got it to work.
import UIKit
import MessageUI
class ViewController: UIViewController, MFMessageComposeViewControllerDelegate {
#IBOutlet weak var phoneNumber: UITextField!
override func viewDidLoad() {
super.viewDidLoad()
}
#IBAction func sendText(sender: UIButton) {
if (MFMessageComposeViewController.canSendText()) {
let controller = MFMessageComposeViewController()
controller.body = "Message Body"
controller.recipients = [phoneNumber.text]
controller.messageComposeDelegate = self
self.presentViewController(controller, animated: true, completion: nil)
}
}
func messageComposeViewController(controller: MFMessageComposeViewController!, didFinishWithResult result: MessageComposeResult) {
//... handle sms screen actions
self.dismissViewControllerAnimated(true, completion: nil)
}
override func viewWillDisappear(animated: Bool) {
self.navigationController?.navigationBarHidden = false
}
}
Swift 3.0 Solution:
func sendSMSText(phoneNumber: String) {
if (MFMessageComposeViewController.canSendText()) {
let controller = MFMessageComposeViewController()
controller.body = ""
controller.recipients = [phoneNumber]
controller.messageComposeDelegate = self
self.present(controller, animated: true, completion: nil)
}
}
func messageComposeViewController(_ controller: MFMessageComposeViewController, didFinishWith result: MessageComposeResult) {
//... handle sms screen actions
self.dismiss(animated: true, completion: nil)
}
override func viewWillDisappear(_ animated: Bool) {
self.navigationController?.isNavigationBarHidden = false
}
For sending iMessage in Swift 5 I use following code
Just MessageUI package and implement MFMessageComposeViewControllerDelegate
import UIKit
import MessageUI
class ViewController: UIViewController, MFMessageComposeViewControllerDelegate {
override func viewDidLoad() {
super.viewDidLoad()
}
#IBAction func sendNewIMessage(_ sender: Any) {
let messageVC = MFMessageComposeViewController()
messageVC.body = "Enter a message details here";
messageVC.recipients = ["recipients_number_here"]
messageVC.messageComposeDelegate = self
self.present(messageVC, animated: true, completion: nil)
}
func messageComposeViewController(_ controller: MFMessageComposeViewController, didFinishWith result: MessageComposeResult) {
switch (result) {
case .cancelled:
print("Message was cancelled")
case .failed:
print("Message failed")
case .sent:
print("Message was sent")
default:
return
}
dismiss(animated: true, completion: nil)
}
}
Simpler solution may be opening html link:
let mPhoneNumber = "1111111111";
let mMessage = "hello%20phone";
if let url = URL(string: "sms://" + mPhoneNumber + "&body="+mMessage) {
UIApplication.shared.open(url)
}
Make sure you replaced spaces with "%20"
Swift 3, 4, 5
#IBAction func sendSmsClick(_ sender: AnyObject) {
guard MFMessageComposeViewController.canSendText() else {
return
}
let messageVC = MFMessageComposeViewController()
messageVC.body = "Enter a message";
messageVC.recipients = ["Enter tel-nr"]
messageVC.messageComposeDelegate = self;
self.present(messageVC, animated: false, completion: nil)
}
func messageComposeViewController(_ controller: MFMessageComposeViewController, didFinishWith result: MessageComposeResult) {
switch (result.rawValue) {
case MessageComposeResult.cancelled.rawValue:
print("Message was cancelled")
self.dismiss(animated: true, completion: nil)
case MessageComposeResult.failed.rawValue:
print("Message failed")
self.dismiss(animated: true, completion: nil)
case MessageComposeResult.sent.rawValue:
print("Message was sent")
self.dismiss(animated: true, completion: nil)
default:
break;
}
}
UI will look like:
If you do not want to depend on an UIViewController, follows a Swift 3.0 solution:
import UIKit
import MessageUI
class ECMMessageComposerBuilder: NSObject {
private dynamic var customWindow: UIWindow?
private var body: String?
private var phoneNumber: String?
fileprivate var messageController: MFMessageComposeViewController?
var canCompose: Bool {
return MFMessageComposeViewController.canSendText()
}
func body(_ body: String?) -> ECMMessageComposerBuilder {
self.body = body
return self
}
func phoneNumber(_ phone: String?) -> ECMMessageComposerBuilder {
self.phoneNumber = phone
return self
}
func build() -> UIViewController? {
guard canCompose else { return nil }
messageController = MFMessageComposeViewController()
messageController?.body = body
if let phone = phoneNumber {
messageController?.recipients = [phone]
}
messageController?.messageComposeDelegate = self
return messageController
}
func show() {
customWindow = UIWindow(frame: UIScreen.main.bounds)
customWindow?.rootViewController = MNViewController()
// Move it to the top
let topWindow = UIApplication.shared.windows.last
customWindow?.windowLevel = (topWindow?.windowLevel ?? 0) + 1
// and present it
customWindow?.makeKeyAndVisible()
if let messageController = build() {
customWindow?.rootViewController?.present(messageController, animated: true, completion: nil)
}
}
func hide(animated: Bool = true) {
messageController?.dismiss(animated: animated, completion: nil)
messageController = nil
customWindow?.isHidden = true
customWindow = nil
}
}
extension ECMMessageComposerBuilder: MFMessageComposeViewControllerDelegate {
func messageComposeViewController(_ controller: MFMessageComposeViewController, didFinishWith result: MessageComposeResult) {
controller.dismiss(animated: true, completion: nil)
hide()
}
}
You call the composer this way:
let phoneNumber = "987654321"
let composer = MNMessageComposerBuilder()
composer.phoneNumber(phoneNumber).show()
or using a lazy var
let phoneNumber = "987654321"
private lazy var messageComposer: MNMessageComposerBuilder = {
let composer = MNMessageComposerBuilder()
return composer
}()
messageComposer.phoneNumber(phoneNumber).show()
#IBAction func sendMessageBtnClicked(sender: AnyObject) {
var messageVC = MFMessageComposeViewController()
messageVC.body = "Enter a message";
messageVC.recipients = ["Enter tel-nr"]
messageVC.messageComposeDelegate = self;
self.presentViewController(messageVC, animated: false, completion: nil)
}
func messageComposeViewController(controller: MFMessageComposeViewController!, didFinishWithResult result: MessageComposeResult) {
switch (result.value) {
case MessageComposeResultCancelled.value:
println("Message was cancelled")
self.dismissViewControllerAnimated(true, completion: nil)
case MessageComposeResultFailed.value:
println("Message failed")
self.dismissViewControllerAnimated(true, completion: nil)
case MessageComposeResultSent.value:
println("Message was sent")
self.dismissViewControllerAnimated(true, completion: nil)
default:
break;
}
}