How would I check for a return key tap on the keyboard when a text view is first responder? So far I think I have to check the text parameter in the shouldChangeTextIn callback method of UITextViewDelegate. How would I check whether text is a return?

How do I copy to file system or play with AVAudioPlayer an MPMediaItem that I get from an MPMediaPickerController initialized with type audio? When I try, I get an error that says:The file “item.mp3” couldn’t be opened because URL type ipod-library isn’t supported.

In Info.plist of my Xcode project, I see for instance "Executable file" is set to "$(EXECUTABLE_NAME)". I believe that "$(EXECUTABLE_NAME)" is called an environment variable. What I'd like to know is where is that environment variable set. I'd like to see where all the environment variables are set so I can use those values.

When I write code for a timer like below, the timer doesn't fire if the device is locked. How do I cause the code in the timer closure to run when the app is in the background? Are there any other ways to cause specific code to run at a certain time when the app is in the background? func setTimer(alarm: UTIAlarm) { let timer = Timer(fire: alarm.date!, interval: 0, repeats: false) { (timer: Timer) in print("timer fire \(self.dateFormatter.string(from: alarm.date!))") do { try AVAudioSession.sharedInstance().setActive(true, options: .notifyOthersOnDeactivation) } catch { print("Failed to setActive AVAudioSession from timer closure.") print(error.localizedDescription) } let predicate = MPMediaPropertyPredicate(value: alarm.mediaItem!.title, forProperty: MPMediaItemPropertyTitle) let query = MPMediaQuery() query.addFilterPredicate(predicate) self.playerController!.setQueue(with: query) self.playerController!.play() } runLoop.add(timer, forMode: .default) timers.append(timer) }

I am having trouble creating a sandbox tester account in App Store. I keep getting an error message saying there are one or more validation errors when I click on "Invite", but there are no indications of any errors. None of the fields are marked with red for an error.What is going on? Is there a limit of the number of sandbox tester accounts I can create? Is anyone else having trouble with this?

Anyone ever tested Apple's sample code for SiriKit UnicornChat? How do I figure out what to say to Siri to see if the sample works?

Anyone have any recommendations on how to resize a screen video of an iPhone from 750x1334 to 1080x1920 as required by App Store Connect? Or any alternative solutions?

I clicked the delete button to an App ID in my developer account and I got a message saying "All certificates associated with the App ID will be deleted and any provisioning profiles associated with this App ID will be invalidated." Why would the entire provisioning profile be invalidated? What about the other App IDs in that provisioning profile? Does that mean I wouldn't be able to use the provisioning profile for those other App IDs at all?

Why am I getting an error message when I try to validate an archive that says, "No accounts with iTunes Connect access have been found for the team. iTunes Connect access is required for App Store distribution."?I have never gotten this error message before. What should I do?

How do I get the microseconds of an object of type Date? I'm open to any suggestions. I'm not able to set the dateFormat property of DateFormatter to be able to show microseconds.

I am using more than one table view cell class on a table view. I have registered the reuse identifiers and the xibs. For some reason the cells are not showing. What should I check. I'm stumped.Here is my code:import UIKit class DetailTableViewController: UITableViewController { let items = [0, 1] override func viewDidLoad() { super.viewDidLoad() tableView.register(DueDateSwitchTableViewCell.self, forCellReuseIdentifier: "DueDateSwitchTableViewCell") let xibDueDateSwitchTableViewCell = UINib(nibName: "DueDateSwitchTableViewCell", bundle: Bundle.main) tableView.register(xibDueDateSwitchTableViewCell, forCellReuseIdentifier: "DueDateSwitchTableViewCell") tableView.register(DueDatePickerTableViewCell.self, forCellReuseIdentifier: "DueDatePickerTableViewCell") let xibDueDatePickerTableViewCell = UINib(nibName: "DueDatePickerTableViewCell", bundle: Bundle.main) tableView.register(xibDueDatePickerTableViewCell, forCellReuseIdentifier: "DueDatePickerTableViewCell") } override func numberOfSections(in tableView: UITableView) -> Int { return 1 } override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int { return items.count } override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell { print("tableView(_:cellForRowAt:)", "indexPath.row=", indexPath.row) let cell = UITableViewCell() switch indexPath.row { case 0: print("\tcase 0") let cell = tableView.dequeueReusableCell(withIdentifier: "DueDateSwitchTableViewCell", for: indexPath) as! DueDateSwitchTableViewCell cell.backgroundColor = UIColor.yellow case 1: print("\tcase 1") let cell = tableView.dequeueReusableCell(withIdentifier: "DueDatePickerTableViewCell", for: indexPath) as! DueDatePickerTableViewCell cell.datePicker.date = Date() default: break } return cell } }The cells show the numbers when I use this code in tableView(_:cellForRowAt:) before the line that says "return cell": cell.textLabel!.text = String(items[indexPath.section].hashValue)

Does Cocoa Touch provide a convenient way for apps to perform logging? Perhaps something similar to the print() command except it is kept after the app is installed?

Anyone know where I can get a list of all the UserDefaults keys? I can't find it in documentation.

I included the Tests and UITests schemas when I created my Xcode project, but now I want to remove them. Even if I delete those groups, I still get build errors on the files and the files still show in the editor. How do I remove those files from my project for good?

If I've already set contraints using code in iOS, how do I change the constraits?