What is the most effective approach to to creating a type of "wizard" interface that takes the user through a process step-by-step, and allows the user to take the steps in any order as he goes along? For instance, the user could start out by selecting from three options: select contacts, select addresses, or selecting a message to send. When he selects one of those options, say select contacts, he sees the interface to allow him to perform that selection, and he sees the other two options to select at any time, which would be select addresses and select message. Say he then selects the option to select a message, he then sees an interface to selecta message and he also sees the other two options. And this continues indefinitely until he selects to send the message. I think the usual view controllers and segues would work for this. Would I need only one subclass of UINavigationController and three subclasses of UIViewControllers? Could this lead to any problems? Is it possible to do this with view controllers and segues? Is there a better way? I do use Swift, but this question doesn't require that I use only Swift, as you can see.

The documentation for DispatchQueue.AutoreleaseFrequency.workItem says , "The queue configures an autorelease pool before the execution of a block, and releases the objects in that pool after the block finishes executing." Does this mean that the dispatch queue releases each work item or each code in ()->Void after each one finishes executing? When it says, "releases the objects in that pool er the block finishes executing", it makes it sound like there is only one block executing and then the entire pool is released. I'm making sure I verify that I understand this correctly.

Why am I not seeing the message instance property of MFMessageComposeViewController? When I type the following, I get a code-time error message in Xcode that says "Value of type 'MFMessageComposeViewController' has no member 'message'" messageComposeViewController.message // error message: "Value of type 'MFMessageComposeViewController' has no member 'message'" There is nothing that explains this in the official Apple documentation: Documentation/Message UI/MFMessageComposeViewController/message

Is there always only one local CNContainer on any iOS device whether the user is logged in to iCloud or not, and whether the device is an iPhone or an iPad?

I'm curious why I don't see posts about Xcode crashing. Since I updated both macOS Monterey 12.6 and Xcode 14, Xcode repeatedly crashes, becoming more frequently, even within 20 seconds between the last two crashes. Am I the only one getting these crashes?

I've been using the CloudKitShare sample code found here as a sample to help me write code for my app. I want to use performWriterBlock and performReaderBlockAndWait as found in BaseLocalCache using a completionHandler without violating the purposes of the design of the code, which focuses on being thread-safe. I include code from CloudKitShare below that are pertinent to my question. I include the comments that explain the code. I wrote comments to identify which code is mine. I would like to be able to use an escaping completionHandler if possible. Does using an escaping completionHandler still comply with principles of thread-safe code, or does it in any way violate the purpose of the design of this sample code to be thread-safe? If I use an escaping completionHandler, I would need to consider when the completionHandler actually runs relative to other code outside of the scope of the actual perform function that uses the BaseLocalCache perform block. I would for one thing need to be aware of what other code runs in my project between the time the method executes and the time operationQueue in BaseLocalCache actually executes the block of code and thus the completionHandler. class BaseLocalCache { // A CloudKit task can be a single operation (CKDatabaseOperation) // or multiple operations that you chain together. // Provide an operation queue to get more flexibility on CloudKit operation management. // lazy var operationQueue: OperationQueue = OperationQueue() // This sample ... // // This sample uses this dispatch queue to implement the following logics: // - It serializes Writer blocks. // - The reader block can be concurrent, but it needs to wait for the enqueued writer blocks to complete. // // To achieve that, this sample uses the following pattern: // - Use a concurrent queue, cacheQueue. // - Use cacheQueue.async(flags: .barrier) {} to execute writer blocks. // - Use cacheQueue.sync(){} to execute reader blocks. The queue is concurrent, // so reader blocks can be concurrent, unless any writer blocks are in the way. // Note that Writer blocks block the reader, so they need to be as small as possible. // private lazy var cacheQueue: DispatchQueue = { return DispatchQueue(label: "LocalCache", attributes: .concurrent) }() func performWriterBlock(_ writerBlock: @escaping () -> Void) { cacheQueue.async(flags: .barrier) { writerBlock() } } func performReaderBlockAndWait<T>(_ readerBlock: () -> T) -> T { return cacheQueue.sync { return readerBlock() } } } final class TopicLocalCache: BaseLocalCache { private var serverChangeToken: CKServerChangeToken? func setServerChangeToken(newToken: CKServerChangeToken?) { performWriterBlock { self.serverChangeToken = newToken } } func getServerChangeToken() -> CKServerChangeToken? { return performReaderBlockAndWait { return self.serverChangeToken } } // Trial: How to use escaping completionHandler? with a performWriterBlock func setServerChangeToken(newToken: CKServerChangeToken?, completionHandler: @escaping (Result<Void, Error>)->Void) { performWriterBlock { self.serverChangeToken = newToken completionHandler(.success(Void())) } } // Trial: How to use escaping completionHandler? with a performReaderBlockAndWait func getServerChangeToken(completionHandler: (Result<CKServerChangeToken, Error>)->Void) { performReaderBlockAndWait { if let serverChangeToken = self.serverChangeToken { completionHandler(.success(serverChangeToken)) } else { completionHandler(.failure(NSError(domain: "nil CKServerChangeToken", code: 0))) } } } }

Is there a way to use code pin iOS to pin a message to the top in the Messages app?

How do I get my iOS app to run code when something specific in a message in Messages happens, like a specific phone number sends a specific phrase?

When I go to the Shortcuts app and add an action, there is a tab that lets me see Apps that has actions I can use. How do I make my iOS app be able to contribute actions for users to use in a shortcut, so that a user creating a shortcut can add an action that does something in my app? An example of this is the Walmart app. A user can create use an action that allows him to check in.

Is there a way for me to put my iOS app in side of the shared with you?

Is there any way I can allow my app to programmatically make a phone call?

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?

What does the following line do in the code snippet from CloudKitShare Apple sample Xcode project that I show after that?   assert(zoneID == self.zone.zoneID) // Update the server change token. // operation.recordZoneChangeTokensUpdatedBlock = { (zoneID, serverChangeToken, _) in   assert(zoneID == self.zone.zoneID)   self.setServerChangeToken(newToken: serverChangeToken) } The documentation for the assert statement says that when the project build is -0none and also in Playground, the code terminates completely, and not just exit from the current code, do I understand that correctly? The documentation seems to assume I understand C-style programming.

I want to check if my code to cache contacts data while my iOS app is running is done well or not. Anyone have any samples I can look at. I did a search on the internet and cannot find much. Maybe code to cache any time of cache would help for me to look at. I am using Xcode 13.4.1, and my app is intended to install on iOS 12.0 up to the most current iOS version. I seem to remember a search class in one of Apple's frameworks for iOS. I don't remember if that was part of the Contacts Framework. I also will have a cache for the Contacts data that I store in CloudKit, so I take that into account to be looking for any way that might make the Contacts cache and the CloudKit cache work together.

Anyone have any words of wisdom about using NSCache and NSPurgeableData for caching in an iOS app, specifically to cache Contacts data from the device contact store? Under what conditions does this work well?