I am relatively new to iOS app development and I'm just trying to figure out some things that, to me, are more abstract. How do apps know when other apps start? The closest example I can think of to what I'm trying to ask is when music is playing in the background and you open another app that has sound and the music stops. Is that the new app taking authority or is there inter app communication? If there is communication how does that communication work? Like is it a message that could be accessed or what?
Sorry if that didn't make much sense, I tried to elaborate the best I could. I couldn't find anything on this on apple's developer website. Thanks in advance!
There is no inter-app communication. Each app is living in its own world, and as far as your app is concerned, it's the only app on the phone. The way communication happens is that an app talks to the system, and the system talks to your app. The way the system sends messages to your app is usually in the delegate of the framework you're working with. In your example, opening your app to play audio will send a message to the system, and the system will tell the other app to stop audio playback. That other app has no idea it was your app that initiated the stop. Another example is the AppDelegate. The app delegate will send your app messages such as application:didFinishLaunchingWithOptions:, which in this method is where you do custom initialization of the app or applicationWillResignActive: which is normally sent when the user presses the home button or receives a phone call, so here you might want to save your game, etc.
In fact the iOS system is quite complicated, much to complicated to be explained in detail here so I highly suggest reading the Apple Developer Documentation, some of it can be a little dry, but they do their best to be coherent with even absolute beginners.
Related
I was wondering how social networking apps, such as Twitter, Facebook and WhatsApp update their user interface in real-time when another user interacts with the user of the app. To use the best example I can think of: when you have a chat window open in WhatsApp, the UI updates automatically (without any user actions required) when the user you're chatting with interacts with you. Messages appear on your screen without refreshing and the "last seen" status at the top of the screen updates automatically when your chat partner either goes offline or comes back online. I can think of two ways to achieve this:
Remote push notifications: this approach strikes me as the 'cleanest' way to do this, but it's probably also the riskiest way. Using silent notifications (content-available) to pass data to another device at the moment a user does something, would probably save you a lot of HTTP requests and therefore would make your app consume a lot less data and CPU usage. The risk of this approach is that a user can easily disable ALL push notifications to save battery power (including silent notifications) and then your app wouldn't be able to get notified on events remotely.
Local UI refreshing: This approach is obviously the safest, but I think it's really 'nasty' and eventually everyone would feel the downside of it. Constantly refreshing the UI and re-retrieving data from the database to make sure the latest messages and statuses are displayed to the user would be safe in the way that your app doesn't have to rely on the device's battery and background mode settings, but the downside is that this will make your app consume a lot of data and battery power, which would be bad for the user's data plan and his device. I also don't think Apple would approve of an app that's consuming so much data and power.
I've just implemented a chat function into my own app, and I want to enable the same real-time UI updating that WhatsApp uses. What would be the best way to do this? Should I use one of the two methods above or can someone think of another way to do this? By the way, I'm a relatively new programmer who just recently learned how to develop iOS apps (Swift). I'm very far from being a pro, so please go easy on the explanations and work method capabilities. Thanks!
The chat apps make use of WebSockets to create a constant connection with the client and a backend server.
This article on Appcoda can help you start learning about Socket.io. It answers your questions and also helps you to create a demo app.
This might be asking for the moon but here goes...
Is it possible to have an iOS app receive data and then forward it all while running in the background?
We're a restaurant currently using an ordering system that uses a main iPad as the till, with a second iPad in the kitchen to receive orders, and another third iPad used by the servers to take orders. Orders are sent to the main till which relays orders to the kitchen.
Works great... Unless someone switches app on the main till iPad to our other (necessary) hosting app, then all hell breaks loose and all orders stop getting sent.
Developer (small team) has told us it's impossible to solve but I have done some digging into recent Apple APIs that allow simple tasks to run in the background and have seen a few promising options, or perhaps it's possible via the External Accessory Framework, or even syncing via iCloud? A question for the more knowledgable than me, but is there currently a workaround to solve this that I could suggest or are they right in that it's currently impossible in iOS?
Yes there are ways to have an app in the background receive data, generally using either:
beginBackgroundTaskWithName:expirationHandler:
or
beginBackgroundTaskWithExpirationHandler:
Take a look at the Background Execution section in the documentation for more info...
I found various threads here about how muting or canceling incoming calls (or messages) with the iOS SDK is not possible, due to the fact that Apple doesn't want an app to access system level settings. Well in fact not possible with the official tools, which means that if you somehow manage to do it, your app will not be accepted in the iTunes store.
Well I have been asked to assess the possibility of such an app that could do just that. Namely my client has seen these two apps
https://itunes.apple.com/us/app/lifesaver-distracted-driving/id874231222?mt=8
https://itunes.apple.com/us/app/at-t-drivemode/id907208943?mt=8
And they are sure that an app, basically exactly like these (based on the functionality) can be made.
So here I am, asking, how did these two apps succeed at the impossible and also how did they manage to get those apps uploaded to the iTunes store, if muting your phone is not an Apple approved option? I am not really asking for source code, although I am certainly not rejecting examples, but moreso I am asking for pointers of what class or book or documentation do I have to look up to figure out if this is possible? Apples CTCall and CT* classes did not seem to help me much.
K
Apple added the CallKit framework in iOS 10 to allow app developers to do this sort of thing, among others. For docs, see:
https://developer.apple.com/reference/callkit
It is now possible to detect and block unwanted phone calls from iOS 10 and above.
See the CallKit framework
The CallKit framework (CallKit.framework) lets VoIP apps integrate
with the iPhone UI and give users a great experience. Use this
framework to let users view and answer incoming VoIP calls on the lock
screen and manage contacts from VoIP calls in the Phone app’s
Favorites and Recents views.
CallKit also introduces app extensions that enable call blocking and
caller identification. You can create an app extension that can
associate a phone number with a name or tell the system when a number
should be blocked.
I'm trying to get into a new project, by creating an iOS application. But before I start I would like to understand some points:
is it possible to let an application make a phone call? So what I mean is, assumed we have a phone number and would like to call it. Would it be possible to use an (my) application to call this number?
is it possible to let an application speak during a phone call? So after the application started the call, would it be possible that some predefined statements are said in the call?
is it possible that this application hears, registers and analyses what the other person on the phone line is saying? (Leaving apart the privacy issue, assuming that the other person is willing to do that).
Could you please help me? If my question aren't clear, please tell me, I will try to explain it in another way.
Many Thanks
F.P.
iOS is very restricted in terms of the system behaviors third party applications can influence.
To answer your question bluntly, a third party application could prompt the user to initiate a phone / FaceTime call. Once the call is initiated however, your app would enter a background state and relinquish control to the system. The app would not be able to contribute or read any data related to the system phone / FaceTime call.
iOS 10 introduces a VoIP extension, CallKit, which allows third party apps to use the built in calling UI with a custom protocol. You could implement your own protocol (and host servers for handling the exchange of information) and build an extension to make it feel like a system call. You'd be responsible for all aspects of the custom call protocol and thus reading voices, contributing audio, etc. would all be possible (and up to your implementation).
Outside of iOS 10, you would have to built your own VoIP system and interface entirely from scratch.
For more info on CallKit:
WWDC Enhancing VoIP Apps with CallKit
CallKit Enabled Sample App
Building a multi player iOS game where players compete one against the other. Nature of the game is synchronous. Basically, players either invite each other through facebook, email, etc and then start playing.
We debate what is the best strategy for facilitating the real time communication between players (sending events, etc). Coming from web development, we used comet and long polling which worked great. However, it's not clear what's the best way to achieve that on iOS.
Seems like APN (Apple Push Notifications) is not suitable in our case for two reasons: the delay can be pretty significant, up to few seconds, as far as we understand. Also, using APN requires the user to authorize notifications. If the user doesn't authorize this then it won't be possible to play the game.
Also, we understand Apple's Game Kit (Game Center) can be of value in our case however it's not clear how it interacts with invites through facebook etc. Also, not clear if we need to get into bed with Apple's Game Center and how it'll affect the user experience.
Any guidance on this matter as well as other options that you might think of would be greatly appreciated.
Thanks for your help.
Before you read the rest, a disclaimer: I work for Realtime.co but I do believe I can help here so I'm not trying to "pitch a sale".
If you need to have real time updates, you can check out Realtime (www.realtime.co). It's basically a set of tools for developers to use real time technologies on their projects. It uses websockets but does fallback to whatever the user's browser supports (such as long polling, for example) if you are using a browser (which is not your case, but it's always good to know).
Behind Realtime you have a one-to-one/one-to-many/many-to-many messaging system that will transport your messages to and from your users.
There's a iOS API too which you can use in your project. You can download it here: http://www.xrtml.org/downloads_62.html#ios and check the documentation here: http://docs.xrtml.org/getting_started/hello_message.html#ios.
There's also a plus which is the fact that the Realtime framework is actually cross-platform. This means that you can even have your iOS players to communicate with players using Android, Windows Phone, HTML5, Flash, etc. if you decide on expanding your game to other platforms.
I hope that helps!
I'll just provide some insights on the question.
APN should never be used for synchro communication as for iOS at least, you'll never have both way communication (basically the Apple APN servers are pushing an information to the device).
You should probably play with C sockets in order to open a tunnel (depends if your game is real time or not).
Using the Apple Framework GameKit is great! But might take some time to understand all the functionnalities.
Check out Gree
https://developer.gree.net/en/
Parse:
https://www.parse.com/
Sparrow:
http://gamua.com/sparrow/
There are a few things that your talking about, there is the joining/starting of a game, and then the communication between the players. They are not necessarily related.
You can use game-center and at the same time another framework for facebook, they are not mutually exclusive (but it would be more work.)