Are separate apps able to share the same binary in a form like a DLL? I know its possible to compile static libraries but I wouldn't count these as the same as a DLL (i.e. a dll is one copy of a binary shared by multiple apps, whereas static libraries are separately included by any using app).
Is each app totally separate from each other, are there any IPC or file sharing mechanisms available for differing apps to communicate and share data?
Is it possible for an app to create a new process in addition to a new thread (I guess not)?
You can't share executable files between applications. Apple requires that all apps function standalone. However you can use a UIDocumentInteractionController to get another program to deal with files you don't understand, and a 'quick view' may be available. That's how Mail works, for example.
Programs from the same vendor can share the keychain and, I think, iCloud storage as of iOS 5, but can't share storage on disk. As they can declare supported file types, UIDocumentInteractionController can be used to push temporary access to a file from one app to another. A custom URL scheme can be used in a similar way to pass fragments of data if that helps.
As a general rule, only one user process may be active at once in iOS - e.g. background processing is essentially event based. So you can't create a second process for yourself.
You can do this if you are developing for a jailbroken phone. Not
otherwise.On jailbroken phones, you can create .dylibs or shared libraries that can be
loaded via the DYLD_INSERT_LIBRARIES environment var (much like on
MacOS)
Apps are sandboxed. However, there are some ways of communicating between apps. You can use
(a) customURL scheme (also mentioned by Tommy above)
(if any) associated with an app to launch an app and send some
parameters to the launching app
(b) If you control communicating
apps, then you can use Message ports (CFMessagePortCreateRemote)
(c) If you control communicating apps, you could use Darwin
NOtification center for distributed apps.
Of course the expectation for (b) and (c) is that the
communicating apps are all running. On iOS since there is only one foreground
process, you'd have to have the other as a background app and that's
restricted to certain kinds of apps on the iOS platform.
Basically, no to all of the above, unless you're targeting jailbroken phones and are bypassing Apple's App Store. If you jailbreak, I believe you have similar options to those you have in Mac OS X.
Related
Just to give some context, there is an iOS app I'm building (in Xamarin) that requires the ability to fetch files (in an automatic way without having the user to navigate to the files and select them manually) that are stored on External Storage Devices (USB Sticks), and are connected (paired) to an iPhone/iPad.
Users connect a lighting cable to the iOS Devices, and plug their USB Sticks into this lighting cable. Here is an example of the cable that end users use to pair the USB Sticks with their iPhone/iPad, and the app then auto fetches these files from the USB Storage Devices.
The app then performs 2 functions:
It listens to notifications, for when a usb stick is paired with the iOS Device.
When it receives this notification, it then proceeds with querying the files on the USB Stick, and reads and processes the files. The app reads these files automatically and the user does not need to manually select these files
I've tried using External Accessory Framework, however that's only suitable for devices that you register with the MFi program.
https://developer.apple.com/documentation/externalaccessory
Notifications Center never seems to work (the Notifications that handle when a Device gets Connected and Disconnected, the delegates never get called), and I've tried using the Microsoft Helpers.
https://learn.microsoft.com/en-us/dotnet/api/externalaccessory.eaaccessorymanager.notifications.observedidconnect?view=xamarin-ios-sdk-12
I've also tried some 3rd party libraries, but haven't found anything useful.
It doesn't look Apple has any Api Available to auto query and read the files, without having to use a DocumentPickerController. I know this is because of the App Sandbox, and I cannot directly access the Removable Storage Devices.
Now for my questions:
Are there any 3rd party libraries anybody can recommend, that can help achieve most of the heavy lifting for this task? I'd prefer a library that's compatible with Xamarin, however if it's a native library (Swift or Objective-C Library, Cocoapods) I'm sure there is a binding I can use on nuget.
Does anybody have any snippets, or documentation, or can point me in the right direction here (Please feel free to post Swift, or Objective-c solutions here if you like)? Where should I look, which Apple Framework (iOS SDK) is most suitable to deal with this situation. And to summarise, is what I'm asking for at all possible on iOS, without having to jailbreak, or get around the App Sandbox?
Update
So I've tried the solution that #Saamer suggested:
Detect if USB is connected to iPhone device
Here is an example I wrote just to verify if the callback gets invoked, and the app can detect if a usb is plugged in.
CFNotificationCenter.Darwin.AddObserver("com.apple.mobile.lockdown.host_attached", null, (e, s) =>
{
MainThread.BeginInvokeOnMainThread(async () =>
{
var picker = await Xamarin.Essentials.FilePicker.PickAsync();
});
}, CFNotificationSuspensionBehavior.DeliverImmediately);
A file picker should immediately get invoked, and open up, once I plug the USB in, however this doesn't happen.
I'm happy for a solution right now which opens up a file picker, when the user plugs in a USB Device, and navigates to the root directory to start off with. So when the File Picker opens up the user should see this. Then they can select the files they want to transfer into the app.
I thought you needed to jailbreak but it seems unlikely, a solution is possible for <iOS 12
CFNotificationCenter's AddObserver seems to be usable for detecting when a device is connected using host attached and detached as shown here
Or if you don’t submit it to the App Store, you can use this
According to the Apple Docs
You can use the Files app and other supported apps to access files stored on external devices, such as USB drives and SD cards, connected to your iPhone.
Essentially you have to make your a "supported app". I have downloaded a free app called "Clockology" that I recommend downloading and playing with, which allows users to see data within the app as you can see below:
You generally use UIDocumentPickerViewController along with the right uttype to get the files from the Files apps or iCloud Drive, and you require activating the Key-value storage and iCloud Documents from iCloud entitlements capability. There's a lot of tutorials on UIDocumentPickerViewController usage, but you specifically want the capabilities that became available from iOS 13 onwards
This video from WWDC is the best example of getting to where you want. I also didn't find any 3rd party libraries that can help with this
——————-
Edit: If the app does not need to be distributed through TestFlight or the App Store, you can use IOKit and distribute through AppCenter, as long as you have the UDIDs of all the devices you need the app installed on (up to 100?)
My understanding is that because of sandboxing, it isn't possible to view any text file (ie config file) associated with an iOS app using another app. Something quite simple with Android. Am I mistaken?
I am trying to implement a text config file with a Unity iOS app that gets loaded and parsed once when the application boots.
This config file would also be able to be edited and saved manually on that actual iOS device.
(addendum)
In Unity there is PersistentDataPath which resolves to /var/mobile/Container/Data/Application/foo/Documents
Is there an iOS supported file explorer app that will allow me view and edit files in this location (without jailbreaking)?
Use can check iOS App Groups. It allows multiple apps access to shared containers and allow interprocess communication. There is no so much documentation about this, but maybe that's what you're looking for. At least you can share NSUserDefaults between the apps.
NSUserDefaults it's a most simple way to save any (not big) configurations for your app. For manual editing: if your app on the device signed with developer certificate, you can connect through any iOS supported file explorer app and edit it. But after release, from App Store, your app installed in restricted/private path, so it's not possible, if only you don't have a jailbreak.
Initial configuration you can put into your app bundle, and at the first run just copy them to NSUserDefaults.
Short answer: There are utilities such as iExplorer - https://macroplant.com - that allow "file manager" type access. However...
Long answer: If your app requires users to buy (or get) other software to modify configuration files, the chances of Apple approving it are slim to none.
The appropriate thing to do is to provide a User Interface in your own app which allows the user to modify / update the settings.
How can I find out programmatically all the files present in iOS device and list them out to user? Also I need to download the file in my local application database?
How this can be achieved with Objective-C.
You cannot access all files in an iOS device outside the sandbox of the app. But there are other ways you can achieve this. What you can do is:
Access all the files in Gallery using UIImagePickerController.
Access all the user files in network- Dropbox/Google drive/iCloud. They all have separate public APIs that can be downloaded and used to download/upload files in network.
In this way, you can access most of the user files and use the same in your application.
Simple answer : you can't (on a non-jailbroken device).
Each app is launched is in own sandbox and can't interact with the others apps, expect using API provided by Apple for app-communication (ex: extension)
You should look at that Apple guide about App Sandboxing, which is valid for OSX and iOS apps.
The main difference between these two OS, as quoted directly from the doc :
iOS Note: Because it is not for user documents, an OS X container
differs from an iOS container—which, in iOS, is the one and only
location for user documents. In addition, an iOS container contains
the app itself. This is not so in OS X.
You cannot access all the files outside the app sandbox. But, if they are available at some shared location(network), you can use third party libraries to access them. For eg.
1. For iCloud- iOS provides inbuilt framework of UIDocument
2. For dropbox- DropBoxAPI is available
3. For Google drive- there is a separate library to access files in the drive.
Hope this helps :)
Is there any way to check version number of other application which is installed from appstore ?
Note:
1. Not in jail broken devices
2. With out using third party library.
Not Possible. your control is upto the level of your App Sandbox.
What is Sandbox?
For security reasons, iOS places each app (including its preferences and data) in a sandbox at install time. A sandbox is a set of fine-grained controls that limit the app’s access to files, preferences, network resources, hardware, and so on. As part of the sandboxing process, the system installs each app in its own sandbox directory, which acts as the home for the app and its data.
It is not possible to check version of another application as in IOS, Applications work in SandBox environment which doesn't allow the application to access other application.
Two applications can communicate with the help of URL schemes,following is the link for URL Schemes of few Applications:
http://wiki.akosma.com/IPhone_URL_Schemes
http://handleopenurl.com/
using URL schemes we can access limited information(Exposed by the Developers of that application)
Although , there are few options,
1)If two application are using same/common web-services ,then this information can be shared
2)using ICloud this can be achieved If two application are using common/public space.
Is it possible to share on-disk data between iOS applications, or are they truly sandboxed? In other words if I wanted to make a shared repository of data to be accessed (and/or modified) by one or more of my apps, could it be done?
One of the listings on the iOS features page is "Share Data Among Apps", but is this what I'm looking for, and what are the related APIs?
Googling hasn't turned up much else in this area and I know I can construct a path to just about anywhere in the iDevice directory structure. Would it be against Apple's TOA, leading my apps directly to rejection, or is there hope for such an architecture?
Nothing too easy unless your app is iPad only. Otherwise this thing speaks about URL Prefixing. See "Implementing Custom URL Schemes" http://developer.apple.com/library/ios/#documentation/iPhone/Conceptual/iPhoneOSProgrammingGuide/StandardBehaviors/StandardBehaviors.html%23//apple_ref/doc/uid/TP40007072-CH4-SW7.
Here is some info on the iPad only Doc support: http://developer.apple.com/library/ios/#documentation/General/Conceptual/iPadProgrammingGuide/CoreApplication/CoreApplication.html%23//apple_ref/doc/uid/TP40009370-CH6-SW2 see "Document Support on iPad Devices". This DOES NOT work on iPhone/iPod
That looks like marketing speak. The only way to share data locally is to pass it in the URL when launching another app. Otherwise, you need an internet server based solution.
Another thought: can you use TCP locally between apps with the new multitasking support? Apps like Air Sharing are allowed to create listening sockets.
using ios keyChain you can share data between apps.