why should i use dynamic framework,not static framework - ios

i create a project with a framework target and a app target.
in the framework target, i create a class called MyButton inherit the UIButton class.
in the app target, i use the stroryboard and put a UIButton on it,now i use the MyButton class in the interface.
the question is when i set framework target's mach-o type with default option Dynamic library ,i can build and run success.
but when i change the mach-o type with Static library option,i can build success but run failed.the error message is "Unknown class MyButton in Interface Builder file."
i am confused with it,anyone can explain it please.
the test demo is here. https://github.com/george-luofz/Test_useFrameworkInXib.git

Elaborating on dasdom's answer, a dynamic framework is effectively a directory which apart from the compiled binary can contain additional resource files like storyboards, xibs, images etc.
A static framework is something fundamentally different - it's a piece of compiled code in intermiedate format that must be eventually linked with the final app executable to become usable. It has no placeholder mechanism for additional resource files and is not distributed in a same manner as a dynamic framework.
A possible (but not very practical) workaround to utilise static framework would be to serialize a binary resource and embed it in code (becoming effectively an array of bytes - a rather huge one most likely). That would become really hard to maintain and require updating the corresponding deserialised array in code every time the binary resource file has changed.

You cannot use Storyboards in a static library.

Related

How to restrict access to .m file of an ios framework while debugging an app?

I have created a framework and importing that into a sample application for testing purpose. When I am debugging the application and click on "STEP INTO", I am able to see the contents of .m file of my framework. what is the possible solution to restrict the access to my .m file ??![enter image description here][1]
Xcode have options of visibility for framework as
Public: The interface is finalized and meant to be used by your product’s clients. A public header is included in the product as readable source code without restriction.
Private: The interface isn’t intended for your clients or it’s in early stages of development. A private header is included in the product, but it’s marked “private.” Thus the symbols are visible to all clients, but clients should understand that they're not supposed to use them.
Project: The interface is for use only by implementation files in the current project. A project header is not included in the target, except in object code. The symbols are not visible to clients at all, only to you.
However, as you mentioned you want something else which secure your code as well so check the post:
How to build a framework or library for other developers, the secure way?

What is a dynamic framework as opposed to a non-dynamic one?

Xcode 6 allows for dynamic frameworks.
What is a dynamic framework?
Both dynamic framework and static framework is a bundle containing a binary and some other things. The binary is called dynamic library or static library.
The binary is what you code is after compiling, your functions, classes, method become binary form, and they are called symbols.
When building your project.
Your code will be built into a binary, let's call it MyProjectBinary.
If your project links to a static library, then after building MyProjectBinary, linker check the symbols in MyProjectBinary and if it uses some part of the static library, for example, use a class in the static library), then linker will copy all the symbols related to the class and combine them in to MyProjectBinary. So no matter how many static library you use, you only get one building result, which is MyProjectBinary.
If you link to dynamic library, then you are telling the linker that, when MyProjectBinary is running, there will be that dynamic library at a suitable place. Dynamic library is not magic, in fact, you've used them for long time. All the frameworks Apple provides are dynamic libraries. They are guaranteed to exist when you app is running on device/simulator.
Let's assume that your project links to a dynamic library called MyDynamicLibrary. When building your project, first MyProjectBinary is still generated the same as using static library. Then, linker just add some information to MyProjectBinary, mark where to find "MyDynamicLibrary" at runtime. Nothing from MyDynamicLibrary will be add to MyProjectBinary
When running your project:
For the project using static library, nothing special happens, since all the code needed is inside MyProjectBinary, it just runs.
For the project using dynamic library, when your code calls a function which is in MyDynamicLibrary, the system tries to find MyDynamicLibrary according to the information stored in MyProjectBinary, if it finds MyDynamicLibrary, then for MyProjectBinary, the function is used like in MyProjectBinary. If it can't find MyDynamicLibrary, them an error will happen and you app will be terminated.
So why do we need dynamic library for iOS 8?
Before iOS8, an app can have only one executable binary, so using static library is OK.
But when iOS 8 comes, you can deliver multiple executable binary in one app, the additional binaries are extensions' executable binaries. This brings up a problem, if there are some code that are uses by multiple executable binaries, and if using static library, same symbols will be copied into every executable, thus takes more space. This is the time when dynamic library comes in handy, we can put these code in dynamic library, and deliver only one copy of the dynamic library for app, the app and its extensions can use the same dynamic library.

Link framework against App and Test Target

I have a custom Framework I use within my normal App target as well as the corresponding UnitTest target. Turns out that confuses the runtime in such way that it is unable to choose the correct implementation since it has multiple choices:
objc[35580]: Class AClass is implemented in both ../MyApp.app/MyApp and ../MyApp.app/MyAppTests. One of the two will be used. Which one is undefined.
That of course leads to weird behavior if you try to check an object's class hierarchy or do any other class related checks.
So it boils down to the following two questions:
I don't see similar logs for e.g. UIKit components, but this framework is also linked to both targets. Have I incorrectly compiled the framework?
Is it just a trivial configuration issue I missed?
PS: I already checked similar posts like 1 or 2, but although everything is configured as described, the problem remains.
You have added the dependency framework to the Tests target. This is flawed thinking. Since your primary application ALSO exports the SAME framework you will receive warnings about duplicated symbols for any classes found in the framework.
By removing your framework from the test target you can resolve the warnings. Remember, you're not losing any functionality by not linking against the same framework in the test target. Trust me, your code is still there.
I ran into a similar problem here: Xcode5: creating new testing target
The key is to create a new unit testing bundle, point it to your original target, and then don't do anything else! If you start including frameworks and source files into the test target, it'll generate these linking errors. The test target is supposed to "inject" the test classes into the actual target, not create a new separate target on it's own. So you just need to import the header files in your test class, and write your test cases.
I think the bundle should only "read" the framework's header files but not build the sources and leave that task to the App (remove the Framework .m files from the UnitTest target).
Right now the App and the UnitTest are both building the Framework, thus the duplicated classes.

Library? Static? Dynamic? Or Framework? Project inside another project

I have an existing iOS app and want to add a large chunk of code that I've been developing as another project just for ease of testing. The new chunk basically deals with saving an image to various sharing services, etc.. Because that sharing code needs a lot of testing and future updating, I was wondering what the best way to incorporate that code chunk into my existing app.
I don't know if it should be a static library, dynamic library or a framework, and honestly, I'm not really sure what the difference is, or how I should go about it and get it set up in Xcode.
All I know is that I need/want to keep a separate testing and updating app for the sharing code and have the main app use it.
First, some general definitions (specific to iOS):
Static library - a unit of code linked at compile time, which does not change.
However, iOS static libraries are not allowed to contain images/assets (only code). You can get around this challenge by using a media bundle though.
A better, more formal definition can be found on Wikipedia here.
Dynamic library - a unit of code and/or assets linked at runtime that may change.
However, only Apple is allowed to create dynamic libraries for iOS . You're not allowed to create these, as this will get your app rejected. (See this other SO post for confirmation and reasoning on such).
Software Framework - a compiled set of code that accomplishes a task... hence, you can actually have a static framework or a dynamic framework, which are typically just the compiled versions of the above.
See the Wiki on Software Framework for more details.
Hence on iOS, your only option is basically to use a static library or static framework (the main difference being that a static framework is distributed as a compiled .a file most often, whereas a static library may simply be included as a subproject - you can see all of the code - which is compiled first and its resulting .a file used as a dependency by the project).
Now that we're clear(er) on these terms, setting up a static library and supporting media bundle for iOS isn't too difficult, and there are many tutorials on how to do such. I personally would recommend this one:
https://github.com/jverkoey/iOS-Framework
This is a pretty straight-forward guide and doesn't have the disadvantage of dealing with "fake static libraries"... check it out for more info...
Once you've created your static library, it's as easy as including it as a submodule within Git for use across different projects.
Good Luck.
EDIT
Regarding a subproject within a project, as far as I know, to get this to work/compile correctly, you essentially have to set up a compile chain where the subproject is compiled first, which creates a static framework .a file that is used as a dependency by the project.
Here's another useful tutorial which talks about this:
http://www.cocoanetics.com/2011/12/sub-projects-in-xcode/
EDIT 2
As of iOS 8, Apple now permits developers to create dynamic frameworks! (Note: your app must have a minimum target of iOS 8 to include a dynamic framework... back porting isn't allowed.)
This has been added as a new project template. In Xcode 6.1, this can be found at:
New Project -> iOS -> Framework & Library -> Cocoa Touch Framework
Mach-O file format(Mach Object - .o)
In iOS world every source file is converted into object files - ABI[About] Mach-O file[About] which will be packaged into a final executable bundle(application, framework), file (library) and it's behavior is determined by Mach-O type[About]
Package is a directory which behavious itself as a file - opaque file. It is created for user experience to complicate making some changes into internal structure that can cause unpredictable program behaviour. Package is used in Document Package or with a Bundle. You can use Show Package Contents in a Finder
Bundle is a directory with a specific structure to organize a binary(executable code) and resources for that code(e.g. images, nibs... Assets.car file[About]).
Bundle contains Info.plist[About] file. Bundle was created for developer experience. Also it can be packaged. There are several types of bundle:
application bundle - Application target
framework bundle and versioned bundle as a subtype - Framework Target
loadable bundle(aka plug-in bundle) - '... Bundle' (UI Testing Bundle, Unit Testing Bundle) - can be loaded at runtime. .bundle extension for Mac OS
[Mac OS] XPC Service - Cross Process Communication is a kind of Inter Process Communication (IPC). It can be used as a module on a different process(managed by launchd root process)[About]
others(dSYM[About] bundle)
Application - .ipa, .app[About] - packaged application bundle - launchable program.
Application extension[About] - from iOS v8 - extends functionality of Application which are available when user interacts with other application. App extension as a bundle is a part of Containing app but it is run on their own sandbox(processor, memory...), app which try to use app extension is called Host App. Types of extension app:
Action
Share
Photo Editing
Today aka widget
...
to share common code and resources. It's available when Deployment target is iOS 8+.
Tests - packaged loadable bundle which is used to test a binary. Plug-in architecture allows us to add a new functionality(test cases) as a separate module into existing binary
Libraries and Frameworks
[Library vs Framework]
Martin Fowler on InversionOfControl
A Library is essentially a set of functions that you can call, these days usually organized into classes. Each call does some work and returns control to the client.
A Framework embodies some abstract design, with more behavior built in. In order to use it you need to insert your behavior into various places in the framework either by subclassing or by plugging in your own classes. The framework's code then calls your code at these points. The main control of the program is inverted, moved away from you to the framework. This phenomenon is Inversion of Control (also known as the Hollywood Principle - "Don't call us, we'll call you"
Libraries and Frameworks on iOS
They can help you to solve: modularity, reusing, encapsulation, improve build time
Library is a collection of Mach-O object files[check static or dynamic] compiled for one or more architectures.
Static library - .a(aka static archive library, static linked shared library[doc]) - When you add it into your application the static linker during compilation time will merge the object files from the library and package them along with the application object files into one single executable file. The disadvantage is a big output file
From Xcode 9.0, Swift static library is supported.
Dynamic library - .dylib(aka dynamic shared library, shared object, dynamically linked library[doc]) is dynamically linked with the app's executable at load or runtime, but not copied into it. On practice app's package will contain Frameworks folder with .dylib file. All iOS and macOS system libraries are dynamic. The disadvantage is a slow launch time since all dynamic libraries should be copied and linked.
[iOS static vs dynamic library]
[Static vs dynamic linking]
Text-based stub library - .tbd[About], it is a text stub of dynamic library which is located on a target device. As a result you should not package a dynamic library into your bundle. It has a size effect.
Framework aka binary framework - .framework is a not packaged framework bundle(to allow developers to easily take a look at headers and resources) which contains a compiled static or dynamic library, header files and resources.
Static framework contain a static library packaged with its resources.
Dynamic framework aka Embedded framework - from iOS v8 - contains the dynamic library and resources. In addition to that, dynamic framework can include different versions of the same dynamic library in a single bundle (versioned bundle). Also Embedded framework is used in App Extension
[Static vs dynamic framework]
Umbrella framework [Aggregate target] is a framework that contains other frameworks. It is not officially supported on iOS and that is why it is not recommended for developers to create them[Official doc]. In actuality it's a set of sub-frameworks(or Nested Frameworks). When you create a framework which has a dependency, a consumer (such as an app) is responsible for adding this dependency along with your framework into the project. As a developer, it's natural to try to find a way to transfer this duty from consumer to your's. As a result you think that Umbrella framework is the rescue but usually it leads to a serious issues with managing versions and complexity of creating and supporting it.
Fake Framework - is a result of specific operations under a static library to create a bundle with .framework extension that will behave yourself as a dynamic framework. This technic was used when Xcode did not support creating a framework since did not have a framework template. One of realisation of a fake framework. With Xcode 6, Apple has added iOS framework support.
Modular Framework[About] - #import it is a framework which contains a .modulemap file inside. Module can contains submodules. The main advantage is that you save a build time with Modular Framework.
Universal Library or Framework (aka Fat) [lipo] [Aggregate target] contains multiple architectures. For example your release build should support a some arch which you can regulate via Build Active Architecture Only [ONLY_ACTIVE_ARCH]
XCFramework[About] was introduced by Xcode 11 and it is a bundle which includes multiple architectures(arm, x86_64...) and platforms(iOS, MacOS...). It should replace a Universal Framework
Dependency[About] You are able to use third party code as a part of your target. It allows you to reuse a code from a lot of sources like - another project, project in the same workspace, another target, library, framework etc.
How to build and use a Static Library:
[Swift consumer -> Swift static library]
[Swift consumer -> Objective-C static library]
[Objective-C consumer -> Swift static library]
[Objective-C consumer -> Objective-C static library]
How to build and use a Dynamic Framework[change to static]
[Swift consumer -> Swift dynamic framework]
[Swift consumer -> Objective-C dynamic framework]
[Objective-C consumer -> Swift dynamic framework]
[Objective-C consumer -> Objective-C dynamic framework]
[Xcode Build System]
[Xcode components]
[Dynamic linker]
You can also create .podspec file for CocoaPods( http://guides.cocoapods.org/making/private-cocoapods.html#1.-create-a-private-spec-repo ) and use it like any other pod with the only difference that it's your private pod and is not visible to outside world(I'm not sure what will happen if your pod should create CoreData model, but that's not the case, as I understand).

iOS include UIViewController from another xcode project

I've spent some time building an iOS project, however I'd like to reuse one of the UITableViewControllers in another project.
This UITableViewControllers is quite complex (being a custom UITableViewController that inherits from another ViewController and contains multiple classes via #imports, so its not simply a case of copying over the .h, .m and .xib file)
Whats the best way to do this in xcode4? The options I've considered are building a library (.a), a framework (.framework) or importing the new xcodeproject into the original one.
Thanks
I think building your custom view controller into a static library would be the easiest method to include it in your new project. But will require a bit of work in the old project to make sure you get everything included and built correctly. With Xcode 4, libraries are no longer built into 1 static fat library, you end up with 1 library just for the specific build. e.g. iphonesimulator-debug. You will need to either include all the different versions of these libraries or add a build script that will build all of them in create just 1 static library (which will make your life much easier I can promise you that).
This post on SO, Build Fat Static Library, saved me hours of work with static libraries. Hopefully it will help you too.

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