Convert .NET Standard class library to native aar/jar

Convert .NET Standard class library to native aar/jar - android

Currently, we are developing a .NET Standard class library that will be used by different Xamarin.* platforms.
I was wondering if there is a way to use the shared code in a native Android project (maybe produce an AAR/JAR file).
The reason I need this functionality is because our company provides an AAR to one of our customers (that is used by a native Android project), and we would like to keep a single source base instead of two.
Thanks in advance!

Update:
The name changed to ".NET Embedding" and it is at v0.4 at the time of this update.
https://developer.xamarin.com/releases/dotnetembedding/dotnetembedding_0/dotnetembedding_0.4/
New instructions:
Installing .NET Embedding
Original post:
You can use Mono's Embeddinator-4000
It supports various language consumers, so it surfaces .NET code as idiomatic code in the target language. This is the list of supported languages at present:
Objective-C: mapping .NET to idiomatic Objective-C APIs.
Java: mapping .NET to idiomatic Java APIs.
C: mapping .NET to an object-oriented like C APIs.
Embeddinator-4000 is a tool that allows your existing .NET Code (C#, F# and others) to be consumed from other programming languages and in various different environments.
Java is currently in a preview state for macOS, Windows, and Android.
The platform is selected by passing the --platform= command-line argument to the embeddinator. Currently macOS, Windows, and Android are supported.
re: https://mono.github.io/Embeddinator-4000/
As a part of the requires For Android you will need Xamarin.Android 7.4.99+ and Android Studio 3+ (Java 1.8) but if you are building Android apps with Xamarin and Java you would have those already.
Note: This tool is in Preview, so review the open issues and post new if needed.
re: https://github.com/mono/Embeddinator-4000/issues
Note: This is not trans-compiling, but embedding Mono's runtime in a native package that allow CIL code, AOT'd (i.e. iOS) or not to run within a different language/runtime.

Related

Any way to export Xamarin.Forms app so that I can call from Android Studio Java App? [duplicate]

Currently, we are developing a .NET Standard class library that will be used by different Xamarin.* platforms.
I was wondering if there is a way to use the shared code in a native Android project (maybe produce an AAR/JAR file).
The reason I need this functionality is because our company provides an AAR to one of our customers (that is used by a native Android project), and we would like to keep a single source base instead of two.
Thanks in advance!

Working with open cv on android using java not c++

I am working with OpenCv on android using c++ ,I want to develop using java
Can I do that
many thanks

Yes, you can, Check out this page. A cut and paste from there states:
OpenCV now has bindings for desktop Java, updating the set of supported languages to C / C++, Python, Android, Java and any JVM language which interops with Java, such as Scala and Clojure. The existing Java API for Android has recently been extended to support desktop Java as well. Unlike the popular JavaCV project, these bindings are automatically generated by parsing the OpenCV C++ headers.
There is also javacv, which can be accessed here.

How to integrate C++ file into Android Application using JNI

I want to use C++ file in my android application via JNI but i don't know how to integrate C++ file and how to Compile and run it.
Please help me if anybody knows about it

You need to do NDK programming. Android NDK
The Android NDK is a toolset that lets you embed components that make use of native code in your Android applications.
Android applications run in the Dalvik virtual machine. The NDK allows you to implement parts of your applications using native-code languages such as C and C++. This can provide benefits to certain classes of applications, in the form of reuse of existing code and in some cases increased speed.

You can use Android NDK for your requirements.
Android-NDK
The NDK is a toolset that allows you to implement parts of your app using native-code languages such as C and C++. For certain types of apps, this can be helpful so that you may reuse existing code libraries written in these languages and possibly increased performance.
Tutorial Advanced Android: Getting Started with the NDK
Using Android NDK create shared library of your C,C++ files and load that library at runtime from your Android application. Look at tutorial I linked.

How do cross platform mobile C++ SDKs generally work under the hood?

I found a related answer here: How do cross-platform mobile app development frameworks work?
but I was thinking more about c++ cross-platform SDKs work (e.g. Corona, Marmalade, EdgeLib, etc.). They provide the ability to export binaries for iOS and Android while allowing the developer to use C++ code. My assumption is listed below, but please correct it if I am wrong anywhere:
User writes code in C++.
SDK has an interface layer with C++ functions called in user code requesting mobile OS specific functionality. This interface layer is built from code required to implement that SDK function call in the specific mobile OS(written in Java for Android and Obj-C for iOS).
Part I am most confused about because I don't have much mobile dev experience points: Do iOS and Android both have C++ cross compilers that can compile the general logic code written in C++ in the user's app?

MoSync is an example of a C++ based cross platform mobile toolkit - this one starts by using the open source GCC compiler to compile your app's C++ code into an assembly-like format. A custom tool by MoSync (called the 'PipeTool') then combines this assembly format with their pre-compiled libraries into various target formats, including java bytecode (for Android) or Objective-C source (for iOS). More detail about this process here.
The final compilation on the target platform (Android or iOS) is left to you, using the native IDE (Xcode for iOS and Eclipse IDE with Android SDK for Android). So to create an iOS application you'll still need to be a member of the Apple iOS developer program (US$99 per year) for example, whereas the Eclipse IDE and Android SDK are free.
Your example of Corona SDK is not fully relevant since Corona builds into the native binary format using their custom build servers in the cloud - what goes on there is not fully documented as its a closed source toolkit. You pay a subscription fee per year to Corona to be able to build apps. I'm not sure about the other ones you mentioned (Marmalade, EdgeLib, etc.) but would assume they are similar to MoSync.

Check out codenameone.com - they use Java but eventually compile into C++ for iOS and Java for Android.
The difference is their environment includes all the graphics and they create the controls themselves so you get an actual native application with just one codebase.

How to create Android apps using Delphi

I have been asked to research on how to make an android app using Delphi, Now I am not sure that this can be done. I have not come across tutorials on the same. Somebody please clarify on this issue.

Delphi cannot create Android apps at present. This is being worked on for a future release.
Update: As of the release of XE5, Delphi now supports Android development for certain ARM hardware using the mobile Delphi compiler.

Free Pascal is now able to produce code for the Java platform - so it might be feasible to create Delphi code which can be compiled to Java bytecode with FPC and then converted for the Dalvik VM.
The FPC backend for the Java Virtual Machine (JVM) generates Java byte
code that conforms to the specifications of the JDK 1.5 (and later).
While not all FPC language features work when targeting the JVM, most
do (or will in the future) and we have done our best to introduce as
few differences as possible.
This FPC JVM backend is not related to Project Cooper by RemObjects,
nor does FPC now support the Oxygene language.

Two choices to follow at present - check out Delphi for Android which is in design/beta phase: http://lenniedevilliers.blogspot.com/
Or, use Prism http://www.embarcadero.com/products/prism (and check out their Oxygen for Java coming soon http://www.remobjects.com/oxygene/java.aspx which is in Beta)

With DWS as backend script compiler and the soon to come Smart Mobile Studio (aka OP4JS) component library and RAD interface it will be possible to make apps running with HTML5 in android applications (and iOS or any other html5 compatible system).
By using object pascal, all Delphi and freepascal users will have a short learning curve and a high code reuse factor.
There are some samples using only the DWS backend here :
taming-the-flock-with-object-pascal
taming-html5-verlets-with-object-pascal
Update :
More samples can now be found on their homepage.

First steps with native Android applications made with Lazarus/FPC are here.

One way is to use a combination of Delphi, Sencha and PhoneGap by leveraging the Raudus framework. You can try the RaudusEmployee.apk example on your phone and see if this method will work for you.
http://www.raudus.com/samples/
This is not a native application, but similar to many new HTML5 applications.

Delphi XE5 is now released with Android support.
http://www.embarcadero.com/products/rad-studio/create-android-apps

Develop Reference

The Android operating system is a mobile operating system that was developed by Google (GOOGL?) to be primarily used for touchscreen devices, cell phones, and tablets.