Android: What is the difference between SDK and library project - android

For applications like facebook, they provide SDK . I have used many third party libraries for different requirements. What is the difference between both the cases . That is the code bundled as library or as sdk

A Library is a chunk of code that you can call from your own code, to help you do things more quickly/easily. For example, a Bitmap Processing library will provide facilities for loading and manipulating bitmap images, saving you having to write all that code for yourself.
An SDK (software development kit) is a library (often with extra tool applications, data files and sample code) that aid you in developing code that uses a particular system (e.g. extension code for using features of an operating system (Windows SDK), drawing 3D graphics via a particular system (DirectX SDK), writing add-ins to extend other applications (Office SDK), or writing code to make a device like an Arduino or a mobile phone do what you want)
From this thread

Android SDK -> is the core features and software tools that allow you to create an app for the Android Platform. An SDK contains lots of libraries and tools which you will use to develop your application.
A Library -> is a collection of pre-built compiled code which you can use to extend your application's features. For example, you may need to show some graphics in your application. Instead of creating this from scratch, you may choose to use a pre-built library someone else has developed which will give you the features you need thus saving you some time.
Thanks to Nithish for this explanations

SDK is software development kit which provides a platform/a way to develop software while library project is a project which have some lines of code to solve any desire problem, it may have design or code files.
Generally library project focus only one problem but SDK is complete kit/tool to develop any task, if want some functionality in your code which is not present in SDK than we will go for any library project.

SDK is so that you can build applications for FaceBook. SDK can usually only be used in a more specific context. A library is so that you can take the library and use it on your own applications. A library is meant to be portable.
You can obviously use code from anywhere to anywhere, but I think thats the main difference.

Related

Android application only in C++

Is it possible to make an Android application only in C++? I don't know Java. I've tried Visual Studio 2019 approach but I guess my computer isn't good enough for emulating Android phone.
You can write code for Android in C++, if you have the appropriate programming tools. You'll need a cross-compiler and linker for the appropriate architecture. These are readily available in Google's Native Development Kit:
https://developer.android.com/ndk/
I don't know if these tools can be used with Visual Studio -- I suspect it will be fiddly to set up.
The problem with programming in C or C++ for Android is that it's hard to integrate the application with the regular launcher and, even if you can do that, it's hard to provide a regular Android graphical user interface. Android simply does not provide a C API for the user interface.
I write/port a lot of command-line stuff for Android, so the lack of a graphical user interface doesn't bother me. However, most developers provide the user interface in Java and, if parts of the app needs to be in C or C++, it gets integrated with the app in the form of a native library.
Android Studio and similar tools know how to manage a project that has a mixture of C or C++ and Java code. Using well-established Android tools for developing complex, mixed-code apps like this is way simpler than trying to figure it all out yourself using a hodge-podge of tools from different places.

I have sdk. Is ndk neccesarry for eclipse

I have eclipse Kepler and I am having "Android-Sdk-Windows" files. But I cannot able to make an android project in eclipse.. Do i need NDK necessary.
I already have experience with opening project with just "sdk" and eclipse.. But this times How can i enter the "sdk" path instead of "ndk".
Or Teach me what is "sdk" and "ndk"
i tried eclipse->preference->android-> But i can only see NDK location.
Native methods are platform-specific code. They are usually written in languages such as C or C++ and contained in libraries(dll's). It is possible to create a hybrid Java application that benefits from such libraries.
Reasons for Using Native Methods
Gaining access to special capabilities of your device or or Android
OS
Gaining extra speed
Gaining access to a large body of existing legacy code
Typically, good use cases for the NDK are CPU-intensive applications such as game engines, signal processing, and physics simulation
The major disadvantage of native methods is that you won't have cross-platform capability.
What is Android NDK
The Android NDK is a companion tool to the Android SDK that lets
you build performance-critical portions of your apps in native code.
It provides headers and libraries that allow you to build activities,
handle user input, use hardware sensors, access application resources,
and more, when programming in C or C++. If you write native code, your
applications are still packaged into an .apk file and they still run
inside of a virtual machine on the device. The fundamental Android
application model does not change.
Now if you don't know what native code is, then probably you don't need to use native code. Android NDK documentation explains this well:
..., you should understand that the NDK will not benefit most apps. As
a developer, you need to balance its benefits against its drawbacks.
Notably, using native code on Android generally does not result in a
noticable performance improvement, but it always increases your app
complexity. In general, you should only use the NDK if it is essential
to your app—never because you simply prefer to program in C/C++. When
examining whether or not you should develop in native code, think
about your requirements and see if the Android framework APIs provide
the functionality that you need.
Yo do not need the ndk, in order to build an android project. If you are having difficulties with eclipse, I would suggest using Android Studio unless you are dead set on eclipse. I use both, and strongly prefer to use Android Studio whenever I can.
If you decide to stay with eclipse, it is as easy as downloading the ADT plugin by putting the url in the input box under Help->Install New Software, launching and downloading the sdk from the Android sdk manager, restarting eclipse, and then starting a new Android project. Hopefully you do not have to do anything to configure java or anything else.
The ndk is a way of accessing things from a lower level, in order to bypass certain things, or squeeze more performance out of a phone for highly intense operations, or finally to be able to port c/c++ code from different project. i.e. You can write a Opengl ES game in c and reuse most the code for web, ios, and android this way. But that goes beyond the scope of the question, and this answer.
Firstly you should ensure you have installed ADT plugin .

Is it possible to compile a Xamarin project as a library for iOS and Android?

I need to create an API library for Android and iOS. I have experience working with Android projects, but zero experties in iOS. I was wondering if I could create a Project library in Xamarin that compiles as a JAR for Android and as an... I-don't-know-which-type for iOS.
No, that isn't possible. Depending on what you are trying to accomplish there may be alternatives. If you are trying to make a library that can be used by others you could make it a Xamarin component - there is a component store you could put it on if you want it to be generally available, otherwise you can use any normal means of source or object distribution.
If you need to interact with a native app/library then you could make the C# code the "owner" of it and have it call into the native code. This works for both IOs and Android (and is used to work with e.g the play services from google).
No, it is unfortunately not possible to do that.
It seems to me that what you need is a Portable Class Library also known as PCL. It allows you to create a project which can be referenced by all Xamarin supported platforms (such as iOs and Android). There are obviously limitations to the approach like not being able to reference platform specific libraries but in your case (of writing an API) it should suffice.
You can read more in this link
Good Luck!

Android Cross-Platforming

I want to know more about Cross-Platform. I'm currently working on my thesis and decided to make an Android Application but not all target users uses Android device. So, We've come up with an idea to Cross-Platform the android application.
I have read the same topic but it didn't get to me too well. iOS / Android cross platform development. I want to know if there is another way than using the frameworks discussed in the link.
I want know what is the best/shortest way to cross platform a Android Application?
Cross Platform tools are in my opinion not a good idea at all. Android is Java, and iOS is Objective C. Android can use NDK to use a C/C++ library so theoretically if you did most of your code in C/C+ it could be used on both sides. I think two natives is more in order. Study NDK to see what could run on both devices. Lets say you built your app as a C++ Library except for UI interactions. Then in theory the library should work on both sides. C/C++ a lot easier on iOS than android however.
Also it really depends on the dependencies your app will have. Lets say you want to use a library but its only available in Java or C++ how does this effect your decision.
You might also consider designing your app so that it just captures data on the devices and the actual processing of the data takes place in a web service.
Another way is use Mobile Web HTML5 Framework like Phonegapp, Sencha touch and more.
Although web technologies don’t perform as well as native, but it is a useful thing that you can try.
See Choosing Mobile Web HTML5 Framework and http://operationproject.com/2011/adventures-in-html5-part-one/
Android application are apk files that are basically zip file that contains dex/odex files and all other resources that you may wish to add.But I think you can use any coding language to develop as long as you have IDE that converts your code to apk and dex .And most important of all your programming language must support corresponding api or must have something similar to cross compile.The reason Google used Java for Android was they felt it is convenient to do it(read it during case Google v/s Oracle)
Personally I feel cross-platform is good since it increases the developers base and understanding of the System (here Android).And I think the same analogy would go with other Systems as well.

Android API from Go

I know that Go programs can be compiled for Android.
How can I use Android specific API, like getting GPS coordinates or opening a URL with the default browser, from within a Go program?
I'm afraid it's hardly possible at the moment. In the "Meet the Go Team" I/O sessions, the guys from the Go team stated that they have no plans to add Android support to Go.
What we have now is just a compiler for ARM architecture. Unfortunately, this is pretty much useless for real Android apps, though such programs can be launched from the command line on Android devices.
Most of the Android framework is written in Java, so to interact with it your code should be compiled to a *.so libary, that will be loaded and called via the JNI interface. And it's not possible with the current Go compiler (gc, not sure about the gccgo).
Maybe you will be able to make bindings to the Android NDK API with cgo, that would allow you to create applications in Go since API level 9 (Android 2.3)
UPD: You can now use JNI from Go and create java bindings automatically with golang.org/x/mobile package. In Go 1.4 it's still experimental, but there are plans to include it into Go 1.5 release. The package also provides bindings for GL, audio and user input (hopefully they would also add iOS support and that would be compatible for Android and iOS one day). Anyway this package is mostly oriented at writing games in Go, rather than using Go as a replacement for Java on Android.
Take a look at my answer to Android App from Go programming language. The goandroid project allows you to create Android apps in Go through the NDK.
(Disclaimer: I'm the author of goandroid)
Edit: As mentioned in the comments, Go 1.5 adds official support for Android apps in pure Go or as a mix of Java and Go. iOS is also expected to arrive in time for the final 1.5 release. See https://github.com/golang/mobile for more details.
GO 1.4 doc says, "Go 1.4 can build binaries for ARM processors running the Android operating system. It can also build a .so library that can be loaded by an Android application using the supporting packages in the mobile subrepository"
There is package app option in "golang.org/x/mobile/app" library that lets you write Apps for Android (and eventually, iOS).
Step 1: Create a platform independent GUI library using Golang that uses OpenGL to draw and an intelligent event and data-binding system to write the apps in. Any software using OpenGL is going to be more-or-less portable. Essentially, re-write Kivy in Golang.
Step 2: Create introspection/reflection based wrapper for using Java classes similar to PyJNIus (also a Kivy project).
Step 3: Lots more hard work, because there is a lot to do to get to the level of Kivy
Step 4: Profit

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