Develop Reference

Why don't we have a single file to open an Android Studio Project?

Why don't we have a file similar to the .xcodeproj (for XCode applications) or an .xds (for Sencha Architect Projects) for our Android Studio Project?
I'm pretty sure a good number of you here have experienced the frustration of trying to import a project you see online in order to piece it apart better and learn how it works. I get that we are supposed to Import Android Projects built using Eclipse and Open Android Projects built using Android Studio.
However, why is it that we have to go through File -> Open -> then pick out the directory of the Android Studio app that we want to open? And the thing is, Android Studio doesn't seem to know it's an Android Studio project until it tries to open and build it. In the screenshot I have below, I have the sample Android Studio projects of ARToolKit, but I've only imported two of them.
As you can see, only those I've imported "can be seen as an Android Studio Project" as indicated that they have the Android Studio logo instead of a Folder.
This can be an issue for those just starting to develop in Android Studio on their own and they try and use existing projects (build from Eclipse or Android Studio) and they hit a snag with just trying to import the projects for reference. They might not know that they should import the folder and not the projectname/src subfolder. It adds to the "steep learning curve" that Android Development has if opening/importing projects aren't streamlined to a degree.
To sum up, my question is:
Why don't we have a single file that we can open that would in turn open Android Studio and import and build the project if it isn't built yet?

Android is not iOS. iOS development is only possible in xcode, hence it makes sense they added a shortcut to open it in xcode directly with a .xcodeproj file. Make life easier for iOS developers.
Android development however can be done outside of android studio as well. Eclipse is just one example, there may be other IDE's that support this. This is possible because android has standalone SDKs and tools that third party applications can use. iOS does not.
Imagine you are working on an android project in android studio. Then your boss tells you someone from 3000km away is going to help you. This guy may be using android studio, but maybe he isn't. When there are multiple options that developers can choose from individually, you do not want to pollute version control with files that you are using, but others may not care about. Each their environment.
This is merely a logical conclusion that you can come to by comparing. The "real" reason why this was done can only be answered by the people that created (adapted intellij) android studio.

This has been very frustrating to me too.
I try to give you a "beta" answer, waiting somebody to confirm it to me.
An Android project is just the composition of many parts that in some cases are concurrent to create the apk file.
It's just like what happens for the whole java projects: you have the main/src/java, the main/src/test, the maver or gradle files, the gradle or maven wrapper, the manifest, the configuration etc.
So you won't have a single project, but a series of folders that can contain many "flavours" or "versions" of the product itself.
The only help it is given to us is the Android studio icon that appears if a folder contains an android project in its subfolders.
I don't know if I have really answered to you, I just have given you my impressions and my thought.

using AndEngine in Android Studio 0.2.10

I'm trying to develop application's Android platform, so far I have programmed in PHP / MySQL, VB.Net, C #, and I have extensive knowledge and experience in this area, I decided to go in developing applications for Android (some of my clients have requirements for such applications). Programming for android I choose android studio (perhaps my decision is wrong), I use the latest version of Android studio (0.2.10) and I install all the SDK and ADT (following the tutorials I googled) and it works.
But currently I am suffering with the installation of AndEngine to Android Studio and compile in AndEngine in Android Studio
I'm trying to add the latest version of AndEngine from github again following tutorials (I googled for it)
Does anyone have any instructions on how to use AndEngine Android Studio 0.2.10, because everything I googled is for older versions of Android studios and i can't get andengine.jar file (which i need ) that can later be used in the studio as Android library
Excuse my bad English (if)

Here is a sample project I used to get AndEngine working in Android Studio.
https://github.com/janebabra/TowerofHanoiProject
All you have to do is add the andengine.jar to your own project and reference it in the project and the Gradle build config.
Hope that helps

Using IntelliJ with Android plugin, rather than using Android Studio

I wonder if there is any difference between using the Android Studio, Google offer to use, and use the IntelliJ Base IDE, and install the Android plugin?
Would it effect the project and module handling?
Would it effect facets?

I've been using IntelliJ IDEA 12 for Android projects for a long time. Android studio has a lot of beneficial additional Android integration, such as:
Inline Lint API checks
Drawable and string previews
Better layout editor
Built in Gradle support
Better DDMS integration
But you can certainly just use the community edition of IntelliJ 12 for Android projects, and for production projects, I would say it's preferable at this time until Android Studio stabilizes. Also, I believe IntelliJ 13 will essentially include all of the Android functionality that Android Studio does, from what I've heard.

This is useful FAQs about Android Studio vs Android Plugin in IntelliJ IDEA.
It is clear to me that
The EAP (Early Access Preview) of IntelliJ IDEA 13, which includes all of the Android Studio features except for the redesigned new project wizard and the App Engine cloud endpoints integration, is available now.
http://blog.jetbrains.com/idea/2013/05/intellij-idea-and-android-studio-faq/

As of today, Android studio actually functions, so I guess this would be my immediate solution. plus I'm not even sure the Android plugin would support all the features as Android studio will, and that there would not be any conflicts... better safe then sorry.

How to install new Android Studio extensions to IntelliJ IDEA

Is it possible at the moment to add the Android Studio extensions to a current IntelliJ IDEA installation?
Xavier Ducrohet and Tor Norbye mentioned in their talk, that Android Studio is an extension to the Community Edition of IntelliJ IDEA and that it's not a fork. So it should be possible to add the extension.
Is there an easy way to do so and probably to revert?
They also mentioned in their talk, that Android Studio uses Gradle as default build system. This should break the builds of current modules. Is this correct?

Thanks for the answers, but I finally found the corresponding statement by JetBrains: http://blog.jetbrains.com/blog/2013/05/15/intellij-idea-is-the-base-for-android-studio-the-new-ide-for-android-developers/
You can upgrade by hitting help -> Checking for updates and then choose Early Access Program as channel in the Update settings. You should receive a notification, that version 13 is available.
This EAP version contains almost all Android Studio features except the new Project Wizard and the App Engine Cloud Endpoints, but they will come soon. The reason for the delay is the Google IO, in the future new Android Studio and IntelliJ versions will be synced (mentioned in the comments of the blog post).

I guess it will be at androidstudio but the project is currently empty.

The installation page is here: Android Studio.
From what I understand in the download page & from what they said in the conference, it's a stand alone IDE based on the intelliJ, but i'm skeptical to whether one can get it as an extension to an already installed intelliJ IDEA.
About the build - in Migrating from Eclipse page they explain how to generate Gradle build files for your projects in Eclipse and then import those projects to Android Studio. It's pretty simple and straight forward.

Having a blackberry J2ME and Android Project under Eclipse

I am building a project under netbeans with a lot of preprocessing instructions. Netbeans handle that pretty well but unfortunately it is not very well supported as an IDE for blackberry and android.
So the idea behind this question is to import the project into eclipse in order to get the new features of every plugin and ease the development. I already found a pretty nice solution for handling preprocessing instructions with Antenna, but I would like to know how to handle the multiple facets of the project : an android project with ADT, a blackberry project with its plugin and finally a J2ME project as well. My goal is to taking advantage of the best plugins eclipse has to offer.
(And the project compiles with ant, so no real problem on this side).
Regards,
Stéphane

Well, you would have to create a separate project for each Android, Blackberry etc in the same workspace, then you would have to define the logical dependency between those projects. So if Project A is dependent on Project B, right-click on Project A in the project tree then Properties > Java Build Path > Projects and add the Project B to the list of projects Project A depends on.
This will allow you to work on Project B as if it was a stand alone project and you and work on Project A as if Project B was a part of it.
You can do this with any number of projects.
Regards,

get BB eclipse plugin from Blackberry site
install Android ADT manager from developer.android
install j2me wireless toolkit
create all project separately into same work space
use relative sdk for build path
after creating project you can also copy your source files to your project n file system, you can defile project dependency as Ali said
i reccomend to disable pre-processing, if you are using ant to build, just disabele it from windows > preference

My Suggestion to you is build your project in HTML5.If you are targeting the android as well as Blackberry .I do not Know How you will do it but It will be really easy to transform the the application of Blackberry to Android.

You have to install the BlackBerry plugin from the RIM site and it is a huge download that includes Eclipse itself. Then you can add the Android plugin via the Eclipse "Install New Software" menu.

I personally did it on my home machine and here is how How I had done
First install the the Eclipse plugin provided on blackberry developer site
Next install the android in same eclipse from Android developer site.
And voilla you are ready for android and blackberry development on single eclipse. I dont know about J2ME bcoz I no longer works on it but I think the plugin for Eclipse will do the work

This may not be quite what you're looking for but perhaps use Ant to do the builds, packaging etc. That makes it easier to support multiple platforms, set preprocessor macros etc. So the IDE would be used for mostly editing. Note that on BB you can have the IDE refer to the .jar thus resolving dependencies.

I had faced a similar issue. I installed Android first and was working on Google maps project .Since I shifted to Blackberry for a while, when i tried installing that plug-in,it did not accept it. Later after much research I found out that the Emulator for android was supporting Maps which inturn does not support installation of BlackBerry. Pretty weird. Like ber444 mentioned, BB plugin is a huge download file of 402 MB which consists of eclipse 3.5 support.
I was working on Ganneymede for android and installed indigo for BB but its not supported