I have an Android code base which uses APIs with settings to get different data for several apps. All apps use the same code base but with one or two design tweaks. So how do I re-use the main code base without having to copy the whole Android project each time?
iPhone uses multiple targets in the same project which works well. If android cant do this do I need to compile binaries of the code base in one project and then import into each new app project? If so how? I'm using Eclipse and am an intermediate Java developer.
Any help much appreciated!
Doug
Check out "Working With Library Projects" from the Android documentation. This should be just what you're looking for: http://developer.android.com/tools/projects/projects-eclipse.html#SettingUpLibraryProject
The current way to approach this issue if you are using Android Studio with Gradle is by using Gradle, Build Type + Product Flavor
http://tools.android.com/tech-docs/new-build-system/user-guide#TOC-Build-Variants
Build Variants
One goal of the new build system is to enable creating different versions of the same application.
There are two main use cases:
Different versions of the same application
For instance, a free/demo version vs the “pro” paid application.
Same application packaged differently for multi-apk in Google Play Store.
This new concept is designed to help when the differences are very minimum. If the answer to “Is this the same application?” is yes, then this is probably the way to go over Library Projects.
Note: This answer is basically obsolete now that one can create .aar libraries with resources. It still works, though, and there may be times when the portability of a .jar is desirable, so I'm leaving it here.
Blumer's answer is a good one, and you should definitely look into Android's idea of library projects. However, there is another alternative. If you have a module that contains only Java code, but no resources of any kind (images, layouts, etc.), you can compile it to a .jar file separately and use the resulting .jar in multiple application projects. It works like this:
Create a new Java project in Eclipse (not an Android project) and move the source code of your module there.
If your module references any classes from the SDK, you'll need to add the Android SDK .jar to the project's classpath (Project > Properties > Java Build Path > Libraries > Add JAR).
When your module is ready to use, bundle up its .class files into a .jar. You can do this manually, or you can look around to figure out how to get Eclipse to do it for you.
Copy your module .jar file into the "libs" directory of your app's main project.
Add the module .jar to the project's classpath (again, Project > Properties > Java Build Path > Libraries > Add JAR).
Now you should be able to build multiple apps using the same .jar, while maintaining only one copy of the module's source code.
Depending on your particular situation, this may or may not work any better for you than the standard Android library mechanism. But it's worth considering as an alternative.
The Android documentation recommends another approach if there aren't too many "different APIs" used.
The idea is to use reflection instead of making direction references to the code. Make sure to use optimized reflection instead of lookups every time.
References
http://developer.android.com/training/multiple-apks/api.html
http://developer.android.com/google/play/publishing/multiple-apks.html#ApiLevelOptions
You might want to consider using a source control system like Subversion (or GIT). Keep your most feature complete version in the trunk, and make branches for your separate versions that use different data sources or require minor layout changes, etc.
Related
I have an old eclipse android workspace which has the following structure:
one library project which has all the code and default graphics and resources
other projects which depend on the library project, but with different package names, different strings.xml and different graphic resources.
Basically what this means is that all my code is in the Library Project, and all other projects are really just different apps, based on the same code, but looking differently with different names
All these were in one Eclipse workspace and now I need to update the project, so upgrading it to Android Studio sounds like the best way to go.
The easy way is to hope that export works for your case. I battled with Eclipse->Studio migration for weeks. I had exactly that situation - one common project and other apps on top of it. Studio will just convert your common project into an Android library module, and other 'app' modules will be converted into Android app modules. Check out this answer: https://stackoverflow.com/a/22797387/2102748
When you're migrated, you should look to move your source files from the ant-style hierarchy to the gradle-style hierarchy. There is a lot of content for that here: http://tools.android.com/tech-docs/new-build-system/user-guide
Android Studio will also ask you to replace .jar libraries it knows about (like appcompat, google-play-services, etc) with gradle dependencies - do it. Life becomes so much easier.
I have started working on a project where I will need to share a bunch of Java classes across a bunch of apps. In Eclipse it was possible to create one project with all such classes and use it as a library in a workspace with all your dependent projects, but in Android Studio it doesn't seem possible to do so (At least not easily).
I have been reading a bunch of posts and a lot of them suggest setting up a library project, generating an aar file and then using that in my projects. But, as I understand it, this will make my library open-source (Am I right?), which I don't want. I am doing this for a client and I want the code base to be private.
Also, I know that a module can be imported into a new project. But this creates a COPY of the original module. This is not what I want at all. I don't wanna maintain multiple copies of the same classes, which completely defeats the purpose of 'code sharing'.
Is there any good way of achieving what I am looking for? Any help is appreciated.
You have a couple different options.
One option is to maintain your libraries as separate projects and compile them to an archive format, such as JAR or AAR; JAR files are for pure Java libraries, and AAR is for Android libraries (which contain code that accesses Android APIs and/or has Android resources). As was pointed out in the comments, AAR doesn't force you to publish your code to the world any more than JAR files would; it's just an archive file format whose files can be local to your machine or your organization.
With that archive file in hand, you can include it in other projects. If you're part of a multi-developer organization, you may find it convenient to use a repository manager to publish and maintain those libraries within your organization, and you can use Maven coordinate-style specs to include libraries in your projects, which you don't have to manually copy over to your development machine.
The disadvantage of this approach is that it makes it a little harder to make changes to those libraries: you need to load up the project, make changes, build an archive, and distribute the archive.
The other approach is to keep the library as a source module like you did in Eclipse. You observed that Android Studio will make a copy of the module if you import it via UI, but if you bypass the UI and modify the build scripts directly, you can do what you want, which is to use the module in-place and share a single copy among multiple projects. To do this, work in your settings.gradle file and add this:
include ':module_name'
project(':module_name').projectDir = new File(settingsDir, '../relative/path/to/module')
I would strongly encourage you to not use a pure relative path here; in this example, the path is anchored to the settingsDir variable supplied by Gradle, which is defined to be the directory where settings.gradle is found. If you use a pure relative path (i.e isn't anchored to anything), you're dependent on the working directory being the same in all environments where the build file is run (command line vs. Android Studio vs. CI server), which isn't a good thing to assume.
You need to think in the eclipse projects as Android Studio/IntelliJ Idea modules. Then, you can generate android (or java) libraries and then include them in your project.
To mark an Android Studio module as a library you can go to File -> Project Structure -> Facets and there click on Library Module
I was in same situation as you, and i founded an approach using git.
Steps to do, to have library:
Create project in Android Studio.
Create android library module in that project.
In that library module create git repository.
Add modulename.iml in .gitignore file
Use GitHub or Bitbucket for private cloud repository. and push your library to it.
Create new android library model in any project that you want.
Close Android Studio (not sure is that mandatory).
Using explorer go to your created module folder.
Remove all data in it, except modulename.iml.
Clone your library from "GitHub" into it.
That's all.
Now you are able to use library in multiple project whether you are at home or at work. Just after finishing you work not forget to push library changes. And after opening new one pull them.
I think you can automate this thing somehow.
The benefit is that you don't need to build any jar, or aar.
You can certainly create and use a library without making it open source or available to others.
First, you don't need to make it an aar unless it contains Resources.
If it's just plain classes, you can just make it a .jar file.
Either way, the easiest way to share these libraries (either aar or jar) is to set up your own repository. Nexus and Artifactory are the two most common repository managers.
You keep the library in its own project, and then publish it to your own, in-house repository.
Then, projects that need to use the library are configured (in gradle) to use the in-house repository, and get the library from it.
I am working on a Android app in which I would like to add plug and play module functionality ,Say I have Two android project
[A] An app for capturing a image using camera and storing it in memory
[B]Enabling map and locate current location .
now I want to add add this functionality in my Another Android app.While going through android developer link and Android Library Projects - Tutorial I figure out that to use plug and play module I have to make my above project as library project so that I can use it in my new app ,now my questions are
1 Is this only way to use library project to add plug and play module
functionally in my app or there are another way also?
2 what are the pros and cons of using library project in order to add
plug and play module functionally?
basically I am researching on how to add plug and play service in my android app and trying to find best solution ,so any clarity on this topic will be extremaly helpful !!!
thanks in advance !!!
An alternative would be to use a linked source folder. In Eclipse, you can set this up in the project settings in the Java Build Path section. You can choose some source code directory outside your project that will virtually be in your project's space (and other projects that use it will do the same). I find this to be handy just from an IDE UI standpoint when I'm co-developing a module along with an app or two. What I don't like about library projects is that they sometimes don't update correctly within your project so you have to rebuild it and your project or clean your project to continue. Also, the module is simpler because it's just a directory of source code files, not an entire Eclipse project.
One other downside of libraries is that they can introduce conflicts that can be a headache to fight. For example, your library might have a different version of the Android compatibility library in it than your main project, and therefore give you compile time errors. Or there are sometimes errors with duplicate libraries, and you have to go fool with the Order and Export settings of your project.
If your module is going to rely on String, layout, and image resources, etc. that are common to all apps that implement the module, then a library project will be easier to work with so you don't have to pass all your resources in through your module's class constructors and duplicate them in each project.
A third option is Gradle, although as far as I know, that would essentially just help automate one of the above two options. I'm not very familiar with Gradle.
So, I've got a handful of "Utility" style classes in some of my projects. I'm curious if I can move them to an Android Library Project that contains all or most of my non-app specific glue code (wrappers and interfaces, mostly).
So, my question is what happens to the files I don't need in that library. I know Android Library Projects basically just copy their code into the other project, so if I say use 25% of the code in my "general purpose" library, will my app actually contain the bytecode for all 100%, or does it properly strip it down to only the stuff I need.
I had some issues with unused classes in Proguard in the past, so I'm just once-bitten, twice shy with the ADT now...
Unfortunately, all your projects will grow when the library is getting bigger - even if most contents of that library are not used. I tested it myself by creating an app A and a library L. If L is a library used in A, the classes.dex file (and therefore the A.apk file) is growing if I add more classes - even if they are not used.
To sum up: Right now I would create a basic library for certain things that are small and that may be used by many projects, and create a new library for every new component that is going to be larger and only is used by some projects. A good candidate for a new library would be a new UI component with multiple images defined in the resources. A good candidate for the base library are commonly-used methods and things like file caches, for example. Compiled code is compressed quite heavily for Dalvik, which you can see here. (The whole presentation is actually fun to watch :-)
Edit: If ProGuard is activated, it will also remove unused code for you. The default proguard.cfg is sufficient. It will not run on the (default) debug built, but when the final .apk is compiled. So it actually is possible!
I have used 3 level deep Android library projects successfully though it is kind of a pain. The primary use-case is when there are a set of resources and classes that you want to share across a few projects. Since I use a version control system, I would rather not use symlinks.
Note that Android Library projects also suffer greatly when dealing with resources. ADT will rebuild R.java once for each library, and each R.java will contain a copy of all resource ids from all libraries. The core problem here is that resources are regenerated for the entire project as a whole, and there is no way to "build a jar" for a dependency as would be expected with normal "libraries". We tried integrating with OpenFeint, and had all kinds of hell dealing with libraries and dependencies. I think we ended up just merging all the OpenFeint source and resource files into our own project and ditching the "Library" project as it was offering little value.
Android Library projects are a clunky way of sharing code between projects and have a number of drawbacks. I've found that everything accomplished with a Library project can also be accomplished with symlinks (symlink source into two projects). I've yet to find a usecase where an Android Library project offered something that wasn't easy to replicate with other, less fragile means.
I am currently working on a Android Project where we are expected to merge our App with 2 more apps from vendors who wouldn't be sharing their code.So just wanted to know Is there any way we could just include there Source code as JAR Files in our project and then include their resources and point to them(I did do it using getResources().getIdentifier("splash", "layout", getPackageName()) But Its still not working ?? I think I have tried all possible methods so hoping you guys could help me with this.
To quote CommonsWare from this question:
Bear in mind that your packaged classes cannot reference resources (at
least not via R. syntax), and that JARs cannot package resources,
manifest entries, etc. If all you are trying to JAR up is pure Java
code (perhaps using Android APIs), then you should be fine.
Basically, you can only use JARs that contain pure java as libraries in your app, not entire other projects.
The Activities can be compiled into a jar and added to the main Android project and we need to add their project's resources into your Project. The only we could make it work is using the getResources().getIdentifier("splash", "layout", getPackageName()). Even the Widgets like TextView, Button and all those should be referred to using the getResources() method. Like, for example, If you want to perform a action on particular button then we need to identify them by getResources().getIdentifier("Button" /*id in the XML File*/, "id"/*type*/, getPackageName()).
One more thing: you need to specify all the Activities in your Main Android Project's AndroidManifest.xml file with their package name. I hope this solves something.
In order to support faster build times, the r16 tools are creating their own jar files inside of Android Library Projects. You can use this feature to solve this issue. If a vendor would like to release their Android Library Project but without source code, they can make a copy of that Android Library Project that contains everything except for the source code tree. Next, include the jar file from the original Android Library Porject (the one that the r16 tools built.) This will allow you to have a component you can distribute that does not require source code. The consumer of this new Android Library Project will need to manually add any necessary meta data to their own project's AndroidManifest.xml file as needed (Activities, Providers, Permissions, etc).