How to create Android library jar if not using resources? - android

I am creating an Android library, and I would like to create a distributable jar without revealing source code. The library does not use resources like layouts, images, etc. I understand that I can just copy the .jar automatically generated in the bin folder of an Eclipse Android project if I check 'is Library' under project properties.
Is there anything else I should be aware of? How does the client project know which permissions my library requires. Should I include those permissions in the Manifest of my library?

I understand that I can just copy the .jar automatically generated in the bin folder of an Eclipse Android project if I check 'is Library' under project properties.
I wouldn't, as you don't know how that JAR was created, and you don't know how that JAR might change as the tools change. That JAR is a side-effect of Android's internal build process and is not designed to be a production artifact. Create your own production JAR yourself (e.g., Ant <jar> task).
How does the client project know which permissions my library requires.
You tell them via well-written documentation.
Should I include those permissions in the Manifest of my library?
Since your JAR does not contain your manifest, that will not help.

Related

Creating jar Library of Android project?

I have a project that uses some resources.I want to create a library from it and publish it.I create a jar file with export option of eclipse,but it did not work.Then I search the we b and it seems that way works if and only if project does not use resources.But I saw this post.Here CommonsWare saya there is a way to create a jar file from a project that uses resources.But that answer has two link that do not open any page on the web and I could not test CommonsWare's answer.So my question is:
Is there any way to create jar library file from project that uses resources?
Note:
I read docs that say:
If you have source code and resources that are common to multiple
Android projects, you can move them to a library project so that it is
easier to maintain across applications and versions.
But as I said before,I want to publish my jar and docs say we can not create jar file from library project.And so I can not publish it.
Here CommonsWare saya there is a way to create a jar file from a project that uses resources.
Not in that answer. You can tell that by actually reading the answer.
But that answer has two link that do not open any page on the web
Sorry, Google reorganized their site and broke the original links. The answer has been updated with current links.
Is there any way to create jar library file from project that uses resources?
No.
You can create an Android library project that includes a JAR instead of Java source code. AFAIK, this recipe still works:
Create an Android library project, with your source code, resources, and such, and get it working
Compile the Java source (e.g., via Ant) and turn it into a JAR file
Create a copy of your original Android library project to serve as a distribution Android library project
Place the compiled JAR from step #2 and put it in libs/ of the distribution library project from step #3.
Delete everything in src/ of the distribution library project (but leave the now-empty src/ directory there)
Distribute the distribution library project (e.g., ZIP it up)
And the new Gradle-based build system supports the AAR package for distributing libraries and such, though I have not played with this yet.

Create a JAR for Android Library Distribution

I am working on an android library, and wish to export a JAR file that I can distribute for others to use in their apps. I don't want to distribute the source code as it contains details on posting to my web server.
I have tried using the JAR file that is created in the bin directory and copying the jar file to my project and referencing it within my project and ticking the export button.
When I try and run my project referencing the library that I've copied, my app throws an exception with NoClassDefFoundError. I've done some Googling and everything I have found suggests you have to provide the source code and let the user import into their IDE and then reference that project into their app which I don't want to do. It must be possible as other companies provide JAR files for libraries that can be included.
Thanks for your help.
I don't want to distribute the source code as it contains details on posting to my web server.
Bear in mind that anyone who wants to can get that data out of the JAR.
It must be possible as other companies provide JAR files for libraries that can be included.
AFAIK, this recipe still works:
Create an Android library project, with your source code, resources, and such, and get it working
Compile the Java source (e.g., via Ant) and turn it into a JAR file
Create a copy of your original Android library project to serve as a distribution Android library project
Place the compiled JAR from step #2 and put it in libs/ of the distribution library project from step #3.
Delete everything in src/ of the distribution library project (but leave the now-empty src/ directory there)
Distribute the distribution library project (e.g., ZIP it up)
This effectively gives you what you see with the Play Services SDK -- a library project with no source code, but instead a JAR in libs/, along with the resources and such.
I will be reconfiming this recipe tomorrow and will try to remember to update this answer if I find that it needs adjusting for the current crop of tools.
And the new Gradle-based build system supports the AAR package for distributing libraries and such, though I have not played with this yet.
UPDATE
This recipe works, so long as the library project does not itself have dependencies upon another JAR or library project. In those cases, things seem to get messed up in the build process -- everything can compile, but class references from the dependencies cannot be resolved at runtime.
Did you try putting your jar file in libs folder?And if you are exporting a jar library for android be sure it has no /res folder. As you know you can't reference to your res folder from a jar therefore you have to use library project to reference your res folder (drawable,xml,ect...)On the other hand you cant make your code safe (the part you say about posting to your web service) by using it as jar since it is so easy to retrieve by reverse engineering. you better use some encoding (like base64 or any algorithm that bouncycastle provides)

How to distribute an Android Library

I've been spinning a jar for android library project and including this jar in my other apps. But on developer.android.com, I see this statement that I can't distribute a library in a jar:
You cannot export a library project to a JAR file
A library cannot be distributed as a binary file (such as a JAR file).
This will be added in a future version of the SDK Tools.
I really don't understand what does that mean.
It is possible to create an Android library project that does not
include source code. The limitations are:
You still have to ship the resources.
You have to rewrite your code to avoid using R. values, as they
will be wrong. You will have to look up all resource IDs using
getResources().getIdentifier() and/or reflection.
I have the instructions in The Busy Coder's Guide to Advanced Android
Development (http://commonsware.com/AdvAndroid), though the
instructions are new enough that none of my free versions have them.
Quoting some of the instructions from the current edition:
"You can create a binary-only library project via the following steps:
Create an Android library project, with your source code and such –
this is your master project, from which you will create a version of
the library project for distribution.
Compile the Java source (e.g., ant compile) and turn it into a JAR file
Create a distribution Android library project, with the same
resources as the master library project, but no source code
Put the JAR file in the distribution Android library project's libs/
directory
The resulting distribution Android library project will have everything a
main project will need, just without the source code."
Personally, I'd just wait a bit. I am hopeful that the official
support for library-projects-as-JARs will be available soonish.
It means that (at the current time) you must distribute your entire project folder. Rather than just a jar file like you can for java libraries.
When someone wants to use your library they will import your project into eclipse, and then in project properties->android they will add your project as an android library.
A few common ways used to distribute a Library project are by using git, or zipping your project folder and making it available online.

Is it possible to create jar that includes android functions?

As the topic indicates I would like to create a jar library that uses some android functions (no layouts) and that will be included in an Android project.
Is that possible and how?
From the research I've made I managed to include a simple jar file that uses pure Java (JAVA SE 1.6), but
when I tried creating a jar file I encountered the following exception when I tried to run the Andoid app: FATAL EXCEPTION: main
java.lang.NoClassDefFoundError: mylib.pleasework.amen
I tried including android.jar in my library and removing the java library, so that the jar file is build against android sdk, but it didn't work.
I tried including the jar file under a /libs folder as it is said to be the correct way to import jars in android projects from ADT v17 and after, but that didn't work either.
The jar I want to create will not use any resources (xml layouts, strings.xml) just Log.d and WifiManager.I am aware of Android Library Project but my library source is sensitive and I am afraid that it won't be safe if exposed in a Android library project. I was thinking of creating a jar and using ProGuard ( http://developer.android.com/tools/help/proguard.html ) obfuscate it.
I think I mentioned everything. Any help will be appreciated.
Thanks,
Thomas
As the topic indicates I would like to create a jar library that uses some android functions (no layouts) and that will be included in an Android project. Is that possible and how?
Use the jar command, or the <jar> Ant task. I am sure that there are ways to export a JAR from Eclipse, but I personally have never used them.
For example, in this GitHub repo I have a reusable component and a sub-project that is a sample app. My build.xml for the repo contains the following custom task:
<target name="jar" depends="debug">
<jar
destfile="bin/CWAC-WakefulIntentService.jar"
basedir="bin/classes"
/>
</target>
This generates a JAR file, that other Android applications can use by adding to their libs/ directories.
I am aware of Android Library Project but my library source is sensitive and I am afraid that it won't be safe if exposed in a Android library project.
It won't be safe exposed as a JAR, then, either. You can create an Android library project for public consumption that replaces the src/ tree's contents with a compiled JAR in libs/ in the library.
The way I did it in the end was: to create an Android Library project (check isLibrary checkbox in project properties) export it through Eclipse (right click on the project->export->jar file, careful to deselect all resources - res folder, androidmanifest.xml, *.png etc) and put it in the project you want by importing it under /libs folder. I don't know if this is the best solution but it worked for me.Used ADT r20, Eclipse 3.7.1, Android api level 7

How to reference an external jar in an Android Library project in Eclipse

Oh Android. How I love your verbiage.
I have a workspace with a few projects in it. App1 and App2 are Android applications. Common is an Android library project. App1 and App2 depend upon Common (linked via the Android tab).
Common has some external dependencies, namely httpmime & apache-mime4j, which exist as jar files.
For some reason, it appears that I need to add my mime jars to the build path of App1 and App2 for compilation to succeed. This seems really dumb. In normal Java, I would add Common to the build path of App1 and App2 and things would work. Is this expected that I have to add my jars to every Android application?
-Andy
Note: If I don't configure the build path as described above, I get "The type org.apache.james.mime4j.message.SingleBody cannot be resolved. It is indirectly referenced from required .class files | DataCallUtil.java | /App1/Common/util | line 364"
I think omermuhammed and Amit didn't get the fact that Visser is talking about a Android Library Project.
For those project, I don't think it is possible to create a jar. ( jar has nothing to do with all the Android resources thing ).
From my experience with Android Library Project, this kind of project are just, basically, the sources and the ressources packaged, and ready to be included in another project.
But the settings are not part of the package, so you have to include the libs for each application.
In my experience, this setting is not something that changes often, so it is not so bad.
Android Library Project are still way from being perfect, but still a huge improvement from what was there before ( ie nothing ).
To augment omermuhammed's reply, if the common project is not one that is being changed frequently, creating a jar and using it in the other projects is a good solution.
To create a jar right-click the project on Eclipse -> Export -> Java -> JAR file, then select the folders you want to include in the JAR, in your case I guess this includes the folders gen and libs (libs being the folder with the httpmime & apache-mime4j JARS), but probably neither res nor the root directory of your project (with files such as AndroidManifest.xml that will cause problems with the same file in the dependent projects).
Try compiling the Common project into a jar and adding it as an external jar to your App1 or App2 projects.

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