How to create a library project in Android Studio and an application project that uses the library project

Question

I m new to the gradle build system and IntelliJ   So how do I create an Android Library Project  e g  com myapp lib1  and the application project  e g  com myapp app  and make the build system include com myapp lib1 on the application project   I went to the Project Structure -  Modules -  My App project and added a dependency to the lib project  IntelliJ now can recognize classes from the lib project when used in the app project  but when I run the app project  there are errors like   Gradle  error  package com myapp lib1 does not exist

User · Answer

I wonder why there is no example of stand alone jar project.

In eclipse, we just check "Is Library" box in project setting dialog.
In Android studio, I followed this steps and got a jar file.

Create a project.
open file in the left project menu.(app/build.gradle): Gradle Scripts > build.gradle(Module: XXX)
change one line: apply plugin: 'com.android.application' -> 'apply plugin: com.android.library'
remove applicationId in the file: applicationId "com.mycompany.testproject"
build project: Build > Rebuild Project
then you can get aar file: app > build > outputs > aar folder
change aar file extension name into zip
unzip, and you can see classes.jar in the folder. rename and use it!

Anyway, I don't know why google makes jar creation so troublesome in android studio.

User · Answer

You can add a new module to any application as Blundell says on his answer and then reference it from any other application   If you want to move the module to any place on your computer just move the module folder  modules are completely independent   then you will have to reference the module   To reference this module you should    On build gradle file of your app add   dependencies       compile project   myandroidlib      On settings gradle file add the following    include   app     myandroidlib   project   myandroidlib   projectDir   new File PATH TO YOUR MODULE

User · Answer

To create a library   File   New Module  select Android Library    To use the library add it as a dependancy   File   Project Structure   Modules   Dependencies    Then add the module  android library  as a module dependency     Run your project  It will work

User · Answer

As theczechsensation comment above I try to search about Gradle Build Varians and I found this link  http   code tutsplus com tutorials using-gradle-build-variants--cms-25005 This is a very simple solution  This is what I did   - In build gradle   flavorDimensions  version   productFlavors       trial          applicationId  org de studio recentappswitcher trial          flavorDimension  version            pro          applicationId  org de studio recentappswitcher pro          flavorDimension  version             Then I have 2 more version of my app  pro and trial with 2 diffrent packageName which is 2 applicationId in above code so I can upload both to Google Play  I still just code in the  main  section and use the getpackageName to switch between to version  Just go to the link I gave for detail

User · Answer

The simplest way for me to create and reuse a library project    On an opened project file  gt  new  gt  new module  and answer the UI questions       check or add if in the file settings gradle  include   myLibrary  check or add if in the file build gradle   dependencies                 compile project   myLibrary      To reuse this library module in another project  copy it s folder in the project instead of step 1 and do the steps 2 and 3     You can also create a new studio application project  You can easily change an existing application module to a library module by changing the plugin assignment in the build gradle file to com android library   apply plugin   com android application   android         to  apply plugin   com android library   android         more here

User · Answer

For Intellij IDEA  and Android Studio  each library is a Module  Think of a Module in Android Studio as an equivalent to project in Eclipse  Project in Android Studio is a collection of modules  Modules can be runnable applications or library modules   So  in order to add a new android library project to you need to create a module of type  Android library   Then add this library module to the dependency list of your main module  Application module

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Had the same question and solved it the following way   Start situation   FrigoShare  root   -Modules     frigoshare    frigoShare-backend   Target  want to add a module named dataformats   Add a new module  e g   Java Library  Make sure your settings gradle look like this  normally automatically     include   frigoshare     frigoShare-backend     dataformats  Make sure  manually  that the build gradle files of the modules that need to use your library have the following dependency   dependencies                       compile project   dataformats

User · Answer

Don t forget to use apply plugin   com android library  in your build gradle instead of apply plugin   com android application

User · Answer

Purpose  Android library at single place - Share across multiple projects http   raevilman blogspot com 2016 02 android-library-project-using-android html

User · Answer

Google   s Gradle Plugin recommended way for configuring your gradle files to build multiple projects has some shortcomings If you have multiple projects depending upon one library project  this post briefly explain Google   s recommended configuration  its shortcomings  and  recommend a different way to configure your gradle files to support multi-project setups in Android Studio   An alternative multiproject setup for android studio  A Different Way    It turns out there   s a better way to manage multiple projects in Android Studio  The trick is to create separate Android Studio projects for your libraries and to tell gradle that the module for the library that your app depends on is located in the library   s project directory  If you wanted to use this method with the project structure I   ve described above  you would do the following    Create an Android Studio project for the StickyListHeaders library Create an Android Studio project for App2 Create an Android Studio project for App1 Configure App1 and App2 to build the modules in the StickyListHeaders project    The 4th step is the hard part  so that   s the only step that I   ll describe in detail  You can reference modules that are external to your project   s directory by adding a project statement in your settings gradle file and by setting the projectDir property on the ProjectDescriptor object that   s returned by that project statement     The code one has to put in settings gradle   include   library1  project   library1   projectDir   new File     StickyListHeader library1     If you   ve done this correctly  you   ll notice that the modules referenced by your project will show up in the project navigator  even if those modules are external to the project directory     This allows you to work on library code and app code simultaneously  Version control integration also works just fine when you reference modules externally this way  You can commit and push your modifications to the library code just like you can commit and push modifications to your app code   This way of setting up multiple projects avoids the difficulties that plague Google   s recommended configuration  Because we are referencing a module that is outside of the project directory we don   t have to make extra copies of the library module for every app that depends on it and we can version our libraries without any sort of git submodule nonsense   Unfortunately  this other way of setting up multiple projects is very difficult to find  Obviously  its not something you   ll figure out from looking at Google   s guide  and at this point  there   s no way to configure your projects in this way by using the UI of Android Studio

User · Answer

In my case  using MAC OS X 10 11 and Android 2 0  and by doing exactly what Aqib Mumtaz has explained   But  each time  I had this message    A problem occurred configuring project   app     Cannot evaluate module xxx   Configuration with name  default  not found    I found that the reason of this message is that Android 2 0 doesn t allow to create a library directly  So  I have decided first to create an app projet and then to modify the build gradle in order to transform it as a library   This solution doesn t work  because a Library project is very different than an app project   So  I have resolved my problem like this     First create an standard app  if needed    Then choose  File Create Module  Go to the finder and move the folder of the module freshly created in your framework directory   Then continue with the solution proposed by Aqib Mumtaz   As a result  your library source will be shared without needing to duplicate source files each time  it was an heresy for me    Hoping that this help you

User · Answer

There are two simplest ways if one does not work please try the other one    Add dependency of the library inside dependency inside build gradle file of the library u r using   and paste ur library in External Libraries    OR   Just Go to your libs folder inside app folder and paste all your  jar e g Library files there Now the trick here is that now go inside settings gradle file now add this line  include   app libs   after  include   app   It will definitely  work

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Check out this link about multi project setups   Some things to point out  make sure you have your settings gradle updated to reference both the app and library modules    settings gradle  include   app     libraries lib1     libraries lib2   Also make sure that the app s build gradle has the followng   dependencies        compile project   libraries lib1       You should have the following structure    MyProject      settings gradle     app        build gradle     libraries        lib1           build gradle       lib2           build gradle   The app s build gradle should use the com android application plugin while any libraries  build gradle should use the com android library plugin   The Android Studio IDE should update if you re able to build from the command line with this setup

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Documentation Way  This is the recommended way as per the advice given in the Android Studio documentation   Create a library module  Create a new project to make your library in  Click File   New   New Module   Android Library   Next    choose name    Finish  Then add whatever classes and resourced you want to your library    When you build the module an AAR file will be created  You can find it in project-name module-name build outputs aar    Add your library as a dependency  You can add your library as a dependency to another project like this    Import your library AAR file with File   New Module    Import  JAR  AAR Package   Next    choose file location    Finish   Don t import the code  otherwise it will be editable in too many places   In the settings gradle file  make sure your library name is there   include   app     my-library-module   In the app s build gradle file  add the compile line to the dependencies section   dependencies       compile project   my-library-module      You will be prompted to sync your project with gradle  Do it    That s it  You should be able to use your library now   Notes  If you want to make your library easily available to a larger audience  consider using JitPac or JCenter

[android-studio] How to create a library project in Android Studio and an application project that uses the library project

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