For a project, I am using Android gradle scripts with CMake, gradle plugin is version 3:0:0, CMake version 3.6. Both gradle and CMake files are pretty simple and uninteresting (just defining the files used - I can still copy-paste them as required).
I have the following project structure; basically a codebase producing a few tens of .so files (the native part for the Android packages that get packaged into an apk, thereby called 'Executables'), which all depend on the same shared library code (static libraries, thereby called 'Libraries'). The Library code is still (relatively) volatile, so I wish the Executables to have project-level dependencies on them, so that whenever the Executables are built, the Libraries are rebuilt on-demand every time their code is changed.
The structure looks like:
+ LibProjects/
---Bin/ (Originally empty)
---Lib1/CMakeLists.txt (+sources files, same level as the CMakeLists.txt)
...
---Lib10/CMakeLists.txt (same)
+ Executables/
---Executable1/CMakeLists.txt (source files here)
--------------/AndroidFiles/build.gradle (and other android project files)(points to the CMakeLists.txt)
...
---Executable40/CMakeLists.txt
The Libraries' CMakeLists redirect their output into the Bin folder using
set(CMAKE_ARCHIVE_OUTPUT_DIRECTORY {CMAKE_CURRENT_SOURCE_DIR}/../Bin/${ANDROID_ABI}/${LibraryName})
The executable's projects add dependencies on the libraries "as normal"
add_subdirectory(${PROJECTS_ROOT}/LibProjects/${LibraryName} ${PROJECTS_ROOT}/Framework/Bin/Android/${ANDROID_ABI}/${LibraryName})...
Everything almost works, in the sense that I can get sensible executables and the Executables trigger builds of the libraries.
The problem is that when building the executables sequentially, each one does NOT reuse the library project outputs of the other ones: When I build Executable1, it will build all libraries (normal) and then it will build itself. Afterwards, when I build Executable2, it will NOT reuse the libraries that were already built for Executable1, and so on - this effectively increases my build time by a factor of ~10.
I can find the output of the build of each library inside the /Bin folder as expected, but they are not reused across executables - there are no CMake "project files" (is this the correct term) in the bin folder, all of them get generated inside the executable build directory.
The problem I am trying to resolve is the build times stemming from the fact that each library gets rebuilt for each executable.
At the moment the solutions I am considering is to somehow instruct CMake to use the Bin folder (or another folder) as a working folder for each library in its own folder instead of with the executable, hoping that the gradle android plugin will be smart enough to then spot that neither the cmakefiles nor the object files need to be regenerated, and avoid the rebuild.
The restriction that I have is that I cannot restructure the codebase itself, and that each Executable must be buildable separately of the others - there is absolutely no possibility of a top-level CMake - each Executable should be able to be triggered on its own.
CMake can guess if the build is up-to-date by reading informations froms the current build directory.
When you run CMake manualy in Executables/<x> directory, cmake retrieve information from the build directory associated to Executable/<x> directory. It then check if the timestamp of the built file correspond to the last build performed in this build directory. If not, it rebuild. What happen is that: Lib1 library file is built after you build Executable1, then you run cmake in Executalbe2, it compares the timestamp of Lib1 target file, see that this file was not produced by this instance of the cmake build and then rebuild the lib. And so on.
So you have two options:
1- Either you build the library and install their target files in the bindirectory (using install cmake command and make install bash command for exemple). Then in the Executalbe<x>/CMakeLists you use find_library command instead of add_subdirectory.
2- Or you create a super project which has the following structure:
+ supper_project
---CMakeLists.txt #add_subdirectory(LibProjects/lib<x>)... add_subdirectory(Executables/Executalbe<x>)...
+ LibProjects/
---Bin/ (Originally empty)
---Lib1/CMakeLists.txt (+sources files, same level as the CMakeLists.txt)
...
---Lib10/CMakeLists.txt (same)
+ Executables/
---Executable1/CMakeLists.txt (source files here)
--------------/AndroidFiles/build.gradle (and other android project files)
(not any more:points to the CMakeLists.txt)
...
---Executable40/CMakeLists.txt
I managed to work around this problem - but in the end it was by working around rather than with CMake.
I removed the CMakeFile-level dependencies (add_subdirectory) and only left the libraries at the linking level (target_link_libraries Executable [the library files])
Afterwards, I created gradle scripts for each library and added dependencies to these scripts in each application gradle script, so that the building of the libraries gets triggered by gradle dependencies instead of CMake dependencies. It's slower than it would be if gradle could be avoided, but much faster than rebuilding every time, and the overhead is at least constant (a few seconds per project).
I think problem lies in the way you have defined your dependencies.
For each executable you are creating separate targets using add_subdirectory.
e.g. for executable 1 you have add_subdirectory(${PROJECTS_ROOT}/LibProjects/${Library1}) and for executable 2 also you have add_subdirectory(${PROJECTS_ROOT}/LibProjects/${Library1}), so cmake will create two separate targets for same library1 in each of the executable's subdirectory and thus it will create separate timestamp and cache files. That is why it looks that it is building the same library for multiple times, but in fact for cmake they are different targets.
To fix this you can include all libraries in top level CMakeLists.txt using add_subdirectory and them in each executable's CMakeLists.txt add the dependency using add_dependencies command.
Related
I have a Java Library project in my AOSP build which creates a jar file and hosts it in system/framework
Everything works as expected, however I now wish to create a JAR file from the same library to allow and application to link and compile against it. Goal is to be able to create APKs against this lib (compileOnly) so that the APK can run and use the library on the ROM.
The problem is that Jack seems to be generating only dexed jar files which cannot be used in Android Studio as libraries.
Is there a way to disable DEXing in the Android.mk ?
I know there is an option in Android.bp (cannot recall it) which gives the option for the build to generate normal jar (with .class files).
Note: I cannot use BUILD_DROIDDOC with stubs due to enviroment issues (custom ROM) assuming BUILD_DROIDDOC is only executed with lunch sdk-eng
This is for a custom ROM with Android 8.1 base. I think the custom option of not dexing in Android.dp file is not supported in this version anyway.
I've synced the entire Android repo, and set up a build environment per the instructions here:
https://source.android.com/source/building
The build instructions seem to be assuming that you want to build the entire Android platform. I'm really interested in building a specific AOSP app, like contacts, SMS, camera, etc. I've seen mirrors of the stock app's code on GitHub, but there doesn't seem to be any build instructions within those, for example:
https://github.com/android/platform_packages_apps_contacts
https://github.com/android/platform_packages_apps_calendar
Is there a build guide for doing this? Am I stuck downloading, modifying, building this huge (100+GB) code set?
Just as you have 'mm' to build a certain target, you can also use 'mma' to build that target with its dependencies. For example:
$ mma Settings -j16
This will scan the project for the dependencies of the Settings app, and will afterward build the dependencies first before commencing the build of the Settings app.
here are compile and module-based compilation commands:
lunch: lunch <product_name>-<build_variant>
tapas: tapas [<App1> <App2> ...] [arm|x86|mips|armv5] [eng|userdebug|user]
croot: Changes directory to the top of the tree.
m: Makes from the top of the tree.
mm: Builds all of the modules in the current directory, but not their dependencies.
mmm: Builds all of the modules in the supplied directories, but not their dependencies.
To limit the modules being built use the syntax: mmm dir/:target1,target2
mma: Builds all of the modules in the current directory, and their dependencies.
mmma: Builds all of the modules in the supplied directories, and their dependencies.
cgrep: Greps on all local C/C++ files.
jgrep: Greps on all local Java files.
resgrep: Greps on all local res/*.xml files.
godir: Go to the directory containing a file.
you can look here for other and more build commands : https://source.android.com/setup/build/building
and here :https://elinux.org/Android_Build_System
And check "build/envsetup.sh" file's comments to see full list.
if I have a project with many library projects linked, could I improve build performances by packaging each of them in an AAR and including it in the main project ? Or this will not make any difference since that when the compiler need to assemble the apk it need to package everything together anyway?
Thanks to any one who will give me some clarifcation about performance differences between the 2 approach
I don't think you will save any build time by wrapping an existing .jar file into a .aar file and using that instead of the original .jar file.
As this SO post notes, .aar files are basically just zip files which may contain a jar file and some android resources.
Also, because .aar files are not precompiled into Dalvik byte code, the build process for your apk file must still carry out that step at least once. So, you won't save dexing time just by wrapping the .jar file into a .aar file either.
If you build a typical Android Studio project (with some Android library dependencies specified in the gradle build file) you can see the directory underneath app/build/intermediates/exploded-aar where these files have been unzipped. That work must still be done by your build machine even though you are using a .aar file.
Finally, as you pointed out, the .apk packaging work must still be done at the end of the build.
I believe the Library projects (which you are using) is the best way to go because of two reasons:
The library project gives the direct access to the code base of the libraries which can be compiled and packaged together with the main app code
In case, multiple .aar files are referenced within the project, then during the apk creation the unpacking, merging of resources and Manifest file will increase the build time.
I created a test project to understand how to build and run the tests using command line tool. I managed to create a project, updated it with
android update project -p .
and debug with
ant debug
When I added a library project to this test project, the ant debug started to fail because it couldn't find the build.xml of the library. The only solution I found atm is to update the library project as well (found here). Is this the correct way? I see pom.xml files in many of the libraries that I use. I know it is used by Maven (although I know nothing about it) and it might help me with another solution.
Ant is the official way to build android apk. Maven is an alternative way of doing it (not officially supported, but it works very well).
There are few differences regarding default project layout when working with maven or ant, but it's possible to have both build system working on the same source code if you do some additionnal configuration work (i.e. some information will be duplicated).
Default project layout with maven
java source files are under `/src/main/java``
dependencies are defined in the pom.xml (using the maven way of defining dependencies, with type apklib for android libraries)
Default project layout with ant (and eclipse ADT plugin)
java source files are under /src
dependencies are defined in /project.properties and are specified using relative path.
Here is an example of project.properties (it's a typical example of a library project referencing 2 other library project):
target=android-15
android.library=true
android.library.reference.1=../somelib
android.library.reference.2=../someOtherLib
(as you can see some additionnal information are stored in this file : the android target and the fact that the project is an library or an app. When you use maven, this information is in the pom.xml)
How to build a maven android lib with ant ?
The problems (when you need to build a maven-layout-android-library with ant) are the following:
having a proper /build.xml (it can be done through android update library-project ... here is the official doc about this command)
having a proper /project.properties (it is partially done by the android update ... command, but you may need to add some android.library.reference by hand or with eclipse ADT plugin)
telling ant that the java source files aren't at the default location, but are under /src/main/java
For this last point, here is how to do it:
create a file /ant.properties (in your maven-layout-android-library)
put the following entry in it:
source.dir=src/main/java
(Important : it is not always required because sometimes the java source files are already under /src in the maven-layout-project and in this case, the pom.xml contains the information that the source dir is /src)
And that's all. Now, your maven-layout-android-library can be build with ant debug
I maintain an Android app and am not using Eclipse. I am not using Eclipse. I am using ant and build.xml and build.properties.
I have places my .jar file into the libs/ directory. My code compiles just dandy. But when I run it on the emulator, the output APK does not include the .jar, so I get a runtime stacktrace:
ERROR/AndroidRuntime(470): java.lang.NoClassDefFoundError: com.google.ads.AdView
my build.properties looks like this:
jar.libs.dir=libs
And the libs/ directory contains my .jar file.
What needs to be in build.xml so that the external .jar file is included in the APK?
Edit: In theory this answer should work, but it doesn't for me. Is it out of date? What gives? How to add external jar libraries to an android project from the command line
I just came over a similar problem and noticed that libraries should not be placed in "myprojectdir\lib". When I moved them to "myprojectdir\libs" everything started to work.
It turns out that I needed to upgrade the version of ant I was using to 1.8. During the compile process, I had been getting this error message:
Warning: Reference out.dex.jar.input.ref has not been set at runtime,
but was found duringbuild file parsing, attempting to resolve. Future
versions of Ant may support referencing ids defined in non-executed
targets.
I googled it, and found that I needed to upgrade Ant, and now I don't get this warning, and my application does not force close.
What needs to be in build.xml so that the external .jar file is included in the APK?
Just putting it in libs/ is sufficient.
my build.properties looks like this:
That line should not be necessary. It does not appear in my build.properties files that build successfully with JAR files.
If you use dexdump -f classes.dex from your project's bin/ directory, you will be able to determine whether com.google.ads.AdView made it in there. If it did not, then something is strange with your build scripts. If it did, then perhaps there is a dependent JAR that you are missing (though I would expect a VerifyError in that case).
You use 3rd party library, but you seem didn't run DX on it. Make sure that not only your code processed by DX tool (I assume Ant does it), but also all 3rd party libraries you use. You can look in 7Bee script I use to convert web applications to Android davlik format, so it can work for you too. You can find more about the script on Atjeews page.
Solution:
right click on the project in project tree and select Project
properties
select Java Build Path
select TAB Order
and Export
check GoogleAdMobAdsSdk-4.0.4.jar (or your
version SDK)
press OK
clean project by menu Project
-> Clean
rebuild project (Project – Build Automatically)