<div dir="ltr"><div>Would it work for your situation for the leaf CMakeLists.txt to include the root CMakeLists.txt? Then have the leaf-specific logic in the leaf CMakeLists.txt?</div><div><br></div><br></div><div class="gmail_extra"><br><div class="gmail_quote">On Mon, Aug 21, 2017 at 9:33 AM, Robert Dailey <span dir="ltr"><<a href="mailto:rcdailey.lists@gmail.com" target="_blank">rcdailey.lists@gmail.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">Basically, yes. We have this sort of structure:<br>
<br>
<Root of git clone>/<br>
Applications/<br>
App1/<br>
build.gradle<br>
CMakeLists.txt<br>
App2/<br>
build.gradle<br>
CMakeLists.txt<br>
App3/<br>
build.gradle<br>
CMakeLists.txt<br>
CommonLib/<br>
build.gradle<br>
CMakeLists.txt<br>
CMakeLists.txt<br>
<br>
The libs are defined as follows:<br>
<br>
* CommonLib is a static library (java code builds into a library)<br>
* No dependencies of its own<br>
* App1 is a shared library (java code builds into a library)<br>
* Dependencies (both java & native): CommonLib<br>
* App2 is a shared library (java code builds into an APK)<br>
* Dependencies (both java & native): App1, CommonLib<br>
* App3 is a shared library (java code builds into an APK)<br>
* Dependencies (both java & native): CommonLib<br>
<br>
In all cases, CMake must be invoked starting at the root<br>
CMakeLists.txt 1 time. Each target can be built from the same binary<br>
directory after that. Previously with ANT, I was building all native<br>
targets first, then moved libs to appropriate directories so that the<br>
'ant' command would package the libs.<br>
<br>
For gradle, I wanted to avoid redundantly specifying the root<br>
directory in each leaf-level project directory. Using the example<br>
above, the leaf-level directories in this case would be App1, App2,<br>
App3, and CommonLib. However I think we only specify the native CMake<br>
stuff for the java targets that actually output an APK (that would be<br>
App2 and App3 only).<br>
<br>
The ultimate goal is to specify stuff that doesn't change per<br>
independent "module" of ours at the top level so it is transitive /<br>
inherited. Then only specify the differences (e.g. the native CMake<br>
target to build) in the leaf build gradle files. However you indicated<br>
this isn't possible.<br>
<div class="HOEnZb"><div class="h5"><br>
<br>
<br>
On Mon, Aug 21, 2017 at 11:11 AM, Jom O'Fisher <<a href="mailto:jomofisher@gmail.com">jomofisher@gmail.com</a>> wrote:<br>
> What you're doing already sounds correct. You can't directly specify<br>
> CMakeLists.txt from the top-level build.gradle. Recommendation is that it<br>
> should be specified from the build.gradle of the module of the APK. Is the<br>
> issue that you have multiple APK modules that all reference the same CMake<br>
> libraries?<br>
><br>
> On Mon, Aug 21, 2017 at 9:00 AM, Robert Dailey <<a href="mailto:rcdailey.lists@gmail.com">rcdailey.lists@gmail.com</a>><br>
> wrote:<br>
>><br>
>> Thanks this is very helpful. The other question I have is: Is there a<br>
>> place to centrally specify the root CMakeLists.txt? Basically, I want<br>
>> to specify the CMake root in 1 place, and have targets (defined<br>
>> further down in subdirectories) that require APK packaging to specify<br>
>> only the native target name that should be built & packaged.<br>
>><br>
>> At the moment we specify the root CMakeLists.txt by walking up the<br>
>> tree, paths like "../../../../CMakeLists.txt". I think this should be<br>
>> put at the top-level build gradle file if possible. Is this doable at<br>
>> the moment? What is the recommended setup?<br>
>><br>
>> On Mon, Aug 21, 2017 at 9:37 AM, Jom O'Fisher <<a href="mailto:jomofisher@gmail.com">jomofisher@gmail.com</a>><br>
>> wrote:<br>
>> > Gradle does introspection on the CMake build to find .so targets and<br>
>> > those<br>
>> > get packaged.<br>
>> > There is also a special case for stl/runtime .so files from the NDK.<br>
>> > Any additional .so files need to specified in build.gradle using jniDirs<br>
>> ><br>
>> > On Mon, Aug 21, 2017 at 7:30 AM, Robert Dailey<br>
>> > <<a href="mailto:rcdailey.lists@gmail.com">rcdailey.lists@gmail.com</a>><br>
>> > wrote:<br>
>> >><br>
>> >> How exactly does Gradle package *.so files in an APK? I know that ANT<br>
>> >> used to do this for any libs under "libs/<ABI>". Does Gradle do some<br>
>> >> introspection into CMake targets to see if outputs are *.so, and copy<br>
>> >> those to some location if needed? What about libraries like<br>
>> >> libgnustl_shared.so that come with the NDK? I'd like to know if any<br>
>> >> manual copy steps are needed in CMake to put outputs in proper<br>
>> >> locations for the APK build step. I had to do this when using ANT.<br>
>> >><br>
>> >> On Mon, Aug 7, 2017 at 6:16 PM, Jom O'Fisher <<a href="mailto:jomofisher@gmail.com">jomofisher@gmail.com</a>><br>
>> >> wrote:<br>
>> >> > 1) There is a folder created for each ABI under the project module<br>
>> >> > folder<br>
>> >> > (so unique per module per ABI)<br>
>> >> > 2) Gradle doesn't specify language level though you can choose to<br>
>> >> > specify it<br>
>> >> > yourself from the build.gradle. This doc does a pretty good job of<br>
>> >> > explaining which variables are set by Gradle:<br>
>> >> > <a href="https://developer.android.com/ndk/guides/cmake.html#variables" rel="noreferrer" target="_blank">https://developer.android.com/<wbr>ndk/guides/cmake.html#<wbr>variables</a>.<br>
>> >> > Philosophically, we try to set as little as we can get away with. In<br>
>> >> > particular, the section titled "Understanding the CMake build<br>
>> >> > command"<br>
>> >> > lays<br>
>> >> > out exactly what we set. You can also see the folders we specify (one<br>
>> >> > per<br>
>> >> > module per ABI)<br>
>> >> > 3) Not sure I understand this.<br>
>> >> ><br>
>> >> > The other document worth taking a look at (if you haven't already)<br>
>> >> > is:<br>
>> >> > <a href="https://developer.android.com/studio/projects/add-native-code.html" rel="noreferrer" target="_blank">https://developer.android.com/<wbr>studio/projects/add-native-<wbr>code.html</a><br>
>> >> ><br>
>> >> ><br>
>> >> > On Mon, Aug 7, 2017 at 3:35 PM, Robert Dailey<br>
>> >> > <<a href="mailto:rcdailey.lists@gmail.com">rcdailey.lists@gmail.com</a>><br>
>> >> > wrote:<br>
>> >> >><br>
>> >> >> Thanks Jom<br>
>> >> >><br>
>> >> >> Honestly, I prefer option 1 to work simply because that's how<br>
>> >> >> Google's<br>
>> >> >> officially supporting CMake. But it also has debugging which is the<br>
>> >> >> #1<br>
>> >> >> reason for me.<br>
>> >> >><br>
>> >> >> However, I'd like to understand a lot more about how the integration<br>
>> >> >> really happens. For example, I have these questions:<br>
>> >> >><br>
>> >> >> 1) How, internally, are CMake build directories managed? Do you<br>
>> >> >> generate 1 per unique android project? What about for each specific<br>
>> >> >> platform (x86, armeabi-v7a, etc)?<br>
>> >> >> 2) Last time I looked into CMake integration, things defined inside<br>
>> >> >> the CMake scripts were ignored because they are specified at the<br>
>> >> >> command line. Namely, all of those settings that are driven by the<br>
>> >> >> Gradle configuration (CXX language level was one in particular I<br>
>> >> >> think; I specify C++14 support via CMake, but I recall this being<br>
>> >> >> overridden from outside)?<br>
>> >> >> 3) How redundant is it to configure individual libraries via the<br>
>> >> >> gradle scripts? In my previous attempts, I wanted to define common<br>
>> >> >> stuff for CMake / native code at the root gradle or settings file,<br>
>> >> >> and<br>
>> >> >> only define the differences in the actual gradle build files for<br>
>> >> >> each<br>
>> >> >> corresponding Java target (like, defining the name of the native<br>
>> >> >> (shared library) target in Gradle, but the command line invocation,<br>
>> >> >> -D<br>
>> >> >> CMake settings, etc would all be common and defined at the root).<br>
>> >> >><br>
>> >> >> The TLDR is, the closer we can stay to CMake's way of doing things<br>
>> >> >> and<br>
>> >> >> keep CMake-related settings self-contained to the CMake scripts<br>
>> >> >> themselves, the better. This also makes cross-platform easier (we<br>
>> >> >> build the native code in Windows, for example, so having settings<br>
>> >> >> specified in the gradle files do not carry over to other platforms.<br>
>> >> >> Namely, settings that are not platform specific like the C++<br>
>> >> >> language<br>
>> >> >> level).<br>
>> >> >><br>
>> >> >> If there's a detailed document / wiki I can read on the intrinsics<br>
>> >> >> of<br>
>> >> >> CMake integration in Gradle / Android Studio, I'd love to read it.<br>
>> >> >> Otherwise, I hope you won't mind if I pick your brain as questions<br>
>> >> >> come up. I think I'm going to try option 1 for now and see how it<br>
>> >> >> goes. It's just black box for me because unlike option 2, I have<br>
>> >> >> very<br>
>> >> >> little control over what happens after building the shared<br>
>> >> >> libraries,<br>
>> >> >> and to make up for that I need to really get a deep understanding of<br>
>> >> >> how it works so I can make sure I code my CMake scripts properly for<br>
>> >> >> not only Android, but my other platforms as well (non-Android<br>
>> >> >> platforms).<br>
>> >> >><br>
>> >> >> Thanks again.<br>
>> >> >><br>
>> >> >> On Mon, Aug 7, 2017 at 5:12 PM, Jom O'Fisher <<a href="mailto:jomofisher@gmail.com">jomofisher@gmail.com</a>><br>
>> >> >> wrote:<br>
>> >> >> > Either option can work fine. Disclosure: I work on Android Studio<br>
>> >> >> > and<br>
>> >> >> > was<br>
>> >> >> > the one that added CMake support.<br>
>> >> >> ><br>
>> >> >> > Option (1) is the way it's designed to work and we're working<br>
>> >> >> > toward<br>
>> >> >> > getting<br>
>> >> >> > rid of the need for the CMake fork. I can't really say when that<br>
>> >> >> > will<br>
>> >> >> > happen<br>
>> >> >> > but if you can get away with an older CMake for now then I'd go<br>
>> >> >> > this<br>
>> >> >> > way.<br>
>> >> >> > As you mentioned, option (1) will allow you to view your source<br>
>> >> >> > file<br>
>> >> >> > structure in Android Studio, edit files, and debug using the<br>
>> >> >> > built-in<br>
>> >> >> > debugging support.<br>
>> >> >> ><br>
>> >> >> > To get option (2) to work, you can use jniDirs setting to tell<br>
>> >> >> > Android<br>
>> >> >> > Gradle where to pick up your built .so files (see<br>
>> >> >> ><br>
>> >> >> ><br>
>> >> >> ><br>
>> >> >> > <a href="https://stackoverflow.com/questions/21255125/how-can-i-add-so-files-to-an-android-library-project-using-gradle-0-7" rel="noreferrer" target="_blank">https://stackoverflow.com/<wbr>questions/21255125/how-can-i-<wbr>add-so-files-to-an-android-<wbr>library-project-using-gradle-<wbr>0-7</a>).<br>
>> >> >> > I'm not aware of any projects that use this approach but it should<br>
>> >> >> > work<br>
>> >> >> > in<br>
>> >> >> > principal.<br>
>> >> >> ><br>
>> >> >> > I hope this helps,<br>
>> >> >> > Jomo<br>
>> >> >> ><br>
>> >> >> ><br>
>> >> >> > On Mon, Aug 7, 2017 at 11:09 AM, Robert Dailey<br>
>> >> >> > <<a href="mailto:rcdailey.lists@gmail.com">rcdailey.lists@gmail.com</a>><br>
>> >> >> > wrote:<br>
>> >> >> >><br>
>> >> >> >> Right now I have custom targets set to execute the "ant release"<br>
>> >> >> >> command after my native targets are built. Part of that command<br>
>> >> >> >> involves copying *.so files to the libs/armeabi-v7a directory so<br>
>> >> >> >> they<br>
>> >> >> >> get packaged in an APK.<br>
>> >> >> >><br>
>> >> >> >> When switching to gradle, I have two options:<br>
>> >> >> >><br>
>> >> >> >> 1. Gradle drives CMake: This means using Android Studio and being<br>
>> >> >> >> locked down to Google's fork of CMake which is a few major<br>
>> >> >> >> releases<br>
>> >> >> >> behind. I see that as a negative.<br>
>> >> >> >><br>
>> >> >> >> 2. CMake drives Gradle: This would be the same or similar to what<br>
>> >> >> >> I'm<br>
>> >> >> >> already doing: The custom targets I have would execute gradle as<br>
>> >> >> >> a<br>
>> >> >> >> separate build step, instead of running ant commands. I'm not too<br>
>> >> >> >> familiar with Gradle, so I'm not sure how you tell it where your<br>
>> >> >> >> shared libraries are for the APK packaging steps.<br>
>> >> >> >><br>
>> >> >> >> Which does everyone recommend? Is anyone using one of these<br>
>> >> >> >> setups<br>
>> >> >> >> successfully? The downside to option 2 is probably no on-device<br>
>> >> >> >> native<br>
>> >> >> >> debugging since Android Studio probably can't handle gradle<br>
>> >> >> >> projects<br>
>> >> >> >> without any external CMake builds set up.<br>
>> >> >> >><br>
>> >> >> >> Would like some general direction & advice before I move away<br>
>> >> >> >> from<br>
>> >> >> >> ANT. Thanks in advance.<br>
>> >> >> >> --<br>
>> >> >> >><br>
>> >> >> >> Powered by <a href="http://www.kitware.com" rel="noreferrer" target="_blank">www.kitware.com</a><br>
>> >> >> >><br>
>> >> >> >> Please keep messages on-topic and check the CMake FAQ at:<br>
>> >> >> >> <a href="http://www.cmake.org/Wiki/CMake_FAQ" rel="noreferrer" target="_blank">http://www.cmake.org/Wiki/<wbr>CMake_FAQ</a><br>
>> >> >> >><br>
>> >> >> >> Kitware offers various services to support the CMake community.<br>
>> >> >> >> For<br>
>> >> >> >> more<br>
>> >> >> >> information on each offering, please visit:<br>
>> >> >> >><br>
>> >> >> >> CMake Support: <a href="http://cmake.org/cmake/help/support.html" rel="noreferrer" target="_blank">http://cmake.org/cmake/help/<wbr>support.html</a><br>
>> >> >> >> CMake Consulting: <a href="http://cmake.org/cmake/help/consulting.html" rel="noreferrer" target="_blank">http://cmake.org/cmake/help/<wbr>consulting.html</a><br>
>> >> >> >> CMake Training Courses: <a href="http://cmake.org/cmake/help/training.html" rel="noreferrer" target="_blank">http://cmake.org/cmake/help/<wbr>training.html</a><br>
>> >> >> >><br>
>> >> >> >> Visit other Kitware open-source projects at<br>
>> >> >> >> <a href="http://www.kitware.com/opensource/opensource.html" rel="noreferrer" target="_blank">http://www.kitware.com/<wbr>opensource/opensource.html</a><br>
>> >> >> >><br>
>> >> >> >> Follow this link to subscribe/unsubscribe:<br>
>> >> >> >> <a href="http://public.kitware.com/mailman/listinfo/cmake" rel="noreferrer" target="_blank">http://public.kitware.com/<wbr>mailman/listinfo/cmake</a><br>
>> >> >> ><br>
>> >> >> ><br>
>> >> ><br>
>> >> ><br>
>> ><br>
>> ><br>
><br>
><br>
</div></div></blockquote></div><br></div>