Android example with newer Android Gradle plugin version

[TimPushkin]

I'm not sure if this issue should be put here or in /~https://github.com/bytedeco/sample-projects, sorry if I misplace it.

So, the current example for Android uses com.android.tools.build:gradle:4.1.1 and it builds fine, but when I update the Android plugin to 7.1.3, the project won't build complaining that jniNativeLibrary.cpp and jnijavacpp.cpp cannot be found:

Build command failed.
Error while executing process C:\Users\<my username>\AppData\Local\Android\Sdk\cmake\3.10.2.4988404\bin\ninja.exe with arguments {-C <my project path>\gradle-javacpp-android\app\.cxx\Debug\3n4fu1n1\arm64-v8a native-lib}
ninja: Entering directory `<my project path>\gradle-javacpp-android\app\.cxx\Debug\3n4fu1n1\arm64-v8a'
[1/3] Building CXX object CMakeFiles/native-lib.dir/jniNativeLibrary.cpp.o
FAILED: CMakeFiles/native-lib.dir/jniNativeLibrary.cpp.o 
C:\Users\<my username>\AppData\Local\Android\Sdk\ndk\21.4.7075529\toolchains\llvm\prebuilt\windows-x86_64\bin\clang++.exe --target=aarch64-none-linux-android21 --gcc-toolchain=C:/Users/<my username>/AppData/Local/Android/Sdk/ndk/21.4.7075529/toolchains/llvm/prebuilt/windows-x86_64 --sysroot=C:/Users/<my username>/AppData/Local/Android/Sdk/ndk/21.4.7075529/toolchains/llvm/prebuilt/windows-x86_64/sysroot  -Dnative_lib_EXPORTS  -g -DANDROID -fdata-sections -ffunction-sections -funwind-tables -fstack-protector-strong -no-canonical-prefixes -D_FORTIFY_SOURCE=2 -Wformat -Werror=format-security   -O0 -fno-limit-debug-info  -fPIC -MD -MT CMakeFiles/native-lib.dir/jniNativeLibrary.cpp.o -MF CMakeFiles\native-lib.dir\jniNativeLibrary.cpp.o.d -o CMakeFiles/native-lib.dir/jniNativeLibrary.cpp.o -c <my project path>/gradle-javacpp-android/app/src/main/cpp/jniNativeLibrary.cpp
clang++: error: no such file or directory: '<my project path>/gradle-javacpp-android/app/src/main/cpp/jniNativeLibrary.cpp'
clang++: error: no input files
[2/3] Building CXX object CMakeFiles/native-lib.dir/jnijavacpp.cpp.o
FAILED: CMakeFiles/native-lib.dir/jnijavacpp.cpp.o 
C:\Users\<my username>\AppData\Local\Android\Sdk\ndk\21.4.7075529\toolchains\llvm\prebuilt\windows-x86_64\bin\clang++.exe --target=aarch64-none-linux-android21 --gcc-toolchain=C:/Users/<my username>/AppData/Local/Android/Sdk/ndk/21.4.7075529/toolchains/llvm/prebuilt/windows-x86_64 --sysroot=C:/Users/<my username>/AppData/Local/Android/Sdk/ndk/21.4.7075529/toolchains/llvm/prebuilt/windows-x86_64/sysroot  -Dnative_lib_EXPORTS  -g -DANDROID -fdata-sections -ffunction-sections -funwind-tables -fstack-protector-strong -no-canonical-prefixes -D_FORTIFY_SOURCE=2 -Wformat -Werror=format-security   -O0 -fno-limit-debug-info  -fPIC -MD -MT CMakeFiles/native-lib.dir/jnijavacpp.cpp.o -MF CMakeFiles\native-lib.dir\jnijavacpp.cpp.o.d -o CMakeFiles/native-lib.dir/jnijavacpp.cpp.o -c <my project path>/gradle-javacpp-android/app/src/main/cpp/jnijavacpp.cpp
clang++: error: no such file or directory: '<my project path>/gradle-javacpp-android/app/src/main/cpp/jnijavacpp.cpp'
clang++: error: no input files
ninja: build stopped: subcommand failed.

And indeed jniNativeLibrary.cpp and jnijavacpp.cpp are not built. I figure that probably JavaCpp tasks dependencies need to be changed in app/build.gradle, but I'm struggling to do it on my own. Can you please update the example project?

[saudet]

Right, that probably needs to be updated. I'm guessing some of the tasks from the plugin for Android have changed, so try to update their names and see if that works.

[TimPushkin]

It seems that the task with name "generateJsonModel$variantName" on which externalNativeBuild<variant name> used to depend no longer exists, but several tasks with names of format "configureCMake$variantName[<ABI name>]" for different ABIs are now among the predecessors of the tasks that build native code with CMake.

So, after I replaced def generateJson = project.tasks.getByName("generateJsonModel$variantName") with

def configureCMake = project.tasks.findAll {
    it.name.startsWith("configureCMake$variantName")
}

and generateJson.dependsOn "javacppBuildCompiler$variantName" with

configureCMake.forEach {
    it.dependsOn "javacppBuildCompiler$variantName"
}

the example builds successfully with com.android.tools.build:gradle:7.1.3.

[saudet]

I've updated the README.md file as per your findings. Thanks for reporting!