pybridge编译

通过JNI实现和python的运行交互

项目地址

• https://github.com/joaoventura/pybridge

编译运行

下载crystax ndk

https://www.crystax.net/
为了在Linux平台编译，此处下载的是crystax-ndk-10.3.2-linux-x86_64.tar.xz，如果要在Windows平台上编译，则下载crystax-ndk-10.3.2-windows-x86.exe即可。

生成so文件

切换到main/jni目录下面。

1. 首先要修改一下Application.mk文件，选取自己需要的平台APP_ABI

APP_PLATFORM := android-19
APP_ABI := armeabi arm64-v8a x86 x86_64 armeabi-v7a  mips mips64

生成各平台so文件的时候如果报类似app/src/main/obj/local/armeabi-v7a/objs/pybridge/pybridge.o.d:1: *** target pattern contains no %'. Stop.的错误，将src/main文件夹下的obj文件夹删除，再次生成即可。

2. 在jni目录下运行path/to/crystax/ndk-build
   最后生成结果:文件都生成在src/main/libs的各平台文件夹下面，取所需要的平台即可。

 happy@ubuntu  ~/Source/pybridge/app/src/main/jni  /home/happy/Source/crystax-ndk-10.3.2/ndk-build
[armeabi] Compile thumb  : pybridge <= pybridge.c
[armeabi] SharedLibrary  : libpybridge.so
[armeabi] Install        : libcrystax.so => libs/armeabi/libcrystax.so
[armeabi] Install        : libpybridge.so => libs/armeabi/libpybridge.so
[armeabi] Install        : libpython3.5m.so => libs/armeabi/libpython3.5m.so
[arm64-v8a] Compile        : pybridge <= pybridge.c
[arm64-v8a] SharedLibrary  : libpybridge.so
[arm64-v8a] Install        : libcrystax.so => libs/arm64-v8a/libcrystax.so
......
[mips64] SharedLibrary  : libpybridge.so
[mips64] Prebuilt       : libgnustl_shared.so <= <NDK>/sources/cxx-stl/gnu-libstdc++/5/libs/mips64/
[mips64] Install        : libcrystax.so => libs/mips64/libcrystax.so
[mips64] Install        : libpybridge.so => libs/mips64/libpybridge.so
[mips64] Install        : libpython3.5m.so => libs/mips64/libpython3.5m.so

运行

在Android studio中构建项目运行即可。

魔改

代码功能

• AssetExtractor.java将APK的assets文件夹下的python文件拷贝到内部存储。很好的工具类，代码见此AssetExtractor
• PyBridge.java控制与python解释器的交互
• pybridge.c实现JNI C接口并处理CPython API
• bootstrap.py Python解释器初始化时运行的脚本
  assets文件夹下的

call python函数的实现

/**
    This function is responsible for receiving a payload string
    and sending it to the router function defined in the bootstrap.py
    file.

*/
JNIEXPORT jstring JNICALL Java_com_jventura_pybridge_PyBridge_call
        (JNIEnv *env, jclass jc, jstring payload)
{
    LOG("Call into Python interpreter");

    // Get the payload string
    jboolean iscopy;
    const char *payload_utf = (*env)->GetStringUTFChars(env, payload, &iscopy);

    // Import module
    PyObject* myModuleString = PyUnicode_FromString((char*)"bootstrap");
    PyObject* myModule = PyImport_Import(myModuleString);

    // Get reference to the router function
    PyObject* myFunction = PyObject_GetAttrString(myModule, (char*)"router");
    PyObject* args = PyTuple_Pack(1, PyUnicode_FromString(payload_utf));

    // Call function and get the resulting string
    PyObject* myResult = PyObject_CallObject(myFunction, args);
    char *myResultChar = PyUnicode_AsUTF8(myResult);

    // Store the result on a java.lang.String object
    jstring result = (*env)->NewStringUTF(env, myResultChar);

    // Cleanup
    (*env)->ReleaseStringUTFChars(env, payload, payload_utf);
    Py_DECREF(myModuleString);
    Py_DECREF(myModule);
    Py_DECREF(myFunction);
    Py_DECREF(args);
    Py_DECREF(myResult);

    return result;
}

参考

• https://www.jianshu.com/p/aba8a1ae783e

• https://blog.csdn.net/ezconn/article/details/82529101#%C2%A0%20%C2%A0%20%C2%A0%20%C2%A0%20%C2%A0%20%C2%A0%20%C2%A0%20%C2%A0%20%C2%A0%20%C2%A0%20%C2%A0%20%C2%A0%20%C2%A0%20%C2%A0%20%C2%A0%20%C2%A0%20%C2%A0%20%C2%A0%C2%A0%20%C2%A0%20%C2%A0%20%E6%89%8B%E5%8A%A8%E7%BC%96%E8%AF%91.so%E6%96%87%E4%BB%B6