[工作积累] NDK通过Java获取package name 和version

//////////////////////////////////////////////////////////////////////////
//Java code snippet
//get APK's versionCode in AndroidManifest.xml
public int getVersionCode() {
int versionCode = 1;
try{
PackageInfo packageInfo = this.getPackageManager().getPackageInfo(getPackageName(), 0);
versionCode = packageInfo.versionCode;
}catch (NameNotFoundException e) {
Log.d(TAG, "cannot get package info.");
}
return versionCode;
}

// --------------------------------------------------------------------

// C code snippet: helper function to get package name from Java
// --------------------------------------------------------------------
static bool Android_GetPackageName(char* outPackageName, size_t length) {

    Android_App* app = Android_GetApp();
    ANativeActivity*activity = app->activity;

    JNIEnv* env = activity->env;
    //note: we need to attach dalvik VM to current thread, as it is not main thread
    JavaVM* vm = activity->vm;
    if ( (*vm)->GetEnv(vm, (void **)&env, JNI_VERSION_1_6) <  )
        (*vm)->AttachCurrentThread(vm, &env, NULL);

    //get package name from Activity Class(context)
    jclass android_content_Context = (*env)->GetObjectClass(env, activity->clazz);
    jmethodID midGetPackageName = (*env)->GetMethodID(env, android_content_Context, "getPackageName", "()Ljava/lang/String;");
    jstring PackageName= (jstring)(*env)->CallObjectMethod(env, activity->clazz, midGetPackageName);

    bool ret = false;
    if( PackageName != null ) {
        // get UTF8 string & copy to dest
const char* charBuff = (*env)->GetStringUTFChars(env, PackageName, NULL);
        strncpy(outPackageName, charBuff, length);
        outPackageName[length-1]='\0';

        (*env)->ReleaseStringUTFChars(PackageName, charBuff);
        (*env)->DeleteLocalRef(env, PackageName);
    }
    (*env)->DeleteLocalRef(env, android_content_Context);

    return ret;
}

// --------------------------------------------------------------------
// helper function to get package version code from Java
// --------------------------------------------------------------------
static int Android_GetVersionCode() {

    Android_App* app = Android_GetApp();
    ANativeActivity*activity = app->activity;

    //get version code from Java
    JNIEnv* env = activity->env;
    //note: we need to attach dalvik VM to current thread, as it is not main thread
    JavaVM* vm = activity->vm;
    if ( (*vm)->GetEnv(vm, (void **)&env, JNI_VERSION_1_6) <  )
        (*vm)->AttachCurrentThread(vm, &env, NULL);

    jclass ActivityClass = (*env)->GetObjectClass(env, activity->clazz);
    jmethodID java_method = (*env)->GetMethodID(env, ActivityClass, (char8*)"getVersionCode", (char8*)"()I");
    assert( java_method != NULL );
    jint ret = (*env)->CallIntMethod(env, activity->clazz , java_method);
    (*env)->DeleteLocalRef(env, ActivityClass);
    return (int)ret;
}

通过以上方法可以动态生成OBB文件名称, 而不使用硬编码.