System App Jni call to Java Fail

fatalfeel — Mon, 11 Sep 2017 07:39:07 GMT

static JavaVM*           s_javavm            = NULL;
static jclass                s_javaclass            = NULL;
static   volatile int    s_thread_work    = 0;
static   volatile int    s_loop_status        = 0;

extern "C"
{
   JNIEXPORT jint JNICALL JNI_OnLoad(JavaVM* vm, void* reserved)
   {
       jclass        cls;
       JNIEnv*    env = NULL;

       if (vm->GetEnv((void**)&env, JNI_VERSION_1_6) != JNI_OK)
       {
           __android_log_write(ANDROID_LOG_ERROR, "sllin", "OnLoad error");
           return JNI_ERR;
       }

s_javavm = vm; //save to use this for the rest of the app.

return JNI_VERSION_1_6;
}

   JNIEXPORT void JNICALL JNI_OnUnload(JavaVM* vm, void* reserved)
   {
        JNIEnv* env = NULL;

        if (vm->GetEnv((void**)&env, JNI_VERSION_1_6) != JNI_OK)
       {
           __android_log_write(ANDROID_LOG_ERROR, "sllin", "OnUnload error");
           return;
       }

s_javavm = NULL;
}
}

static JNIEnv* GetJavaVmEnv()
{
JNIEnv* env;

   if( s_javavm )
   {
       if( s_javavm->GetEnv((void **)&env, JNI_VERSION_1_6) != JNI_OK )
       {
           __android_log_write(ANDROID_LOG_ERROR, "sllin", "GetJavaVmEnv error");
           env = NULL;
       }
   }

return env;
}

void Interface_InitJniClass(JNIEnv* env, jobject obj)
{
jclass cls;
JNIEnv* jvmenv = GetJavaVmEnv();

   if( s_javaclass == NULL )
   {
       cls               = jvmenv->FindClass("com/android/linbusconfig/LinbusConfig");
       //cls               = jvmenv->FindClass("com/android/linbusconfig/ReceiveAPI");
       s_javaclass    = (jclass)jvmenv->NewGlobalRef(cls);
       jvmenv->DeleteLocalRef(cls);
   }
}

void Interface_ReleaseJniClass(JNIEnv* env, jobject obj)
{
JNIEnv* vmenv = GetJavaVmEnv();

   if( s_javaclass )
   {
       vmenv->DeleteGlobalRef(s_javaclass);
       s_javaclass = NULL;
   }
}

void Interface_ReceiveData(int can_id, unsigned char can_dlc, unsigned char* data)
{
   jint                ret;
   jmethodID   mid;
   jbyteArray   jbarray;
   int               length   = sizeof( ((struct can_frame *)0)->data );
   JNIEnv*        jvmenv   = GetJavaVmEnv();

mid = jvmenv->GetStaticMethodID(s_javaclass, "ReceiveLinStatic", "(IB[B)I"); //int byte bytearray
//mid = jvmenv->GetMethodID(s_javaclass, "ReceiveLinDynamic", "(IB[B)V");

   if( mid )
   {
       jbarray = jvmenv->NewByteArray( length );

jvmenv->SetByteArrayRegion(jbarray, 0, length, (jbyte*)data);

ret = jvmenv->CallStaticIntMethod(s_javaclass, mid, can_id, can_dlc, jbarray);
//jvmenv->CallVoidMethod(s_javaclass, mid, can_id, can_dlc, jbarray);

jvmenv->DeleteLocalRef(jbarray);
}
}

///

JNIEXPORT void JNICALL Java_com_android_linbusconfig_LinbusConfig_nativeInitJniClass(JNIEnv* env, jobject obj)
{
Interface_InitJniClass(env, obj);
}

JNIEXPORT void JNICALL Java_com_android_linbusconfig_LinbusConfig_nativeReleaseJniClass(JNIEnv* env, jobject obj)
{
Interface_ReleaseJniClass(env, obj);
}

////

public class LinbusConfig extends Activity
{

    public static int ReceiveLinStatic(int can_id, byte can_dlc, byte[] data)
   {
       return can_id;
   }

    @Override
    public void onCreate(Bundle savedInstanceState)
    {
       System.loadLibrary("linattach");

       super.onCreate(savedInstanceState);
       setContentView(R.layout.main);

        nativeInitJniClass();

}

///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////

mid = jvmenv->GetStaticMethodID(s_javaclass, "ReceiveLinStatic", "(IB[B)I"); //int byte bytearray

in system app the mid always return 0x00

but use install apk mid is good id

Re: System App Jni call to Java Fail

fatalfeel — Mon, 11 Sep 2017 07:40:37 GMT

I got answer

in Android.mk LOCAL_PROGUARD_ENABLED -> need disable

LOCAL_PATH:= $(call my-dir)

include $(CLEAR_VARS)
LOCAL_PACKAGE_NAME := LinbusConfig
LOCAL_MODULE_TAGS := optional
LOCAL_PRELINK_MODULE := false
LOCAL_PROGUARD_ENABLED := disabled //////////////////////////please add this line!!!
LOCAL_SRC_FILES := $(call all-subdir-java-files)
LOCAL_SDK_VERSION := current
LOCAL_CERTIFICATE := platform
LOCAL_JNI_SHARED_LIBRARIES := liblinattach

include $(call all-makefiles-under,$(LOCAL_PATH))

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