通过JNA调用方法进行回调

Question

I need to invoke a method using JNA through a callback, the problem is that api not recognize the method, because JNA callback doesn't contain a function where you pass by a method parameter.

the function in C is :

Result API LS800AutoDocHandle(...
int          (__stdcall *userfunc1)(S_CODELINE_INFO_LS800 *CodelineInfo),
int          (__stdcall *userfunc2)(S_IMAGE_INFO_LS800 *ImageInfo),
int          (__stdcall *userfunc3)(S_IMAGE_INFO_LS800 *ImageInfo),
...);

this function invoke this method

    Reply = LS800AutoDocHandle(...
    (CodelineType == READ_CODELINE_MICR ? OnCodelineRead : 0),
    (CodelineType == NO_READ_CODELINE ? OnImageFrontReady : 0),
    NULL,//OnImageBackReady,
    ...);                  // Reserved3    

then my question is, how I can call the method OnCodelineRead through a callback with JNA?

Answer 1

JNA uses Callback objects to represent function pointers, and includes a description of callback usage .

Native code:

int LS800AutoDocHandle(
                       int (__stdcall *userfunc1)(S_CODELINE_INFO_LS800* info),
                       int (__stdcall *userfunc2)(S_CODELINE_INFO_LS800* info),
                       int (__stdcall *userfunc3)(S_CODELINE_INFO_LS800* info)
                      );

JNA mapping (should probably use StdCallLibrary , API is probably __stdcall ):

public interface CodeLineRead extends StdCallCallback {
    int invoke(S_IMAGE_INFO_LS800 info);
}
public interface ImageFrontReady extends StdCallCallback {
    int invoke(S_IMAGE_INFO_LS800 info);
}
public interface ImageBackReady extends StdCallCallback {
    int invoke(S_IMAGE_INFO_LS800 info);
}

int LS800AutoDocHandle(CodeLineRead f1, ImageFrontReady f2, ImageBackReady f3);