JNA 数组结构指针

Question

I use java to call the .dll,Now I have a structure with a pointer variable "pBuf"in it. I need to convert an array into a pointer and store it in this pointer variable.

Struct:

public static class NET_DVR_BUF_INFO extends Structure {
   public Pointer pBuf;
   public int nLen;
   @Override
   protected List<String> getFieldOrder() {
      return Arrays.asList("pBuf", "nLen");
   }
}

Array:

HCNetSDK.NET_DVR_VIDEOWALLWINDOWPOSITION[] net_dvr_videowallwindowpositions =
                (HCNetSDK.NET_DVR_VIDEOWALLWINDOWPOSITION[]) new  HCNetSDK.NET_DVR_VIDEOWALLWINDOWPOSITION().toArray(windows.size());

I need put net_dvr_videowallwindowpositions to pBuf .

What can i do？

Answer 1

JNA's Structure class has a getPointer() method that returns the pointer to the structure that you need. Since you have an array of structures, you want the pointer to the first element, index 0:

NET_DVR_BUF_INFO bufInfo = new NET_DVR_BUF_INFO();
bufInfo.pBuf = net_dvr_videowallwindowpositions[0].getPointer();

Since you defined the array using the Structure's toArray() method, the other elements of the array will be in contiguous memory expected on the native side.