Question

我试图通过JNA在c ++ dll和我的java项目之间建立连接。 dll.h位于这个gitHub：dll.h。

EXTERN_C DLLEXPORT int STDCALL SolveBoard(
  struct deal dl,
  int target,
  int solutions,
  int mode,
  struct futureTricks * futp,
  int threadIndex);
struct deal
{
  int trump;
  int first;
  int currentTrickSuit[3];
  int currentTrickRank[3];
  unsigned int remainCards[DDS_HANDS][DDS_SUITS];
};
struct futureTricks
{
  int nodes;
  int cards;
  int suit[13];
  int rank[13];
  int equals[13];
  int score[13];
};

我对JNA和c ++很新鲜，我尝试用Java编写代码：

public interface DllAl extends StdCallLibrary{
DllAl instanceDll = (DllAl)Native.loadLibrary("dds",DllAl.class);
public int SolveBoard(deal deal,int target,int solutions,int mode, futureTricks fut,int threadIndex);
public int PrintFut(char title[],futureTricks fut);

public static class deal extends Structure{
      public int trump;
      public int first;
      public int currentTrickSuit[] = new int [3];
      public int currentTrickRank[] = new int [3];
      public int remainCards[][] = new int[4][4];
      public static class ByReference extends deal implements Structure.ByReference {}  
      public static class ByValue extends deal implements Structure.ByValue {}
        @Override
        protected List<String> getFieldOrder() {
            return Arrays.asList(new String[]{"trump", "first", "currentTrickSuit", "currentTrickRank","remainCards"});  
        }  

}
public static class futureTricks extends Structure{
    public int nodes;
    public int cards;
    public int suit[] = new int [13];
    public int rank[] = new int [13];
    public int equals[] = new int[13];
    public int score[] = new int[13];
      public static class ByReference extends futureTricks implements Structure.ByReference {}  
      public static class ByValue extends futureTricks implements Structure.ByValue {}
        @Override
        protected List<String> getFieldOrder() {
            return Arrays.asList(new String[]{"nodes", "cards", "suit", "rank","equals","score"});  
        }  

}

} 但是，它会返回错误：

Exception in thread "main" java.lang.NullPointerException
at java.lang.reflect.Array.getLength(Native Method)
at com.sun.jna.Native.getNativeSize(Native.java:1162)
at com.sun.jna.Structure.getNativeAlignment(Structure.java:1360)
at com.sun.jna.Structure.getNativeAlignment(Structure.java:1385)
at com.sun.jna.Structure.deriveLayout(Structure.java:1221)
at com.sun.jna.Structure.calculateSize(Structure.java:1053)
at com.sun.jna.Structure.allocateMemory(Structure.java:380)
at com.sun.jna.Structure.ensureAllocated(Structure.java:356)
at com.sun.jna.Structure.ensureAllocated(Structure.java:346)
at com.sun.jna.Structure.write(Structure.java:737)
at com.sun.jna.Structure.autoWrite(Structure.java:2047)
at com.sun.jna.Function.convertArgument(Function.java:512)
at com.sun.jna.Function.invoke(Function.java:305)
at com.sun.jna.Library$Handler.invoke(Library.java:236)
at com.sun.proxy.$Proxy0.SolveBoard(Unknown Source)
at DllAl.main(DllAl.java:98)

Answer 1

JNA不会映射2D（或3D，4D等）数组。如果您需要映射2D数组you should replace it with a 1D array，然后编写自己的代码进行翻译。

您需要更改此行：

View view = new View(getContext());
GradientDrawable iconPlayShape = new GradientDrawable();
iconPlayShape.setShape(GradientDrawable.RECTANGLE);
iconPlayShape.setColor(Color.WHITE);
RotateDrawable iconPlayRotate = new RotateDrawable();
iconPlayRotate.setFromDegrees(45.0f);
iconPlayRotate.setToDegrees(45.0f);
iconPlayRotate.setPivotXRelative(true);
iconPlayRotate.setPivotYRelative(true);
iconPlayRotate.setPivotX(0.13f);
iconPlayRotate.setPivotY(-0.4f);
iconPlayRotate.setDrawable(iconPlayShape);
iconPlayRotate.setLevel(1);
view.setBackground(iconPlayRotate);

为：

public int remainCards[][] = new int[4][4];

然后添加一个方法，将2D坐标（例如，手，套装）转换为1D索引（例如，4 *指针+套装）。

如何在JNA中使用Java中的这种方法？

1 个答案: