User32 接口(平台库)缺少一些 WinAPI 函数,所以我尝试扩展它:
package myapp
import com.sun.jna.platform.win32.W32API
public interface User32 extends com.sun.jna.platform.win32.User32 {
myapp.User32 INSTANCE
boolean IsWindow(W32API.HWND hWnd)
}
但随后调用myapp.User32.INSTANCE.FindWindow(..)
结果java.lang.NullPointerException: Cannot invoke method FindWindow() on null object