如何在JNA中創建結構？

我運行下面的代碼時出現此錯誤;如何在JNA中創建結構？

Exception in thread "AWT-EventQueue-0" java.lang.Error: Structure.getFieldOrder() on class javaapplication2.NewJFrame$APPBARDATA returns names ([cbSize, hWnd, jCallbackMessage, jEdge, rc, sParam]) which do not match declared field names ([]) 
    at com.sun.jna.Structure.getFields(Structure.java:872) 
    at com.sun.jna.Structure.deriveLayout(Structure.java:983) 
    at com.sun.jna.Structure.calculateSize(Structure.java:908) 
    at com.sun.jna.Structure.calculateSize(Structure.java:896) 
    at com.sun.jna.Structure.allocateMemory(Structure.java:357) 
    at com.sun.jna.Structure.<init>(Structure.java:191) 
    at com.sun.jna.Structure.<init>(Structure.java:180) 
    at com.sun.jna.Structure.<init>(Structure.java:167) 
    at com.sun.jna.Structure.<init>(Structure.java:159) 
    at javaapplication2.NewJFrame$APPBARDATA.<init>(NewJFrame.java:31) 
    at javaapplication2.NewJFrame.<init>(NewJFrame.java:56) 
    at javaapplication2.NewJFrame$7.run(NewJFrame.java:255) 
    at java.awt.event.InvocationEvent.dispatch(InvocationEvent.java:251) 
    at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:721) 
    at java.awt.EventQueue.access$200(EventQueue.java:103) 
    at java.awt.EventQueue$3.run(EventQueue.java:682) 
    at java.awt.EventQueue$3.run(EventQueue.java:680) 
    at java.security.AccessController.doPrivileged(Native Method) 
    at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:76) 
    at java.awt.EventQueue.dispatchEvent(EventQueue.java:691) 
    at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:242) 
    at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:161) 
    at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:150) 
    at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:146) 
    at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:138) 
    at java.awt.EventDispatchThread.run(EventDispatchThread.java:91)

我的課：

class APPBARDATA extends Structure { 

    WinUser.DWORD cbSize; 
    WinUser.HWND hWnd; 
    WinUser.UINT_PTR uCallbackMessage; 
    WinUser.UINT_PTR uEdge; 
    WinUser.RECT rc; 
    WinUser.LPARAM lParam; 

    @Override 
    protected List getFieldOrder() { 
     return Arrays.asList(new String[]{"cbSize", "hWnd", "uCallbackMessage", "uEdge", "rc", "lParam"}); 
    } 
} 

    APPBARDATA pdata = new APPBARDATA(); 
    pdata.lParam = new WinUser.LPARAM(0); 
    pdata.cbSize = new WinUser.DWORD(32); 
    pdata.hWnd = WinUser.HWND_BROADCAST;

有什麼不對？

來源

2013-02-24 MOD

將您的屬性標記爲公開，因爲as specified in the doc，JNA使用class.getFields()來獲取屬性列表。

的Javadoc Class.getFields()：

Returns an array containing Field objects reflecting all the accessible public fields of the class or interface represented by this Class object. ...

來源

2013-02-24 10:30:16 Aubin

現在我得到這個錯誤; 線程「AWT-EventQueue-0」中的異常java.lang.Error：類javaapplication2.NewJFrame中的異常閱讀字段'cbSize'$ APPBARDATA：java.lang.IllegalAccessException：類com.sun.jna.Structure無法訪問類javaapplication2.NewJFrame的成員$ APPBARDATA與修飾符「公衆」 – MOD 2013-02-24 11:29:12

好吧，這是因爲該類不公開。你的回答是對的。類和字段都必須公開 – MOD 2013-02-24 11:33:00

如何在JNA中創建結構？

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