Qt Zebra扫码枪的命令发送和接收com组件的事件

如题,zebra官网给出的扫码枪SDK示例是基于MFC的,自己用的是QT,加大了开发难度(悔不当初用MFC),同时也对com组件不熟悉,导致折腾了好几天才搞定。也不知道这么做能不能满足QT跨平台的初衷,Windows是能用的,给大家参考一下。

1、下面是代码,命令发送这部分很容易解决,稍微改下就行,主要是接收com组件的事件,我这边采用了回调函数的方式接收信息。

 1 private:
 2     DWORD m_dwRefCount;
 3     Callback  //自己定义的回调函数
 4     void * user;
 5 public:    
 6     void SetCallbackFunc(CallbackGetScannerData cbk, void* user)
 7     {
 8         this->cbkGetData = cbk;
 9         this->user = user;
10     }
11     
12     CEventSink() { m_dwRefCount = 0; }
13     virtual ~CEventSink(void) {}
14     
15     STDMETHODIMP GetTypeInfoCount(UINT *pctinfo) { return E_NOTIMPL; }
16     STDMETHODIMP GetTypeInfo(UINT iTInfo, LCID lcid, ITypeInfo **ppTInfo) { return E_NOTIMPL; }
17     STDMETHODIMP GetIDsOfNames(REFIID riid, LPOLESTR *rgszNames, UINT cNames, LCID lcid, DISPID *rgDispId) { return E_NOTIMPL; }
18     
19     STDMETHODIMP Invoke(DISPID dispIdMember, REFIID riid, LCID lcid, WORD wFlags, DISPPARAMS *pDispParams, VARIANT *pVarResult, EXCEPINFO *pExcepInfo, UINT *puArgErr)
20     {
21         LONG *lValue = pVarResult->plVal;
22         switch (dispIdMember)
23         {
24         case 3:      //能获取到扫描枪扫的条码信息
25         {
26             VARIANT varlValue;
27             VARIANT varlValue1;
28             short lValue = 0;
29             BSTR lValue1;
30             varlValue = (pDispParams->rgvarg)[1];
31             varlValue1 = (pDispParams->rgvarg)[0];
32             //varlValue1.pbstrVal
33             lValue = V_I2(&varlValue);
34             lValue1 = SysAllocString(*(varlValue1.pbstrVal));
35             if(cbkGetData)
36                 //放自己定义的回调函数
37             break;
38         }
39         default:
40             break;
41         }
42         //printf(" ---------the result %d
", *lValue);
43         //OnReceiver(lValue);
44         return S_OK;
45     }
46     STDMETHOD(QueryInterface)(REFIID iid, LPVOID* ppv)
47     {
48         if ((iid == __uuidof(_ICoreScannerEvents)) || //(iid == __uuidof(IMarshal)) ||
49             (iid == __uuidof(IDispatch)) ||
50             (iid == __uuidof(IUnknown)))
51         {
52             m_dwRefCount++;
53             *ppv = this;
54         }
55         else
56         {
57             *ppv = NULL;
58             return E_NOINTERFACE;
59         }
60         return S_OK;
61     }
62     STDMETHOD_(ULONG, AddRef)()
63     {
64         return InterlockedIncrement(&m_dwRefCount);
65     }
66     STDMETHOD_(ULONG, Release)()
67     {
68         InterlockedDecrement(&m_dwRefCount);
69         if (m_dwRefCount != 0)
70             return m_dwRefCount;
71         delete this;
72         return 0;
73     }
74 };

2、下面是调用的这个类的代码

 1  if(ScannerInterface)
 2     {
 3         HRESULT hr = S_FALSE;
 4         //Create the Scanner COM object
 5         IConnectionPointContainer *pCPC;
 6         hr = ScannerInterface->QueryInterface(IID_IConnectionPointContainer, (void **)&pCPC);
 7         if (!SUCCEEDED(hr))
 8         {
 9             return -1;
10         }
11 
12         //获取连接点
13         hr = pCPC->FindConnectionPoint(DIID__ICoreScannerEvents, &pCP);
14         if (!SUCCEEDED(hr))
15         {
16             return -1;
17         }
18         pCPC->Release();
19 
20         IUnknown *pSinkUnk;
21         ScannerEventSink = new CEventSink();
22         ScannerEventSink->SetCallbackFunc(//自定义的回调函数, user);
23 
24         hr = ScannerEventSink->QueryInterface(DIID__ICoreScannerEvents, (void **)&pSinkUnk);
25         hr = pCP->Advise(pSinkUnk, &dwAdvise);//注册其接收接口指针
26         if (!SUCCEEDED(hr))
27         {
28             return -1;
29         }
30     }
原文地址:https://www.cnblogs.com/ybqjymy/p/15137734.html