MTK VENUSMMI VfxSignal的理解

来源：互联网发布：淘宝上的折扣店编辑：程序博客网时间：2024/05/29 17:34

查看venusmmi的代码时，经常会看到以下的代码：

    VFX_OBJ_CREATE(m_delayPenDownTimer, VfxTimer, this);    m_delayPenDownTimer->m_signalTick.connect(this, &VappKeyMainmenuPageMenu::onDelayPenDownTimerTick);

代码的意思很明了，就是创建一个定时器，然后超时的时候自动进行相关的操作。发现这个很好用，很方便，决定研究一下是怎么实现的。

以vfxsignal1为例：

/***************************************************************************** * Class VfxSignal1 *****************************************************************************//* * Signal with one parameter */template <class _arg1_type>   //类模板，<span style="font-family: Arial, Helvetica, sans-serif;">_arg1_type为虚拟类型参数</span>class VfxSignal1 : public VfxBaseSignal{    VFX_DECLARE_NO_COPY_CLASS(VfxSignal1);private:    typedef void (VfxObject::*obj_mem_funcptr_type)(_arg1_type arg1);    typedef VfxSignalArg1 <_arg1_type> Argument;public:    // default constructor    VfxSignal1()    {    }    // Set the default slot    template <class _func_type>    void connectFront(VfxObject *obj, _func_type func)    {        baseConnectFront(obj, (VfxSlotObjMemFuncPtr)VFX_STATIC_CAST(func, obj_mem_funcptr_type));    }        // connect to a member-to-function pointer    template <class _func_type>    void connect(VfxObject *obj, _func_type func)    {        baseConnect(obj, (VfxSlotObjMemFuncPtr)VFX_STATIC_CAST(func, obj_mem_funcptr_type));    }        // disconnect from a member-to-function pointer    template <class _func_type>    void disconnect(VfxObject *obj, _func_type func)    {        baseDisconnect(obj, (VfxSlotObjMemFuncPtr)VFX_STATIC_CAST(func, obj_mem_funcptr_type));    }    // connect to a callback object    void connect(VfxCallback1<_arg1_type> cb)    {        baseConnect(cb.m_objPtr.get(), cb.m_callback);    }    // disconnect from a callback object    void disconnect(VfxCallback1<_arg1_type> cb)    {        baseDisconnect(cb.m_objPtr.get(), cb.m_callback);    }    // invoke a single signal function    static void emitEntry(VfxObject *obj, VfxSlotObjMemFuncPtr callback, VfxSignalArg *arguments)    {        Argument* arg = (Argument*) arguments;        (obj->* obj_mem_funcptr_type(callback))(arg->arg1);    }    // trigger this signal    void emit(_arg1_type arg1) const    {        if (!m_slotList.isEmpty())        {            Argument arg(arg1);            VfxSlotList tmpSlotList(m_slotList);            emitSlots(&tmpSlotList, (VfxEmitEntryFuncPtr)&VfxSignal1::emitEntry, (void*)&arg);        }    }    // post emit a signal    template <class _func_type>    void postEmit(        _arg1_type arg1,        VfxObject *obj,      // [IN] after emiting the signal, callback to which object         _func_type func      // [IN] after emiting the signal, callback to which member function of this object    ) const    {        Argument *arg;        VFX_SYS_NEW_EX(arg, Argument, (arg1));        VFX_REG_POSTEMIT(VfxSignal1, arg, obj, func);    }    // post emit a signal without callback    void postEmit(        _arg1_type arg1    ) const    {        if (!m_slotList.isEmpty())        {            Argument *arg;            VFX_SYS_NEW_EX(arg, Argument, (arg1));            VFX_REG_POSTEMIT(VfxSignal1, arg, NULL, NULL);        }    }}

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