xbmc从onEvent到onkey创建CKey对象的过程

注我们以遥控器音量加键为说明例子

//xbmc/Application.cppbool CApplication::OnEvent(XBMC_Event& newEvent){  switch(newEvent.type)  {    case XBMC_QUIT: //退出xbmc        ...        CApplicationMessenger::Get().Quit();    break;    case XBMC_KEYDOWN:        g_application.OnKey(g_Keyboard.ProcessKeyDown(newEvent.key.keysym));    break;    }}

/*xbmc/input/KeyboardStat.cpp*/const CKey CKeyboardStat::ProcessKeyDown(XBMC_keysym& keysym){ uint8_t vkey;  wchar_t unicode;  char ascii;  uint32_t modifiers;  unsigned int held;  XBMCKEYTABLE keytable;  ...   //这里一句输出了：Keyboard: scancode: 0x18, sym: 0x002b, unicode: 0x0000, modifier: 0x0  CLog::Log(LOGDEBUG, "Keyboard: scancode: 0x%02x, sym: 0x%04x, unicode: 0x%04x, modifier: 0x%x",   keysym.scancode, keysym.sym, keysym.unicode, keysym.mod); if (LookupSymAndUnicodePeripherals(keysym, &vkey, &ascii))  {    CLog::Log(LOGDEBUG, "%s - keypress translated by a HID peripheral", __FUNCTION__);  }  // Continue by trying to match both the sym and unicode. This will identify  else if (KeyTableLookupSymAndUnicode(keysym.sym, keysym.unicode, &keytable))  {    vkey = keytable.vkey;    ascii = keytable.ascii;  }  // If we failed to match the sym and unicode try just the unicode. This  else if (KeyTableLookupUnicode(keysym.unicode, &keytable))  {    vkey = keytable.vkey;    ascii = keytable.ascii;  }  // If there is still no match try the sym我们按音量加进入了这里  else if (KeyTableLookupSym(keysym.sym, &keytable))  {    vkey = keytable.vkey;    if (keytable.unicode == 0 && unicode != 0)      unicode = 0;    else if (keysym.unicode > 32 && keysym.unicode < 128)      ascii = unicode & 0x7f;  }  ...  //我们点击遥控器音量加到这里是 vkey:+, unicode:0x0000, ascii:null, modifiers:0x0000, held:0  CKey key(vkey, unicode, ascii, modifiers, held);  return key;}

/*xbmc/input/XBMC_keytable.cpp*/bool KeyTableLookupSym(uint16_t sym, XBMCKEYTABLE* keytable){  ...  // Look up the sym in XBMCKeyTable  for (int i = 0; i < XBMCKeyTableSize; i++)  { if (sym == XBMCKeyTable[i].sym)    { *keytable = XBMCKeyTable[i];      return true;    }  }  return false;}

这里会查找XBMCKeyTable这个数组，以找到sym号相同的的数组。我们知道sym为0x002b，这个
值是在AndroidKey.cpp将键盘scancode转化为sym而来。

/*xbmc/input/XBMC_keytable.h*/typedef struct struct_XBMCKEYTABLE{  uint16_t sym;  uint16_t unicode;  char     ascii;  uint32_t    vkey;  const char* keyname;}static const XBMCKEYTABLE XBMCKeyTable[] ={  ...  // Misc printing characters  { XBMCK_PLUS,                 '+',  '+', XBMCVK_PLUS,            "plus" }  ...}

到此，我们就解析完了CKey对象的创建过程，然后它被传递给了

//xbmc/Application.cppbool CApplication::OnKey(const CKey& key){  // get the current active window  int iWin = GetActiveWindowID();  // this will be checked for certain keycodes that need  // special handling if the screensaver is active  CAction action = CButtonTranslator::GetInstance().GetAction(iWin, key);    ....  if (!key.IsAnalogButton())    CLog::LogF(LOGDEBUG, "%s pressed, action is %s",         g_Keyboard.GetKeyName((int) key.GetButtonCode()).c_str(), action.GetName().c_str());  return ExecuteInputAction(action);}