xbmc遥控音量加处理过程总结

AndroidKey.cpp将scancode装换为sym，并形成XBMC_Key

[code]//xbmc/android/activity/AndroidKey.cpp
typedef struct {
  int32_t nativeKey;
  int16_t xbmcKey;
} KeyMap;

static KeyMap keyMap[] = {
  { AKEYCODE_VOLUME_UP       , XBMCK_PLUS },
};
bool CAndroidKey::onKeyboardEvent(AInputEvent *event)
{
  int32_t flags   = AKeyEvent_getFlags(event);
  int32_t state   = AKeyEvent_getMetaState(event);
  int32_t action  = AKeyEvent_getAction(event);
  int32_t repeat  = AKeyEvent_getRepeatCount(event);
  int32_t keycode = AKeyEvent_getKeyCode(event);

  int32_t deviceId = AInputEvent_getDeviceId(event);
  CJNIKeyCharacterMap map = CJNIKeyCharacterMap::load(deviceId);
  uint16_t unicode = map.get(keycode, state);
  // Check if we got some special key
  uint16_t sym = XBMCK_UNKNOWN;
  for (unsigned int index = 0; index < sizeof(keyMap) / sizeof(KeyMap); index++)
  {
    if (keycode == keyMap[index].nativeKey)
    {
      sym = keyMap[index].xbmcKey;
      break;
    }
  }
  switch (action)
  {
    case AKEY_EVENT_ACTION_DOWN:
  CXBMCApp::android_printf("CAndroidKey: key down (code: %d; repeat: %d; flags: 0x%0X; alt: %s; shift: %s; sym: %s)",
        keycode, repeat, flags,
        (state & AMETA_ALT_ON) ? "yes" : "no",
        (state & AMETA_SHIFT_ON) ? "yes" : "no",
        (state & AMETA_SYM_ON) ? "yes" : "no");
      XBMC_Key((uint8_t)keycode, sym, modifiers, unicode, false);
      return true;
  ...
   }
}

keyMap[index].nativeKey的值在这儿定义的这句话

[code]/*
tools/depends/target/android-sources-ics/android-source/frameworks/base/native/include/android/keycodes.h
*/
enum {
    AKEYCODE_VOLUME_UP       = 24,
    ...
}

接下来就是把android键盘打包为xbmc内部的XBMC_Event，扔到消息队列中

[code]void CAndroidKey::XBMC_Key(uint8_t code, uint16_t key, uint16_t modifiers, uint16_t unicode, bool up)
{
  XBMC_Event newEvent;
  memset(&newEvent, 0, sizeof(newEvent));
  unsigned char type = up ? XBMC_KEYUP : XBMC_KEYDOWN;
  newEvent.type = type;
  newEvent.key.type = type;
  newEvent.key.keysym.scancode = code;
  newEvent.key.keysym.sym = (XBMCKey)key;
  newEvent.key.keysym.unicode = unicode;
  newEvent.key.keysym.mod = (XBMCMod)modifiers;

  //CXBMCApp::android_printf("XBMC_Key(%u, %u, 0x%04X, %d)", code, key, modifiers, up);
  CWinEvents::MessagePush(&newEvent);
}

传到Application.cpp的OnEvent，由XBMC_Event获得CKey对象

[code]//xbmc/Application.cpp
bool CApplication::OnEvent(XBMC_Event& newEvent)
{
  switch(newEvent.type)
  {
    case XBMC_QUIT: //退出xbmc
        ...
        CApplicationMessenger::Get().Quit();
    break;
    case XBMC_KEYDOWN:
        //这里一句输出了：Keyboard: scancode: 0x18, sym: 0x002b, unicode: 0x0000, modifier: 0x0
        g_application.OnKey(g_Keyboard.ProcessKeyDown(newEvent.key.keysym));
    break;  
  }
}

CKey获取CAction对象

[code]//xbmc/Application.cpp
bool CApplication::OnKey(const CKey& key)
{
...
  int iWin = GetActiveWindowID();
  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);
}

[code]bool CApplication::ExecuteInputAction(const CAction &action)
{
  bool bResult = false;

  // play sound before the action unless the button is held,
  // where we execute after the action as held actions aren't fired every time.
    bResult = OnAction(action);
    ...
  g_audioManager.PlayActionSound(action);//播放按键音
  return bResult;
}
bool CApplication::OnAction(const CAction &action)
{
    ...
  if (action.GetAmount() && (action.GetID() == ACTION_VOLUME_UP || action.GetID() == ACTION_VOLUME_DOWN))
  {
    if (!m_pPlayer->IsPassthrough())
    {
    ...
      SetVolume(volume, false);
    }
    ShowVolumeBar(&action);
    return true;
  }
    ...
}

ACTION_VOLUME_UP的值在哪里定义的呢

[code]//xbmc/guilib/Key.h
#define ACTION_VOLUME_UP            88

[code]void CApplication::VolumeChanged() const
{
  CVariant data(CVariant::VariantTypeObject);
  data["volume"] = GetVolume();
  data["muted"] = m_muted;
  CAnnouncementManager::Get().Announce(Application, "xbmc", "OnVolumeChanged", data);

  // if player has volume control, set it.
  if (m_pPlayer->ControlsVolume())
  {
     m_pPlayer->SetVolume(m_volumeLevel);
     m_pPlayer->SetMute(m_muted);
  }
}