Grabbing Hardware Key Events

The applications do not normally grab hardware key events, because each key event is delivered to the focused window by default. Some applications, however, have more advanced functionalities and behavior. For example, a memo application can use the volume key to resize the text. However, in most cases, if the volume keys are pressed, a volume control popup opens. To receive special hardware key events in the application, use the eext_win_keygrab_set() and eext_win_keygrab_unset() functions.

To grab hardware key events:

To use the functions and data types of the EFL Extension API (in mobile and wearable applications), include the <efl_extension.h> header in your application:
```
#include <efl_extension.h>
```

Create the objects using the window. For more information, see UI Containers.

static void
create_base_gui(appdata_s *ad)
{
   Evas_Object *win = NULL;

   // Create the window
   win = elm_win_util_standard_add(NULL, "extension sample");
   evas_object_smart_callback_add(win, "delete,request", _win_del, NULL);

   // Show the window
   evas_object_show(win);
}

Eina_Bool ctrl_pressed = EINA_FALSE;

static Eina_Bool
_key_down_cb(void *data __UNUSED__, int type __UNUSED__, void *ev)
{
   // The callback is used with the ECORE_EVENT_KEY_DOWN signal: the
   // parameter "void *ev" is therefore of the actual Ecore_Event_Key type
   // The following renders its fields accessible
   Ecore_Event_Key *event = ev;

   // Test whether the key that is pressed is Ctrl
   if (!strcmp("Control_L", event->key))
   {
      // If it is, store that piece of information
      ctrl_pressed = EINA_TRUE;
   }

   // Let the event continue to other callbacks which have not been called yet
   return ECORE_CALLBACK_PASS_ON;
}

ecore_event_handler_add(ECORE_EVENT_KEY_DOWN, _key_down_cb, NULL);

Grab the key events using the eext_win_keygrab_set() function. The parameters are the window object created in step 2 above, and the key string.
```
eext_win_keygrab_set(win, "XF86AudioRaiseVolume")
```
When the application no longer needs to grab the key events, use the eext_win_keygrab_unset() function to ungrab them:
```
eext_win_keygrab_unset(win, "XF86AudioRaiseVolume")
```

The following table lists the hardware keys from which you can grab events in different profiles.

Table: Supported hardware keys
Key	Description	Mobile	Wearable	TV
"XF86AudioRaiseVolume"	Key to raise the volume	Yes	Yes	Yes
"XF86AudioLowerVolume"	Key to lower the volume	Yes	Yes	Yes
"XF86PowerOff"	Power key to switch the device on and off	Yes	Yes	Yes
"XF86Menu"	Application-specific menu key	Yes	Yes	Yes
"XF86Home"	Key to go to the home screen	Yes	Yes	Yes
"XF86Back"	Key to go back to the previous status or page	Yes	Yes	Yes
"XF86Camera"	Half shutter key to do something before taking a picture on the camera	Yes	-	-
"XF86Camera_Full"	Key to take a picture on the camera	Yes	Yes	Yes
"XF86Search"	Key to go to the search application	Yes	Yes	Yes
"XF86AudioPlay"	Key to play media	Yes	Yes	Yes
"XF86AudioPause"	Key to pause the media being played	Yes	Yes	Yes
"XF86AudioStop"	Key to stop the media being played	Yes	Yes	Yes
"XF86AudioNext"	Key to go to the next media item	Yes	Yes	Yes
"XF86AudioPrev"	Key to go to the previous media item	Yes	Yes	Yes
"XF86AudioRewind"	Key to rewind the playing position of the media	Yes	Yes	Yes
"XF86AudioForward"	Key to forward the playing position of the media	Yes	Yes	Yes
"XF86AudioMedia"	Key to go to the media player	Yes	Yes	Yes
"XF86AudioPlayPause"	Key to toggle between play and pause	Yes	Yes	Yes
"XF86AudioMute"	Key to mute the media	Yes	Yes	Yes
"XF86AudioRecord"	Key to start recording media	Yes	Yes	Yes
"Cancel"	Key to cancel the action triggered by the previous keys	Yes	Yes	Yes
"XF86SoftKBD"	Key to show and hide the soft keyboard	Yes	Yes	Yes
"XF86QuickPanel"	Key to toggle the quick panel	Yes	-	Yes
"XF86TaskPane"	Key to toggle the task switcher	Yes	Yes	Yes
"XF86HomePage"	Key to go to the homepage of the user-defined Web browser	Yes	-	Yes
"XF86WWW"	Key to launch the user-defined Web browser	Yes	-	Yes
"XF86Mail"	Key to go to the user-defined email application	Yes	-	Yes
"XF86ScreenSaver"	Key to activate the screen lock (such as a pattern lock or a PIN lock)	Yes	Yes	Yes
"XF86MonBrightnessDown"	Key to lower the screen brightness	Yes	Yes	Yes
"XF86MonBrightnessUp"	Key to raise the screen brightness	Yes	Yes	Yes
"XF86Voice"	Key to activate a voice-related application	Yes	Yes	Yes
"Hangul"	Key to toggle the current language	Yes	-	Yes
"XF86Apps"	Key to call the application holder application	Yes	Yes	Yes
"XF86Call"	Key to launch the call application	Yes	Yes	Yes
"XF86Game"	Key to go to the game application	Yes	-	Yes
"XF86VoiceWakeUp_LPSD"	Key to wake up from voice input (LPSD)	Yes	Yes	Yes
"XF86VoiceWakeUp"	Key to wake up from voice input	Yes	Yes	Yes
"XF86TV"	Key to display the TV screen directly	-	-	Yes
"XF86Display"	Key to toggle the video source	-	-	Yes
"XF86RCConfig"	Key to set the remote control's specific configuration	-	-	Yes
"XF86RCMode"	Key to show and hide the virtual remote control on the screen	-	-	Yes
"1"	Numeric key 1 on the remote control	-	-	Yes
"2"	Numeric key 2 on the remote control	-	-	Yes
"3"	Numeric key 3 on the remote control	-	-	Yes
"4"	Numeric key 4 on the remote control	-	-	Yes
"5"	Numeric key 5 on the remote control	-	-	Yes
"6"	Numeric key 6 on the remote control	-	-	Yes
"7"	Numeric key 7 on the remote control	-	-	Yes
"8"	Numeric key 8 on the remote control	-	-	Yes
"9"	Numeric key 9 on the remote control	-	-	Yes
"0"	Numeric key 0 on the remote control	-	-	Yes
"-"	Minus key on the remote control	-	-	Yes
"XF86LowerChannel"	Key to lower the channel number	-	-	Yes
"XF86RaiseChannel"	Key to raise the channel number	-	-	Yes
"XF86ChannelList"	Key to display the channel list	-	-	Yes
"XF86PreviousChannel"	Key to display the previous channel	-	-	Yes
"XF86SysMenu"	Key to launch the system menu	-	-	Yes
"XF86SimpleMenu"	Key to launch the simple menu	-	-	Yes
"XF86History"	Key to launch the history functionality	-	-	Yes
"XF86Favorites"	Key to launch the favorite channels functionality	-	-	Yes
"Up"	Arrow key UP on the remote control	-	-	Yes
"Down"	Arrow key DOWN on the remote control	-	-	Yes
"Left"	Arrow key LEFT on the remote control	-	-	Yes
"Right"	Arrow key RIGHT on the remote control	-	-	Yes
"Return"	OK key on the remote control to confirm or select an item	-	-	Yes
"XF86Close"	Exit key on the remote control to terminate the current menu or application	-	-	Yes
"XF86Info"	Key to display the basic and auxiliary information on the screen	-	-	Yes
"XF86Red"	Key to execute the functionality registered to the RED key	-	-	Yes
"XF86Green"	Key to execute the functionality registered to the GREEN key	-	-	Yes
"XF86Yellow"	Key to execute the functionality registered to the YELLOW key	-	-	Yes
"XF86Blue"	Key to execute the functionality registered to the BLUE key	-	-	Yes
"XF86ProgInfo"	Key to display the program information	-	-	Yes
"XF86PictureMode"	Key to change the screen mode	-	-	Yes
"XF86PictureSize"	Key to change the screen size and aspect ratio	-	-	Yes
"XF86PIP"	Key to set the PIP (Picture-In-Picture) mode to display one screen on the other	-	-	Yes
"XF86Guide"	Key to display the user guide	-	-	Yes
"XF86AudioMode"	Key to set or change the audio mode	-	-	Yes
"XF86Subtitle"	Key to display or hide the subtitles	-	-	Yes
"XF863D"	Key to set or change the 3D mode	-	-	Yes