Virtual keyboard Event should also support key press event and key release event

1. There are two kinds of virtual keyboard at least.

2. First, the virtual keyboard is the same as the physical
   keyboard except that the virtual keyboard is displayed
   on the screen while the physical keyboard not. So, the
   virtual keyboard and the physical keyboard should use
   the same logic of input method engine.

3. Second, the virtual keyboard use a different logic of
   input method engine which is dedicated to the virtual
   keyboard. In this case, the press event and the release
   event may not be so important.

src/lib/fcitx/event.cpp

@@ -11,9 +11,11 @@ namespace fcitx {
 
 class VirtualKeyboardEventPrivate {
 public:
-    VirtualKeyboardEventPrivate(int time) : time_(time) {}
+    VirtualKeyboardEventPrivate(bool isRelease, int time)
+        : isRelease_(isRelease), time_(time) {}
 
     Key key_;
+    bool isRelease_ = false;
     int time_ = 0;
     uint64_t userAction_ = 0;
     std::string text_;
@@ -28,9 +30,10 @@ KeyEventBase::KeyEventBase(EventType type, InputContext *context, Key rawKey,
     : InputContextEvent(context, type), key_(rawKey.normalize()),
       origKey_(rawKey), rawKey_(rawKey), isRelease_(isRelease), time_(time) {}
 
-VirtualKeyboardEvent::VirtualKeyboardEvent(InputContext *context, int time)
+VirtualKeyboardEvent::VirtualKeyboardEvent(InputContext *context,
+                                           bool isRelease, int time)
     : InputContextEvent(context, EventType::InputContextVirtualKeyboardEvent),
-      d_ptr(std::make_unique<VirtualKeyboardEventPrivate>(time)) {}
+      d_ptr(std::make_unique<VirtualKeyboardEventPrivate>(isRelease, time)) {}
 
 FCITX_DEFINE_DEFAULT_DTOR(VirtualKeyboardEvent);
 
@@ -58,7 +61,8 @@ std::unique_ptr<KeyEvent> fcitx::VirtualKeyboardEvent::toKeyEvent() const {
 
     Key key{d->key_.sym(), d->key_.states() | KeyState::Virtual,
             d->key_.code()};
-    return std::make_unique<KeyEvent>(inputContext(), key, false, time());
+    return std::make_unique<KeyEvent>(inputContext(), key, d->isRelease_,
+                                      time());
 }
 
 } // namespace fcitx

src/lib/fcitx/event.h

@@ -339,7 +339,7 @@ class VirtualKeyboardEventPrivate;
 
 class FCITXCORE_EXPORT VirtualKeyboardEvent : public InputContextEvent {
 public:
-    VirtualKeyboardEvent(InputContext *context, int time = 0);
+    VirtualKeyboardEvent(InputContext *context, bool isRelease, int time = 0);
     ~VirtualKeyboardEvent();
 
     int time() const;

src/ui/virtualkeyboard/virtualkeyboard.cpp

@@ -153,7 +153,7 @@ void VirtualKeyboardBackend::processKeyEvent(uint32_t keyval, uint32_t keycode,
         return;
     }
 
-    VirtualKeyboardEvent event(inputContext, time);
+    VirtualKeyboardEvent event(inputContext, isRelease, time);
     event.setKey(Key(static_cast<KeySym>(keyval), KeyStates(state), keycode));
 
     auto eventConsumed = inputContext->virtualKeyboardEvent(event);