Fix dropdown mouse capture behavior

CHANGELOG

@@ -1,3 +1,6 @@
+v0.2.2 (WIP)
+- Fix dropdown mouse capture behavior
+
 v0.2.1 (2020-01-01)
 - Add initial mouse support (some widgets are unsupported)
 - Add window size change handler

application.go

@@ -85,6 +85,9 @@ type Application struct {
 	// be forwarded).
 	mouseCapture func(event *EventMouse) *EventMouse
 
+	// A temporary capture function overriding the above.
+	tempMouseCapture func(event *EventMouse) *EventMouse
+
 	lastMouseX, lastMouseY int
 	lastMouseBtn           tcell.ButtonMask
 	lastMouseTarget        Primitive // nil if none
@@ -124,7 +127,9 @@ func (a *Application) GetInputCapture() func(event *tcell.EventKey) *tcell.Event
 // choose to forward that event (or a different one) by returning it or stop
 // the event processing by returning nil.
 func (a *Application) SetMouseCapture(capture func(event *EventMouse) *EventMouse) *Application {
+	a.Lock()
 	a.mouseCapture = capture
+	a.Unlock()
 	return a
 }
 
@@ -134,6 +139,22 @@ func (a *Application) GetMouseCapture() func(event *EventMouse) *EventMouse {
 	return a.mouseCapture
 }
 
+// SetTemporaryMouseCapture temporarily overrides the normal capture function.
+// Calling this function from anywhere other than a widget may result in
+// unexpected behavior.
+func (a *Application) SetTemporaryMouseCapture(capture func(event *EventMouse) *EventMouse) *Application {
+	a.Lock()
+	a.tempMouseCapture = capture
+	a.Unlock()
+	return a
+}
+
+// GetTemporaryMouseCapture returns the function installed with
+// SetTemporaryMouseCapture() or nil if no such function has been installed.
+func (a *Application) GetTemporaryMouseCapture() func(event *EventMouse) *EventMouse {
+	return a.tempMouseCapture
+}
+
 // SetScreen allows you to provide your own tcell.Screen object. For most
 // applications, this is not needed and you should be familiar with
 // tcell.Screen when using this function.
@@ -263,6 +284,7 @@ EventLoop:
 			p := a.focus
 			inputCapture := a.inputCapture
 			mouseCapture := a.mouseCapture
+			tempMouseCapture := a.tempMouseCapture
 			screen := a.screen
 			root := a.root
 			a.RUnlock()
@@ -373,6 +395,13 @@ EventLoop:
 				event2 := NewEventMouse(event, ptarget, a, act)
 
 				// Intercept event.
+				if tempMouseCapture != nil {
+					event2 = tempMouseCapture(event2)
+					if event2 == nil {
+						a.draw()
+						continue // Don't forward event.
+					}
+				}
 				if mouseCapture != nil {
 					event2 = mouseCapture(event2)
 					if event2 == nil {

demos/presentation/main.go

@@ -108,7 +108,7 @@ func main() {
 
 	app.SetMouseCapture(func(event *cview.EventMouse) *cview.EventMouse {
 		atX, atY := event.Position()
-		if event.Action()&cview.MouseClick != 0 && atY == screenHeight-1 {
+		if event.Action()&cview.MouseDown != 0 && atY == screenHeight-1 {
 			slideClicked := -1
 			for i, region := range slideRegions {
 				if atX >= region {

dropdown.go

@@ -440,7 +440,7 @@ func (d *DropDown) openList(setFocus func(Primitive), app *Application) {
 	d.list.SetSelectedFunc(func(index int, mainText, secondaryText string, shortcut rune) {
 		// An option was selected. Close the list again.
 		d.currentOption = index
-		d.closeList(setFocus)
+		d.closeList(setFocus, app)
 
 		// Trigger "selected" event.
 		if d.selected != nil {
@@ -461,14 +461,14 @@ func (d *DropDown) openList(setFocus func(Primitive), app *Application) {
 			d.evalPrefix()
 		} else if event.Key() == tcell.KeyEscape {
 			d.currentOption = optionBefore
-			d.closeList(setFocus)
+			d.closeList(setFocus, app)
 		} else {
 			d.prefix = ""
 		}
 		return event
 	})
 	if app != nil {
-		app.SetMouseCapture(func(event *EventMouse) *EventMouse {
+		app.SetTemporaryMouseCapture(func(event *EventMouse) *EventMouse {
 			if d.open {
 				// Forward the mouse event to the list.
 				atX, atY := event.Position()
@@ -490,8 +490,7 @@ func (d *DropDown) openList(setFocus func(Primitive), app *Application) {
 					// Mouse not within the list.
 					if event.Action()&MouseDown != 0 {
 						// If a mouse button was pressed, cancel this capture.
-						app.SetMouseCapture(nil)
-						d.closeList(event.SetFocus)
+						d.closeList(event.SetFocus, app)
 					}
 				}
 			}
@@ -501,7 +500,11 @@ func (d *DropDown) openList(setFocus func(Primitive), app *Application) {
 	setFocus(d.list)
 }
 
-func (d *DropDown) closeList(setFocus func(Primitive)) {
+func (d *DropDown) closeList(setFocus func(Primitive), app *Application) {
+	if app != nil {
+		app.SetTemporaryMouseCapture(nil)
+	}
+
 	d.open = false
 	if d.list.HasFocus() {
 		setFocus(d)
@@ -532,7 +535,7 @@ func (d *DropDown) MouseHandler() func(event *EventMouse) {
 			//d.open = !d.open
 			//event.SetFocus(d)
 			if d.open {
-				d.closeList(event.SetFocus)
+				d.closeList(event.SetFocus, event.Application())
 			} else {
 				d.openList(event.SetFocus, event.Application())
 			}