add a way to hide a window instead of destroying it

changelog

@@ -1,4 +1,18 @@
-2017-06-30 - Version 0.6.0
+2017-07-04 - Version 0.6.1
+[*] Fix selection Window with mouse: clicking non-active Window makes the
+    Window active (unless the top Window is modal one)
+[*] TableView does not fire OnSelectionChange event if a user clicked outside
+    the table. Before the fix a callback got selected index greater than
+    the total number of rows and might crash a callback
+[+] Add a new feature to Windows: to keep all changes the Windows can be
+    hidden instead of destroying when a user clicks window close button. It
+    can be done with overriding OnClose and returning 'true' if Windows must
+    be kept. To remove the Window from screen use SetVisible(false)
+[*] Window OnClose callback event now must return boolean. See change above
+[*] Fix typo: TableView did not send TableDelete event if the selected Row
+    was Row number 1
+
+2017-06-30 - Version 0.6.0
 [+] Added new control TextReader - a virtual text view control with
     built-in support of some hots keys to list the text
 [+] Added a new global event to close active view

composer.go

@@ -65,7 +65,10 @@ func RefreshScreen() {
 	term.Clear(ColorWhite, ColorBlack)
 
 	for _, wnd := range comp.windows {
-		wnd.Draw()
+		v := comp.topWindow().(*Window)
+		if v.Visible() {
+			wnd.Draw()
+		}
 	}
 
 	term.Flush()
@@ -144,18 +147,36 @@ func (c *Composer) moveActiveWindowToBottom() bool {
 		return false
 	}
 
+	anyVisible := false
+	for _, w := range c.windows {
+		v := w.(*Window)
+		if v.Visible() {
+			anyVisible = true
+			break
+		}
+	}
+	if !anyVisible {
+		return false
+	}
+
 	event := Event{Type: EventActivate, X: 0} // send deactivated
 	c.sendEventToActiveWindow(event)
 
-	last := c.topWindow()
+	for {
+		last := c.topWindow()
+		for i := len(c.windows) - 1; i > 0; i-- {
+			c.windows[i] = c.windows[i-1]
+		}
+		c.windows[0] = last
 
-	for i := len(c.windows) - 1; i > 0; i-- {
-		c.windows[i] = c.windows[i-1]
-	}
+		v := c.topWindow().(*Window)
+		if v.Visible() {
+			if !c.activateWindow(c.topWindow()) {
+				return false
+			}
 
-	c.windows[0] = last
-	if !c.activateWindow(c.topWindow()) {
-		return false
+			break
+		}
 	}
 
 	event = Event{Type: EventActivate, X: 1} // send 'activated'
@@ -246,13 +267,14 @@ func (c *Composer) closeTopWindow() {
 	if len(c.windows) > 1 {
 		view := c.topWindow()
 		event := Event{Type: EventClose, X: 1}
-		c.sendEventToActiveWindow(event)
 
-		c.DestroyWindow(view)
-		activate := c.topWindow()
-		c.activateWindow(activate)
-		event = Event{Type: EventActivate, X: 1} // send 'activated'
-		c.sendEventToActiveWindow(event)
+		if c.sendEventToActiveWindow(event) {
+			c.DestroyWindow(view)
+			activate := c.topWindow()
+			c.activateWindow(activate)
+			event = Event{Type: EventActivate, X: 1} // send 'activated'
+			c.sendEventToActiveWindow(event)
+		}
 
 		RefreshScreen()
 	} else {
@@ -451,9 +473,9 @@ func (c *Composer) processMouse(ev Event) {
 			return
 		}
 	} else if !c.topWindow().Modal() {
-        c.activateWindow(view)
-        return
-    }
+		c.activateWindow(view)
+		return
+	}
 
 	if ev.Key == term.MouseLeft {
 		c.lastX = ev.X

dialog.go

@@ -111,7 +111,7 @@ func CreateConfirmationDialog(title, question string, buttons []string, defaultB
 
 	CreateFrame(frm1, 1, 1, BorderNone, 1)
 
-	dlg.view.OnClose(func(ev Event) {
+	dlg.view.OnClose(func(ev Event) bool {
 		if dlg.result == DialogAlive {
 			dlg.result = DialogClosed
 			if ev.X != 1 {
@@ -121,6 +121,7 @@ func CreateConfirmationDialog(title, question string, buttons []string, defaultB
 				go dlg.onClose()
 			}
 		}
+		return true
 	})
 
 	return dlg
@@ -220,7 +221,7 @@ func CreateSelectDialog(title string, items []string, selectedItem int, typ Sele
 	ActivateControl(dlg.view, btn2)
 	CreateFrame(frm1, 1, 1, BorderNone, 1)
 
-	dlg.view.OnClose(func(ev Event) {
+	dlg.view.OnClose(func(ev Event) bool {
 		if dlg.result == DialogAlive {
 			dlg.result = DialogClosed
 			if ev.X != 1 {
@@ -230,6 +231,8 @@ func CreateSelectDialog(title string, items []string, selectedItem int, typ Sele
 				go dlg.onClose()
 			}
 		}
+
+		return true
 	})
 
 	return dlg

tableview.go

@@ -793,7 +793,7 @@ func (l *TableView) ProcessEvent(event Event) bool {
 				go l.onAction(ev)
 			}
 		case term.KeyDelete:
-			if l.selectedRow != 1 && l.onAction != nil {
+			if l.selectedRow != -1 && l.onAction != nil {
 				ev := TableEvent{Action: TableActionDelete, Col: l.selectedCol, Row: l.selectedRow}
 				go l.onAction(ev)
 			}

window.go

@@ -16,9 +16,10 @@ type Window struct {
 	origHeight int
 	origX      int
 	origY      int
+	hidden     bool
 
-	onClose func(Event)
-    onKeyDown func(Event) bool
+	onClose   func(Event) bool
+	onKeyDown func(Event) bool
 }
 
 func CreateWindow(x, y, w, h int, title string) *Window {
@@ -211,8 +212,11 @@ func (c *Window) ProcessEvent(ev Event) bool {
 		c.PlaceChildren()
 	case EventClose:
 		if c.onClose != nil {
-			c.onClose(ev)
+			if !c.onClose(ev) {
+				return false
+			}
 		}
+        return true
 	case EventKey:
 		if ev.Key == term.KeyTab {
 			aC := ActiveControl(c)
@@ -229,13 +233,13 @@ func (c *Window) ProcessEvent(ev Event) bool {
 			}
 			return true
 		} else {
-            if SendEventToChild(c, ev) {
-                return true
-            }
-            if c.onKeyDown != nil {
-                return c.onKeyDown(ev)
-            }
-            return false
+			if SendEventToChild(c, ev) {
+				return true
+			}
+			if c.onKeyDown != nil {
+				return c.onKeyDown(ev)
+			}
+			return false
 		}
 	default:
 		if ev.Type == EventMouse && ev.Key == term.MouseLeft {
@@ -247,7 +251,7 @@ func (c *Window) ProcessEvent(ev Event) bool {
 	return false
 }
 
-func (w *Window) OnClose(fn func(Event)) {
+func (w *Window) OnClose(fn func(Event) bool) {
 	w.onClose = fn
 }
 
@@ -282,3 +286,24 @@ func (w *Window) SetMaximized(maximize bool) {
 func (w *Window) Maximized() bool {
 	return w.maximized
 }
+
+// Visible returns if the window must be drawn on the screen
+func (w *Window) Visible() bool {
+	return !w.hidden
+}
+
+// SetVisible allows to temporarily remove the window from screen
+// and show it later without reconstruction
+func (w *Window) SetVisible(visible bool) {
+	if w.hidden == visible {
+		w.hidden = !visible
+		if w.hidden {
+			w.SetModal(false)
+			if composer().topWindow() == w {
+				composer().moveActiveWindowToBottom()
+			}
+		} else {
+			composer().activateWindow(w)
+		}
+	}
+}