io/key: improve InputOp focus and blur

The existing implementation cannot remove the focus of some widget,
doesn't have an option to focus without display the on-screen keyboard
and it automatically focuses the first InputOp, aggressively.

That change aims to make possible: remove focus from any widget. Add
focus without displaying the on-screen-keyboard/soft keyboard. Don't
automatically focus any widget. Don't recover focus when the widget is
visible again.

Fixes gio#180.

Signed-off-by: Inkeliz <inkeliz@inkeliz.com>

internal/opconst/ops.go

@@ -21,7 +21,8 @@ const (
 	TypePointerInput
 	TypePass
 	TypeKeyInput
-	TypeHideInput
+	TypeKeyFocus
+	TypeKeySoftKeyboard
 	TypePush
 	TypePop
 	TypeAux
@@ -30,25 +31,26 @@ const (
 )
 
 const (
-	TypeMacroLen          = 1 + 4 + 4
+	TypeMacroLen           = 1 + 4 + 4
-	TypeCallLen           = 1 + 4 + 4
+	TypeCallLen            = 1 + 4 + 4
-	TypeTransformLen      = 1 + 4*6
+	TypeTransformLen       = 1 + 4*6
-	TypeLayerLen          = 1
+	TypeLayerLen           = 1
-	TypeRedrawLen         = 1 + 8
+	TypeRedrawLen          = 1 + 8
-	TypeImageLen          = 1
+	TypeImageLen           = 1
-	TypePaintLen          = 1
+	TypePaintLen           = 1
-	TypeColorLen          = 1 + 4
+	TypeColorLen           = 1 + 4
-	TypeLinearGradientLen = 1 + 8*2 + 4*2
+	TypeLinearGradientLen  = 1 + 8*2 + 4*2
-	TypeAreaLen           = 1 + 1 + 4*4
+	TypeAreaLen            = 1 + 1 + 4*4
-	TypePointerInputLen   = 1 + 1 + 1
+	TypePointerInputLen    = 1 + 1 + 1
-	TypePassLen           = 1 + 1
+	TypePassLen            = 1 + 1
-	TypeKeyInputLen       = 1 + 1
+	TypeKeyInputLen        = 1
-	TypeHideInputLen      = 1
+	TypeKeyFocusLen        = 1 + 1
-	TypePushLen           = 1
+	TypeKeySoftKeyboardLen = 1 + 1
-	TypePopLen            = 1
+	TypePushLen            = 1
-	TypeAuxLen            = 1
+	TypePopLen             = 1
-	TypeClipLen           = 1 + 4*4 + 4 + 2 + 4
+	TypeAuxLen             = 1
-	TypeProfileLen        = 1
+	TypeClipLen            = 1 + 4*4 + 4 + 2 + 4
+	TypeProfileLen         = 1
 )
 
 func (t OpType) Size() int {
@@ -66,7 +68,8 @@ func (t OpType) Size() int {
 		TypePointerInputLen,
 		TypePassLen,
 		TypeKeyInputLen,
-		TypeHideInputLen,
+		TypeKeyFocusLen,
+		TypeKeySoftKeyboardLen,
 		TypePushLen,
 		TypePopLen,
 		TypeAuxLen,

io/key/key.go

@@ -20,16 +20,22 @@ import (
 
 // InputOp declares a handler ready for key events.
 // Key events are in general only delivered to the
-// focused key handler. Set the Focus flag to request
+// focused key handler.
-// the focus.
 type InputOp struct {
-	Tag   event.Tag
+	Tag event.Tag
-	Focus bool
 }
 
-// HideInputOp request that any on screen text input
+// SoftKeyboardOp shows or hide the on-screen keyboard, if available.
-// be hidden.
+type SoftKeyboardOp struct {
-type HideInputOp struct{}
+	Show bool
+}
+
+// FocusOp sets or clears the keyboard focus.
+type FocusOp struct {
+	// Focus, if set, moves the focus to the current InputOp. If Focus
+	// is false, the focus is cleared.
+	Focus bool
+}
 
 // A FocusEvent is generated when a handler gains or loses
 // focus.
@@ -115,14 +121,22 @@ func (m Modifiers) Contain(m2 Modifiers) bool {
 func (h InputOp) Add(o *op.Ops) {
 	data := o.Write1(opconst.TypeKeyInputLen, h.Tag)
 	data[0] = byte(opconst.TypeKeyInput)
-	if h.Focus {
+}
+
+func (h SoftKeyboardOp) Add(o *op.Ops) {
+	data := o.Write(opconst.TypeKeySoftKeyboardLen)
+	data[0] = byte(opconst.TypeKeySoftKeyboard)
+	if h.Show {
 		data[1] = 1
 	}
 }
 
-func (h HideInputOp) Add(o *op.Ops) {
+func (h FocusOp) Add(o *op.Ops) {
-	data := o.Write(opconst.TypeHideInputLen)
+	data := o.Write(opconst.TypeKeyFocusLen)
-	data[0] = byte(opconst.TypeHideInput)
+	data[0] = byte(opconst.TypeKeyFocus)
+	if h.Focus {
+		data[1] = 1
+	}
 }
 
 func (EditEvent) ImplementsEvent()  {}

io/router/key.go

@@ -20,15 +20,18 @@ type keyQueue struct {
 }
 
 type keyHandler struct {
-	active bool
+	// visible will be true if the InputOp is present
+	// in the current frame.
+	visible bool
+	new     bool
 }
 
 type listenerPriority uint8
 
 const (
-	priNone listenerPriority = iota
+	priDefault listenerPriority = iota
-	priDefault
 	priCurrentFocus
+	priNone
 	priNewFocus
 )
 
@@ -49,18 +52,27 @@ func (q *keyQueue) Frame(root *op.Ops, events *handlerEvents) {
 		q.handlers = make(map[event.Tag]*keyHandler)
 	}
 	for _, h := range q.handlers {
-		h.active = false
+		h.visible, h.new = false, false
 	}
 	q.reader.Reset(root)
-	focus, pri, hide := q.resolveFocus(events)
+
+	focus, pri, keyboard := q.resolveFocus(events)
+	if pri == priNone {
+		focus = nil
+	}
 	for k, h := range q.handlers {
-		if !h.active {
+		if !h.visible {
 			delete(q.handlers, k)
 			if q.focus == k {
+				// Remove the focus from the handler that is no longer visible.
 				q.focus = nil
-				hide = true
+				keyboard = TextInputClose
 			}
 		}
+		if h.new && k != focus {
+			// Reset the handler on (each) first appearance.
+			events.Add(k, key.FocusEvent{Focus: false})
+		}
 	}
 	if focus != q.focus {
 		if q.focus != nil {
@@ -70,17 +82,10 @@ func (q *keyQueue) Frame(root *op.Ops, events *handlerEvents) {
 		if q.focus != nil {
 			events.Add(q.focus, key.FocusEvent{Focus: true})
 		} else {
-			hide = true
+			keyboard = TextInputClose
 		}
 	}
-	switch {
+	q.state = keyboard
-	case pri == priNewFocus:
-		q.state = TextInputOpen
-	case hide:
-		q.state = TextInputClose
-	default:
-		q.state = TextInputKeep
-	}
 }
 
 func (q *keyQueue) Push(e event.Event, events *handlerEvents) {
@@ -89,49 +94,49 @@ func (q *keyQueue) Push(e event.Event, events *handlerEvents) {
 	}
 }
 
-func (q *keyQueue) resolveFocus(events *handlerEvents) (event.Tag, listenerPriority, bool) {
+func (q *keyQueue) resolveFocus(events *handlerEvents) (tag event.Tag, pri listenerPriority, keyboard TextInputState) {
-	var k event.Tag
-	var pri listenerPriority
-	var hide bool
 loop:
 	for encOp, ok := q.reader.Decode(); ok; encOp, ok = q.reader.Decode() {
 		switch opconst.OpType(encOp.Data[0]) {
+		case opconst.TypeKeyFocus:
+			op := decodeFocusOp(encOp.Data, encOp.Refs)
+			if op.Focus {
+				pri = priNewFocus
+			} else {
+				pri, keyboard = priNone, TextInputClose
+			}
+		case opconst.TypeKeySoftKeyboard:
+			op := decodeSoftKeyboardOp(encOp.Data, encOp.Refs)
+			if op.Show {
+				keyboard = TextInputOpen
+			} else {
+				keyboard = TextInputClose
+			}
 		case opconst.TypeKeyInput:
 			op := decodeKeyInputOp(encOp.Data, encOp.Refs)
-			var newPri listenerPriority
+			if op.Tag == q.focus && pri < priCurrentFocus {
-			switch {
+				pri = priCurrentFocus
-			case op.Focus:
-				newPri = priNewFocus
-			case op.Tag == q.focus:
-				newPri = priCurrentFocus
-			default:
-				newPri = priDefault
-			}
-			// Switch focus if higher priority or if focus requested.
-			if newPri.replaces(pri) {
-				k, pri = op.Tag, newPri
 			}
 			h, ok := q.handlers[op.Tag]
 			if !ok {
-				h = new(keyHandler)
+				h = &keyHandler{new: true}
 				q.handlers[op.Tag] = h
-				// Reset the handler on (each) first appearance.
-				events.Add(op.Tag, key.FocusEvent{Focus: false})
 			}
-			h.active = true
+			h.visible = true
-		case opconst.TypeHideInput:
+			tag = op.Tag
-			hide = true
 		case opconst.TypePush:
-			newK, newPri, h := q.resolveFocus(events)
+			newK, newPri, newKeyboard := q.resolveFocus(events)
-			hide = hide || h
+			if newKeyboard > keyboard {
+				keyboard = newKeyboard
+			}
 			if newPri.replaces(pri) {
-				k, pri = newK, newPri
+				tag, pri = newK, newPri
 			}
 		case opconst.TypePop:
 			break loop
 		}
 	}
-	return k, pri, hide
+	return tag, pri, keyboard
 }
 
 func (p listenerPriority) replaces(p2 listenerPriority) bool {
@@ -144,7 +149,24 @@ func decodeKeyInputOp(d []byte, refs []interface{}) key.InputOp {
 		panic("invalid op")
 	}
 	return key.InputOp{
-		Tag:   refs[0].(event.Tag),
+		Tag: refs[0].(event.Tag),
+	}
+}
+
+func decodeSoftKeyboardOp(d []byte, refs []interface{}) key.SoftKeyboardOp {
+	if opconst.OpType(d[0]) != opconst.TypeKeySoftKeyboard {
+		panic("invalid op")
+	}
+	return key.SoftKeyboardOp{
+		Show: d[1] != 0,
+	}
+}
+
+func decodeFocusOp(d []byte, refs []interface{}) key.FocusOp {
+	if opconst.OpType(d[0]) != opconst.TypeKeyFocus {
+		panic("invalid op")
+	}
+	return key.FocusOp{
 		Focus: d[1] != 0,
 	}
 }

io/router/key_test.go

@@ -0,0 +1,311 @@
+// SPDX-License-Identifier: Unlicense OR MIT
+
+package router
+
+import (
+	"reflect"
+	"testing"
+
+	"gioui.org/io/event"
+	"gioui.org/io/key"
+	"gioui.org/op"
+)
+
+func TestKeyMultiples(t *testing.T) {
+	handlers := make([]int, 3)
+	ops := new(op.Ops)
+	r := new(Router)
+
+	key.SoftKeyboardOp{Show: true}.Add(ops)
+	key.InputOp{Tag: &handlers[0]}.Add(ops)
+	key.FocusOp{Focus: true}.Add(ops)
+	key.InputOp{Tag: &handlers[1]}.Add(ops)
+
+	// The last one must be focused:
+	key.InputOp{Tag: &handlers[2]}.Add(ops)
+
+	r.Frame(ops)
+
+	assertKeyEvent(t, r.Events(&handlers[0]), false)
+	assertKeyEvent(t, r.Events(&handlers[1]), false)
+	assertKeyEvent(t, r.Events(&handlers[2]), true)
+	assertFocus(t, r, &handlers[2])
+	assertKeyboard(t, r, TextInputOpen)
+}
+
+func TestKeyStacked(t *testing.T) {
+	handlers := make([]int, 4)
+	ops := new(op.Ops)
+	r := new(Router)
+
+	s := op.Push(ops)
+	key.InputOp{Tag: &handlers[0]}.Add(ops)
+	// FocusOp must not overwrite the
+	// FocusOp{Focus: true}.
+	key.FocusOp{Focus: false}.Add(ops)
+	s.Pop()
+	s = op.Push(ops)
+	key.SoftKeyboardOp{Show: false}.Add(ops)
+	key.InputOp{Tag: &handlers[1]}.Add(ops)
+	key.FocusOp{Focus: true}.Add(ops)
+	s.Pop()
+	s = op.Push(ops)
+	key.InputOp{Tag: &handlers[2]}.Add(ops)
+	// SoftwareKeyboardOp will open the keyboard,
+	// overwriting `SoftKeyboardOp{Show: false}`.
+	key.SoftKeyboardOp{Show: true}.Add(ops)
+	s.Pop()
+	s = op.Push(ops)
+	key.SoftKeyboardOp{Show: false}.Add(ops)
+	key.InputOp{Tag: &handlers[3]}.Add(ops)
+	// FocusOp must not overwrite the
+	// FocusOp{Focus: true}.
+	key.FocusOp{Focus: false}.Add(ops)
+	s.Pop()
+
+	r.Frame(ops)
+
+	assertKeyEvent(t, r.Events(&handlers[0]), false)
+	assertKeyEvent(t, r.Events(&handlers[1]), true)
+	assertKeyEvent(t, r.Events(&handlers[2]), false)
+	assertKeyEvent(t, r.Events(&handlers[3]), false)
+	assertFocus(t, r, &handlers[1])
+	assertKeyboard(t, r, TextInputOpen)
+}
+
+func TestKeySoftKeyboardNoFocus(t *testing.T) {
+	ops := new(op.Ops)
+	r := new(Router)
+
+	// It's possible to open the keyboard
+	// without any active focus:
+	key.SoftKeyboardOp{Show: true}.Add(ops)
+
+	r.Frame(ops)
+
+	assertFocus(t, r, nil)
+	assertKeyboard(t, r, TextInputOpen)
+}
+
+func TestKeyRemoveFocus(t *testing.T) {
+	handlers := make([]int, 2)
+	ops := new(op.Ops)
+	r := new(Router)
+
+	// New InputOp with Focus and Keyboard:
+	s := op.Push(ops)
+	key.InputOp{Tag: &handlers[0]}.Add(ops)
+	key.FocusOp{Focus: true}.Add(ops)
+	key.SoftKeyboardOp{Show: true}.Add(ops)
+	s.Pop()
+
+	// New InputOp without any focus:
+	s = op.Push(ops)
+	key.InputOp{Tag: &handlers[1]}.Add(ops)
+	s.Pop()
+
+	r.Frame(ops)
+
+	// Add some key events:
+	event := event.Event(key.Event{Name: key.NameTab, Modifiers: key.ModShortcut, State: key.Press})
+	r.Add(event)
+
+	assertKeyEvent(t, r.Events(&handlers[0]), true, event)
+	assertKeyEvent(t, r.Events(&handlers[1]), false)
+	assertFocus(t, r, &handlers[0])
+	assertKeyboard(t, r, TextInputOpen)
+
+	ops.Reset()
+
+	// Will get the focus removed:
+	s = op.Push(ops)
+	key.InputOp{Tag: &handlers[0]}.Add(ops)
+	s.Pop()
+
+	// Unchanged:
+	s = op.Push(ops)
+	key.InputOp{Tag: &handlers[1]}.Add(ops)
+	s.Pop()
+
+	// Removing any Focus:
+	s = op.Push(ops)
+	key.FocusOp{Focus: false}.Add(ops)
+	s.Pop()
+
+	r.Frame(ops)
+
+	assertKeyEvent(t, r.Events(&handlers[0]), false)
+	assertKeyEventUnexpected(t, r.Events(&handlers[1]))
+	assertFocus(t, r, nil)
+	assertKeyboard(t, r, TextInputClose)
+
+	ops.Reset()
+
+	s = op.Push(ops)
+	key.InputOp{Tag: &handlers[0]}.Add(ops)
+	s.Pop()
+
+	// Setting Focus without InputOp:
+	s = op.Push(ops)
+	key.FocusOp{Focus: true}.Add(ops)
+	s.Pop()
+
+	s = op.Push(ops)
+	key.InputOp{Tag: &handlers[1]}.Add(ops)
+	s.Pop()
+
+	r.Frame(ops)
+
+	assertKeyEventUnexpected(t, r.Events(&handlers[0]))
+	assertKeyEventUnexpected(t, r.Events(&handlers[1]))
+	assertFocus(t, r, nil)
+	assertKeyboard(t, r, TextInputKeep)
+
+	ops.Reset()
+
+	// Set focus to InputOp which already
+	// exists in the previous frame:
+	s = op.Push(ops)
+	key.FocusOp{Focus: true}.Add(ops)
+	key.InputOp{Tag: &handlers[0]}.Add(ops)
+	key.SoftKeyboardOp{Show: true}.Add(ops)
+	s.Pop()
+
+	// Tries to remove focus:
+	// It must not overwrite the previous `FocusOp`.
+	s = op.Push(ops)
+	key.InputOp{Tag: &handlers[1]}.Add(ops)
+	key.FocusOp{Focus: false}.Add(ops)
+	s.Pop()
+
+	r.Frame(ops)
+
+	assertKeyEvent(t, r.Events(&handlers[0]), true)
+	assertKeyEventUnexpected(t, r.Events(&handlers[1]))
+	assertFocus(t, r, &handlers[0])
+	assertKeyboard(t, r, TextInputOpen)
+}
+
+func TestKeyFocusedInvisible(t *testing.T) {
+	handlers := make([]int, 2)
+	ops := new(op.Ops)
+	r := new(Router)
+
+	// Set new InputOp with focus:
+	s := op.Push(ops)
+	key.FocusOp{Focus: true}.Add(ops)
+	key.InputOp{Tag: &handlers[0]}.Add(ops)
+	key.SoftKeyboardOp{Show: true}.Add(ops)
+	s.Pop()
+
+	// Set new InputOp without focus:
+	s = op.Push(ops)
+	key.InputOp{Tag: &handlers[1]}.Add(ops)
+	s.Pop()
+
+	r.Frame(ops)
+
+	assertKeyEvent(t, r.Events(&handlers[0]), true)
+	assertKeyEvent(t, r.Events(&handlers[1]), false)
+	assertFocus(t, r, &handlers[0])
+	assertKeyboard(t, r, TextInputOpen)
+
+	ops.Reset()
+
+	//
+	// Removed first (focused) element!
+	//
+
+	// Unchanged:
+	s = op.Push(ops)
+	key.InputOp{Tag: &handlers[1]}.Add(ops)
+	s.Pop()
+
+	r.Frame(ops)
+
+	assertKeyEventUnexpected(t, r.Events(&handlers[0]))
+	assertKeyEventUnexpected(t, r.Events(&handlers[1]))
+	assertFocus(t, r, nil)
+	assertKeyboard(t, r, TextInputClose)
+
+	ops.Reset()
+
+	// Respawn the first element:
+	// It must receive one `Event{Focus: false}`.
+	s = op.Push(ops)
+	key.InputOp{Tag: &handlers[0]}.Add(ops)
+	s.Pop()
+
+	// Unchanged
+	s = op.Push(ops)
+	key.InputOp{Tag: &handlers[1]}.Add(ops)
+	s.Pop()
+
+	r.Frame(ops)
+
+	assertKeyEvent(t, r.Events(&handlers[0]), false)
+	assertKeyEventUnexpected(t, r.Events(&handlers[1]))
+	assertFocus(t, r, nil)
+	assertKeyboard(t, r, TextInputKeep)
+
+}
+
+func assertKeyEvent(t *testing.T, events []event.Event, expected bool, expectedInputs ...event.Event) {
+	t.Helper()
+	var evtFocus int
+	var evtKeyPress int
+	for _, e := range events {
+		switch ev := e.(type) {
+		case key.FocusEvent:
+			if ev.Focus != expected {
+				t.Errorf("focus is expected to be %v, got %v", expected, ev.Focus)
+			}
+			evtFocus++
+		case key.Event, key.EditEvent:
+			if len(expectedInputs) <= evtKeyPress {
+				t.Errorf("unexpected key events")
+			}
+			if !reflect.DeepEqual(ev, expectedInputs[evtKeyPress]) {
+				t.Errorf("expected %v events, got %v", expectedInputs[evtKeyPress], ev)
+			}
+			evtKeyPress++
+		}
+	}
+	if evtFocus <= 0 {
+		t.Errorf("expected focus event")
+	}
+	if evtFocus > 1 {
+		t.Errorf("expected single focus event")
+	}
+	if evtKeyPress != len(expectedInputs) {
+		t.Errorf("expected key events")
+	}
+}
+
+func assertKeyEventUnexpected(t *testing.T, events []event.Event) {
+	t.Helper()
+	var evtFocus int
+	for _, e := range events {
+		switch e.(type) {
+		case key.FocusEvent:
+			evtFocus++
+		}
+	}
+	if evtFocus > 1 {
+		t.Errorf("unexpected focus event")
+	}
+}
+
+func assertFocus(t *testing.T, router *Router, expected event.Tag) {
+	t.Helper()
+	if router.kqueue.focus != expected {
+		t.Errorf("expected %v to be focused, got %v", expected, router.kqueue.focus)
+	}
+}
+
+func assertKeyboard(t *testing.T, router *Router, expected TextInputState) {
+	t.Helper()
+	if router.kqueue.state != expected {
+		t.Errorf("expected %v keyboard, got %v", expected, router.kqueue.state)
+	}
+}

widget/editor.go

@@ -399,7 +399,11 @@ func (e *Editor) layout(gtx layout.Context) layout.Dimensions {
 		e.shapes = append(e.shapes, line{off, path})
 	}
 
-	key.InputOp{Tag: &e.eventKey, Focus: e.requestFocus}.Add(gtx.Ops)
+	key.InputOp{Tag: &e.eventKey}.Add(gtx.Ops)
+	if e.requestFocus {
+		key.FocusOp{Focus: true}.Add(gtx.Ops)
+		key.SoftKeyboardOp{Show: true}.Add(gtx.Ops)
+	}
 	e.requestFocus = false
 	pointerPadding := gtx.Px(unit.Dp(4))
 	r := image.Rectangle{Max: e.viewSize}