Ensure that popups and menus fit within the screen bounds for mobile …

…devices

Fixes fyne-io#1358

driver/mobile/device.go

@@ -1,8 +1,13 @@
 // Package mobile provides mobile specific driver functionality.
 package mobile
 
+import "fyne.io/fyne"
+
 // Device describes functionality only available on mobile
 type Device interface {
+	// ScreenInsets returns the space around a mobile screen that should not be drawn used for interactive elements
+	ScreenInsets() (topLeft, bottomRight fyne.Size)
+
 	// Request that the mobile device show the touch screen keyboard (standard layout)
 	ShowVirtualKeyboard()
 	// Request that the mobile device show the touch screen keyboard (custom layout)

internal/driver/glfw/canvas.go

@@ -602,6 +602,7 @@ func newCanvas() *glCanvas {
 	c.overlays = &overlayStack{
 		OverlayStack: internal.OverlayStack{
 			OnChange: c.overlayChanged,
+			Canvas:   c,
 		},
 	}
 

internal/driver/gomobile/canvas.go

@@ -85,25 +85,16 @@ func (c *mobileCanvas) Refresh(obj fyne.CanvasObject) {
 	}
 }
 
-func (c *mobileCanvas) edgePadding() (topLeft, bottomRight fyne.Size) {
-	scale := fyne.CurrentDevice().SystemScaleForWindow(nil) // we don't need a window parameter on mobile
-
-	dev, ok := fyne.CurrentDevice().(*device)
-	if !ok {
-		return fyne.NewSize(0, 0), fyne.NewSize(0, 0) // running in test mode
-	}
-
-	return fyne.NewSize(int(float32(dev.insetLeft)/scale), int(float32(dev.insetTop)/scale)),
-		fyne.NewSize(int(float32(dev.insetRight)/scale), int(float32(dev.insetBottom)/scale))
-}
-
 func (c *mobileCanvas) sizeContent(size fyne.Size) {
 	if c.content == nil { // window may not be configured yet
 		return
 	}
 
 	offset := fyne.NewPos(0, 0)
-	devicePadTopLeft, devicePadBottomRight := c.edgePadding()
+	devicePadTopLeft, devicePadBottomRight := fyne.Size{}, fyne.Size{}
+	if dev, ok := fyne.CurrentDevice().(mobile.Device); ok { // not present in testing
+		devicePadTopLeft, devicePadBottomRight = dev.ScreenInsets()
+	}
 
 	if c.windowHead != nil {
 		topHeight := c.windowHead.MinSize().Height
@@ -519,7 +510,7 @@ func NewCanvas() fyne.Canvas {
 	ret.lastTapDownPos = make(map[int]fyne.Position)
 	ret.lastTapDown = make(map[int]time.Time)
 	ret.minSizeCache = make(map[fyne.CanvasObject]fyne.Size)
-	ret.overlays = &internal.OverlayStack{}
+	ret.overlays = &internal.OverlayStack{Canvas: ret}
 
 	ret.setupThemeListener()
 

internal/driver/gomobile/device.go

@@ -20,6 +20,18 @@ var (
 // Declare conformity with Device
 var _ fyne.Device = (*device)(nil)
 
+func (*device) ScreenInsets() (topLeft, bottomRight fyne.Size) {
+	scale := fyne.CurrentDevice().SystemScaleForWindow(nil) // we don't need a window parameter on mobile
+
+	dev, ok := fyne.CurrentDevice().(*device)
+	if !ok {
+		return fyne.NewSize(0, 0), fyne.NewSize(0, 0) // running in test mode
+	}
+
+	return fyne.NewSize(int(float32(dev.insetLeft)/scale), int(float32(dev.insetTop)/scale)),
+		fyne.NewSize(int(float32(dev.insetRight)/scale), int(float32(dev.insetBottom)/scale))
+}
+
 func (*device) Orientation() fyne.DeviceOrientation {
 	switch currentOrientation {
 	case size.OrientationLandscape:

internal/driver/gomobile/menu.go

@@ -59,7 +59,10 @@ func (c *mobileCanvas) showMenu(menu *fyne.MainMenu) {
 	shadow := canvas.NewHorizontalGradient(theme.ShadowColor(), color.Transparent)
 	c.menu = fyne.NewContainer(panel, shadow)
 
-	devicePadTopLeft, devicePadBottomRight := c.edgePadding()
+	devicePadTopLeft, devicePadBottomRight := fyne.Size{}, fyne.Size{}
+	if dev, ok := fyne.CurrentDevice().(*device); ok { // not present in testing
+		devicePadTopLeft, devicePadBottomRight = dev.ScreenInsets()
+	}
 	padY := devicePadTopLeft.Height + devicePadBottomRight.Height
 	panel.Move(fyne.NewPos(devicePadTopLeft.Width, devicePadTopLeft.Height))
 	panel.Resize(fyne.NewSize(panel.MinSize().Width+theme.Padding(), c.size.Height-padY))

internal/overlay_stack.go

@@ -4,12 +4,15 @@ import (
 	"sync"
 
 	"fyne.io/fyne"
+	"fyne.io/fyne/driver/mobile"
 	"fyne.io/fyne/internal/app"
+	"fyne.io/fyne/internal/widget"
 )
 
 // OverlayStack implements fyne.OverlayStack
 type OverlayStack struct {
 	OnChange      func()
+	Canvas        fyne.Canvas
 	focusManagers []*app.FocusManager
 	overlays      []fyne.CanvasObject
 	propertyLock  sync.RWMutex
@@ -28,6 +31,20 @@ func (s *OverlayStack) Add(overlay fyne.CanvasObject) {
 		return
 	}
 	s.overlays = append(s.overlays, overlay)
+
+	devicePadTopLeft, devicePadBottomRight := fyne.Size{}, fyne.Size{}
+	if dev, ok := fyne.CurrentDevice().(mobile.Device); ok { // not present in testing
+		devicePadTopLeft, devicePadBottomRight = dev.ScreenInsets()
+	}
+	innerSize := s.Canvas.Size().Subtract(devicePadTopLeft).Subtract(devicePadBottomRight)
+	topLeft := fyne.NewPos(devicePadTopLeft.Width, devicePadTopLeft.Height)
+
+	// TODO this should probably apply to all once #707 is addressed
+	if _, ok := overlay.(*widget.OverlayContainer); ok {
+		overlay.Resize(innerSize)
+		overlay.Move(topLeft)
+	}
+
 	s.focusManagers = append(s.focusManagers, app.NewFocusManager(overlay))
 	if s.OnChange != nil {
 		s.OnChange()

internal/overlay_stack_test.go

@@ -7,11 +7,12 @@ import (
 
 	"fyne.io/fyne"
 	"fyne.io/fyne/internal"
+	"fyne.io/fyne/test"
 	"fyne.io/fyne/widget"
 )
 
 func TestOverlayStack(t *testing.T) {
-	s := &internal.OverlayStack{}
+	s := &internal.OverlayStack{Canvas: test.NewCanvas()}
 	o1 := widget.NewLabel("A")
 	o2 := widget.NewLabel("B")
 	o3 := widget.NewLabel("C")

test/testcanvas.go

@@ -55,13 +55,14 @@ func Canvas() fyne.Canvas {
 
 // NewCanvas returns a single use in-memory canvas used for testing
 func NewCanvas() WindowlessCanvas {
-	return &testCanvas{
+	c := &testCanvas{
 		focusMgr: app.NewFocusManager(nil),
-		overlays: &internal.OverlayStack{},
 		padded:   true,
 		scale:    1.0,
 		size:     fyne.NewSize(10, 10),
 	}
+	c.overlays = &internal.OverlayStack{Canvas: c}
+	return c
 }
 
 // NewCanvasWithPainter allows creation of an in-memory canvas with a specific painter.

widget/menu.go

@@ -3,6 +3,7 @@ package widget
 import (
 	"fyne.io/fyne"
 	"fyne.io/fyne/canvas"
+	"fyne.io/fyne/driver/mobile"
 	"fyne.io/fyne/internal/widget"
 	"fyne.io/fyne/layout"
 	"fyne.io/fyne/theme"
@@ -160,7 +161,12 @@ func (r *menuRenderer) Layout(s fyne.Size) {
 	scrollSize := boxSize
 	if c := fyne.CurrentApp().Driver().CanvasForObject(r.m); c != nil {
 		ap := fyne.CurrentApp().Driver().AbsolutePositionForObject(r.m)
-		if ah := c.Size().Height - ap.Y; ah < boxSize.Height {
+		bottomEdge := 0
+		if dev, ok := fyne.CurrentDevice().(mobile.Device); ok {
+			_, bottomRight := dev.ScreenInsets()
+			bottomEdge = bottomRight.Height
+		}
+		if ah := c.Size().Height - bottomEdge - ap.Y; ah < boxSize.Height {
 			scrollSize = fyne.NewSize(boxSize.Width, ah)
 		}
 	}