[internal/driver/mobile] fix absolute position computation for padded…

… child windows

This led to misplaced pop-ups.

internal/driver/mobile/driver.go

@@ -123,11 +123,8 @@ func (d *mobileDriver) AbsolutePositionForObject(co fyne.CanvasObject) fyne.Posi
 	pos := driver.AbsolutePositionForObject(co, mc.ObjectTrees())
 	inset, _ := c.InteractiveArea()
 
-	if mc.windowHead != nil {
-		if len(mc.windowHead.(*fyne.Container).Objects) > 1 {
-			topHeight := mc.windowHead.MinSize().Height
-			pos = pos.Subtract(fyne.NewSize(0, topHeight))
-		}
+	if chromeBoxOffset := mc.chromeBoxVerticalOffset(); chromeBoxOffset > 0 {
+		pos = pos.SubtractXY(0, chromeBoxOffset)
 	}
 	return pos.Subtract(inset)
 }

internal/driver/mobile/driver_test.go

@@ -0,0 +1,82 @@
+package mobile
+
+import (
+	"image/color"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+
+	"fyne.io/fyne/v2"
+	"fyne.io/fyne/v2/canvas"
+	"fyne.io/fyne/v2/container"
+	"fyne.io/fyne/v2/widget"
+)
+
+func Test_mobileDriver_AbsolutePositionForObject(t *testing.T) {
+	for name, tt := range map[string]struct {
+		want          fyne.Position
+		windowIsChild bool
+		windowPadded  bool
+	}{
+		"for an unpadded primary (non-child) window it is (0,0)": {
+			want:          fyne.NewPos(0, 0),
+			windowIsChild: false,
+			windowPadded:  false,
+		},
+		"for a padded primary (non-child) window it is (padding,padding)": {
+			want:          fyne.NewPos(4, 4),
+			windowIsChild: false,
+			windowPadded:  true,
+		},
+		"for an unpadded child window it is (0,0)": {
+			want:          fyne.NewPos(0, 0),
+			windowIsChild: true,
+			windowPadded:  false,
+		},
+		"for a padded child window it is (padding,padding)": {
+			want:          fyne.NewPos(4, 4),
+			windowIsChild: true,
+			windowPadded:  true,
+		},
+	} {
+		t.Run(name, func(t *testing.T) {
+			var o fyne.CanvasObject
+			size := fyne.NewSize(100, 100)
+			d := &mobileDriver{}
+			w := d.CreateWindow("main")
+			w.SetPadded(tt.windowPadded)
+			l := widget.NewLabel("main window")
+			if !tt.windowIsChild {
+				o = l
+			}
+			w.SetContent(l)
+			w.Show()
+			w.Resize(size)
+			w = d.CreateWindow("child1")
+			w.SetContent(widget.NewLabel("first child"))
+			if tt.windowIsChild {
+				w.Show()
+			}
+			w.Resize(size)
+			w = d.CreateWindow("child2 - hidden")
+			w.SetContent(widget.NewLabel("second child"))
+			w.Resize(size)
+			w = d.CreateWindow("child3")
+			r := canvas.NewRectangle(color.White)
+			r.SetMinSize(fyne.NewSize(42, 17))
+			w.SetPadded(tt.windowPadded)
+			w.SetContent(container.NewVBox(r))
+			if tt.windowIsChild {
+				w.Show()
+				o = r
+			}
+			w.Resize(size)
+			w = d.CreateWindow("child4 - hidden")
+			w.SetContent(widget.NewLabel("fourth child"))
+			w.Resize(size)
+
+			got := d.AbsolutePositionForObject(o)
+			assert.Equal(t, tt.want, got)
+		})
+	}
+}