Allow other libs/apps to interact with the container-ish items Split …

…and Scroll

Simplify for now by adding Stack container as a child in every drop spot.

internal/guidefs/widget.go

@@ -762,7 +762,7 @@ func initWidgets() {
 				split.Refresh()
 			},
 			Create: func() fyne.CanvasObject {
-				return container.NewScroll(&dropZone{})
+				return container.NewScroll(container.NewStack())
 			},
 			Edit: func(obj fyne.CanvasObject, props map[string]string) []*widget.FormItem {
 				return []*widget.FormItem{}
@@ -789,15 +789,13 @@ func initWidgets() {
 				split := parent.(*container.Split)
 				if split.Leading == nil {
 					split.Leading = o
-				} else if _, ok := split.Leading.(*dropZone); ok {
-					split.Leading = o
 				} else {
 					split.Trailing = o
 				}
 				split.Refresh()
 			},
 			Create: func() fyne.CanvasObject {
-				return container.NewHSplit(container.NewStack(), container.NewStack()) //&dropZone{}, &dropZone{})
+				return container.NewHSplit(container.NewStack(), container.NewStack())
 			},
 			Edit: func(obj fyne.CanvasObject, _ map[string]string) []*widget.FormItem {
 				split := obj.(*container.Split)
@@ -866,7 +864,3 @@ func InitOnce() {
 		initWidgets()
 	})
 }
-
-type dropZone struct {
-	canvas.Rectangle
-}

pkg/gui/widget.go

@@ -1,9 +1,25 @@
 package gui
 
-import "github.com/fyne-io/defyne/internal/guidefs"
+import (
+	"reflect"
+
+	"fyne.io/fyne/v2"
+	"github.com/fyne-io/defyne/internal/guidefs"
+)
 
 // WidgetClassList returns the list of supported widget & container classes.
 // These can be used for passing to `CreateNew` or `EditorFor`.
 func WidgetClassList() []string {
 	return guidefs.WidgetNames
 }
+
+func DropZonesForObject(o fyne.CanvasObject) []fyne.CanvasObject {
+	class := reflect.TypeOf(o).String()
+	info := guidefs.Widgets[class]
+
+	if !info.IsContainer() {
+		return nil
+	}
+
+	return info.Children(o)
+}