Can't get List.FocusGained to work...

[bobhibberdine2]

Hello,
I am a newcomer to Fyne and currently feeling my way through the library as I write a small application.
My problem is that I cannot get the FocusGained() to work on a Lisit widget.
I have tried to extend the List as per the docs but nothing happens.
Here is the code:

package main

import (
	"fmt"
	"fyne.io/fyne/v2"
	"fyne.io/fyne/v2/app"
	"fyne.io/fyne/v2/container"
	"fyne.io/fyne/v2/driver/desktop"
	"fyne.io/fyne/v2/widget"
)

type MyList struct {
  widget.List
}

func newMyList(length func() int, createItem func() fyne.CanvasObject, updateItem func(id widget.ListItemID, item fyne.CanvasObject)) *MyList {
	l := &MyList{}
	l.Length = length
	l.CreateItem = createItem
	l.UpdateItem = updateItem
	l.ExtendBaseWidget(l)
	return l
}

func (l *MyList) FocusGained() {
	l.List.FocusGained()
	
       fmt.Println("FocusGained")
}

func main() {
	app := app.New()
	win := app.NewWindow("FOCUS")

	desk, ok := app.Driver().(desktop.Driver)
	if !ok {
		panic("could not get desktop-driver for app!")
	}

	data := []string{"one", "two", "three"}

	l := newMyList(
		func() int {
			return len(data)
		},
		func() fyne.CanvasObject {
			return widget.NewLabel("template")
		},
		func(id widget.ListItemID, o fyne.CanvasObject) {
			o.(*widget.Label).SetText(data[id])
		},
	)
	l.OnSelected = func(id widget.ListItemID) {
		modifiers := desk.CurrentKeyModifiers()
		fmt.Println("Selected ", data[id], modifiers)
	}


	c := container.NewBorder(nil, nil, nil, nil,l,)

	win.SetContent(c)
	win.CenterOnScreen()
	win.Resize(fyne.NewSize(1024, 760))
	win.ShowAndRun()
}

Currently the list "works"; it does the println in OnSelelected() but the println in FocusGained() never gets called...

I think I am missing something fundamental here :-)..
Hope some one can help.
Thanks
Bob

[andydotxyz]

How are you focusing the list to determine whether or not the focus callbacks are working?

[bobhibberdine2]

With the mouse. I am assuming that when the item is highlighted it has focus.
Of course that assumption may be completely wrong :-)

[bobhibberdine2]

How would you suggest I focus the list?
I ask because it's just occurred to me that may be the highlighted item does not indicate that the list has focus...

[andydotxyz]

It seems to relate to the extended list somehow - it works on a basic list but when extended the tap won't focus it, but then tapping "Tab" will (not the expected behaviour)

[andydotxyz]

Yes, you have found a bug in List.

I think this fixes it (we will need to check other collection widgets too)

--- a/widget/list.go
+++ b/widget/list.go
@@ -697,9 +697,9 @@ func (l *listLayout) setupListItem(li *listItem, id ListItemID, focus bool) {
        }
        li.onTapped = func() {
                if !fyne.CurrentDevice().IsMobile() {
-                       canvas := fyne.CurrentApp().Driver().CanvasForObject(l.list)
+                       canvas := fyne.CurrentApp().Driver().CanvasForObject(l.list.super())
                        if canvas != nil {
-                               canvas.Focus(l.list.impl.(fyne.Focusable))
+                               canvas.Focus(l.list.super().(fyne.Focusable))
                        }

[andydotxyz]

Moved to issue #5997

[bobhibberdine2]

Thank you for your swift response. I can confirm that this fix to the List widget made the function, func (l *MyList) FocusGained() in the code above, work.
Thanks again for that!

However, your fix showed that I was mistaken about FocusGained in the context of a List. What I actually want is to know when a List item gets Highlighted_ not Selected.
So, if you show a basic List, without any extensions, and you just move the mouse pointer down through the List items, the background colour of the item changes as the mouse pointer hovers over that item.
Is there any method / callback that lets me know when that happens?

[andydotxyz]

I guess you are looking for the recent List.OnHighlighted callback #5961 - you can use this by upgrading to version develop or using the SHA in the version instead.

[bobhibberdine2]

Yes, I have just seen the new Fyne collection items demo which has all this and more!
I will download the develop version and play...
Thanks alot for all your work...

[bobhibberdine2]

Well, that is the perfect demo for my use case. The OnHighlighted callback is also perfect!
Thanks...

[bobhibberdine2]

Forgot to leave a link the the demo mentioned above:

https://github.com/coolapso/fyne-collection-highlight-hover-demo/

[bobhibberdine2]

And finally :-)

You need to apply the patch supplied by Andy above for TypedKey event to work as expected i the demo