Custom UI to change a Keymap in addon's preferences : "preferences.keyitem_restore" is grayed out

Coding Python Support
1

Hello,

I’m trying to write a template for specific keymaps to let the user change the shortcuts similarly to Blender’s way, but in the addon’s preferences UI.
Here I list the specific keymaps by their idnames. When the shortcut is not changed, there is a box that appears (placeholder to prevent them from deleting the keymap from the addon’s preferences. But if they change it, it becomes a Restore button. And my problem is that this line row.operator("preferences.keyitem_restore", text="", icon = "BACK").item_id = kmi.id is grayed out, and I don’t understand what’s missing?

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class Addon_Keymaps_Items(Operator):
    bl_idname = "addon_keymaps_items.keymap_template"
    bl_label = "Keymap Item Test"
    bl_options = {'REGISTER', 'UNDO'}
    
    def draw(self, context):
        layout = self.layout
        layout.ui_units_x = 30.0
        layout.label(text = "TEST PANEL", icon = "MENU_PANEL")

        wm = context.window_manager
        kc = wm.keyconfigs.user
        
        if kc:
            for km in kc.keymaps:
                for kmi in km.keymap_items:
                    if (kmi.idname == 'wm.call_menu' and kmi.properties.name == 'TOPBAR_MT_file_new' or
                        kmi.idname == 'wm.open_mainfile' or
                        kmi.idname == 'wm.save_mainfile'):

                        col = layout.column(align=True)
                        box = col.box()

                        split = box.split()
                        row = split.row(align=True)
                        row.prop(kmi, "show_expanded", text="", emboss=False)
                        row.prop(kmi, "active", text="", emboss=False)
                        row.label(text=kmi.name)

                        row = split.row()
                        row.prop(kmi, "map_type", text="")
                        row.prop(kmi, "type", text="", full_event=True)
                        if (not kmi.is_user_defined) and kmi.is_user_modified:
                            row.operator("preferences.keyitem_restore", text="", icon = "BACK").item_id = kmi.id
                        else:
                            box = row.box()
                            box.scale_x = 0.75
                            box.scale_y = 0.55
                            box.label(text = "", icon = "BLANK1")
2

Upon further investigation, I think it might be grayed out because it’s failing a poll().

So I looked at Blender’s implementation of the preferences.keyitem_restore:

class PREFERENCES_OT_keyitem_restore(Operator):
    """Restore key map item"""
    bl_idname = "preferences.keyitem_restore"
    bl_label = "Restore Key Map Item"

    item_id: IntProperty(
        name="Item Identifier",
        description="Identifier of the item to restore",
    )

    @classmethod
    def poll(cls, context):
        keymap = getattr(context, "keymap", None)
        return keymap

    def execute(self, context):
        km = context.keymap
        kmi = km.keymap_items.from_id(self.item_id)

        if (not kmi.is_user_defined) and kmi.is_user_modified:
            km.restore_item_to_default(kmi)

        return {'FINISHED'}

Does anyone have an idea of what exactly it is failing?

3

in the context you’re in, there is no ‘keymap’ attribute. either override the context or find the keymap manually in the window manager object.

4

Just before your row.operator(...) try something like row.context_pointer_set("keymap", km) ?

5

I solved the issue like this, by implementing another class and having this km.restore_item_to_default(kmi) being responsible for restoring the item. But it would have been better to be able to spare a class just to use that.

def filter_keymap_items(kmi):
    return (
	kmi.idname == 'wm.call_menu' and kmi.properties.name == 'TOPBAR_MT_file_new' or
        kmi.idname == 'wm.open_mainfile' or
        kmi.idname == 'wm.save_mainfile'
    )

And the execute method of the class:

    def execute(self, context):
        wm = context.window_manager
        kc = wm.keyconfigs.user

        if kc:
            for km in kc.keymaps:
                for kmi in filter(filter_keymap_items, km.keymap_items):
                    km.restore_item_to_default(kmi)
        
        return {'FINISHED'}

@Gorgious
I couldn’t make it work with what you proposed.