[IMP] base,mail: allow to customize the activity view

The activity view has been greatly improved to allow to customize it
more easily. It works quite similarly to the kanban view, defining
`<field>` tags at the top and using these fields in the `<template>`
section. The template name used to define the activity cards is
`activity-box`.

Note that these activity cards are rendered using `KanbanRecord` widget
(this has implied that ActivityView inherits from `BasicView`).

Also note that the view validation has been moved in base to include the
common grammar.

Task 1894990

1 files changed, 19 insertions, 0 deletions

diff --git a/addons/mail/models/models.py b/addons/mail/models/models.py
new file mode 100644
index 00000000000..4c85b08d2af
--- /dev/null
+++ b/addons/mail/models/models.py
@@ -0,0 +1,19 @@
+# -*- coding: utf-8 -*-
+from odoo import models, api
+from lxml.builder import E
+
+
+class BaseModel(models.AbstractModel):
+    _inherit = 'base'
+
+    @api.model
+    def _get_default_activity_view(self):
+        """ Generates an empty activity view.
+
+        :returns: a activity view as an lxml document
+        :rtype: etree._Element
+        """
+        field = E.field(name=self._rec_name_fallback())
+        activity_box = E.div(field, {'t-name': "activity-box"})
+        templates = E.templates(activity_box)
+        return E.activity(templates, string=self._description)