product_print_zpl_barcode: print multi labels at once

Print from product tree view and form view (product.product and product.template)
Print from done stock picking using must_print_barcode

product_print_zpl_barcode/models/__init__.py

@@ -1 +1,2 @@
 from . import product
+from . import stock_picking

product_print_zpl_barcode/models/product.py

@@ -29,22 +29,6 @@ class ProductTemplate(models.Model):
                 % (self.display_name, self.product_variant_count))
         return self.product_variant_ids[0].generate_barcode_from_product_product()
 
-    def print_zpl_barcode_from_product_template(self):
-        self.ensure_one()
-        if self.product_variant_count != 1:
-            raise UserError(_(
-                "You cannot call the method "
-                "print_zpl_barcode_from_product_template on product '%s' "
-                "because it has %d variants and not just one.")
-                % (self.display_name, self.product_variant_count))
-        action = self.env["ir.actions.actions"]._for_xml_id(
-            'product_print_zpl_barcode.product_print_zpl_barcode_action')
-        action['context'] = {
-            'active_id': self.product_variant_ids[0].id,
-            'active_model': 'product.product',
-            }
-        return action
-
 
 class ProductProduct(models.Model):
     _inherit = 'product.product'

product_print_zpl_barcode/models/stock_picking.py

@@ -0,0 +1,25 @@
+# Copyright 2023 Akretion France (http://www.akretion.com/)
+# @author: Alexis de Lattre <alexis.delattre@akretion.com>
+# License AGPL-3.0 or later (http://www.gnu.org/licenses/agpl).
+
+from odoo import api, fields, models
+from odoo.tools import float_compare
+
+
+class StockPicking(models.Model):
+    _inherit = "stock.picking"
+
+    show_print_zpl_barcode = fields.Boolean(compute='_compute_show_print_zpl_barcode')
+
+    @api.depends('state')
+    def _compute_show_print_zpl_barcode(self):
+        prec = self.env['decimal.precision'].precision_get('Product Unit of Measure')
+        for picking in self:
+            show = False
+            if picking.state == 'done' and picking.picking_type_code != 'outgoing':
+                for line in picking.move_line_ids:
+                    if (
+                            line.product_id.must_print_barcode and
+                            float_compare(line.qty_done, 0, precision_digits=prec) > 0):
+                        show = True
+            picking.show_print_zpl_barcode = show