Let mobile form declare if/how to auto-focus a field

and for mobile ordering, auto-focus the "units" field when editing a row

tailbone/forms/core.py

@@ -330,7 +330,7 @@ class Form(object):
 
     def __init__(self, fields=None, schema=None, request=None, mobile=False, readonly=False, readonly_fields=[],
                  model_instance=None, model_class=None, nodes={}, enums={}, labels={}, renderers=None,
-                 hidden={}, widgets={}, defaults={}, validators={}, required={}, helptext={},
+                 hidden={}, widgets={}, defaults={}, validators={}, required={}, helptext={}, focus_spec=None,
                  action_url=None, cancel_url=None):
 
         self.fields = None
@@ -362,6 +362,7 @@ class Form(object):
         self.validators = validators or {}
         self.required = required or {}
         self.helptext = helptext or {}
+        self.focus_spec = focus_spec
         self.action_url = action_url
         self.cancel_url = cancel_url
 
@@ -717,6 +718,8 @@ class Form(object):
         # TODO: deprecate / remove the latter option here
         if self.auto_disable_save or self.auto_disable:
             context['form_kwargs']['class_'] = 'autodisable'
+        if self.focus_spec:
+            context['form_kwargs']['data-focus'] = self.focus_spec
         context['request'] = self.request
         context['readonly_fields'] = self.readonly_fields
         context['render_field_readonly'] = self.render_field_readonly