I create a status bar for a model but view field does not load properly. (odoo v12)

the below code only shows the text of the current set status. But with the same set of code i'm able to load all the status properly in a different model.

i'm unable to paste the image here, to show the actual result. need help for that too.

python: 

status = fields.Selection([
    ('draft', 'Draft'),
    ('posted', 'Posted'),
    ('active', 'Active'),
    ('closed', 'Closed'),],string='Status Type', required = True,default = 'draft')

xml:

<field name="status" widget="statusbar" options="{'fold_field': 'fold'}" readonly="1"/>