Hi, I need to add a button to a row in tree view to change the state, how can I achieve it?

I'm adding the button directly like this:
​

<record id="view_xxx_tree" model="ir.ui.view">
<field name="name">xxx.tree</field>
<field name="model">xxx</field>
<field name="arch" type="xml">

<tree decoration-info="state=='draft'" name="appointment_tree">
<field name="sequence" widget="handle"/>
<field name="name" string="Name"/>
<field name="patient_id"/>
<field name="date"/>
<field name="responsible_id" invisible="1"/>
<field name="create_uid"/>

<field name="state"/>

<button name="draft" type="object" string="Draft" class="oe_highlight"/>

</tree>
</field>

</record>​

but it's not showing on the tree view