i want hole checkbox like when i click one checkbox select all checkboxes.what you said is which one you want click one after one i wont like this

Ok, then you don't need to set any widget it's by default feature, you can select multiple records in many2many fields, if any records in relation table.

but the view is different it shows like table

i want in that particular field entering all the data at a time by cick checkboxes

Then you can do like:

<field name="many2many_field">

<tree>

<!-- Here you can use any sub field of many2many field table --!>

</tree>

</field>

not working

my dout is how to select all the values at a time that is i am asking in many2many