Set focus on Extjs textfield

Question

Currently I got problem with setting focus on extjs textfield. When form show, I want to set focus to First name text box and I try to use build in function focus() but stil

Answer 1

You should use "afterrender" event for your textfield if you want to set focus after form is rendered.

    {
        fieldLabel: 'First Name',
        name: 'first',
        id: 'first_name',
        allowBlank: false,
        listeners: {
          afterrender: function(field) {
            field.focus();
          }
        }
    }