title: Show/Hide fields on One2many tree - Odoo v8
body: <p>I have some fields I'm showing in my <code>One2many</code> tree view:</p>
  
  <pre><code>  &lt;page string="Budget Lines Planned"&gt;
              &lt;field name="account_budget_bsi_line" colspan="4" nolabel="1" attrs="{'readonly':[('state','!=','draft')]}"&gt;
                  &lt;tree string="Budget Lines Planned" editable="bottom" &gt;
                      &lt;field name="opening_stock"/&gt;
                      &lt;field name="sales_planned" /&gt;
                      &lt;field name="amount_total"/&gt;
                      &lt;field name="interauxiliary_transfers_planned" /&gt;
                      &lt;field name="interauxiliary_receipts_planned" /&gt;
                      &lt;field name="prod_purchased_planned" /&gt;
                      &lt;field name="closing_stock_planned" /&gt;
                  &lt;/tree&gt;
              &lt;/field&gt;
      &lt;/page&gt;
  </code></pre>
  
  <p>This is from a custom module, which has a workflow with states, ie: <code>draft, approved, next, done</code> etc.</p>
  
  <p>Suppose on <code>next</code> state, I want to hide <code>opening_stock</code> field, and show some other field.</p>
  
  <p>I know this can be achieved on forms by using <code>attrs="{'readonly':[('state','!=','draft')]}"</code> or invisible or whatever.</p>
  
  <p>But doesn't seem to work on <code>One2many</code> tree views, so, how can I achieve that in this case?</p>