web/web_widget_color/static/src/xml/widget.xml

<?xml version="1.0" encoding="UTF-8"?>
<templates>
    <t t-name="FieldColor">
        <span t-att-class="'oe_form_field '+widget.widget_class" t-att-style="widget.node.attrs.style">
            <t t-if="!widget.get('effective_readonly')">
                <input type="text"
                       t-att-id="widget.id_for_label"
                       t-att-tabindex="widget.node.attrs.tabindex"
                       t-att-autofocus="widget.node.attrs.autofocus"
                       t-att-placeholder="widget.node.attrs.placeholder"
                       t-att-maxlength="widget.field.size"
                       class="color {hash:true, required:false}"
                        />
            </t>
            <t t-if="widget.get('effective_readonly')">
                <div/>
                <span class="oe_form_char_content"></span>
            </t>
        </span>
    </t>
    <tr t-extend="ListView.row">
        <t t-jquery="t td t" t-operation="replace"><t t-if="column.widget =='color' || column.type == 'color'"><div class="color_box" t-att-style="'background-color:' + render_cell(record, column)"/></t><t t-raw="render_cell(record, column)"/></t>
    </tr>
</templates>