Hello everyone, I create a custom widget, then I set it for a field () in formview ,widget show in form, but however when I save form , I can not update value in that field , It still get old value.

Here is my js code

odoo.define('my_widget.rule_widget', function (require) {
'use strict'; 
var basic_fields = require('web.basic_fields'); 
var core = require('web.core'); 
var field_registry = require('web.field_registry'); var _t = core._t;
var RuleWidget = basic_fields.FieldChar.extend({ 
    template: 'RuleWidget', 
    events: { 'click .btn_setting': '_onClickSetting', }, 
    start: function () { 
        return this._super.apply(this, arguments); 
    },
    _render: function () { 
        this._super.apply(this, arguments);
    },
     _onClickSetting: function () { 
        this.do_action({ 
            name: 'Setting Rule', 
            type: 'ir.actions.act_window', 
            res_model: 'wizard.rule', 
            target: 'new', 
            views: [[false, 'form']], 
        }); 
    },
}); 
field_registry.add('rule', RuleWidget)
xml code
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