form-generator动态设置schema的时候，中间的可视区没有绘制对应的表单

[yuluojun]

通过useState设置form-generator schema的时候，中间的可视区并没有绘制对应的表单。代码如下：
`import React, { memo, useEffect, useRef, useState } from 'react';
import DripFormGenerator from '@jdfed/form-generator';
import '@jdfed/form-generator/dist/index.css';

const Edit = memo(() => {
const generatorRef = useRef();
const [schema, setSchema] = useState({});

useEffect(() => {
const schemaJson = {
type: 'object',
validateTime: 'change',
ui: {
containerStyle: {
width: '33%',
padding: '0 10px 0 0',
},
},
theme: 'antd',
schema: [
{
type: 'array',
title: '多选框',
ui: {
type: 'checkbox',
theme: 'antd',
},
fieldKey: 'checkbox_ZkO_mT',
},
{
type: ['string', 'number', 'array'],
title: '选择器',
ui: {
type: 'select',
theme: 'antd',
style: {
width: 120,
},
options: [],
},
fieldKey: 'select_M0AZMz',
},
{
type: 'string',
title: '输入框',
ui: {
type: 'text',
style: {
width: '100%',
},
theme: 'antd',
},
fieldKey: 'text_HYrE2k',
},
{
type: 'array',
title: '级联选择',
ui: {
type: 'cascader',
theme: 'antd',
},
fieldKey: 'cascader_j2ndy2',
},
{
type: 'string',
title: '时间选择框',
ui: {
type: 'timePicker',
theme: 'antd',
},
fieldKey: 'timePicker_y9cE6R',
},
{
type: 'number',
title: '滑动输入条',
ui: {
type: 'slider',
theme: 'antd',
},
fieldKey: 'slider_a-imkw',
},
],
};
generatorRef.current = schemaJson;
const newSchema = { ...generatorRef.current };
setSchema(newSchema);
});

return (

{console.log('schema->', schema)}

);
});

Edit.displayName = 'GeneratorApp';

export default Edit;
`

[yuluojun]

[mengshang918]

参考#272