Magento – Magento 2 ui component form add extra input in the same admin field control

Try this code :-

$fieldset->addField(
            'sorting_order',
            'text',
            array(
                'name' => 'sorting_order',
                'label' => __('Sort Order'),
                'title' => __('Sort Order'),
                'required' => false,
                'class' => 'validate-number'
            )
);

The quick answer is Yes, everything is possible with UI Components because it's really flexible as its introductions.

Otherwise, I don't think depending/overriding on default UI element (like you mentioned in the post - ui-select) is a good idea. So, in this tutorial, I will create a new UI element for the tags. It could be use not only in product form but the cms page form or whatever depends on the UI forms.

Now let the fun begin!

Firstly, your ui_component form should looks like this

StackOverflow/Catalog/view/adminhtml/ui_component/product_form.xml

<field name="parent">
    <argument name="data" xsi:type="array">
        <item name="config" xsi:type="array">
            <item name="label" xsi:type="string" translate="true">Tags</item>
            <item name="componentType" xsi:type="string">field</item>
            <item name="formElement" xsi:type="string">input</item>
            <item name="component" xsi:type="string">StackOverflow_Catalog/js/form/element/tags</item>
            <item name="elementTmpl" xsi:type="string">StackOverflow_Catalog/form/element/tags</item>
            <item name="dataScope" xsi:type="string">data.parent</item>
            <item name="filterOptions" xsi:type="boolean">true</item>
            <item name="showCheckbox" xsi:type="boolean">false</item>
            <item name="disableLabel" xsi:type="boolean">true</item>
            <item name="levelsVisibility" xsi:type="number">1</item>
            <item name="sortOrder" xsi:type="number">20</item>
            <item name="required" xsi:type="boolean">true</item>
            <item name="validation" xsi:type="array">
                <item name="required-entry" xsi:type="boolean">true</item>
            </item>
            <item name="listens" xsi:type="array">
                <item name="${ $.namespace }.${ $.namespace }:responseData" xsi:type="string">setParsed</item>
            </item>
        </item>
    </argument>
</field>

Take a note to formElement, component and elementTmpl. It should be a normal input field.

Now, we need to create the view renderer for that UI element

StackOverflow/Catalog/view/base/web/js/form/element/tags.js

/**
 * StackOverflow Catalog.
 *
 * @category  Mage
 *
 * @author    Toan Nguyen <me@nntoan.com>
 * @copyright 2018 Toan Nguyen (https://nntoan.com)
 */
define([
    'underscore',
    'mageUtils',
    'Magento_Ui/js/form/element/abstract',
    'ko',
    'Magento_Ui/js/lib/validation/validator'
], function (_, utils, Element, ko, validator) {
    'use strict';

    return Element.extend({
        defaults: {
            list: ([]),
            valueUpdate: 'afterkeydown',
            listens: {
                'valueArea': 'onUpdateArea'
            }
        },

        initialize: function () {
            this._super();
            this.on('value', this.onUpdateArea.bind(this));
            var self = this;
            var list = this.value().split(',');
            _.each(list, function (value, index) {
                if (value.length > 0) {
                    self.list.push(value.trim());
                }
            });

            return this;
        },

        initObservable: function () {
            this._super();
            this.observe(['valueArea']);
            this.observe('list', this.list);
            return this;
        },

        onUpdateArea: function (value) {
            if (value.length > 1) {
                if (value.indexOf(',') !== -1 || value.indexOf(' ') !== -1) {
                    var newValue = value.slice(0, -1);
                    this.correctValue(newValue);
                }
            }
        },

        correctValue: function (tag) {
            if (this.hasTag(tag)) {
                this.valueArea('');
                return false;
            }
            if (this.isValidTag(tag).passed) {
                this.list.push(tag);
                this.joinList(this.list());
                this.valueArea('');
                return true;
            }

            return false;
        },

        isValidTag: function (tag) {
            return validator('validate-alphanum', tag);
        },

        OnBlurEvent: function (object) {
            if (this.valueArea() && this.valueArea().length > 0) {
                if (!this.correctValue(this.valueArea())) {
                    this.valueArea('');
                }
            }
        },

        deleteTag: function (self, value, event) {
            event ? event.stopPropagation() : false;
            var key = -1;
            _.each(this.list(), function (element, index) {
                if (value === element) {
                    key = index;
                }
            });
            if (key > -1) {
                this.list.splice(key, 1);
                this.joinList(this.list());
                this.valueArea('');
            }
        },

        joinList: function (array) {
            this.value(array.join(','));
        },

        hasTag: function (value) {
            return this.list().indexOf(value) !== -1;
        }
    });
});

the knockout template is on the way...

StackOverflow/Catalog/view/base/web/template/form/element/tags.html

<div class="tags">
    <div class="admin__control-text">
        <div class="apps-share-chips-editor">
            <input class="admin__control-text" type="hidden"
                   data-bind="
        value: value,
        valueUpdate: valueUpdate,
        attr: {
            name: inputName,
            placeholder: placeholder,
            'aria-describedby': noticeId,
            id: uid,
            disabled: disabled
    }"/>
            <span data-bind="foreach: { data: list, as: 'item' }">
                <span class="field-tag-chip">
                <div class="field-tag-content" data-bind="text: item"></div>
                <div class="field-tag-close-before">
                    <span class="field-tag-close" data-bind="event: {click: $parent.deleteTag.bind($parent, $index)}"></span>
                </div>
                </span>
            </span>
            <textarea
                    class="field-tag-input" placeholder="Add more tags..." data-bind="
        event: {change: userChanges, blur: OnBlurEvent},
        hasFocus: focused,
        valueUpdate: valueUpdate,
        value: valueArea
        "></textarea>
        </div>
    </div>
</div>

some styling maybe?...

StackOverflow/Catalog/view/base/web/css/tags.css

.field-tag-content {
    display: inline-block;
    overflow: hidden;
    text-overflow: ellipsis;
    vertical-align: middle;
    white-space: nowrap;
}

.field-tag-chip {
    background: #e0e0e0;
    border: 1px solid #e0e0e0;
    display: inline-block;
    -webkit-border-radius: 3px;
    color: #444;
    margin: 4px 1px 0 2px;
    outline: none;
    vertical-align: middle;
    cursor: default;
    padding: 0;
    -webkit-border-radius: 2px;
    border-radius: 2px;
    overflow: hidden;
    padding:5px;
    padding-right:25px;
}

.field-tag-input {
    display: inline-block;
    margin: 10px 4px 0 4px;
    vertical-align: middle;
    background: none;
    border: 0;
    height: 25px;
    outline: 0;
    overflow-x: hidden;
    overflow-y: auto;
    padding: 0 0 0 5px;
    position: relative;
    resize: none;
    width:50%;
}
.field-tag-close-before {
    position:relative;
}
.field-tag-close{
    position: absolute;
    top: -10px;
    right: -5px;
    cursor: pointer;
}

.field-tag-close:before,
.field-tag-close:after {
    content: "";
    position: absolute;
    top: 0px;
    left: 0px;
    width: 15px;
    height: 4px;
    background: #303030;
}

.field-tag-close:before {
    webkit-transform: rotate(45deg);
    transform: rotate(45deg);
}

.field-tag-close:after {
    webkit-transform: rotate(-45deg);
    transform: rotate(-45deg);
}

Why put everything in the view/base? I don't have a clear answer for it, but it seems right for me because Magento team is placing all their UI elements in the view/base as well? :)

And finally, you will need to add your tags.css to the view/adminhtml/layout/catalog_product_edit.xml and the view/adminhtml/layout/catalog_product_new.xml.

So that it's it! Now your input should look like this:

Cheers.