Magento 2 custom module configuration settings not display in admin

Question

I have created custom module configuration in admin panel to Enable in frontend and Modify Heading title. But the settings are not visible in the admin Store > Settings > Configuration.

I am following the below tutorial steps:

http://www.mage-world.com/blog/how-to-create-the-configuration-via-backend-for-a-custom-module.html

I have run the command setup:upgrade and cache:flush already and also it's not showing any error. I am using Magento ver. 2.1.3.

Please see the attached screenshot.

My system.xml file code is:

<?xml version="1.0"?>

<config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
xsi:noNamespaceSchemaLocation="urn:magento:module:Magento_Config:etc/system_file.xsd">
    <system>
        <tab id="tutorial" translate="label" sortOrder="1">
            <label>Tutorial</label>
        </tab>
        <section id="tutorial_simplenews" translate="label" sortOrder="1" showInDefault="1" 
showInWebsite="1" showInStore="1">
            <label>Simple News</label>
            <tab>tutorial</tab>
            <resource>Tutorial_SimpleNews::config</resource>
            <group id="general" translate="label" type="text" sortOrder="1" showInDefault="1" 
showInWebsite="1" showInStore="1">
                <label>General Settings</label>
                <field id="enable_in_frontend" translate="label" type="select" sortOrder="1" 
showInDefault="1" showInWebsite="1" showInStore="1">
                    <label>Enable in frontend</label>
                    <source_model>Magento\Config\Model\Config\Source\Yesno</source_model>
                </field>
                <field id="head_title" translate="label comment" type="text" sortOrder="2" 
showInDefault="1" showInWebsite="1" showInStore="1">
                    <label>Head title</label>
                    <comment>Fill head title of news list page at here</comment>
                    <validate>required-entry</validate>
                </field>
                <field id="lastest_news_block_position" translate="label" type="select" 
sortOrder="3" showInDefault="1" showInWebsite="1" showInStore="1">
                    <label>Lastest news block position</label>
                    <source_model>
                        Tutorial\SimpleNews\Model\System\Config\LastestNews\Position
                    </source_model>
                </field>
            </group>
        </section>
    </system>
</config>

Below is \Tutorial\SimpleNews\Model\System\Config\LastestNews\Position.php file code:

<?php

namespace Tutorial\SimpleNews\Model\System\Config\LastestNews;

use Magento\Framework\Option\ArrayInterface;

class Position implements ArrayInterface
{
    const LEFT      = 1;
    const RIGHT     = 2;
    const DISABLED  = 0;

    /**
     * Get positions of lastest news block
     *
     * @return array
     */
    public function toOptionArray()
    {
        return [
            self::LEFT => __('Left'),
            self::RIGHT => __('Right'),
            self::DISABLED => __('Disabled')
        ];
    }
}

Answer 1

Its because you haven't written the source_model node correctly, There should be no spaces while specifying its value.

<?xml version="1.0"?>

<config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
xsi:noNamespaceSchemaLocation="urn:magento:module:Magento_Config:etc/system_file.xsd">
    <system>
        <tab id="tutorial" translate="label" sortOrder="1">
            <label>Tutorial</label>
        </tab>
        <section id="tutorial_simplenews" translate="label" sortOrder="1" showInDefault="1" 
showInWebsite="1" showInStore="1">
            <label>Simple News</label>
            <tab>tutorial</tab>
            <resource>Tutorial_SimpleNews::config</resource>
            <group id="general" translate="label" type="text" sortOrder="1" showInDefault="1" 
showInWebsite="1" showInStore="1">
                <label>General Settings</label>
                <field id="enable_in_frontend" translate="label" type="select" sortOrder="1" 
showInDefault="1" showInWebsite="1" showInStore="1">
                    <label>Enable in frontend</label>
                    <source_model>Magento\Config\Model\Config\Source\Yesno</source_model>
                </field>
                <field id="head_title" translate="label comment" type="text" sortOrder="2" 
showInDefault="1" showInWebsite="1" showInStore="1">
                    <label>Head title</label>
                    <comment>Fill head title of news list page at here</comment>
                    <validate>required-entry</validate>
                </field>
                <field id="lastest_news_block_position" translate="label" type="select" 
sortOrder="3" showInDefault="1" showInWebsite="1" showInStore="1">
                    <label>Lastest news block position</label>
                    <source_model>Tutorial\SimpleNews\Model\System\Config\LastestNews\Position</source_model>
                </field>
            </group>
        </section>
    </system>
</config>

Use this modified code and check.

Answer 2

  <?xml version="1.0"?>

<config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
xsi:noNamespaceSchemaLocation="urn:magento:module:Magento_Config:etc/system_file.xsd">
    <system>
        <tab id="tutorial" translate="label" sortOrder="1">
            <label>Tutorial</label>
        </tab>
        <section id="tutorial_simplenews" translate="label" sortOrder="1" showInDefault="1" 
showInWebsite="1" showInStore="1">
            <label>Simple News</label>
            <tab>tutorial</tab>
            <resource>Tutorial_SimpleNews::config</resource>
            <group id="general" translate="label" type="text" sortOrder="1" showInDefault="1" 
showInWebsite="1" showInStore="1">
                <label>General Settings</label>
                <field id="enable_in_frontend" translate="label" type="select" sortOrder="1" 
showInDefault="1" showInWebsite="1" showInStore="1">
                    <label>Enable in frontend</label>
                    <source_model>Magento\Config\Model\Config\Source\Yesno</source_model>
                </field>
                <field id="head_title" translate="label comment" type="text" sortOrder="2" 
showInDefault="1" showInWebsite="1" showInStore="1">
                    <label>Head title</label>
                    <comment>Fill head title of news list page at here</comment>
                    <validate>required-entry</validate>
                </field>
                <field id="lastest_news_block_position" translate="label" type="select" 
sortOrder="3" showInDefault="1" showInWebsite="1" showInStore="1">
                    <label>Lastest news block position</label>
                    <source_model>Tutorial\SimpleNews\Model\System\Config\LastestNews\Position</source_model>
                </field>
            </group>
        </section>
    </system>
</config>

Try

<?php
namespace Tutorial\SimpleNews\Model\System\Config\LastestNews;

class Position implements \Magento\Framework\Option\ArrayInterface
{
    public function toOptionArray()
    {
        return [
            ['value' => '0', 'label' => __('Disabled')],
            ['value' => '1', 'label' => __('LEFT')],
            ['value' => '2', 'label' => __('Right')],           

        ];
    }
}