这是在PHP应用程序中包含HTML的好方法吗？

I am learning PHP for couple of months. I can write a small blog or a simple cms. Can someone with more experience tell me if I'm doing things the right way?

I make view pages in this way :

<?php 

$postFound = isset($onePost);
if ($postFound === false) {
    $onePost = new StdClass();
    $onePost->post_id = 0;
    $onePost->title = "";
    $onePost->post_text = "";
}

return
"<form method='post' action='admin.php?page=form' id='editor'>
    <fieldset id='text-area'>
        <legend>Create new post</legend>
        <input type='hidden' name='id' value=$onePost->post_id>
        <label>Title</label>
        <input type='text' name='title' value=$onePost->title>
        <label>Write post</label>
        <textarea type='text' name='post-text'>$onePost->post_text</textarea>     
        <fieldset id='submit-area'>
            <input type='submit' name='action' value='save'>
            <input type='submit' name='action' value='delete'>
        </fieldset>
    </fieldset>
</form>";

This is my Front-Controller:

<?php

error_reporting(E_ALL);
ini_set("display_errors", true);

include_once "model/Layout.class.php";

$pageData = new Layout ();
$pageData->title = "Admin";
$pageData->addCss("assets/css/style.css");
$pageData->content = include_once 'view/admin/admin_navigation.html.php';

//navigation controll
$navClicked = isset($_GET['page']); 
if ($navClicked) {
    $link = $_GET['page'];

}else {
    $link = 'posts';
}
$pageData->content .= include_once "controller/admin/$link.ctrl.php";


$layout = include_once "view/template/layout.html.php";
echo $layout;

I echo the view through an object property in Front-Controller. Is it good practice, to return html chunk of code like I do in the view file and then echo it? Or there is something bad going on behind the scenes which I am not awere? And Is there a better way?

Thanks in advance.

There's no reason to have this in a PHP tag and use

echo

. You can include it even if it's just raw HTML.