Can't create a shortcode?

Question

WordPress

Hello.
I can't create a shortcode, I'm probably doing it wrong.

function true_misha_func( $atts ){ ?>
    <div class="slider">
        <div class="slider-init">
            <?php foreach(getSlider() as $slider_post): setup_postdata($slider_post); ?>
            <div class="slider-item">
                <div class="container">
                    <div class="slider-item-inner">
                        <div class="slider-info">
                            <?php the_field('text_slider', $slider_post->ID) ?>
                        </div>
                        <a href="<?php the_field('link_slider', $slider_post->ID); ?>" class="slider-link" style="background-color: <?php the_field('button_slider_color', $slider_post->ID); ?>; color: <?php the_field('button_slider_color2', $slider_post->ID); ?>"><?php the_field('text_btn_slider', $slider_post->ID); ?></a>
                    </div>
                </div>
            </div>
        <?php endforeach; ?>
        </div>
    </div>
<?php }
add_shortcode( 'slider', 'true_misha_func' );

Answer 1

The shortcode function should return the variable return , and not output echo as you currently have. This can be done in two ways
1. Declare an output buffer ob_start()and return it withob_get_contents()

function slider_shortcode_func( $atts ) { 
  ob_start(); ?>
  
  <div class="slider">
    <div class="slider-init">
      <h2>Slider Content</h2>
    </div>
  </div>

  <?php ob_get_contents();
}
add_shortcode( 'slider', 'slider_shortcode_func' );

2. Collect and return a variable using string concatenation

function slider_shortcode_func( $atts ) { 

  $html = '';

  $html .= '<div class="slider">';
    $html .= '<div class="slider-init">';
      $html .= '<h2>Slider Content</h2>';
    $html .= '</div>';
  $html .= '</div>';

  return $html;
}
add_shortcode( 'slider', 'slider_shortcode_func' );

In this case, the functions the_field()need to be rewritten in get_field()
PS. Once you pass ID to them $slider_post->ID, the function is setup_postdata()not needed by
PSS. Of course, the function getSlider()must return an array of records to work, nothing will work without it