Why is my custom block template not being picked up?

Question

I am working on a custom slider programmatically. I create a custom module (block_example) and make a block (BlockExample.php) and a twig file (blockexample.html.twig) and also a module file (block_example.module). I want to place some code in twig file and call it in block file.

This is build function from block file (BlockExample.php)

public function build() {

  $renderable = [
    '#theme' => 'blockexample',
  ];

  return $renderable;
}

This is (blockexample.html.twig) file code

<div class="col-sm-3">
  <h1>This is Title</h1>
  <p>Description Coming From Twig File</p>
</div>

This is (block_example.module) file code

function block_example_theme() {
  return [
    'block_example' => [
      'variables' => ['test_var' => NULL],
    ],
  ];
}

Now main question is how to print twig file in BlockExample.php

Answer 1

The theme key you use in you build funtions should be the same with the one you are using in your hook_theme.

In that case you code should look like so

public function build() {

  $renderable = [
    '#theme' => 'block_example',
  ];

  return $renderable;
}

Keep in mind to avoid dashes in those values, since they are used for the template naming.

Best regards.