How do I define checkboxes in a form?

Question

I have a form where I need to add a checkboxes field. The purpose of this form is to display some values from the database. I would like to display id from my database table as checkbox' value (when "active" = 1) and url as checkbox' labels.

The database table's structure is the following.

id | uid | hash          | url          | active

1  | 1   | myhashstring1 | example_url  | 1
2  | 1   | myhashstring3 | example_url4 | 1
3  | 1   | myhashstring2 | example_url2 | 0

How can I achieve this?

Answer 1

1. Creating an '_form' type entry in the mymodule.routing.yml
2. Form controller will first always do a database query \Drupal::database()->select('mytable')...
3. You will need the id, url, and active values.
4. You need to prepare the "options" array like this: array("id" => "url", ...)
5. And the default array should contain all the active=1 records.
6. Create the checkbox field item based on Form API description.
7. In form submission (submitForm) you save back the results (which elements newly activated / deactivated) to the database.

Answer 2

As per Drupal 8 form api you can define checkboxes like below:

$form['high_school']['tests_taken'] = array(
  '#type' => 'checkboxes',
  '#options' => array('SAT' => $this->t('SAT'), 'ACT' => $this->t('ACT')),
  '#title' => $this->t('What standardized tests did you take?'),
  ...
);

In your case you can update above code

$options = array();
$options[1] = 'example_url';
$options[2] = 'example_url4';
$options[3] = 'example_url2';

$form['items_selected'] = array(
  '#type' => 'checkboxes',
  '#options' => $options,
  '#title' => $this->t('Title you want to give'),
  ...
);