Change the state of a checkboxes field

Question

I know how to use conditions with Form API for fields like text-field, checkbox, for example, showing or hiding a field when a checkbox is checked.

$form['lorem'] = [
  '#type' => 'checkbox',
  '#attributes' => [
    'name' => 'field_lorem',
  ]
];

$form['ipsum'] = [
  '#type' => 'checkbox',
  '#states' => [
    'visible' => [
      ':input[name="field_lorem"]' => ['checked' => true]
    ],
  ],
];

However, I can't manage to do it with a checkboxes field.

// This code does not work.
$form['lorem'] = [
  '#type' => 'checkbox',
  '#attributes' => [
    'name' => 'field_lorem',
  ]
];

$options = [
  'test_1' => 'Test 1',
  'test_2' => 'Test 2',
];

$form['ipsum'] = [
  '#type' => 'checkboxes',
  '#options' => $options,
  '#states' => [
    'visible' => [
      ':input[name="field_lorem"]' => array('checked' => true)
    ],
    // Ideally, I would like to have all the checkboxes checked but the problem is mainly at the state level
    'checked' => [
      ':input[name="field_lorem"]' => ['checked' => TRUE],
    ],
  ],
];

I can do it with custom JavaScript code, but I ideally wanted to do it with the form API.

What #states property do I need to achieve this?

Answer 1

You need to add #states to every checkbox.

$form['select_all'] = [
  '#title' => $this->t('Select all'),
  '#type' => 'checkbox',
  '#attributes' => [
    'name' => 'all'
  ]
];

$options = [
 'item_0' => 'value',
 'item_1' => 'value',
 'item_2' => 'value',
];

$form['my_checkboxes'] = [
 '#type' => 'checkboxes',
 '#options' => $options,
 'item_0' => [
    '#states' => [
      'checked' => [
        ':input[name="all"]' => [
          'checked' => TRUE
        ]
      ]
    ]
  ]
];

foreach ($options as $key => $item) {
  $form['my_checkboxes'][$key]['#states']['checked'][':input[name="all"]']['checked'] = TRUE;
}

Answer 2

You can wrap the checkboxes in a details (fieldset).

$form['controlling_checkbox'] = [
  '#type' => 'checkbox',
  '#title' => ['Switch me on and off'],
];
$options = ['a' => 'b', 'c' => 'd'];
$form['wrapper'] = [
  '#type' => 'details',
  '#title' => 'Wrap me up',
  '#collapsible' => TRUE,
  '#open' => TRUE,
  '#states' => [
    'disabled' => [
      ':input[name="controlling_checkbox"]' => [
          ['checked' => TRUE],
      ],
    ],
  ]
];
$form['wrapper']['lots_of_boxes'] = [
  '#type' => 'checkboxes',
  '#options' => $options,
];