1 form_example_states.inc | form_example_states_form($form, &$form_state) |
States demo form.
This form shows off the #states system by dynamically showing parts of the form based on the state of other parts.
The basic idea is that you add a #states property to the element which is to be changed based on some action elsewhere on the form. The #states property lists a change which is to be made, and under what conditions that change should be made.
For example, in the 'tests_taken' form element below we have:
'#states' => array(
'visible' => array(
':input[name="student_type"]' => array('value' => 'high_school'),
),
),
Meaning that the element is to be made visible when the condition is met. The condition is a combination of a jQuery selector (which selects the element we want to test) and a condition for that element. In this case, the condition is whether the return value of the 'student_type' element is 'high_school'. If it is, this element will be visible.
So the syntax is:
'#states' => array(
'action_to_take_on_this_form_element' => array(
'jquery_selector_for_another_element' => array(
'condition_type' => value,
),
),
),
If you need an action to take place only when two different conditions are true, then you add both of those conditions to the action. See the 'country_writein' element below for an example.
Note that the easiest way to select a textfield, checkbox, or select is with the ':input' jquery shortcut, which selects any of those.
There are examples below of changing or hiding an element when a checkbox is checked, when a textarea is filled, when a select has a given value.
See backdrop_process_states() for full documentation.
See also
forms_api_reference.html
Related topics
File
- modules/
examples/ form_example/ form_example_states.inc, line 62 - An example of how to use the new #states Form API element, allowing dynamic form behavior with very simple setup.
Code
function form_example_states_form($form, &$form_state) {
$form['student_type'] = array(
'#type' => 'radios',
'#options' => array(
'high_school' => t('High School'),
'undergraduate' => t('Undergraduate'),
'graduate' => t('Graduate'),
),
'#title' => t('What type of student are you?'),
);
$form['high_school'] = array(
'#type' => 'fieldset',
'#title' => t('High School Information'),
// This #states rule says that the "high school" fieldset should only
// be shown if the "student_type" form element is set to "High School".
'#states' => array(
'visible' => array(
':input[name="student_type"]' => array('value' => 'high_school'),
),
),
);
// High school information.
$form['high_school']['tests_taken'] = array(
'#type' => 'checkboxes',
'#options' => backdrop_map_assoc(array(t('SAT'), t('ACT'))),
'#title' => t('What standardized tests did you take?'),
// This #states rule says that this checkboxes array will be visible only
// when $form['student_type'] is set to t('High School').
// It uses the jQuery selector :input[name=student_type] to choose the
// element which triggers the behavior, and then defines the "High School"
// value as the one that triggers visibility.
'#states' => array(
// Action to take.
'visible' => array(
':input[name="student_type"]' => array('value' => 'high_school'),
),
),
);
$form['high_school']['sat_score'] = array(
'#type' => 'textfield',
'#title' => t('Your SAT score:'),
'#size' => 4,
// This #states rule limits visibility to when the $form['tests_taken']
// 'SAT' checkbox is checked."
'#states' => array(
// Action to take.
'visible' => array(
':input[name="tests_taken[SAT]"]' => array('checked' => TRUE),
),
),
);
$form['high_school']['act_score'] = array(
'#type' => 'textfield',
'#title' => t('Your ACT score:'),
'#size' => 4,
// Set this element visible if the ACT checkbox above is checked.
'#states' => array(
// Action to take.
'visible' => array(
':input[name="tests_taken[ACT]"]' => array('checked' => TRUE),
),
),
);
// Undergrad information.
$form['undergraduate'] = array(
'#type' => 'fieldset',
'#title' => t('Undergraduate Information'),
// This #states rule says that the "undergraduate" fieldset should only
// be shown if the "student_type" form element is set to "Undergraduate".
'#states' => array(
'visible' => array(
':input[name="student_type"]' => array('value' => 'undergraduate'),
),
),
);
$form['undergraduate']['how_many_years'] = array(
'#type' => 'select',
'#title' => t('How many years have you completed?'),
// The options here are integers, but since all the action here happens
// using the DOM on the client, we will have to use strings to work with
// them.
'#options' => array(
1 => t('One'),
2 => t('Two'),
3 => t('Three'),
4 => t('Four'),
5 => t('Lots'),
),
);
$form['undergraduate']['comment'] = array(
'#type' => 'item',
'#description' => t("Wow, that's a long time."),
'#states' => array(
'visible' => array(
// Note that '5' must be used here instead of the integer 5.
// The information is coming from the DOM as a string.
':input[name="how_many_years"]' => array('value' => '5'),
),
),
);
$form['undergraduate']['school_name'] = array(
'#type' => 'textfield',
'#title' => t('Your college or university:'),
);
$form['undergraduate']['school_country'] = array(
'#type' => 'select',
'#options' => backdrop_map_assoc(array(t('UK'), t('Other'))),
'#title' => t('In what country is your college or university located?'),
);
$form['undergraduate']['country_writein'] = array(
'#type' => 'textfield',
'#size' => 20,
'#title' => t('Please enter the name of the country where your college or university is located.'),
// Only show this field if school_country is set to 'Other'.
'#states' => array(
// Action to take: Make visible.
'visible' => array(
':input[name="school_country"]' => array('value' => t('Other')),
),
),
);
$form['undergraduate']['thanks'] = array(
'#type' => 'item',
'#description' => t('Thanks for providing both your school and your country.'),
'#states' => array(
// Here visibility requires that two separate conditions be true.
'visible' => array(
':input[name="school_country"]' => array('value' => t('Other')),
':input[name="country_writein"]' => array('filled' => TRUE),
),
),
);
$form['undergraduate']['go_away'] = array(
'#type' => 'submit',
'#value' => t('Done with form'),
'#states' => array(
// Here visibility requires that two separate conditions be true.
'visible' => array(
':input[name="school_country"]' => array('value' => t('Other')),
':input[name="country_writein"]' => array('filled' => TRUE),
),
),
);
// Graduate student information.
$form['graduate'] = array(
'#type' => 'fieldset',
'#title' => t('Graduate School Information'),
// This #states rule says that the "graduate" fieldset should only
// be shown if the "student_type" form element is set to "Graduate".
'#states' => array(
'visible' => array(
':input[name="student_type"]' => array('value' => 'graduate'),
),
),
);
$form['graduate']['more_info'] = array(
'#type' => 'textarea',
'#title' => t('Please describe your graduate studies'),
);
$form['graduate']['info_provide'] = array(
'#type' => 'checkbox',
'#title' => t('Check here if you have provided information above'),
'#disabled' => TRUE,
'#states' => array(
// Mark this checkbox checked if the "more_info" textarea has something
// in it, if it's 'filled'.
'checked' => array(
':input[name="more_info"]' => array('filled' => TRUE),
),
),
);
$form['average'] = array(
'#type' => 'textfield',
'#title' => t('Enter your average'),
// To trigger a state when the same controlling element can have more than
// one possible value, put all values in a higher-level array.
'#states' => array(
'visible' => array(
':input[name="student_type"]' => array(
array('value' => 'high_school'),
array('value' => 'undergraduate'),
),
),
),
);
$form['expand_more_info'] = array(
'#type' => 'checkbox',
'#title' => t('Check here if you want to add more information.'),
);
$form['more_info'] = array(
'#type' => 'fieldset',
'#title' => t('Additional Information'),
'#collapsible' => TRUE,
'#collapsed' => TRUE,
// Expand the expand_more_info fieldset if the box is checked.
'#states' => array(
'expanded' => array(
':input[name="expand_more_info"]' => array('checked' => TRUE),
),
),
);
$form['more_info']['feedback'] = array(
'#type' => 'textarea',
'#title' => t('What do you have to say?'),
);
$form['submit'] = array(
'#type' => 'submit',
'#value' => t('Submit your information'),
);
return $form;
}