For specific use-cases, you can define a custom callback to generate dynamic content.
Example One: Hello World
Firstly, implement hook_empty_fields(). This returns an array indexed by the class name that implements the handler.
Note: This differs from version 1.x that used hook_empty_field_callbacks().
<?php
/**
* Implements hook_empty_fields().
*/
function HOOK_empty_fields() {
$items = array(
'HelloWorldEmptyFieldHandler'=> array(
'title'=> t('Display "Hello World" if empty'),
),
);
return $items;
}
?>Create a new concrete class that extends the abstract class EmptyFieldHandler.
<?php
/**
* @file
* Contains the HelloWorldEmptyFieldHandler plugin for EmptyFieldHandler.
*/
/**
* Defines HelloWorldEmptyFieldHandler class.
*/
class HelloWorldEmptyFieldHandler extends EmptyFieldHandler {
/**
* Implementation of EmptyFieldText::react().
*/
public function react($context) {
return t('Hello World!');
}
/**
* Implementation of EmptyFieldText:summaryText().
*/
public function summaryText() {
return t('Empty Text: "Hello World!"');
}
}
?>Register this class in your modules info file
files[] = plugins/hello_world_empty_field_handler.incThe context has the entity_type, entity, view_mode as well as the empty field details, field and instance.
If the callback is empty or a zero-length string, the empty field will not be rendered.
Example Two: Coupled fields
The following is based on a use-case to couple a Name field with a Text field to provide a nickname field.
Set up:
1) Add these fields to a bundle.
Name field (field_name) - note do not use this machine name if you plan to enable the field collection module that incorrectly uses this internally.
Textfield (field_nickname)
2) Enable the nick example module
3) To display a nickname, goto the display settings.
- Hide the name field
- Show the nickname field
- Click the cog beside the nickname field and select the Display a name field option
- Click Update, then Save at the bottom of the page
So if a nickname was not given, but the first name was, the first name will show as the users nickname.
Note that the module contains another example to reverse this. To show the nickname if the name field is empty.
| Attachment | Size |
|---|---|
| nick.zip | 1.97 KB |