View source for Creating a simple module/Adding Form Fields/de

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{{J3.x:Creating_a_simple_module/de}}
Form fields give a great deal of customisation in Joomla and for modules are the sole way of allowing the user to tweak the module to the needs of their site.

== Adding Form Fields to the Module ==
In this case we are going to extend our previous example using the database to provide a list of languages for the user to select from. To allow this to happen we will use the SQL form field type. (The full details for this is on the [[S:MyLanguage/SQL_form_field_type|SQL Form Field]] docs page).

First of all we are going to add a form field into our ''.xml'' file. Remember those config tags that we added in earlier? Now inside these tags we are going to add the following code:

<source lang="xml">
<fields name="params">
    <fieldset name="basic">
        <field
               name="lang"
               type="sql"
               default="1"
               label="Select a language"
               query="SELECT id AS value, lang FROM #__helloworld" />
    </fieldset>
</fields>
</source>

This selects the languages from the database table and allows the user to choose one from a select element.

If you were to install the module as it is now you would see if you were to access the module in the backend of Joomla that a dropdown has appeared (although picking an option won't affect the module at the moment).

''Note:'' The form field parameters are stored for each module in the ''#__modules'' table under the ''params'' field as JSON-encoded string.

Now let's make the form field do something!

Go into the ''mod_helloworld.php'' file and retrieve the parameter. (Note that you '''cannot''' retrieve the parameter in the helper.) Then pass it into the helper function.

<source lang="php">
/**
  * This retrieves the lang parameter we stored earlier. Note the second part
  * which assigns the default value of 1 if the parameter cannot be
  * retrieved for some reason.
**/
$language = $params->get('lang', '1');
$hello    = modHelloWorldHelper::getHello( $language );
</source>

Now let's edit our database query in the helper file to reflect our parameter choice.

<source lang="php">
// Obtain a database connection.
$db = JFactory::getDbo();
// Retrieve the shout. Note that we are now retrieving the id not the lang field.
$query = $db->getQuery(true)
            ->select($db->quoteName('hello'))
            ->from($db->quoteName('#__helloworld'))
            ->where('id = '. $db->Quote($params));
// Prepare the query
$db->setQuery($query);
// Load the row.
$result = $db->loadResult();
// Return the Hello.
return $result;
</source>

== Conclusion ==
Form fields give the user an easy way to customise the module to their site's settings. This allows the module's scope to be increased as well for many languages and applications.

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