Hi I'm trying to convert from a "example" wp_list_table that displays an array of data on the same page, to a "real life" table the pulls data from the database. I have the code setup to where I just need to add the DB query to make it work.
I just don't know how to query the database and make it display correctly. Would someone be willing to look at the code below and tell me how to make a query to the "links" database table in wordpress? I was thinking the query below would work, but I don't think it jives with my "example" table row and columns.
$sql = "SELECT * FROM links";
$data = $wpdb->get_results($sql);
In the code below, scrolling down about 3/4 ($data = $this->example_data;), you will see the area where it would create a database query if this were a working piece of code.
Here's my functions.php file.
<?php
/* == NOTICE ===================================================================
* Please do not alter this file. Instead: make a copy of the entire plugin,
* rename it, and work inside the copy. If you modify this plugin directly and
* an update is released, your changes will be lost!
* ========================================================================== */
/*************************** LOAD THE BASE CLASS *******************************
*******************************************************************************
* The WP_List_Table class isn't automatically available to plugins, so we need
* to check if it's available and load it if necessary.
*/
if(!class_exists('WP_List_Table')){
require_once( ABSPATH . 'wp-admin/includes/class-wp-list-table.php' );
}
/************************** CREATE A PACKAGE CLASS *****************************
*******************************************************************************
* Create a new list table package that extends the core WP_List_Table class.
* WP_List_Table contains most of the framework for generating the table, but we
* need to define and override some methods so that our data can be displayed
* exactly the way we need it to be.
*
* To display this example on a page, you will first need to instantiate the class,
* then call $yourInstance->prepare_items() to handle any data manipulation, then
* finally call $yourInstance->display() to render the table to the page.
*
* Our theme for this list table is going to be movies.
*/
class TT_Example_List_Table extends WP_List_Table {
/** ************************************************************************
* Normally we would be querying data from a database and manipulating that
* for use in your list table. For this example, we're going to simplify it
* slightly and create a pre-built array. Think of this as the data that might
* be returned by $wpdb->query().
*
* @var array
**************************************************************************/
var $example_data = array(
array(
'ID' => 1,
'title' => '300',
'rating' => 'R',
'director' => 'Zach Snyder'
),
array(
'ID' => 2,
'title' => 'Eyes Wide Shut',
'rating' => 'R',
'director' => 'Stanley Kubrick'
),
array(
'ID' => 3,
'title' => 'Moulin Rouge!',
'rating' => 'PG-13',
'director' => 'Baz Luhrman'
),
array(
'ID' => 4,
'title' => 'Snow White',
'rating' => 'G',
'director' => 'Walt Disney'
),
array(
'ID' => 5,
'title' => 'Super 8',
'rating' => 'PG-13',
'director' => 'JJ Abrams'
),
array(
'ID' => 6,
'title' => 'The Fountain',
'rating' => 'PG-13',
'director' => 'Darren Aronofsky'
),
array(
'ID' => 7,
'title' => 'Watchmen',
'rating' => 'R',
'director' => 'Zach Snyder'
)
);
/** ************************************************************************
* REQUIRED. Set up a constructor that references the parent constructor. We
* use the parent reference to set some default configs.
***************************************************************************/
function __construct(){
global $status, $page;
//Set parent defaults
parent::__construct( array(
'singular' => 'movie', //singular name of the listed records
'plural' => 'movies', //plural name of the listed records
'ajax' => false //does this table support ajax?
) );
}
/** ************************************************************************
* Recommended. This method is called when the parent class can't find a method
* specifically build for a given column. Generally, it's recommended to include
* one method for each column you want to render, keeping your package class
* neat and organized. For example, if the class needs to process a column
* named 'title', it would first see if a method named $this->column_title()
* exists - if it does, that method will be used. If it doesn't, this one will
* be used. Generally, you should try to use custom column methods as much as
* possible.
*
* Since we have defined a column_title() method later on, this method doesn't
* need to concern itself with any column with a name of 'title'. Instead, it
* needs to handle everything else.
*
* For more detailed insight into how columns are handled, take a look at
* WP_List_Table::single_row_columns()
*
* @param array $item A singular item (one full row's worth of data)
* @param array $column_name The name/slug of the column to be processed
* @return string Text or HTML to be placed inside the column <td>
**************************************************************************/
function column_default($item, $column_name){
switch($column_name){
case 'rating':
case 'director':
return $item[$column_name];
default:
return print_r($item,true); //Show the whole array for troubleshooting purposes
}
}
/** ************************************************************************
* Recommended. This is a custom column method and is responsible for what
* is rendered in any column with a name/slug of 'title'. Every time the class
* needs to render a column, it first looks for a method named
* column_{$column_title} - if it exists, that method is run. If it doesn't
* exist, column_default() is called instead.
*
* This example also illustrates how to implement rollover actions. Actions
* should be an associative array formatted as 'slug'=>'link html' - and you
* will need to generate the URLs yourself. You could even ensure the links
*
*
* @see WP_List_Table::::single_row_columns()
* @param array $item A singular item (one full row's worth of data)
* @return string Text to be placed inside the column <td> (movie title only)
**************************************************************************/
function column_title($item){
//Build row actions
$actions = array(
'edit' => sprintf('<a href="?page=%s&action=%s&movie=%s">Edit</a>',$_REQUEST['page'],'edit',$item['ID']),
'delete' => sprintf('<a href="?page=%s&action=%s&movie=%s">Delete</a>',$_REQUEST['page'],'delete',$item['ID']),
);
//Return the title contents
return sprintf('<a href="#"><b>%1$s</b></a> %3$s',
/*$1%s*/ $item['title'],
/*$2%s*/ $item['ID'],
/*$3%s*/ $this->row_actions($actions)
);
}
/** ************************************************************************
* REQUIRED if displaying checkboxes or using bulk actions! The 'cb' column
* is given special treatment when columns are processed. It ALWAYS needs to
* have it's own method.
*
* @see WP_List_Table::::single_row_columns()
* @param array $item A singular item (one full row's worth of data)
* @return string Text to be placed inside the column <td> (movie title only)
**************************************************************************/
function column_cb($item){
return sprintf(
'<input type="checkbox" name="%1$s[]" value="%2$s" />',
/*$1%s*/ $this->_args['singular'], //Let's simply repurpose the table's singular label ("movie")
/*$2%s*/ $item['ID'] //The value of the checkbox should be the record's id
);
}
/** ************************************************************************
* REQUIRED! This method dictates the table's columns and titles. This should
* return an array where the key is the column slug (and class) and the value
* is the column's title text. If you need a checkbox for bulk actions, refer
* to the $columns array below.
*
* The 'cb' column is treated differently than the rest. If including a checkbox
* column in your table you must create a column_cb() method. If you don't need
* bulk actions or checkboxes, simply leave the 'cb' entry out of your array.
*
* @see WP_List_Table::::single_row_columns()
* @return array An associative array containing column information: 'slugs'=>'Visible Titles'
**************************************************************************/
function get_columns(){
$columns = array(
'cb' => '<input type="checkbox" />', //Render a checkbox instead of text
'title' => 'Custom Widget Name',
'rating' => 'Rating',
'director' => 'Director'
);
return $columns;
}
/** ************************************************************************
* Optional. If you want one or more columns to be sortable (ASC/DESC toggle),
* you will need to register it here. This should return an array where the
* key is the column that needs to be sortable, and the value is db column to
* sort by. Often, the key and value will be the same, but this is not always
* the case (as the value is a column name from the database, not the list table).
*
* This method merely defines which columns should be sortable and makes them
* clickable - it does not handle the actual sorting. You still need to detect
* the ORDERBY and ORDER querystring variables within prepare_items() and sort
* your data accordingly (usually by modifying your query).
*
* @return array An associative array containing all the columns that should be sortable: 'slugs'=>array('data_values',bool)
**************************************************************************/
function get_sortable_columns() {
$sortable_columns = array(
'title' => array('title',true), //true means its already sorted
'rating' => array('rating',false),
'director' => array('director',false)
);
return $sortable_columns;
}
/** ************************************************************************
* Optional. If you need to include bulk actions in your list table, this is
* the place to define them. Bulk actions are an associative array in the format
* 'slug'=>'Visible Title'
*
* If this method returns an empty value, no bulk action will be rendered. If
* you specify any bulk actions, the bulk actions box will be rendered with
* the table automatically on display().
*
* Also note that list tables are not automatically wrapped in <form> elements,
* so you will need to create those manually in order for bulk actions to function.
*
* @return array An associative array containing all the bulk actions: 'slugs'=>'Visible Titles'
**************************************************************************/
function get_bulk_actions() {
$actions = array(
'delete' => 'Delete'
);
return $actions;
}
/** ************************************************************************
* Optional. You can handle your bulk actions anywhere or anyhow you prefer.
* For this example package, we will handle it in the class to keep things
* clean and organized.
*
* @see $this->prepare_items()
**************************************************************************/
function process_bulk_action() {
//Detect when a bulk action is being triggered...
if( 'delete'===$this->current_action() ) {
wp_die('Items deleted (or they would be if we had items to delete)!');
}
}
/** ************************************************************************
* REQUIRED! This is where you prepare your data for display. This method will
* usually be used to query the database, sort and filter the data, and generally
* get it ready to be displayed. At a minimum, we should set $this->items and
* $this->set_pagination_args(), although the following properties and methods
* are frequently interacted with here...
*
* @uses $this->_column_headers
* @uses $this->items
* @uses $this->get_columns()
* @uses $this->get_sortable_columns()
* @uses $this->get_pagenum()
* @uses $this->set_pagination_args()
**************************************************************************/
function prepare_items() {
/**
* First, lets decide how many records per page to show
*/
$per_page = 5;
/**
* REQUIRED. Now we need to define our column headers. This includes a complete
* array of columns to be displayed (slugs & titles), a list of columns
* to keep hidden, and a list of columns that are sortable. Each of these
* can be defined in another method (as we've done here) before being
* used to build the value for our _column_headers property.
*/
$columns = $this->get_columns();
$hidden = array();
$sortable = $this->get_sortable_columns();
/**
* REQUIRED. Finally, we build an array to be used by the class for column
* headers. The $this->_column_headers property takes an array which contains
* 3 other arrays. One for all columns, one for hidden columns, and one
* for sortable columns.
*/
$this->_column_headers = array($columns, $hidden, $sortable);
/**
* Optional. You can handle your bulk actions however you see fit. In this
* case, we'll handle them within our package just to keep things clean.
*/
$this->process_bulk_action();
/**
* Instead of querying a database, we're going to fetch the example data
* property we created for use in this plugin. This makes this example
* package slightly different than one you might build on your own. In
* this example, we'll be using array manipulation to sort and paginate
* our data. In a real-world implementation, you will probably want to
* use sort and pagination data to build a custom query instead, as you'll
* be able to use your precisely-queried data immediately.
*/
$data = $this->example_data;
/**
* This checks for sorting input and sorts the data in our array accordingly.
*
* In a real-world situation involving a database, you would probably want
* to handle sorting by passing the 'orderby' and 'order' values directly
* to a custom query. The returned data will be pre-sorted, and this array
* sorting technique would be unnecessary.
*/
function usort_reorder($a,$b){
$orderby = (!empty($_REQUEST['orderby'])) ? $_REQUEST['orderby'] : 'title'; //If no sort, default to title
$order = (!empty($_REQUEST['order'])) ? $_REQUEST['order'] : 'asc'; //If no order, default to asc
$result = strcmp($a[$orderby], $b[$orderby]); //Determine sort order
return ($order==='asc') ? $result : -$result; //Send final sort direction to usort
usort($data, 'usort_reorder');
}
/**
* REQUIRED for pagination. Let's figure out what page the user is currently
* looking at. We'll need this later, so you should always include it in
* your own package classes.
*/
$current_page = $this->get_pagenum();
/**
* REQUIRED for pagination. Let's check how many items are in our data array.
* In real-world use, this would be the total number of items in your database,
* without filtering. We'll need this later, so you should always include it
* in your own package classes.
*/
$total_items = count($data);
/**
* The WP_List_Table class does not handle pagination for us, so we need
* to ensure that the data is trimmed to only the current page. We can use
* array_slice() to
*/
$data = array_slice($data,(($current_page-1)*$per_page),$per_page);
/**
* REQUIRED. Now we can add our *sorted* data to the items property, where
* it can be used by the rest of the class.
*/
$this->items = $data;
/**
* REQUIRED. We also have to register our pagination options & calculations.
*/
$this->set_pagination_args( array(
'total_items' => $total_items, //WE have to calculate the total number of items
'per_page' => $per_page, //WE have to determine how many items to show on a page
'total_pages' => ceil($total_items/$per_page) //WE have to calculate the total number of pages
) );
}
}
/** ************************ REGISTER THE TEST PAGE ****************************
*******************************************************************************
* Now we just need to define an admin page. For this example, we'll add a top-level
* menu item to the bottom of the admin menus.
*/
function tt_add_menu_items(){
add_menu_page('Custom Widgets', 'Custom Widgets', 'activate_plugins', 'tt_list_test', 'tt_render_list_page');
} add_action('admin_menu', 'tt_add_menu_items');
/***************************** RENDER TEST PAGE ********************************
*******************************************************************************
* This function renders the admin page and the example list table. Although it's
* possible to call prepare_items() and display() from the constructor, there
* are often times where you may need to include logic here between those steps,
* so we've instead called those methods explicitly. It keeps things flexible, and
* it's the way the list tables are used in the WordPress core.
*/
function tt_render_list_page(){
//Create an instance of our package class...
$testListTable = new TT_Example_List_Table();
//Fetch, prepare, sort, and filter our data...
$testListTable->prepare_items();
?>
<div class="wrap" style="width:70%">
<div id="icon-themes" class="icon32"><br/></div>
<h2>Custom Widgets</h2>
<?php
$active_tab = isset( $_GET[ 'tab' ] ) ? $_GET[ 'tab' ] : 'custom_widget_manager';
?>
<h2 class="nav-tab-wrapper">
<a href="?page=tt_list_test&tab=custom_widget_manager" class="nav-tab <?php echo $active_tab == 'custom_widget_manager' ? 'nav-tab-active' : ''; ?>">Custom Widget Manager</a>
<a href="?page=tt_list_test&tab=add_custom_widget" class="nav-tab <?php echo $active_tab == 'add_custom_widget' ? 'nav-tab-active' : ''; ?>">Add Custom Widget</a>
</h2>
<!-- Forms are NOT created automatically, so you need to wrap the table in one to use features like bulk actions -->
<form id="movies-filter" method="get">
<!-- For plugins, we also need to ensure that the form posts back to our current page -->
<input type="hidden" name="page" value="<?php echo $_REQUEST['page'] ?>" />
<!-- Now we can render the completed list table -->
<?php $testListTable->display(); ?>
</form>
</div>
<?php
}
