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php开发代表列表todo代码（类似递归显示评论）

2013-05-17 15:03  youxin  阅读(621)  评论(0)  编辑  收藏  举报

我们要开发的todo列表类似菜单项，每个菜单可以有多个菜单项，每个菜单项又可以有多个子菜单，我们的todo有一系列任务，每个任务又有多个子任务，以此类推。数据库设计：

 

每个task有一个parent_id，task_id与parent_id之间形成一种伪外主键关系。

代码：

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
        "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">
<head>
    <meta http-equiv="content-type" content="text/html; charset=iso-8859-1" />
    <title>View Tasks</title>
</head>
<body>
<h3>Current To-Do List</h3>
<?php # Script 1.5 - view_tasks2.php

/*    This page shows all existing tasks.
 *    A recursive function is used to show the 
 *    tasks as nested lists, as applicable.
 *    Tasks can now be marked as completed.
 */

// Retrieve all the uncompleted tasks:
// Connect to the database:
$dbc = @mysqli_connect ('localhost', 'username', 'password', 'test') OR die ('<p>Could not connect to the database!</p></body></html>');

$q = 'SELECT task_id, parent_id, task FROM tasks WHERE date_completed="0000-00-00 00:00:00" ORDER BY parent_id, date_added ASC'; 
$r = mysqli_query($dbc, $q);

// Initialize the storage array:
$tasks = array();

while (list($task_id, $parent_id, $task) = mysqli_fetch_array($r, MYSQLI_NUM)) {

    // Add to the array:
    $tasks[$parent_id][$task_id] =  $task; 
  会形成这种形式:
Array
  (
  [0] => Array
  (
  [2] => task2
  [3] => task3
  [1] => task1
  )
   
  [1] => Array
  (
  [4] => task11
  [5] => task12
  [6] => task13
  )
   
  ) 


}
可以看到所有父级都在$task[0]里面，$task[1]则存储了父级1的儿子。

// Function for displaying a list.
// Receives one argument: an array.
function make_list ($parent) { 调用时$parent=$task[0]

    // Need the main $tasks array:
    global $tasks;

    // Start an ordered list:
    echo '<ol>';
    
    // Loop through each subarray:
    foreach ($parent as $task_id => $todo) {
        
        // Display the item:
        // Start with a checkbox!
        echo <<<EOT
<li><input type="checkbox" name="$tasks[$task_id]" value="done" /> $todo
EOT;
            
        // Check for subtasks:
        if (isset($tasks[$task_id])) { 
            
            // Call this function:
            make_list($tasks[$task_id]);
            
        }
            
        // Complete the list item:
        echo '</li>'; 这才结束li
    
    } // End of FOREACH loop.
    
    // Close the ordered list:
    echo '</ol>';

} // End of make_list() function.



// Check if the form has been submitted:
if (isset($_POST['submitted']) && isset($_POST['tasks']) && is_array($_POST['tasks'])) {

    // Define the query:
    $q = 'UPDATE tasks SET date_completed=NOW() WHERE task_id IN (';
    
    // Add each task ID:
    foreach ($_POST['tasks'] as $task_id => $v) {
        $q .= $task_id . ', ';
    }
    
    // Complete the query and execute:
    $q = substr($q, 0, -2) . ')';
    $r = mysqli_query($dbc, $q);

    // Report on the results:
    if (mysqli_affected_rows($dbc) == count($_POST['tasks'])) {
        echo '<p>The task(s) have been marked as completed!</p>';
    } else {
        echo '<p>Not all tasks could be marked as completed!</p>';
    }

} // End of submission IF.



// For debugging:
//echo '<pre>' . print_r($tasks,1) . '</pre>';

// Make a form:
echo '<p>Check the box next to a task and click "Update" to mark a task as completed (it, and any subtasks, will no longer appear in this list).</p>
<form action="view_tasks2.php" method="post">
';

// Send the first array element
// to the make_list() function:
make_list($tasks[0]);

// Complete the form:
echo '<input name="submitted" type="hidden" value="true" />
<input name="submit" type="submit" value="Update" />
</form>
';

?>
</body>
</html>

我们代码的关键是建立一个二维数组，第一维是表示父级，

0表示最高级。

1表示以task_id=1为父的所有子集

第二维表示某个task_id. 

代码来自:php Advance visual quickPro guide 这本书