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Posts posted by chriscam19

  1. Hi. I keep getting 1 Notice and 1 Error after I delete all the tasks from the view_tasks2.php in chapter 1 Advanced PHP Object Oriented Programming.

    Here is the output after I delete all the tasks:



    Current To-Do List

    The task(s) have been marked as completed!

    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).

    1. Notice: Undefined offset: 0 in C:\xampp\htdocs\aqp\chp1\view_tasks2.php on line 83
    2. Warning: Invalid argument supplied for foreach() in C:\xampp\htdocs\aqp\chp1\view_tasks2.php on line 23


    Can someone help me with the errors?


    here is my code for the view_tasks.php file. It is the exact same code that is provided from the book source code minus my database username, password settings. I have labeled lines 83 and 23 so you can find them easier.


    <!doctype html>
    <html lang="en">
        <meta charset="utf-8">
        <title>View Tasks</title>
        <link rel="stylesheet" href="style.css">
    <h2>Current To-Do List</h2>
    <?php # Script 1.6 - 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.
    // Function for displaying a list.
    // Receives one argument: an array.
    function make_list ($parent) {
        global $tasks;
        echo '<ol>'; // Start an ordered list.
        foreach ($parent as $task_id => $todo) {              //line 23
            // Start with a checkbox!
            echo <<<EOT
    <li><input type="checkbox" name="tasks[$task_id]" value="done"> $todo
            // Check for subtasks:
            if (isset($tasks[$task_id])) { 
            echo '</li>'; // Complete the list item.    
        } // End of FOREACH loop.
        echo '</ol>'; // Close the ordered list.
    } // End of make_list() function.
    // Connect to the database:
    $dbc = mysqli_connect('localhost', 'root', 'password', 'my_db');
    // Check if the form has been submitted:
    if (($_SERVER['REQUEST_METHOD'] == 'POST') 
        && isset($_POST['tasks']) 
        && is_array($_POST['tasks'])
        && !empty($_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.
    // Retrieve all the uncompleted tasks:
    $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);
    $tasks = array();
    while (list($task_id, $parent_id, $task) = mysqli_fetch_array($r, MYSQLI_NUM)) {
        $tasks[$parent_id][$task_id] =  $task;
    // Make a form:
    echo <<<EOT
    <p>Check the box next to a task and click "Update" to mark a task as completed (it, and any subtasks, will no longer appear in this list).</p>
    <form action="view_tasks2.php" method="post">
    make_list($tasks[0]);              //line 83
    // Complete the form:
    echo <<<EOT
    <input name="submit" type="submit" value="Update" />
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