Foreach loop breaks, when database query returns no/empty results

Question

I have a foreach loop to display data from a query, when the query does not return any results - which will be the case sometimes I want it to not display any data but I get the following error:

Warning: Invalid argument supplied for foreach() in /home/u913241783/public_html/editmeeting.php on line 29

The segment to display the data is:

<?php
    foreach($activities as $k=>$v) {
?>
<tr class="table-row">
    <td><?php echo $k+1; ?></td>
    <td contenteditable="true" onBlur="saveToDatabase(this,'title', 'activities', 'activityid','<?php echo $activities[$k]["activityid"]; ?>')" onClick="showEdit(this);"><?php echo $activities[$k]["title"]; ?></td>
    <td contenteditable="true" onBlur="saveToDatabase(this,'description','activities','activityid','<?php echo $activities[$k]["activityid"]; ?>')" onClick="showEdit(this);"><?php echo $activities[$k]["description"]; ?></td>
    <td contenteditable="true" onBlur="saveToDatabase(this,'leaders','activities','activityid','<?php echo $activities[$k]["activityid"]; ?>')" onClick="showEdit(this);"><?php echo $activities[$k]["leaders"]; ?></td>
    <td contenteditable="true" onBlur="saveToDatabase(this,'time','activities','activityid','<?php echo $activities[$k]["activityid"]; ?>')" onClick="showEdit(this);"><?php echo $activities[$k]["time"]; ?></td>
</tr>
<?php
    }

EDIT:

Full code is:

<?require_once("dbcontroller.php");
$db_handle = new DBController(); ?>
<h1 class="regular brown bottom_line">Activity Test</h1>
<div class="clear"></div>
</header>

<?
include'connect_db.php';
//get variables
$input1 = $_SESSION[ 'unitid' ];
$id=($_GET['id']);
$activities=array();

        $sql = "SELECT activityid, activitynumber, title, description, time, leaders FROM activities WHERE meetingid='$id'";
        $activities = $db_handle->runQuery($sql);?>
       <table class="tbl-qa">
          <thead>
              <tr>
                <th class="table-header" width="10%">Activity No.</th>
                <th class="table-header">Title</th>
                <th class="table-header">Description</th>
                <th class="table-header">Leaders</th>
                <th class="table-header">Time</th>

              </tr>
          </thead>
          <tbody>
          <?php
          print_r($activities);
          foreach($activities as $k=>$v) {
          ?>
              <tr class="table-row">
                <td><?php echo $k+1; ?></td>
                <td contenteditable="true" onBlur="saveToDatabase(this,'title', 'activities', 'activityid','<?php echo $activities[$k]["activityid"]; ?>')" onClick="showEdit(this);"><?php echo $activities[$k]["title"]; ?></td>
                <td contenteditable="true" onBlur="saveToDatabase(this,'description','activities','activityid','<?php echo $activities[$k]["activityid"]; ?>')" onClick="showEdit(this);"><?php echo $activities[$k]["description"]; ?></td>
                <td contenteditable="true" onBlur="saveToDatabase(this,'leaders','activities','activityid','<?php echo $activities[$k]["activityid"]; ?>')" onClick="showEdit(this);"><?php echo $activities[$k]["leaders"]; ?></td>
                <td contenteditable="true" onBlur="saveToDatabase(this,'time','activities','activityid','<?php echo $activities[$k]["activityid"]; ?>')" onClick="showEdit(this);"><?php echo $activities[$k]["time"]; ?></td>
              </tr>
        <?php
        }
        ?>
          </tbody>
        </table>
    </body>
</html>

dbcontroller.php

<?php
class DBController {
    private $host = "***********";
    private $user = "***********";
    private $password = "***************";
    private $database = "***********";



    function __construct() {
        $conn = mysqli_connect($this->host,$this->user,$this->password,$this->database) OR die ( mysqli_connect_error() );
    }

    function runQuery($query) {
        $conn = mysqli_connect($this->host,$this->user,$this->password);
        mysqli_select_db($conn, $this->database);
        $result = mysqli_query($conn, $query)or die(mysqli_error($conn));
        while($row=mysqli_fetch_assoc($result)) {
            $resultset[] = $row;
        }       
        if(!empty($resultset))
            return $resultset;
    }

    function numRows($query) {
        $result  = mysqli_query($conn, $query);
        $rowcount = mysqli_num_rows($result);
        return $rowcount;   
    }
}
?>

Answer 1

The problem is with your method runQuery, because it doesn't return anything if the results are empty. Simply add an else case where you just return an empty array, so that the foreach loop doesn't run e.g.

function runQuery($query) {
    $conn = mysqli_connect($this->host,$this->user,$this->password);
    mysqli_select_db($conn, $this->database);
    $result = mysqli_query($conn, $query)or die(mysqli_error($conn));
    while($row=mysqli_fetch_assoc($result)) {
        $resultset[] = $row;
    }       
    if(!empty($resultset))
        return $resultset;
    else
        return array();
}

Also I would recommend you to save your connection into a property and then use the property as connection variable, e.g.

function __construct() {
    $this->conn = mysqli_connect($this->host,$this->user,$this->password,$this->database) OR die ( mysqli_connect_error() );
  //^^^^^^^^^^^
}   

Then you can use it in other methods with $this->conn.

You also might want to take a look into mysqli_* prepared statements, it's much safer.