如何使用wordpress创建csv导出按钮

Question

大家好，所有wordpress开发者：请帮我看看如何创建将导出csv的按钮。我在下面创建了一些函数作为csv输出，但我现在的问题是如何使用按钮或href调用此函数。用wordpress方式谢谢。

function csv(){

    global $wpdb;

    $sql = "SELECT * from activity  WHERE activity_date = '2016-08-07' ";
    $MyQuery = $wpdb->get_results($sql);

// Process report request
 if (! $MyQuery) {
    $Error = $wpdb->print_error();
    die("The following error was found: $Error");

 } else {

    $csv_fields=array();
    $csv_fields[] = 'Activity Date';
    $csv_fields[] = 'Name';
    $csv_fields[] = 'Activity Name';
    $csv_fields[] = 'Email Address';
    $csv_fields[] = 'Phone No.';

    $output_filename = 'MyReport.csv';
    $output_handle = fopen( 'php://output', 'w' );

    header('Content-Disposition:attachment'); 
    header('Content-type: application/csv');
    header('Content-Disposition: attachment; filename="'.$output_filename.'"' );

// Insert header row
    fputcsv( $output_handle, $csv_fields );

foreach ($MyQuery as $Result) {
    $leadArray = (array) $Result; // Cast the Object to an array
        fputcsv( $output_handle, $leadArray );
    }
  exit;
  }
}