$ list必须是一个数组，您可以像下面的代码中那样将项目推入其中:

$list needs to be an array, and you can just push items to it like in this code:

$list = array();
while($stmt->fetch()){
    $list[] = array('id' => $fid, 'name' => $fname);
}
$stmt->free_result();
$stmt->close();
echo json_encode($list);

您还可以使用方法 fetch_all()来获取所有行一次，而不是循环遍历.尽管在此示例中，您将获得所选的所有字段，而不仅仅是ID和名称.

You could also use the method fetch_all() to get all rows at once, instead of iterating with a loop. Although in this example you'd get all fields that you've selected, instead of just id and name.

$list = $stmt->fetch_all();
$stmt->free_result();
$stmt->close();
echo json_encode($list);