搜索已登录用户的名称

Question

Well I've got a website, in the header of this website I've got two links, one to login and another one to register. I want that, when the user is logged in, those two links disappear, so i can have one saying "Hello " followed by a link to the control panel. like "Hello . . The thing is that it isn't searching the name of the user. It just doesn't show the name. The user is logged with the email and password, and the function usuarioEstaLogado() is the one that confirm the user is logged. Here's the codes:

   function nomeUsuario($conexao){
        $usuarios = array();
        $query = "select nome from usuarios where email = '{$mail}'";
        $resultado = mysqli_query($conexao, $query);
        while($usuario = mysqli_fetch_assoc($resultado)){
            array_push($usuarios, $usuario);
        }
        return $usuarios;
    }


<?php
session_start();
function usuarioEstaLogado() {
    return isset($_SESSION["usuario_logado"]);
}

<div class="container container-twelve">

        <header>
            <div class="twelve columns top remove-bottom">
                <div class="three columns offset-by-nine">
                    <?php 
                        if(usuarioEstaLogado()){
                            $usr = nomeUsuario($conexao);
                            echo" <p>Ola " . $usr['nome'];
                            "<a href='admin'> Painel de Controle</a></p>";
                        }
                    ?>
                    <p><a href="cadastro.php">Cadastre-se</a> | 
                    <a href="login.php">Login <span class="icon-user"></span></a></p>
                </div>

Answer 1

In your top function

    $query = "select nome from usuarios where email = '{$mail}'";

$mail is undefined, you haven't pulled it from global, nor passed it to the nomeUsario function, so that query probably doesn't return anything.

Your nome function should probably accept an email. Additionally, you probably want the first match in the db, not all of them, like:

function nomeUsuario($conexao, $mail) {
    $query = "select nome from usuarios where email = '{$mail}'";
    $resultado = mysqli_query($conexao, $query);
    if ($usuario = mysqli_fetch_assoc($resultado)) {
        return $usuario;
    } else {
        return false;
    }
}

and when you call it, you need the email address, which I am *guessing* is in the $_SESSION?

$usr = nomeUsuario($conexao,$_SESSION['usuario_email']); //or whatever the name may be :-)
echo" <p>Ola " . $usr['nome'];