Android-检查MySQL中的SELECT语句返回值

Question

I will explain what I want to do before getting in the codes, I have Android project, connected to MySQL database, and I have a password recovery activity in my app, in this activity the user will type his email in order to get his log in information, so when the user click send the app will check if the email exists in the database or not, if yes will send an email and if no will notify the user.

Now, in the PHP side every thing works will, I wrote the query and it returns correct values.

public function getUName($UEmail) {
    if ($UEmail != NULL) {
        $data = array();    
        $sql = "Select UName FROM `user` WHERE `Email`= '" . $UEmail . "'"; 
        $result = $this->db->query($sql);
                    while ($row = $result->fetch_array(MYSQLI_ASSOC)) {
        $data[] = $row;
    }

    return $this->_jsonEncode( $data );

    }
}

I know that in PHP if I want to check if the SELECT statement return value or not I will write something like:

if (mysql_num_rows($result) > 0) 

But what about in Android side? I have this function:

private boolean getUserInfo(String uEmail)
{
    String getInfo_URL = SERVER_URL + "GetInfo.php?email=" + uEmail;
    new CommunicatetoServer().execute(getEmail_URL);
    return true;
}

I want this function to return true if the SELECT statement returned value, and false otherwise.

Thank you in advance.

Answer 1

new CommunicatetoServer().execute(getEmail_URL);

You must implement CommunicatetoServer in such way, that after executing http request, it will get data received from the server.

You really need implement HTTP request in another thread, for example using AsyncTask (or using external libs for http requests) and to use Callback that will be triggered when CommunicatetoServer will receive data returned from the server.

In your case, PHP script returns JSON data. You just need to parse received JSON data to an java object representation.

You can use for example GSON library for JSON parsing in Android

Some notes:

• Your PHP code is very bad. It's insecure - you have SQL injection vulnerability
• Is field "Email" unique in DB? (It must be) - If yes, use fetch_row() instead fetch_array()