Non Static instance to static Android Studio

Question

I create a project for my work, and I need to filter by User the data store on MySQL and sent to a listview with this:

MainActivity

public class pendientes extends AppCompatActivity{

//tvuser is elegible: John, Mike, etc
TextView tvuser;

private static final String BASE_URL = "http://jjj.freeoda.com/json_user_fetch.php?user=";
private static final String USUARIO = tvuser.getText().toString()+"";
private static final String apiurl = BASE_URL + USUARIO;

But I receive the follow error message: Non-static field 'USUARIO' cannot be referenced from a static context

DB MySQL:

ID	Person	User
1	Juan Lopez	jhon
2	Esteban Morales	mike
3	Luis Miguel	jhon
4	Juan Gabriel	jhon

In example, if I choose John, my listview only populate with: Juan Lopez Luis Miguel Juan Gabriel

If I choose Mike the results: Esteban Morales

My PHP API

<?php
$conn=mysqli_connect("localhost","user","pass");
mysqli_select_db($conn,"dbname");
$user=$_GET['user'];
$qry="select * from jurado where user= '$user'";
$raw=mysqli_query($conn,$qry);
while($res=mysqli_fetch_array($raw))
{
     $data[]=$res;
}
print(json_encode($data));
?>

How could I do to send a variable data (USER) to URL?

Answer 1

You make at least 2 mistakes

TextView tvuser; is a non-static class field that does not exist until you create an instance of class pendientes

and also if tvuser were static you couldn't call .getText() on it since you would do it over a null reference. In java object variables are null until you assign them an object, usually using new.