为什么我的Android应用程序中的JSON数组无法正确打印？

In my PHP file I have code including:

    while ($row = $result->fetch_assoc()) {

  //make an array called $results
    $results = array();

    $results[] = array(
    'contact_phonenumber' => $row['username'], 
         );


    $json2 = json_encode($results); 
   //this is the response which we want in the Android app
    echo $json2;

And in my Android App I have:

public void onResponse(String response) {
   //print the JSON Array from the php file
   System.out.println("the jsonarray is : " + response;

The response I get when I print is in the format :

[{"contact_phonenumber":"+11111"}][{"contact_phonenumber":"+22222"}][{"contact_phonenumber":"+33333"}][{"contact_phonenumber":"+44444"}][{"contact_phonenumber":"+55555"}]

But shouldn't it be in the format ? :

[{"contact_phonenumber":"+11111"}, {"contact_phonenumber":"+22222"},{"contact_phonenumber":"+33333"}, {"contact_phonenumber":"+44444"},{"contact_phonenumber":"+55555"}]

How can I acheive this?

Try this:

$result = [];
while ($row = $result->fetch_assoc()) {
  array_push(['contact_phonenumber' => $row['username']], $result);
}
$json2 = json_encode($result); 
//this is the response which we want in the Android app
echo $json2;