我的应用程序有问题我的数据库中有一个用户表，有3列，现在我想从我的数据库（服务器）获取用户注册时间并发送到我的应用程序，它显示在应用程序的用户配置文件（作为对话框）中。这是我的php代码：

function get(){

$connection = connectToDatabase();
$Username = $_REQUEST['Username'];
$Pass = $_REQUEST['Pass'];

if($Username!="" && $Pass!=""){

        $result = mysqli_query($connection,"select Date from users where Username='$Username' and Pass='$Pass');

    $array_finish = array();
    while($row = mysqli_fetch_array($result)){

        $record = array();
        $record['Date'] = $row['Date'];
        $array_finish[] = $record ;
    }

    echo json_encode($array_finish);

}else {
    print "null";
}
mysqli_close($connection); }

但我在这个代码中有一些错误，我不知道如何在我的应用程序中获取这些信息。我知道我的安卓系统代码不正确，是我的安卓系统代码：

private void ShowProfile(){

    profile = new MaterialDialog.Builder(MainActivity.this)
            .customView(R.layout.alert_aprofile,false)
            .show();

    AsyncHttpPost post = new AsyncHttpPost(
            "http://********/profile.php"
    );

    post.setTimeout(5000);
    MultipartFormDataBody body = new MultipartFormDataBody();
    body.addStringPart("Username",sp.getString("Username", null));
    body.addStringPart("Pass",sp.getString("Pass", null));
    post.setBody(body);

    AsyncHttpClient.getDefaultInstance().executeString(post, new AsyncHttpClient.StringCallback() {
                @Override
                public void onCompleted(final Exception e, AsyncHttpResponse source, final String row) {

                    if (e != null) {
                        MainActivity.this.runOnUiThread(new Runnable() {
                            @Override
                            public void run() {
                              wait.dismiss();
                                Toast.makeText(MainActivity.this, "no connection", Toast.LENGTH_LONG).show();
                                e.printStackTrace();
                            }
                        });
                    }

                    if (!row.equals("")) {
                        profile_time = (TextView)profile.findViewById(R.id.profile_time);
                        profile_time.setText(row);
                    }else if(row.equals("null")){

                        runOnUiThread(new Runnable() {
                            @Override
                            public void run() {
                                wait.dismiss();
              ;
                            }
                        });

                    }
                }
});

请帮我纠正一下。。
我编辑android代码到新的代码，但我知道这是不正确的，不工作。。。

private void ShowProfile(){

    profile = new MaterialDialog.Builder(MainActivity.this)
            .customView(R.layout.alert_aprofile,false)
            .show();

    AsyncHttpPost post = new AsyncHttpPost(
            "http://****************profile.php"
    );

    post.setTimeout(5000);
    MultipartFormDataBody body = new MultipartFormDataBody();
    body.addStringPart("Username",sp.getString("Username", null));
    body.addStringPart("Pass",sp.getString("Pass", null));
    post.setBody(body);

    AsyncHttpClient.getDefaultInstance().executeString(post, new AsyncHttpClient.StringCallback() {
                @Override
                public void onCompleted(final Exception e, AsyncHttpResponse source, final String result) {

                    if (e != null) {
                        MainActivity.this.runOnUiThread(new Runnable() {
                            @Override
                            public void run() {
                                wait.dismiss();
                                Toast.makeText(MainActivity.this, "no connection", Toast.LENGTH_LONG).show();
                                e.printStackTrace();
                            }
                        });
                    }

                    if (!result.equals("")) {
                        MainActivity.this.runOnUiThread(new Runnable() {
                            @Override
                            public void run() {
                                items.clone();
                                try {
                                    JSONArray jsonArray = new JSONArray(result);
                                    for (int i = 0; i < jsonArray.length(); i++) {
                                        JSONObject object = jsonArray.getJSONObject(i);
                                        HashMap<String, Object> hash_add = new HashMap<String, Object>();

                                        hash_add.put("Date", object.getString("Date"));

                                        hash_all.add(hash_add);
                                        items = new String[hash_all.size()];
                                    }

                                } catch (Exception e) {
                                    e.printStackTrace();
                                }
                            }
                        });
                    }
                }

});