解析没有值的数据org.json.JSONException时出错

Question

我遇到了问题，我无法弄清楚出了什么问题

这是我用json响应的php

 //Verificado
if ($tag == 'reqSalasCheck') {
    $sala = filter_input(INPUT_POST, 'sala');
    $inicio = filter_input(INPUT_POST, 'inicio');
    $fim = filter_input(INPUT_POST, 'fim');
    $data = filter_input(INPUT_POST, 'dataFinal');
    $dias = strftime('%A', strtotime($data));
    $newDate = date("Y-m-d", strtotime($data));
    $diaId = mysql_query("SELECT * FROM `ebspma_paad_ebspma`.`semana_dias` WHERE dia ='$dias'");
    $diaRow = mysql_fetch_row($diaId)or die(mysql_error());
    $Dias = $diaRow[0];
    if ($Dias != null) {
        $inicioId = mysql_query("SELECT `idtempo` FROM `ebspma_paad_ebspma`.`req_material_tempo` WHERE `inicio`='$inicio'");
        $inicioRow = mysql_fetch_row($inicioId)or die(mysql_error());
        $inicio = $inicioRow[0];
        if ($inicio != null) {
            $salaId = mysql_query("SELECT `idsala` FROM `ebspma_paad_ebspma`.`req_material_sala` WHERE `sala` = '$sala'");
            $salaRow = mysql_fetch_row($salaId)or die(mysql_error());
            $sala = $salaRow[0];
            if ($sala != null) {
                $fimId = mysql_query("SELECT `idtempo` FROM `ebspma_paad_ebspma`.`req_material_tempo` WHERE `fim`= '$fim'");
                $fimRow = mysql_fetch_row($fimId)or die(mysql_error());
                if ($fim != null) {
                    $checkIfOcupado = mysql_query("SELECT COUNT(id_dia) FROM `ebspma_paad_ebspma`. `sala_ocupacao` WHERE id_dia = '$Dias' AND id_sala= '$sala' AND id_tempo = '$inicio'");
                    $checkResult = mysql_fetch_row($checkIfOcupado) or die($checkIfOcupado . "<br/><br/>" . mysql_error());
                    $checkResultado = $checkResult[0];
                    if ($checkResultado > 0) {
                        $response["error"] = 2;
                        $response["error_msg"] = "Hora marcada no ano";
                        echo json_encode($response);
                    } else {
                        $checkIfReservado = mysql_query("SELECT COUNT(*) AS total FROM `ebspma_paad_ebspma`.`req_material_reserva` 
                        WHERE `ebspma_paad_ebspma`.`req_material_reserva`.`idsala` = '$sala'
                        AND (((`req_material_reserva`.`idtempoInicio` BETWEEN '$inicio' AND '$fim') AND (`req_material_reserva`.`idTempoFim` BETWEEN '$inicio' AND '$fim'))
                        OR (`req_material_reserva`.`idtempoInicio` <= '$inicio' AND `req_material_reserva`.`idTempoFim` >= '$fim'))
                        AND `req_material_reserva`.`data` = '$newDate'");
                        $checkReserva = mysql_fetch_row($checkIfReservado) or die($checkIfReservado . "<br/><br/>" . mysql_error());
                        $checkReservado = $checkReserva[0];
                        if ($checkReservado > 0) {
                            $response["error"] = 2;
                            $response["error_msg"] = "Oops! Sala reservada";
                            echo json_encode($response);
                        } else {
                            $response["success"] = 1;
                            $response["message"] = "Sala disponível.";
                            echo json_encode($response);
                        }
                    }
                }
            }
        }
    }
}

这是我的android java，其中称为

private static final String KEY_MESSAGE = "message";
private static final String KEY_MESSAGE_ERROR = "error_msg";     
JSONObject salasCheck = userFunctions.reqSalasCheck(sala, inicio, fim, dataReserva);
        try {
            String res = salasCheck.getString(KEY_SUCCESS);
            Log.d("Mensagem", res);
            String error = salasCheck.getString(KEY_ERROR);
            Log.d("Mensagem", error);
            if (Integer.parseInt(res) == 1) {
                String messageOK = salasCheck.getString(KEY_MESSAGE);

但我收到此错误

解析数据时出错org.json.JSONException：字符0处的输入结束 org.json.JSONException：消息没有值

我的php定义了消息..