BarcodeBC > Articles > How to Change the Intermediate Screen When the QR Code Is Scanned?
This is a tutorial for changing the intermediate screen when the QR Code is scanned. The user will open the app, install the app, or open details from the website. You will see general steps and C#/Python/Java coding examples below.
To change the intermediate screen when the QR Code is scanned, you will need to modify the code of your QR Code reader app. Here are some general steps you can follow.
1. Identify the section of your code that displays the intermediate screen after the QR Code is scanned. This is usually where you process the QR Code data and perform any necessary actions.
2. Modify the code to include logic that checks whether the user has installed the app or opened it before. If the user has installed or opened the app before, you can skip the intermediate screen and take them directly to the appropriate screen in the app.
3. If the user has not installed or opened the app before, you can display a different screen that prompts them to install or open the app. This screen can include information about the app and a call-to-action to download or open it.
4. If the QR Code contains details from a website, you can modify the code to open the website in a webview or redirect the user to their default web browser.
Keep in mind that the specific implementation will depend on the programming language and framework you are using to build the QR Code reader app.
Here's an example code in C# using BarcodeBC.com .NET Barcode Reader library to decode the QR Code and send the data to a server via HTTP POST request
using System;
using System.Collections.Generic;
using System.IO;
using System.Net;
using System.Text;
using BC.NetBarcodeReaderTrial.All;
namespace QRCodeScannerBot
{
class Program
{
static void Main(string[] args)
{
// Initialize the BarcodeBC.com .NET Barcode Reader object
ReadOneBarcodeTypefromImage();
// Read the QR Code from an image file
string[] qrCodeData = NetBarcodeReader.Recognize("C:\path\to\qr\code\image.png", NetBarcodeReader.Qrcode);
// Send the QR Code data to the server via HTTP POST request
string url = "http://example.com/qr-code-handler";
Dictionary<string, string> postData = new Dictionary<string, string>()
{
{ "qr_code_data", qrCodeData }
};
string response = SendPostRequest(url, postData);
// Display the server response
Console.WriteLine(response);
}
static string SendPostRequest(string url, Dictionary<string, string> postData)
{
string result = string.Empty;
HttpWebRequest request = (HttpWebRequest)WebRequest.Create(url);
request.Method = "POST";
request.ContentType = "application/x-www-form-urlencoded";
string postDataString = string.Empty;
foreach (KeyValuePair<string, string> pair in postData)
{
postDataString += string.Format("{0}={1}&", pair.Key, pair.Value);
}
byte[] postDataBytes = Encoding.UTF8.GetBytes(postDataString);
request.ContentLength = postDataBytes.Length;
using (Stream stream = request.GetRequestStream())
{
stream.Write(postDataBytes, 0, postDataBytes.Length);
}
HttpWebResponse response = (HttpWebResponse)request.GetResponse();
using (StreamReader reader = new StreamReader(response.GetResponseStream(), Encoding.UTF8))
{
result = reader.ReadToEnd();
}
return result;
}
}
}
Note that you need to replace the imagePath, url, and postData variables with your own values. Also, make sure to import the BarcodeBCEncodeDecode namespace and add a reference to the BC.NetBarcodeReader.dll library in your project. BTW, the BC.NetBarcodeReaderTrial.All is for the trial version.
Here's an example code in Python using the pyzbar library and Telegram Bot API to scan a QR Code and send the data to a server, and then receive a confirmation message from the server.
import requests
import telegram
from telegram.ext import Updater, CommandHandler, MessageHandler, Filters
from pyzbar.pyzbar import decode
from PIL import Image
# Enter your Telegram bot token here
BOT_TOKEN = 'your_bot_token'
# Enter your server URL here
SERVER_URL = 'your_server_url'
# Initialize the Telegram bot
bot = telegram.Bot(token=BOT_TOKEN)
# Define a command handler to start the bot
def start(update, context):
update.message.reply_text('Hello! Send me a QR Code to scan.')
# Define a message handler to scan the QR Code
def qr_scan(update, context):
# Get the photo file from the message
photo_file = update.message.photo[-1].get_file()
# Download the photo file and save it as a PIL Image object
photo = Image.open(requests.get(photo_file.file_path, stream=True).raw)
# Decode the QR Code in the image using pyzbar
qr_data = decode(photo)
if qr_data:
# Get the data from the QR Code
qr_data = qr_data[0].data.decode('utf-8')
# Send the data to the server
response = requests.post(SERVER_URL, data={'qr_data': qr_data})
# Check the response status code
if response.status_code == 200:
# If the server returns a success message, send it to the user
update.message.reply_text('QR Code data sent to server. '
'Server response: {}'.format(response.text))
else:
# If the server returns an error message, send it to the user
update.message.reply_text('QR Code data sent to server, '
'but server returned an error. '
'Server response: {}'.format(response.text))
else:
# If no QR Code is found, send a message to the user
update.message.reply_text('No QR Code found in the photo. '
'Please try again.')
# Initialize the Telegram bot updater and dispatcher
updater = Updater(token=BOT_TOKEN, use_context=True)
dispatcher = updater.dispatcher
# Add the command and message handlers to the dispatcher
dispatcher.add_handler(CommandHandler('start', start))
dispatcher.add_handler(MessageHandler(Filters.photo, qr_scan))
# Start the bot
updater.start_polling()
Note that this code assumes that you have set up a server that can receive POST requests with the QR Code data in the qr_data parameter, and return a success or error message. You will need to modify the SERVER_URL variable to match your server's URL.
Here's an example code in Java for a Telegram bot that scans QR Codes and sends the data to a server, and then receives a confirmation message from the server.
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.URL;
import java.net.URLEncoder;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.Future;
import org.telegram.telegrambots.bots.TelegramLongPollingBot;
import org.telegram.telegrambots.meta.api.methods.send.SendMessage;
import org.telegram.telegrambots.meta.api.objects.Update;
import org.telegram.telegrambots.meta.exceptions.TelegramApiException;
import com.google.zxing.BarcodeFormat;
import com.google.zxing.BinaryBitmap;
import com.google.zxing.DecodeHintType;
import com.google.zxing.MultiFormatReader;
import com.google.zxing.ReaderException;
import com.google.zxing.Result;
import com.google.zxing.client.j2se.BufferedImageLuminanceSource;
import com.google.zxing.common.HybridBinarizer;
public class MyTelegramBot extends TelegramLongPollingBot {
private static final String BOT_TOKEN = "YOUR_BOT_TOKEN";
private static final String BOT_USERNAME = "YOUR_BOT_USERNAME";
private static final String SERVER_URL = "http://your.server.com/qrcode_handler.php?data=";
private ExecutorService executor = Executors.newSingleThreadExecutor();
private Future currentTask = null;
@Override
public void onUpdateReceived(Update update) {
String chatId = update.getMessage().getChatId().toString();
String text = update.getMessage().getText();
if (text != null && text.startsWith("/start")) {
SendMessage message = new SendMessage()
.setChatId(chatId)
.setText("Welcome to my QR Code scanner bot! Please scan a QR Code.");
try {
execute(message);
} catch (TelegramApiException e) {
e.printStackTrace();
}
} else if (update.getMessage().getPhoto() != null) {
String fileId = update.getMessage().getPhoto().get(update.getMessage().getPhoto().size()-1).getFileId();
String filePath = getFilePath(fileId);
String decodedData = decodeQRCode(filePath);
SendMessage message = null;
if (decodedData == null) {
message = new SendMessage()
.setChatId(chatId)
.setText("Sorry, I couldn't decode the QR Code. Please try again.");
} else {
message = new SendMessage()
.setChatId(chatId)
.setText("QR Code data: " + decodedData);
// Send the QR Code data to the server
if (currentTask != null && !currentTask.isDone()) {
currentTask.cancel(true);
}
currentTask = executor.submit(new Runnable() {
@Override
public void run() {
try {
String encodedData = URLEncoder.encode(decodedData, "UTF-8");
URL url = new URL(SERVER_URL + encodedData);
HttpURLConnection con = (HttpURLConnection) url.openConnection();
con.setRequestMethod("GET");
BufferedReader in = new BufferedReader(new InputStreamReader(con.getInputStream()));
in.close();
} catch (IOException e) {
e.printStackTrace();
}
}
});
}
try {
execute(message);
} catch (TelegramApiException e) {
e.printStackTrace();
}
}
}
private String getFilePath(String fileId) {
try {
GetFile getFileMethod = new GetFile();
getFileMethod.setFileId(fileId);
File file = execute(getFileMethod);
return file.getFilePath();
} catch (TelegramApiException e)