Every time you open the app it downloads the most recent price data. The app uses the 4-hours interval price data (like viewing a candle chart where each candle represents 4 hours). That means you get 6 price points in one day. Logically, the biggest "delay" - compared to the current price can be 4 hours. I tried to make the interval 1 hour, or even 15 minutes, but then the app gets very laggy.
Thanks for your reply

So it's give right time data from binance exchange ? That's actually I am looking but it's looks like the application you build is only working on PC . Do you have mobile app or are you planning to make mobile if for example many people use the app you make. Its very helpful for traders if you have it in mobile so they can monitor the price wherever they go and with only need data connection to open.