How do I make an app in a video?(message box)

ummary: When a shock is detected, Arduino transmits data to the smartphone via Bluetooth communication. At this time, the following message box appears on the background screen.

  1. How do I make the message box pop up?
  2. How do you plan to respond to receiving Bluetooth data even when the application is closed?
  3. How do I turn the app back on the message box?

How do I make an app in a video?
Please help me.

A good start is by checking this previous post: Notification builder

However, I don’t think the demo is complete as there are other technicalities that has to be addressed in the design. You need to have a look at