If you constantly listen to music on your smartphone, or above all do exercise with it, the Android app Headphone Connect might be quite helpful, as it allows you to launch the app of your choice automatically when you connect headphones to your device, whether via cable or Bluetooth.
The app’s main task is to make a small menu appear on your phone with a shortcut to a series of apps when headphones are detected, and can also be set up so that if you make an app launch, it will open directly and will start playing immediately.
Imagine you’re going out running with your smartphone strapped to your arm or stashed in your pocket. With this app you’ll save yourself the hassle of having to take out the device and manually start the desired app.
From the context menu in the upper right part of the app you can access various settings that let you make Headphone Connect run automatically when you start your smartphone or delete automatic Android notifications from the program and thus keep your upper notifications bar clear.
Further options including presetting your phone’s sound at a particular volume when you connect or programming an X-second delay from when the headphones are connected before doing the action.
My latest app allows you do choose any app to launch when headphones are connected. It also allows you to set up “reactions” for Bluetooth connect/disconnect (profiles for each device), WiFi connect/disconnect, incoming calls and power connections.
You can find it on Google Play and Amazon
YouBlue React
https://play.google.com/store/apps/details?id=com.kevinersoy.youbluereact