To install this app, you have to open the project (findable here [créer le lien adéquat]) on Android Studio. For this, follow File>New>Import Project… and then select the app, and you are good to go. The huge advantage of this app is that you can modify if as desired, for example, if you want to have a button to toggle a light, it would be pretty easy to do.
The thing is: it does not support older versions of Android, so if you need to do some testing with an older phone, you can use myMQTT, an app you can find on the Play Store. It should be noticed that the two applications have no problem what so ever to communicate: they seem fully compatible, so it’s not a problem if some of you have the Paho one and others have the myMQTT one.
To realize your app, I advise you to open two instances of the project and, for the second one, rename it once you have selected the file (you should be on a popup with only one field, “Import Destination Directory:”, at this point). This will allow you to have both one app that you are sure it is working, and the app you will create. On this app, my last advice will be to strip it off to its bones, to have only the libraries and the needed basic structure, and to start over from this point.
To use the basic application, press the “+” at the top right of the screen to start a new connection, choose your client name (it must be unique on the network) and the server ip: 192.168.12.172 and finally the port: 1883. All those values are the default ones for or network but can be modified (if so, be careful and stay coherent between the server and