Please explain why the library is not working? I can neither write to activity_main.xml nothing and in MainActivity.class .

[woors]

the library just refuses to work. I also can't launch the application I downloaded (source code). Nothing helps

[jacksonke]

the library just refuses to work. I also can't launch the application I downloaded (source code). Nothing helps

I don't think it is maintained now. In the past, the library is uploaded to jcenter, but not to mavenCentral. Now, jcenter is deprecated.