Please use File - Export as zip when uploading projects.
Don't change the activity color. Change the theme in the manifest editor:
B4X:
CreateResourceFromFile(Macro, Themes.LightTheme)
Complete code:
B4X:
Activity.LoadLayout("Layout1")
Spinner1.AddAll( Array As String("Ok", "Le voci piu corte", "Su device Huawei", "Non prendono il click","Se non dove ho del testo", "Prova a premere la voce ok ma sulla destra"))
Spinner1.TextSize = 15