This is probably important. I notice that in real-time text communication I can't really hold my full attention on the relationship because there just isn't enough there to work with, so I tend to try to switch back and forth between the conversation and my own internal world... it doesn't work very well; the rhythm of the communication is all wrong. If your friend is like me, then what you see as disinterest is probably more like "huhwhat? I was thinking about something else." (like
this)
You might want to consider sticking to voice (where the rhythms work more naturally) and non-real-time text (where short-term rhythms don't really matter).