you tell what app may i develop ?
no, not really. It’s something you need to figure out. I’m not saying this to avoid helping you; if you’re going to work on something and be successful at it, it needs to be something you have taken to heart and really need/want/understand. That’s not something someone else can do for you. It’s like choosing your favorite color: I simply can’t tell you what it is.
I can tell you that you probably won’t find your ideal app in “a week or so.” My framework, for example, is the result of years and years of other ideas. If I’d tried to make it when I was just starting out, after a week of thought, it would have fallen flat on its face.
So, seriously, choose one, simple idea and make that first. It will be an achievable task, and you’ll learn lots of useful stuff in doing it.