Looking for Android help

[Lokaser]

Since I'm quite terrible with searching, I'd like to ask for your help.
I'm looking for a way to backup contacts to computer , calendar and texts (and possibly more) on my Android phone through a computer. I'd like to be able to edit them, make a backup of them, and selectively copy them from one phone to another.
Now the problems:
1. I don't want a synchronization. I want an editor that works on the current data.
2. I don't want a cloud solution. I trust no-one and don't want my personal data somewhere on the web.
3. The solution has to be open-source. As I said, I'm paranoid and trust no-one.

Can you recommend anything? So far I haven't been able to find an app that would satisfy all of my requirements. The only solution that seems usable to me is MobilEdit, but it's proprietary (and I used to work for them, so I really really don't trust it

Alternatively, I'd like to write such an app, but I'm not so good with Android development, last time I tried something was with the 2.3 version, it's completely different nowadays. So if someone wants to help me make this happen, by providing the Android-side of things, let me know.

Well, accroding to your needs , you can install a Android data manager or Android data assistant , 
They are able to manage Android data , and you can transfer messages .contacts calendar and texts to computer for backup . you can even edit them on computer ,
You mean that i need to transfer contacts and SMS to computer , then we can manage these data on computer , 

The Android assistant doesn't work for me . it can even be described as bad ,especially in data transfer......