Apps First android app - avatar widget on home screen



I want to build a widget for my android device, this is my very first android app but for me would be a very nice feeling to have created this specific one.

I would like the widget to be able to display my users avatars on there phone home screen. The images should load different when they input there username onto the settings for the widget, therefore loading a different image for each user.

How can i make this basic app, any tutorials for this, specifically?