在加载更多之前等待加载块

I'm building an app, where I need to load data in chunks, I mean first load 5 items and then proceed with another 5, but I can't figure out how to do that. At the moment I chunk up my list of items, so I get a list of lists with 5 items in each. Right now the for-loop just fires away with requests, but I want to wait for the response and then proceed in the for loop.I'm building an app, where I need to load data