Haven’t worked on a just-in-time loader in awhile but I imagine what you would do is:
-
Either using event.phase == “moved” (if the scrollView supports it?) or a Runtime listener, keep a variable going that reports back :getContentPosition() so you know how much scrolling is going on.
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Whenever the scroll exceeds a certain amount (say, rowHeight), load one row and unload another (create and delete) based on the direction it’s moving.
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Save something on the row data so you know where it belongs from the table. Let’s say that all of your users are being stored in a table, so that users[1] = “Jacky”, users[2] = “Florence”, and so on.
for i = 1, 8 do -- let's say you're making 8 rows
local row = display.newRect(0,0,32,32) -- or whatever display object/group it is
row.id = i -- "i" is the index from the table, in this case users{}
scrollView:insert(row)
end
- Then, when you use Runtime to update the rows…
if scrolling \<= rowHeight then -- scrolling has exceeded 1 row upwards
-- [1] delete the topmost row from scrollView
-- [2] add a new row to the bottom of scrollView
elseif scrolling \>= rowHeight then -- same thing, but downwards
-- [1] delete the bottomMost
-- [2] add a new row to the top
end
Now, assuming scrollView content works like other display Groups (previously it didn’t, but a quick look right now says it does, am I right?) you would do this:
-- To find the id above the topmost row
local newRow\_id = scrollView[1].id - 1
-- To find the id below the bottommost row
local newRow\_id = scrollView[scrollView.numChildren].id + 1
(Just make sure to check that the id never becomes 0 or a number bigger than the table itself)
tl;dr
The basic idea is to just render as normal and then append one-at-a-time as you go. (Although, if scrollspeed is *too* fast, you may need to render two or more at a time…) [import]uid: 41884 topic_id: 34443 reply_id: 136904[/import]
