Scroll to bottom does not work correctly if the newest message in the conversation is long

[ThiemNguyen]

Hi,

I've just found another glitch with scroll-to-bottom feature which hasn't seem to be reported yet. Steps to reproduce:

• Open demo app (it's not necessary to start with an empty conversation).
• Type in a fairly long lorem ipsum message (around 15-line one in my test case).

Issue:

• When I send the message, it actually scrolls way down but just around a little bit more than half of the message's height, causing the keyboard to hide the message partially.
• When I pull to dismiss the keyboard, and manually scroll to bottom, then tap textview to active the keyboard again, similar issue is happened.

Here is the screenshot:

The full message:

Another point I noticed is that this issue only happens if that long message is the latest one in the conversation. If we add a short message after it, the collection view scrolls correctly.

[jessesquires]

Thanks @ThiemNguyen - sounds related to #256

[gblazex]

With #256 resolved this could be closed for now as well.

[jessesquires]

@galambalazs - can you confirm that this is fixed?

(I think I tested the other day and could still reproduce....)

[gblazex]

You are right, I just thought it was the same issue. Still happening.
Let's see if I can track down what's causing this.

[toblerpwn]

This issue appears to be caused by using the wrong scroll position at JSQMessagesViewController.m:368. Using UICollectionViewScrollPositionBottom fixes the problem.

See PR #644

[gblazex]

Yes I noticed this too and it's logical. You want it to be bottom aligned (instead of sending the last message to the top, because for long messages it means the bottom part will be cut off).

The only problem is that this doesn't leave a nice margin below the last cell.

If we could crack that we are golden.

[toblerpwn]

My PR #644 addresses both cases as best we can: small cells get 'Top' scroll position, and large cells get 'Bottom'. It is slightly imperfect for large cell bottom padding (for the issues you mention) but certainly an improvement.

[gblazex]

Yes maybe it could be added as a temporary fix

(although when those two words bond together time seems to fade away... :-)

[toblerpwn]

Agreed; it is better than what is in field for handling huge cells, but still imperfect due to (probably) UIKit native margin handling. Will make note stating the same in the PR.