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Listview scroller stuck on iPhone

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This is a migrated thread and some comments may be shown as answers.

Ron asked on 03 Aug 2015, 04:53 PM

We have received a bug report from a user with our app, and we believe we have an idea where the cause might be.

Our App does a local-datasource set when the user edits a record, it then calls an API on our server and if the results from this API is OK, we perform a datasource sync.

Sometimes (it is not consistent) - the list-view scrolling gets stuck on an iPhone (we were unable to reproduce in Chrome, did not test it on Android) following one or more of these edit operations.

We managed to recreate the issue with a small sample (remember, you need to test it from a device, it does not happen in Chrome).

http://dojo.telerik.com/aReBU/10

We tried to simulate our app by doing the following:

When we edit, we do a set on the record, wait a random amount of time (to simulate the round trip to our server) and perform a sync on the datasource.

Please notice that to make the debugging easy, you actually do not need to change any values in the edit screen, just press the done button in it - and it will add a suffix to a field which will be set to the datasource and later synced.

It is important to remember to try and scroll the listview once the edit-dialog is closed - and repeat the edit/done/scroll until it gets stuck - it does not happen consistently and sometimes takes us 5 or 6 tries to get it stuck.

We suspect that the issue is related to the sync operation, but are not sure.

16 Answers, 1 is accepted

answered on 04 Aug 2015, 01:45 PM

Petyo, thanks,

We tried this suggestion and unfortunately, it did not help. The updated sample with the additional data-use-native-scrolling="true" is available at http://dojo.telerik.com/aReBU/11

At first it did seem faster and smoother but after about 7 times when clicking the Done button the scroller was stuck.

Is there no way to copy that bound events from the old DOM elements to the new ones on Sync?

If there is no way to do it automatically as part of the sync operation - Is there a way for us to manually unbind them before calling sync and manually bind them again after the sync is done?

answered on 10 Aug 2015, 11:57 PM

Petyo, Thanks. There is some progress, but unfortunately, one step forward, one step back.

When testing this version of the dojo on iPhone 5s the scroller was not stuck, but it seems that we lost the click evens handler.

In the first trial we edited 3 items (simply by clicking "Done"; Once clicked you can see the sufix "-X" was added was added to the item). After those 3 edit actions the items lost their click events and I could no longer edit any item. Unfortunately, this is as bad as a stuck scroller as both means the user must restart the app.

In another trial it only happen after the tenth edit operation. So it is not a consistent problem - but still unstable and problematic to release to actual users.

Is there a way to handle this case of click events that are not working while using the view native scrolling? Is there some other solution that will not force the users to restart the app?

answered on 12 Aug 2015, 08:38 AM

Screen-Shot-2015-08-12-at-11-34-03-AM.png

Hello Ron,

I am not sure what may cause this - the approach you have taken should work in general and the native scrolling should not interact with the taps. I tested the provided dojo in the native iOS emulator, and successfully edited a lot of items; see screenshot.

If you don't use the kendo touch events for something else, you may try using the listview click event instead. perhaps this will improve your case.

Regards,
Petyo
Telerik

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answered on 12 Aug 2015, 08:29 PM

Hello Petyo,

Thanks for you continued help. As suggested we edited the dojo, removed the touch events and added the listview click event. We performed several tests with this dojo (as before, simply by clicking the "Done" which adds "-X" suffix). The updated dojo is available at http://dojo.telerik.com/aReBU/15 and is based on the dojo you prepared for us earlier.

All our tests were done on a real iPhone 5s device with iOS 8.4 and all the tests ended in the same way: the click event eventually stopped working (which means that even when we clicked an item we stayed in the same view).

In some tests it happened after less than 5 edits while in others we managed to do more edits before the click was lost. The "longest rally" we had involved about 20 edits.

We appreciate your assistance on this matter and look forward to find a solution.

Thanks,

Ron.