Re: QuickChart doesn't display reliably on iPhones

Kirk_Masden · 02-19-2022 05:08 AM

I posted this in "Tips & Resources" by mistake. I couldn't figure out how to change the category so I'm posting it again and will erase the post in "Tips & Resources" once I confirm that this has been posted properly.

Background: If you are unfamiliar with QuickChart and are interested in expanding the native charting capabilities of AppSheet, please see the following post:

Using QuickChart in your apps
Posted on 01-06-2021 09:17 AM
https://www.googlecloudcommunity.com/gc/Tips-Tricks/Using-QuickChart-in-your-apps/m-p/255189

Issue: I would like to report an issue I have experienced and plan to report to AppSheet via Support. As far as I can ascertain, this issue only occurs under the following conditions:

When using an app on an iPhone (Android devices and web browsers work fine)
When Behavior --> Offline/Sync --> "Store content for offline use" is turned on I
When the QuickChart URL is fairly long because the chart is somewhat complicated (the URL in the example I introduce here today is a little over 1300 characters long)

I've made a sample app that demonstrates the issue (and, serves as an example of how QuickChart can be used in AppSheet):

QuickChart-iPhone issue

https://www.appsheet.com/templates?appGuidString=16c871db-8589-409d-baa4-13414bff34ce

The problem is that white space is show where the chart should be. The following gif shows the problem (white space at first where the graph should be and then two ways the user can get the graph to display):

There's a third way to get the graph to display: tap on the white space to display an enlarged version of the graph. That works but the graph space reverts to white afterward.

Ive known about this issue for a couple of months now. I found that turning Behavior --> Offline/Sync --> "Store content for offline use" off fix the display issue with QuickChart graphs but, recently, I've decided to switch back to "Store content for offline use." Offline use isn't the main reason; it's that I want images that supply user feedback ("Good job" or "Keep going" etc.) to appear instantly instead of after a delay of a second or two. I hope that the good people at AppSheet will view this as a bug worth fixing. I inquired about the same basic issue a couple of months ago and at that time the impression I got was that the person who helped me thought I should either just deactivate "Store content for offline use" or find a way to make the URL shorter. I've really tried but I can't make the URL much shorter than this and I think that any moderately complicated chart will be this long or longer. So, I've decided to request that the bug be looked at once more.

If you have any ideas for workarounds or other words of wisdom, please share them with me.

P.S. "Store content for offline use" is a global (whole app) setting. If we could adjust this by table, etc. that would be a big help. I want "system" images (cute animals, words of encouragement, etc.) to appear immediately but the rest of the content can be a little slower. It's too bad there's only one setting.

WillowMobileSys

I played with the sample app, on my desktop, iPhone and in the Editor. I do not see the issue you described.

Kirk_Masden

I see. Thanks for your help. I have an iPhone Xs and my wife has an iPhone 11. Perhaps newer iPhones are less likely to experience this issue. Could I ask what kind of iPhone you're using?

WillowMobileSys

I still have an iPhone 7!! 😫

Kirk_Masden

Interesting. I tried it on an old iPhone 6 that we're using as a music player but the result was the same.

Kirk_Masden

I think I'm going to give up for now, unless anyone else has any good ideas. I probably won't contact support about this again for the time being because my previous inquiry didn't get anywhere. In that case, the phenomenon was recognized but I guess it wasn't considered significant enough to try to remedy. So, for the time being, I've put the following in the heading above the graphic:

if(CONTEXT("Host")="Device","Graphic overview (tap if not showing)","Graphic overview")

This way, since the problem only occurs on mobile devices, only those users will see that they might want to tap the screen to make the image visible (for some reason, zooming temporarily fixes the problem).

Kirk_Masden

I should also note that the way to replicate the problem on an iPhone is to change the number of Apples in detail view. If the graph disappears and then reappears without doing anything else, the app is working properly on your iPhone. If, however, the chart part of the screen goes white and you have to do something to get it to reappear, then that's the issue I'm writing about. I assume you were able to change the value and that chart bounced back after recalculating without any problem.

Kirk_Masden

One more note: I just played around with my sample on my iPhone Xs and, in the process, it started to work. I'm not sure what would explain that but I can say that in the context of a more complicated app I'm working on, where the URL must be composed instantly from a variety of variables, it never works on my iPhone X (that is, never without navigating away once -- then it works) but always works right away on my browser and on my Android device. Hmmmm.

Kirk_Masden

I've continued to have issues with extremely long QuickChart URLs when I have "Offline use" turned on. An issue that is related to the issue in this thread is that long QuickChart URLs interfere with the loading of images when "Offline use" is on. I'm currently having it looked at by Support. See the following:

https://www.googlecloudcommunity.com/gc/AppSheet-Q-A/Image-loading-gets-stuck/m-p/460685/highlight/t...

I've suggested a resolution to the problem here:

https://www.googlecloudcommunity.com/gc/Feature-Ideas/Finer-grain-control-over-local-image-caching/i...