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Testing and Issues

You can test this app and submit issues during the testing period of the Android Chart contest.

Entries with serious issues will not be able to win the contest, but even minor issues might be important for overall results.


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Some glitches, but good speed and nice animations. Well done.

I seem to have caught a crash on Samsung A7, but couldn't reproduce.
Samsung Galaxy S4, Android 5.0.1
Desert Gorilla Aug 8, 2019 at 09:25
Source code for this contest can be found at
Fair Mammoth Apr 28, 2019 at 18:01
– Very good speed and performance.
– Short delay on launch.
– Filtered values in the data point info are not disappear, they're just blurred.
– Bonus goal is completed, but the values logic on the pie chart is incorrect (the attached video). The slider changes the position after scrolling by itself.
LG Nexus 5X, Android 8.1.0; Samsung Galaxy J7, Android 8.1.0
Show same distance between grid lines, but not same difference between values
Desert Gorilla Apr 19, 2019 at 16:31
Indeed, thanks for reporting.
The values themselves have uniform distribution, it is a rounding issue introduced by labels formatter. This is how it looks without formatter:
For the pie chart the task was to show average values, not the sum
All devices
Desert Gorilla Apr 19, 2019 at 13:34
Indeed, missed this part, thanks for reporting
Tooltip still opened without displaying selected sector
Xiaomi A1 / Anroid 9
Desert Gorilla Apr 24, 2019 at 02:25
Agree, should be hidden in this case
X scale on 29 April 2018 in the 4th chart starts from 08:40
All devices
Desert Gorilla Apr 19, 2019 at 13:35
Thanks for reporting! This is what we actually have in provided data, I didn't apply any data fixes in the chart widget.
The first three chart have skipped points in the zoom mode on 29 April 2018
All devices
Desert Gorilla Apr 19, 2019 at 10:01
Same as above, this is what we actually have in provided data and the chart is showing it as is.
Charts state is not preserved on orientation change
All devices
Desert Gorilla Apr 19, 2019 at 10:15
Thanks for noting, indeed, there is no state restoration. But most of other contestants don't have landscape orientation at all, so I could just lock the app into portrait.
Poor performance on transitions
Xiaomi A1 / Android 9
Desert Gorilla Apr 24, 2019 at 11:41
Hm, that's unfortunate, works fine on all my test devices, strange to see such issues on a modern device. There is definitely a room for optimizations here.

I want to note, that the charts themselves should work smoothly on this device as well (I would expect you to create a dedicated issue if it wasn't a case), so only the transition for bonus part may lag on some devices.
1. Wrong Clip Bounds.
The screenshot is made DURING RUNNING ANIMATION, in order to show clip bounds.
Umi Super, Android
No points "run" animation on selection change. But you've managed to do the bonus tasks, so it's not a big deal :) Congrats :)
Redmi note 5 / Android 8.1.0
Desert Gorilla Apr 20, 2019 at 06:40
Thanks! I was considering adding this "point run" animation, but it also requires a proper snapping animation which would take much more time, so it was in my low pri features list. Otherwise showing intermediate points leads to invalid data presentation as can be seen in other apps.
No preventing last line disabling results in empty view.
No label position animation and no sliding points on the lines.
In separate mode disabling one line affect zoom to the other.
Probably, poor performance on last chart (based on GPU profiling).
101% in label.
Desert Gorilla Apr 18, 2019 at 15:59
* Last line disabling: This is intentional, imo it isn't nice to disallow users doing something.

* Labels animation: I was considering adding it, but didn't find a good way to animate only some of date parts as in mocks, since their sizes are constantly changing and adding static gaps looks bad, e.g. check app #128 ;). Also too much animations does not make the app look "slick", imo.

* Sliding points: That's true, it was in my list but with low pri, and I didn't have enough time for it after all.

* Separate line: In chart #2 I applied a static multiplier to scale both charts in the same way. Otherwise they should better be shown using separate chart views.

* Last chart performance: As of my testing (checked about 25% of the apps on Nexus 5 now) it has one of the best performance out there.

* 101% in label: There is no good way to round percents but keep 100%. E.g. [49.(6)%, 49.(6)%, 0.(6)%]. It is better to show individual values correctly than struggling to have 100% in total.
Nice app, you are in my 'vote up' list. Vote up mine, if it's good enough
One Plus X
Values in the info window are trimmed
Nexus 5
Desert Gorilla Apr 20, 2019 at 06:43
Indeed, thanks for reporting. I'm testing on Nexus 5 as well and somehow I don't see such a problem. But it is definitely a bug.
According to the design guidelines the date should looks like "Saturday, 28 April 2018"
All devices
Desert Gorilla Apr 19, 2019 at 10:05
You are right, but when showing full months names they are getting truncated when shown in ranges, so this was a consiuos decision.
Hello. I tested your app on 2 real devices. I found one
Very strange x labels datetime, when I zome charts, sometimes. (13 apr, 14 apr, 15 apr, 4 am, 4 am, 8 am, 8 am)
I notice, that I can show this issue when time not equal values, that I can devide on 3.
Innos d6000 (API 22 - android 5.1.1), OUKITEL C5 (Api 24 - android 7.0).
Desert Gorilla Apr 23, 2019 at 02:42
Thanks for reporting, but it seems to be a duplicate of issue reported by Kingly Boar above.
The problem here is that some of the provided data (e.g. for Apr 16 and App 18) is incomplete and can start e.g. with 4:00 instead of 0:00, it makes x labels distribution looks quite random for such dates.
Note though, that there are only a few such broken dates, other dates should look fine, see attached screenshot.
Weird discrete range selector behavior
Xiaomi A1 / Android 9
Desert Gorilla Apr 24, 2019 at 02:27
Confirm, seems to be an issue when right range selector is in the right most position under pie chart, in other cases it should work fine.
Range selector not animated as on mockups when enter to zoomed mode
Xiaomi A1 / Android 9
Desert Gorilla Apr 24, 2019 at 02:34
Yes, but it was not a strong requirement from Telegram:
"Note that you are not expected to implement the zooming transitions exactly as shown in the video demonstrations. They may be replaced with any slick and fast transition of your choice."
Wrong date format when displaying date range, used format for single date (should be 7 Dec 2018 - 6 Apr 2019)
Desert Gorilla Apr 24, 2019 at 02:40
I'm using a system date formatter which respects month position for your locale (US I suppose?). So "Dec 7" is a correct format for your locale but "7 Dec" is not. You can check how it will look with e.g. Russian locale.
Maybe not an issue, wrong time format
Desert Gorilla Apr 24, 2019 at 02:44
Hm, I'm using a system time formatter which respects your 12h / 24h setting, and it seems like you have 12h format enabled. Though status bar shows time in 24h format and it is strange indeed.
Sometimes, row labels are wrong
SGS5 / 6.0.1
Desert Gorilla Apr 24, 2019 at 17:49
Thanks. This is a labels rounding issue (similar issue is already reported), looks like the actual value for Y grid is around 1470, so 1490 point is shown above, but then the label is rounded to 1500.
I agree that it should not work like this, labels rounding should be synchronized with grid step rounding logic.
Performance (a lot of calculations in onDraw) and chart's quality degradation while changing date range of the last chart
SGS5 / 6.0.1
Desert Gorilla Apr 24, 2019 at 17:58
Hm, your screenshot shows that performance is not an issue actually, I don't see high GPU bars there.

Last chart performance is tricky (as you can see in other apps) and you actually found one of my secret optimizations here: I'm reducing drawing qaulity during animations. Good thing is that you won't notice it without magnifier, and once all the interactions are finished the chart is cristal clear again. So it is more like an advantage than an issue in my opinion :)
2. Not completely correct Auto Height Wrap logic. Lines outside main calculation bounds is not considered visible
Umi Super, Android
Nobody added any issues yet...