Thanks for your report!
You are totally right about poor performance.
Check for drag & drop feature and side scrolling on main chart.

Hi!
1. What do you mean under invisible filters?
2. There is a circular reveal effect on night mode change. It is sad if it blinks on your device.

I found out that these drawing overlay bars do not represent how smoothly widget is working. 
There is a trick - if you make a widget based on texture view or surface view - this widget performance won't be shown at all in these bars. Eventually, you could find yourself in the situation when your widget (chart based on TextureView or SurfaceView) could be very buggy with visual lags, but drawing bars will show that everything is fine (because everything indeed would be fine on the main thread).

Yes. My fault. I do need to organize the database. Instead, I hardcode ready to use data in the dataset file with the proper model. So the first start of the app (or configuration changes) suffers from this and results in long loading time. This issues could be easily eliminated creating a database - ROOM, SQLite or Realm. Indeed I have ROOM database in first stage. But then I eliminate it. I thought it would save me a few kb from app size.

Thank you for your detailed review.

Yes. It is due to wrong rounding when I define absolute coordinate for each data set in loop.

Thanks. As I said previously I change colors manually. Obviously I miss this resource.

Keep Calm. I know that I cannot win because of:
- not good enough performance
- no bonus tasks

About curved hands. I have at least tried my best creating this charts, do you? All those issues (except performance and probably stack bars strange overlaps) could be fixed in few hours. 

Keep calm - I won't win. This rating means far less that you may expect. 

I know that there are lot of issues. The main issue - performance. Sorry. I have still plenty to learn. Why so aggresive?

Issue duplicated. I have already answered above.

1. Yes. I admit I have also come across this issue. This small issue happens due to a popup window (date dialog). When in NestedScrollView on some devices when the popup is on the screen you cannot scroll until you dismiss/hide popup explicitly. Though I write specific logic to dismiss offscreen dialogs.

2. Of course, they are different. This last date above chart is equal to the last date at main preview bounds (see the width of Y lines).

3. Yes. This small issue related to android TextSwitcher widget. When data are swapped rapidly and in the dialog then wrong measuring may occur. In this case, "060" are wrong measured width of "1060". I think I should have set "android:measureAllChildren" attribute.

4. Many other participants locked screen orientation. But I don't want to. I do made the height of chart constant, which is not the best decision. But it is not even an issue, considering the feature of side-edge scrolling of main chart and pinch-to-zoom on the preview chart.

Thanks. In rush I did not pay enough attention to this. When I was reserving space in view for date labels row, I add textSize, offset, etc. That when you draw text you specify x and baseline instead of top comparing to line. And thing come to my mind that I should have been added to baseline extra offset - difference between descent and baseline

Thank you for your detailed review.

Duplicated. Come on, as I said many times here, performance is the weakeast point of me app. I know that.

1. Regretfully, performance is not the best I admit. Probably due to inner precise but heavy logic. Also, I did clip rect of the main chart viewport. For some strange reasons popup drop overall performance. Probably it is due to the heavy calculations of diff utils for data dynamic animated sorting (nobody did that) each time date are changed
2. Duplicated. See explanation of this issue above.
3. Of course, it lags due to circular reveal effect and a whole lot of custom color remapping. Very custom approach when every theme-based colors are changed. All dialog theme, recycler items of every chart, all 10 chart's colors are swapped and invalidated.
4. DRAG & DROP. I am the only one who made this. For line chart rearranging items influence drawing order, for stack sharts - stack order. LONG CLICK - drag & drop. DOUBLE TAP - Filter Others.
Strange delay time on single click is always present if you support click along with double tap.
Thank you for your detailed review.
DRAG AND DROP VIDEO:

Could you provide video proof? (Not emulator simulated screen size)

Duplicated.
See "Stout Ladybird Apr 19 at 19:33" 3rd answer below.

Guys, I would really appreciate If you share your knowledge of how to change theme dynamically without recreating activity and without lags considering NestedScrollView, 10 main charts, 9 preview chart, possible few dialogs on screen and a whole bunch of color that are needed to be swapped instantly. Also there is a circular reveal effect.

Thank you for your detailed review.

Could you provide a video demonstration? Because from dialog above screenshot was made during running animation.

WITHOUT VIDEO PROOF I CAN STATE THAT THIS ISSUE IS NOT REAL.

Yes, sure. I disable paint antialias flag. Not a big deal to add it. Actually I should have added this flag on text paint.

Thank you for this pixel level review. It mean that my app attract your attention. If you would like me to add it later - I will.

Yep, my fault.

Thanks, dude.

It is above toolbar just because of elevation. (popup elevation seems higher that toolbar elevation). Could be fixed changing literally one value. I found this issue not critical, do you?

But I want to report the bug I have found. On some devices under not yet defined circumstances, visible popup prevents nested scroll view from scrolling. Though, I have written the logic that dismisses offscreen dialogs.

1. Again. I could say that video and screenshot provided by telegram were different (because the video is general and probably for web or ios). But the control zone does semi-transparent in android screenshots. Also, the widget is heavily customizable. For instance, for the control zone, you could change width\hight of control zone, side touch zone color, area control color. In other words, everything is customizable.

2. Night mode icon. Does it really matter? Seems that no one cares about this in the first stage. But in the first stage, I was amongst a few persons who did this exact icon. I do not think that another similar icon is an issue.

3. Also each chart area elevation? As my first answer. I do not think that elevation here is an issue (could be literally changed setting one value). Also, consider that there were not any specification about outer layout like.

1. This dialog placement is not an issue. Logic is next: priority to show dialog window to left of date vertical line. If there is no place to completely show the dialog and do not overlap intersect dots, the dialog will be shown at right. Its position is also always coerced to visible screen range.

2. This is not an issue. Logic is next: User can specify how many y line he wants to see. That proper values are shown at each position of screen

Yes. In the first stage, I made ROOM database with all dataset. But nobody cares about this at that time. Everyone cares about app size (which is strange to my opinion).

Size of the app is relatively high due to android appcompat library. It is not correct in my opinion to assess chart app by the size of the whole sample app, rather than chart module size (chart widget related files) itself.

The is the drawback of the next approach (I think the best one):

1. First, one may specify how many date labels they want to see.
2. Then, First and Last dates are always added and moreover, they have a sticky effect and properly shifted to align start/end of the chart, respectively.
3. Other dates are calculated with measured step.

So is some scales there will be gaps between pre-last and last date. Probably there is still a small issue in the calculation. It seems that in StackBarChart I have eliminated this issue. Forgot to fix logic in other charts due to lack of time.

Thank you for your detailed review.

Duplicated. See anwer above. Date range is shown for inner area, where chart begins and ends (see width of y lines)

P.S. Do not be too selfish. You can't state "nobody cares". You are not everybody to said that.

Actually, I think that at least few people here may find my explanations usefull.

Disagree with that. Because lines support drawing order. See by yourself - long press on list item init drag and drop. The circles are parts of respetive lines, and not drawn on top lines. The main thing here, that if line below the higher's line dot - it won't be cut. See screenshot below.

It is obvious due to rounding. But it is not critical in my opinion. Moreover, there could be only 1 percent total discrepancy (again, due to rounding)

Thanks for that review.
Nice to hear that you found drag&drop and tooltip sidescrolling additional features useful.

Performance could be better. Probably I should rework it later on TextureView or so.

About first init time. I admit - there is an issue. I have expalained this somewhere above. But it is related more to app architecture, because of database, not to chart widget itself.

Again, thank you for your detailed review.