Show dot only on vertical line selection

[Nico]

Is there a way to show the dot only on the vertical line selection?

[Terry Worona]

I assume you mean to only show a dot when there is a selection on that particular data point?

Yes.

Implement:

- (UIColor *)lineChartView:(JBLineChartView *)lineChartView selectionColorForDotAtHorizontalIndex:(NSUInteger)horizontalIndex atLineIndex:(NSUInteger)lineIndex
{
    // return color of dot on selection
}

and:

- (UIColor *)lineChartView:(JBLineChartView *)lineChartView colorForDotAtHorizontalIndex:(NSUInteger)horizontalIndex atLineIndex:(NSUInteger)lineIndex
{
    return [UIColor clearColor]; // hide all dots during non-selection
}

Hope this helps.

[Nico]

Thanks Terry, that's indeed what I meant. I did that but I got all the dots on selection as I cannot find a way to get the index on the selection. The method

- (void)lineChartView:(JBLineChartView *)lineChartView didSelectLineAtIndex:(NSUInteger)lineIndex horizontalIndex:(NSUInteger)horizontalIndex;

is called after

- (UIColor *)lineChartView:(JBLineChartView *)lineChartView selectionColorForDotAtHorizontalIndex:(NSUInteger)horizontalIndex atLineIndex:(NSUInteger)lineIndex

so I don't know how to get the selected horizontalIndex by the time I return the dot color for the selection.

[Terry Worona]

You're model should be structured in a way for you to supply the desired 'styling' for a given index.

I'm not sure how else I can help - the functionality is exposed for you to achieve the desired effect, you just need to access your model to get the information required.

[Nico]

There is something I'm missing obviously.

Let's say I have on line chart with 10 value [1, 2, 3, 4, 5, 6, 7, 8, 9, 0].

What I would like to achieve is when I tap with my finger on the value let's say 4, only the dot on of my line for the value for will appear. I don't want any special style, just the same style for all the dots, just that the dot appears only on its selection like this screenshot:

From what I could see,

- (UIColor *)lineChartView:(JBLineChartView *)lineChartView selectionColorForDotAtHorizontalIndex:(NSUInteger)horizontalIndex atLineIndex:(NSUInteger)lineIndex

is called once for every value of my line chart per touch. So to hide or show the dot on selection, I need to be able to match the "horizontalIndex" of this method with the index of the current selection. How do I get this index? Like is there a method that, when I touch the screen on the chart, will give the current selection index?

Thanks for your patience with we anyway :)

[Terry Worona]

Oh I get it. I'm sorry I misinterpreted what you wanted to do.

Unfortunately that's not possible with the current set of API's.

[Nico]

Ahah too bad, I started to have some hopes for it.

Any hint where I should look in your library to implement it myself? I'm a swift guy, but I can read objective-c. Or I might try to do it directly in my project. Thanks anyway.

[Terry Worona]

Yeah the logic would have to reside in:

touchesBeganOrMovedWithTouches

of JBLineChartView.

There you have pretty much all the information you need. You could iterate over all the dots in the dot view and just hide/show the one closest to the horizontal index your touch is at.

Hope this helps.

[Nico]

Awesome I made it. Thanks a lot!

[Terry Worona]

Awesome! No prob.