iOS-Charts how to allow clicks only on plotted points? - ios

Question

I'm using iOS charts framework to plot this chart, I want to detect tap or touch only on the line's path or on the small circle's on the lines.
My question is,
Is there any default code block to do this?
I tried comparing the entry.value with the array plotted(as in the following code), but it doesn't workout.
-(void)chartValueSelected:(ChartViewBase *)chartView entry:(ChartDataEntry *)entry dataSetIndex:(NSInteger)dataSetIndex highlight:(ChartHighlight *)highlight{
if ([arrayOfPlottedValues containsObject:[NSNumber numberWithInt:(int)entry.value]]) {
//Tapped on line path
}
else{
//Tapped on empty area
}
}
Any insights will be appreciated.
eg : Line chart

Answer 1

I found a way by considering #Wingzero's suggestion, but the major difference was that, I just used the touch point to find out if its on the "marker" or if its outside it. I'm not sure if its the right way, but the solution is,
-(void)chartValueSelected:(ChartViewBase *)chartView entry:(ChartDataEntry *)entry dataSetIndex:(NSInteger)dataSetIndex highlight:(ChartHighlight *)highlight{
//-----------------------------------------------------getting recognizer value
UIGestureRecognizer *recognisedGesture = [chartView.gestureRecognizers objectAtIndex:0];
CGPoint poinOfTouch =[recognisedGesture locationInView:chartView];
CGPoint poinOfMarker =[chartView getMarkerPositionWithEntry:entry highlight:highlight];
if (check if the chartview is BarChartView and if true) {
//-----------------------------------------------------If you want to detect touch/tap only on barchartview's bars
if (poinOfTouch.y > poinOfMarker.y) {
NSLog(#"within the bar area!");
}
else{
NSLog(#"Outside the bar area!");
}
}
else
{
//-----------------------------------------------------If you want to detect touch/tap only on linechartView's markers
//-----------------------------------------------------creating two arrays of x and y points(possible nearby points of touch location)
NSMutableArray *containingXValue = [[NSMutableArray alloc]init];
NSMutableArray *containingYValue = [[NSMutableArray alloc]init];
for (int i =0 ; i<5; i++) {
int roundedX = (poinOfMarker.x + 0.5);
int sumXValuesPositive = roundedX+i;
[containingXValue addObject:[NSNumber numberWithInt:sumXValuesPositive]];
int sumXValuesNegative = roundedX-i;
[containingXValue addObject:[NSNumber numberWithInt:sumXValuesNegative]];
int roundedY = (poinOfMarker.y + 0.5);
int sumYValuesPositive = roundedY+i;
[containingYValue addObject:[NSNumber numberWithInt:sumYValuesPositive]];
int sumYValuesNegative = roundedY-i;
[containingYValue addObject:[NSNumber numberWithInt:sumYValuesNegative]];
}
//-----------------------------------------------------------------------------------------------------------------------------------------
int roundXPointTOuched = (poinOf.x + 0.5);
int roundYPointTOuched = (poinOf.y + 0.5);
//-----------------------------------------------------check if touchpoint exists in the arrays of possible points
if ([containingXValue containsObject:[NSNumber numberWithInt:roundXPointTOuched]] && [containingYValue containsObject:[NSNumber numberWithInt:roundYPointTOuched]])
{
// continue, the click is on marker!!!!
}
else
{
// stop, the click is not on marker!!!!
}
//-----------------------------------------------------------------------------------------------------------------------------------------
}
}
}
Edit : The initial solution was applicable only for the line chart, Now if this same situation arises for bar chart, you could handle it with the above code itself.
Man, I'd been running around it for a while now, feeling really great for getting a positive lead. There is no direction for this issue yet, hope this will be useful for someone like me cheers!
P.S. I'm marking this as answer just to make sure, it reaches the needful :). Thanks

Answer 2

It has a default highlight logic, that is, calculate the closest dataSet and xIndex, so we know which data to highlight.
You can customize this logic to restrain the allowed smallest distance. e.g. define the max allowed distance is 10, if the touch point is away from the closest dot > 10, you return false and not highlgiht.
Highlighter is a class, like BarChartHighlighter, ChartHighlighter, etc.
Update towards your comment:
when you tapped, the delegate method get called, so you know which data is highlighted. Your codes seems fine, however the condition code is blackbox to me. But the delegate will be called for sure, so you only have to worry about your logic.