CODEWITHSUNDEEP
iosswiftchartsios-charts
ventuz
ventuz

Reputation: 1141

Add point when user clicks on Charts - 'LineChartView' (iOS-Charts)

There's a way to implement a method where, when user clicks on chart, I can know the x-y values to insert in my array?

I'm trying to use:

func chartValueSelected(_ chartView: ChartViewBase, entry: ChartDataEntry, highlight: Highlight) {}

but this method shows me the nearest point that I already have.

If I use:

@IBOutlet var chart: LineChartView! 

let tap = UITapGestureRecognizer(target: self, action: #selector(self.longTouch(_:)))
self.chartView.addGestureRecognizer(tap)

func touch(_ sender: UIGestureRecognizer) {
    let touchPoint = sender.location(in: self.chart)
}

the 'touchPoint' return the absolute view's x-y and not related to the chart.

Someone can help me? Thanks!

Upvotes: 1

Views: 1600

Answers (1)

ventuz
ventuz

Reputation: 1141

I've resolved adding a gesture recognizer to the view:

// Gesture Recognizer to add a new value
func addGesture() {
    let gesture = UILongPressGestureRecognizer(target: self, action: #selector(gestureRecognizerShouldBegin(_:)))
    gesture.minimumPressDuration = 0.3
    _chartView?.addGestureRecognizer(gesture)
}

in the gesture method I've used the valueForTouchPoint(point: _) that inerith to the LineChartView.

func gestureRecognizerShouldBegin(_ gestureRecognizer: UIGestureRecognizer) -> Bool {

    if gestureRecognizer.state == .began {

        // Recognize the location in the view
        let touchLocation = gestureRecognizer.location(in: self._chartView)
        // The 'x-y' value where user touch the view
        let touchedPoint: CGPoint? = self._chartView?.valueForTouchPoint(point: touchLocation, axis: .right)

        guard let point = touchedPoint else { return false }

        // save the value...

    return true
}

And, if I zoom or pan the chart, the method return the correct value x-y values.

Hope this will help someone!

Upvotes: 2

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