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iosswiftgraphlinechartios-charts

Set the maximum of the Y-Axis of a LineChartView | pod 'Charts'

I have created a LineChartView using the 'Charts' pod.

I have made the plotted line follow a function (f(x) = ax^2) where the value 'a' is being randomized as soon as the user touches the LineChartView. The x-axis has a defined maximum of 100 through a for in loop. This has however led to the y-axis having a defined maximum value of a*10000, where a is randomly created every time the user touches the LineChartView.

This means that it does not actually look like the graph changes at all. The only visible change is that the y-axis gets a new maximum value each time a is getting randomly created. I would like a way to set the maximum value for the y-axis. Something along the lines of:

chartView.YAxisMaximum = 10000

Down below is the entire code:

import UIKit
import Charts


class ViewController: UIViewController {
    
    var a: Double = 1
   
    var line = LineChartDataSet()
    let chartView = LineChartView()
    let data = LineChartData()
    
    @objc private func didSwipe(_ sender: UIPanGestureRecognizer) {
        if sender.state == .changed{
            
            a = Double.random(in: 0.0...4.0)
            
            
            data.removeDataSet(line)
            line.removeAll()
            
            line.colors = [.black]
            line.drawCirclesEnabled = false
            line.label = nil
            
            for i in 0...100{
                let value = ChartDataEntry(x: Double(i), y: Double(i*i) * a)
                line.append(value)
            }
            data.addDataSet(line)
            chartView.data = data
            
            
            
  
        }
        
    }
    

    override func viewDidLoad() {
        super.viewDidLoad()
        
        let swipe = UIPanGestureRecognizer()
        swipe.addTarget(self, action: #selector(didSwipe(_:)))
        

        
        line.colors = [.black]
        line.drawCirclesEnabled = false
        line.label = nil
        
        
        for i in 0...100{
            let value = ChartDataEntry(x: Double(i), y: Double(a) * Double(i*i))
            line.append(value)
        }
        
        data.addDataSet(line)
        
        
        chartView.data = data
        chartView.leftAxis.enabled = true
        chartView.rightAxis.enabled = false
        chartView.xAxis.enabled = false
        chartView.pinchZoomEnabled = false
        chartView.doubleTapToZoomEnabled = false
        chartView.animate(xAxisDuration: 1)
        chartView.frame = view.safeAreaLayoutGuide.layoutFrame
        chartView.addGestureRecognizer(swipe)
        
        view.addSubview(chartView)
    }
}
Solution

  • Yes, you can set a maximum for y-axis as below by configuring leftAxis and rightAxis properties of the LineChartView instance.

    let chartView = LineChartView()

let maxYVal = 4.0 * 10000
chartView.leftAxis.axisMaximum = maxYVal
chartView.rightAxis.axisMaximum = maxYVal