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swiftios-charts

Different colors for bars in BarChart depend on value


How can I change the color of a single bar, dependent on its value, in a bar chart? For example: I have five different values (= five different bars) in my bar chart. All bars that have a value less than 30 should be red, all bars between 30 and 70 orange, and all bars above 70 should be green.


Solution

  • In ios-charts, the colors of the bars are set in an array. If your dataset is called barChartDataset, for example, you would set the colors like this

    barChartDataset.colors = [UIColor.red,UIColor.orange,UIColor.green,UIColor.black,UIColor.blue]
    

    The bars will have these colors in this order and will repeat. So if you have 10 bars, you would have 2 red bars etc.

    In your case, you just have to write a function to return the right color value, and attach it to the array. Reference the code below.

    func setColor(value: Double) -> UIColor{
    
        if(value < 30){
            return UIColor.red
        }
        else if(value <= 70 && value >= 30){
            return UIColor.orange
        }
        else if(value > 70){
            return UIColor.green
        }
    
        else { //In case anything goes wrong
        return UIColor.black
        }
    }
    

    And then wherever you are setting the chart use

     barChartDataset.colors = [setColor(barOneValue),setColor(barTwoValue),setColor(barThreeValue),setColor(barFourValue),setColor(barFiveValue)]
    

    Hope this helps!