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最近项目中遇到了需要获取网站上的数据，然后以折线图的方式表示出来的需求。于是发现了swift下非常强大的图表库-# Charts
下面是这个系列的几篇汇总：
1、折线图
2、柱状图
3、饼状图
下面开始折线图的实现
首先，我们可以通过cocoapods 的方式，方便的导入Charts，接下来我们就可以撸代码了。
因为代码中基本每个功能后都有注释，所以就不多做解释，直接贴代码：
func test2()
{
//let lineChartView = LineChartView()
lineChartView.frame = CGRect(x: 20, y: 60, width: self.view.bounds.width - 40, height: 600)
self.view.addSubview(lineChartView)
lineChartView.delegate = self
lineChartView.backgroundColor = UIColor(red: 230/255.0, green: 253/255.0, blue: 253/255.0, alpha: 1.0)
lineChartView.noDataText = "暂无数据"
//设置交互样式
lineChartView.scaleYEnabled = false //取消Y轴缩放
lineChartView.doubleTapToZoomEnabled = true //双击缩放
lineChartView.dragEnabled = true //启用拖动手势
lineChartView.dragDecelerationEnabled = true //拖拽后是否有惯性效果
lineChartView.dragDecelerationFrictionCoef = 0.9 //拖拽后惯性效果的摩擦系数(0~1)，数值越小，惯性越不明显
//设置X轴样式
let xAxis = lineChartView.xAxis
xAxis.axisLineWidth = 1.0/UIScreen.main.scale //设置X轴线宽
xAxis.labelPosition = .bottom //X轴的显示位置，默认是显示在上面的
xAxis.drawGridLinesEnabled = false;//不绘制网格线
xAxis.spaceMin = 4;//设置label间隔
xAxis.axisMinimum = 0
xAxis.labelTextColor = UIColor.blue//label文字颜色
//设置Y轴样式
lineChartView.rightAxis.enabled = false //不绘制右边轴
let leftAxis = lineChartView.leftAxis
leftAxis.labelCount = 16 //Y轴label数量，数值不一定，如果forceLabelsEnabled等于YES, 则强制绘制制定数量的label, 但是可能不平均
leftAxis.forceLabelsEnabled = false //不强制绘制指定数量的label
leftAxis.axisMinimum = 0 //设置Y轴的最小值
leftAxis.drawZeroLineEnabled = true //从0开始绘制
//leftAxis.axisMaximum = 1000 //设置Y轴的最大值
leftAxis.inverted = false //是否将Y轴进行上下翻转
leftAxis.axisLineWidth = 1.0/UIScreen.main.scale //设置Y轴线宽
leftAxis.axisLineColor = UIColor.cyan//Y轴颜色
//leftAxis.valueFormatter = NumberFormatter()//自定义格式
//leftAxis.s //数字后缀单位
leftAxis.labelPosition = .outsideChart//label位置
leftAxis.labelTextColor = UIColor.red//文字颜色
leftAxis.labelFont = UIFont.systemFont(ofSize: 10)//文字字体
//设置网格样式
leftAxis.gridLineDashLengths = [3.0,3.0] //设置虚线样式的网格线
leftAxis.gridColor = UIColor.init(red: 200/255.0, green: 200/255.0, blue: 200/255.0, alpha: 1) //网格线颜色
leftAxis.gridAntialiasEnabled = true //开启抗锯齿
//添加限制线
let litmitLine = ChartLimitLine(limit: 260, label: "限制线")
litmitLine.lineWidth = 2
litmitLine.lineColor = UIColor.green
litmitLine.lineDashLengths = [5.0,5.0] //虚线样式
litmitLine.labelPosition = .rightTop // 限制线位置
litmitLine.valueTextColor = UIColor.brown
litmitLine.valueFont = UIFont.systemFont(ofSize: 12)
leftAxis.addLimitLine(litmitLine)
leftAxis.drawLimitLinesBehindDataEnabled = true //设置限制线绘制在折线图的后面
//设置折线图描述及图例样式
lineChartView.chartDescription?.text = "折线图" //折线图描述
lineChartView.chartDescription?.textColor = UIColor.cyan //描述字体颜色
lineChartView.legend.form = .line // 图例的样式
lineChartView.legend.formSize = 20 //图例中线条的长度
lineChartView.legend.textColor = UIColor.darkGray
//设置折线图的数据
let xValues = ["x1","x2","x3","x4","x5","x6","x7","x8","x9","x10","x11","x12","x13","x14","x15","x16","x17","x18","x19","x20","x21","x22","x23","x24","x25","x26"]
lineChartView.xAxis.valueFormatter = KMChartAxisValueFormatter.init(xValues as NSArray)
//ineChartView.xAxis.labelCount = 12
//lineChartView.leftAxis.valueFormatter = KMChartAxisValueFormatter.init()
//在这里如果不需要自定义x轴的数据格式，可以使用原生的格式如下：
//`lineChartView.xAxis.valueFormatter = IndexAxisValueFormatter.init(values: xValues)`
let leftValueFormatter = NumberFormatter() //自定义格式
leftValueFormatter.positiveSuffix = "亿" //数字后缀单位
lineChartView.leftAxis.valueFormatter = DefaultAxisValueFormatter.init(formatter: leftValueFormatter)
var yDataArray1 = [ChartDataEntry]()
for i in 0...xValues.count-1 {
let y = arc4random()%500
let entry = ChartDataEntry.init(x: Double(i), y: Double(y))
yDataArray1.append(entry)
}
let set1 = LineChartDataSet.init(values: yDataArray1, label: "test1")
set1.colors = [UIColor.orange]
set1.drawCirclesEnabled = false //是否绘制转折点
set1.lineWidth = 1
set1.mode = .horizontalBezier //设置曲线是否平滑
var yDataArray2 = [ChartDataEntry]();
for i in 0...(xValues.count-1) {
let y = arc4random()%500+1
let entry = ChartDataEntry.init(x: Double(i), y: Double(y))
yDataArray2.append(entry);
}
let set2 = LineChartDataSet.init(values: yDataArray2, label: "test1")
set2.colors = [UIColor.green]
set2.drawCirclesEnabled = false
set2.lineWidth = 1.0
let data = LineChartData.init(dataSets: [set1,set2])
lineChartView.data = data
//lineChartView.animate(xAxisDuration: 1.0, yAxisDuration: 1.0, easingOption: .easeInBack)
lineChartView.animate(xAxisDuration: 1) //设置动画时间
}
func showMarkerView(value:String)
{
let marker = MarkerView.init(frame: CGRect(x: 20, y: 20, width: 60, height: 20))
marker.chartView = self.lineChartView
let label = UILabel(frame: CGRect(x: 0, y: 0, width: 60, height: 20))
label.text = value
label.textColor = UIColor.white
label.font = UIFont.systemFont(ofSize: 12)
label.backgroundColor = UIColor.gray
label.textAlignment = .center
marker.addSubview(label)
self.lineChartView.marker = marker
}
func chartValueSelected(_ chartView: ChartViewBase, entry: ChartDataEntry, highlight: Highlight)
{
self.showMarkerView(value: "\(entry.y)")
}
在文中提到的
KMChartAxisValueFormatter这是我自定义的一个类，用于处理x轴的数据格式。实现代码如下：
import Foundation
class KMChartAxisValueFormatter: NSObject,IAxisValueFormatter,IValueFormatter
{
func stringForValue(_ value: Double, entry: ChartDataEntry, dataSetIndex: Int, viewPortHandler: ViewPortHandler?) -> String
{
//print("======\(value)")
return String(format:"%.2f%%",value)
}
var values:NSArray?
override init()
{
super.init()
}
init(_ values: NSArray)
{
super.init()
self.values = values
}
func stringForValue(_ value: Double, axis: AxisBase?) -> String
{
//此处的value指的是x轴上的第几个数据
if values == nil {
return "\(value)"
}
//print("\(Int(value))")
return self.values![Int(value)] as! String;
}
}
由于作者水平有限，对于文中出现的错误，欢迎批评、指正。