swift - iOS 图表库 - 如何处理 X 轴重复值

Question

我使用@danielgindi 的图表库为我的 iOS 应用程序生成图表。一切似乎都很好，但我们面临着 X 轴数据重复的问题。

图表的输入数据(X 轴值，Y 轴值)

("29/03/2017 00:00:00","2.7")

("29/03/2017 00:00:00","2.4")

("29/03/2017 00:10:00","1.3")

("29/03/2017 00:10:00","1.5")

("29/03/2017 00:20:00","1.8")

....

....

....

("29/03/2017 01:00:00","1.2")

("29/03/2017 09:00:00","2.7")

("29/03/2017 09:10:00","-10.8")

....

....

....

("29/03/2017 13:10:00","3.9")

("29/03/2017 13:20:00","-.8")

("29/03/2017 13:20:00","5.9"

其中 X 轴值是日期时间，Y 轴值是与该日期时间关联的 Double 值。

我使用了以下代码来格式化 X 轴

class ChartStringFormatter: NSObject, IAxisValueFormatter {

    public func stringForValue(_ value: TimeInterval, axis: AxisBase?) -> String {

        let date = Date(timeIntervalSince1970: value)
        return date.toString(format: "hh:mm a")
    }
}

但是当我缩放图表时，它有多个 X 轴值。我该如何解决这个问题？

X 轴值的预期输出:

最初 - [12:00 AM、03:00 AM、06:00 AM、09:00 AM、12:00 PM、03:00 PM、06:00 PM、09:00 PM、12:00 PM ]

缩放时 - [12:00 AM, 01:00 AM, 02:00 AM, 03:00 ...... 12:00 PM]

再次缩放 - [12:00 AM、12:30 AM、01:00 AM、01:30 AM、02:00 AM、02:30 AM、03:00 AM ...... 12:00 PM ]

再次放大 - [12:00 AM, 12:10 AM, 12:20 AM, 12:30 AM ...... 12:00 PM]

Sample GIF file:

iOS 图表库链接:https://github.com/danielgindi/Charts

Answer 1

如 iOS-Charts 库文档中所述:

When true, axis labels are controlled by the granularity property.

When false, axis values could possibly be repeated.

...

@property (nonatomic) BOOL granularityEnabled;

和:

The minimum interval between axis values.

This can be used to avoid label duplicating when zooming in.

default: 1.0

@property (nonatomic) double granularity;

所以我很确定这些行会为您完成工作:

<strong>[yourChart.xAxis setGranularityEnabled:YES];</strong>

<strong>[yourChart.xAxis setGranularity:1.0];</strong>