核心情节：轴交替带填充与自定义轴标签答案

【问题标题】：Core plot: axis alternatingBandFills with custom axis labels核心情节：轴交替带填充与自定义轴标签
【发布时间】：2012-02-23 15:41:07
【问题描述】：

我正在使用 Core Plot 库在 iOS 上绘制图表。我想在 yAxis 的网格线之间添加颜色。我设法通过设置轴的alternatingBandFills 属性来做到这一点。但是，我还必须在 yAxis 上使用自定义标签，并且当我提供自定义标签时，alternatingBandFills 属性由于某种原因不起作用。

任何帮助如何添加颜色到 yAxis 上网格线之间的空间以及使用自定义标签将不胜感激。

我现在使用的代码如下：

    CPTXYAxisSet *axisSet = (CPTXYAxisSet *)self.hostedGraph.axisSet;
    CPTXYAxis *yAxis = axisSet.yAxis; 

    yAxis.orthogonalCoordinateDecimal = CPTDecimalFromDouble(minValueX);        
    yAxis.labelingPolicy = CPTAxisLabelingPolicyNone;

    NSArray *yAxisTickLocations = [NSArray arrayWithObjects:
                                   [NSDecimalNumber numberWithDouble:lowerRedRangeFrom],
                                   [NSDecimalNumber numberWithDouble:lowerOrangeRangeFrom],
                                   [NSDecimalNumber numberWithDouble:greenRangeFrom],
                                   [NSDecimalNumber numberWithDouble:upperOrangeRangeFrom],
                                   [NSDecimalNumber numberWithDouble:upperRedRangeFrom],
                                   [NSDecimalNumber numberWithDouble:upperRedRangeTo],
                                   nil];
    NSArray *yAxisLabels = [NSArray arrayWithObjects:@"Label1",@"Label2", @"Label3",@"Label4",@"Label5",@"Label6", nil];

    NSUInteger labelLocationY = 0;
    NSMutableArray *customLabelsY = [NSMutableArray arrayWithCapacity:[yAxisLabels count]];
    for (NSNumber *tickLocation in yAxisTickLocations) {

        CPTAxisLabel *newLabel = [[CPTAxisLabel alloc] initWithText: [yAxisLabels objectAtIndex:labelLocationY++] textStyle:axisSet.xAxis.labelTextStyle];
        newLabel.tickLocation = [tickLocation decimalValue];
        newLabel.offset = axisSet.xAxis.labelOffset + axisSet.xAxis.majorTickLength;
        newLabel.rotation = M_PI/4;
        [customLabelsY addObject:newLabel];
    }

    axisSet.yAxis.axisLabels =  [NSSet setWithArray:customLabelsY];
    yAxis.alternatingBandFills = [NSArray arrayWithObjects:
                                  [CPTColor redColor],
                                  [CPTColor orangeColor],
                                  [CPTColor greenColor],
                                  [CPTColor orangeColor],
                                  [CPTColor redColor], nil];

【问题讨论】：

标签： ios objective-c colors core-plot

【解决方案1】：

我想通了：

轴的标签策略应该是：CPTAxisLabelingPolicyLocationsProvided，文档声明：“用户设置刻度位置；轴制作标签。”。

现在我们只需要指定刻度的位置。这是通过创建带有位置的NSSetobject 来完成的。然后我们要设置轴的majorTickLocations属性。

所以我的代码现在看起来像：

    CPTXYAxisSet *axisSet = (CPTXYAxisSet *)self.hostedGraph.axisSet;
    CPTXYAxis *yAxis = axisSet.yAxis;

    yAxis.orthogonalCoordinateDecimal = CPTDecimalFromDouble(minValueX);        
    yAxis.labelingPolicy = CPTAxisLabelingPolicyLocationsProvided;

    NSSet *majorTickLocations = [NSSet setWithObjects:
                                 [NSDecimalNumber numberWithDouble:lowerRedRangeFrom],
                                 [NSDecimalNumber numberWithDouble:lowerOrangeRangeFrom],
                                 [NSDecimalNumber numberWithDouble:greenRangeFrom],
                                 [NSDecimalNumber numberWithDouble:upperOrangeRangeFrom],
                                 [NSDecimalNumber numberWithDouble:upperRedRangeFrom],
                                 [NSDecimalNumber numberWithDouble:upperRedRangeTo],
                                 nil];
    yAxis.majorTickLocations = majorTickLocations;

    yAxis.alternatingBandFills = [NSArray arrayWithObjects:
                                  [CPTColor redColor],
                                  [CPTColor orangeColor],
                                  [CPTColor greenColor],
                                  [CPTColor orangeColor],
                                  [CPTColor redColor], nil];

【讨论】：