ios - 核心剧情: Grid lines don't appear when labeling policy is not automatic

Question

我正在尝试在 iPhone 应用程序中使用 Core Plot 绘制简单的统计数据。我最初将标签策略用作两个轴的 CPTAxisLabelingPolicyAutomatic，并且网格线看起来很好，如下所示:

您可以看到该图同时具有垂直和水平网格线。然后，我将标签策略更改为

    axisSet.xAxis.labelingPolicy = CPTAxisLabelingPolicyNone;
    axisSet.yAxis.labelingPolicy = CPTAxisLabelingPolicyAutomatic;

NSUInteger labelLocation = 0;
NSMutableArray *customLabels = [NSMutableArray arrayWithCapacity:xAxisLabels.count];
CPTMutableTextStyle *textStyle = [[CPTMutableTextStyle alloc] init];
textStyle.color = [CPTColor lightGrayColor];

for (NSNumber *tickLocation in customTickLocations) {
    CPTAxisLabel *newLabel = [[CPTAxisLabel alloc]
                              initWithText:[NSString stringWithFormat:@"%@",(NSDate *)[xAxisLabels objectAtIndex:labelLocation++]] textStyle:textStyle];
    newLabel.tickLocation = [tickLocation decimalValue];
    newLabel.rotation = 25.0;
    newLabel.offset = 10.0;
    [customLabels addObject:newLabel];
}
axisSet.xAxis.axisLabels =  [NSSet setWithArray:customLabels];

但是，因为当我为 X 轴添加自定义标签时，X 轴网格线(即垂直网格线)没有出现。只能看到水平网格线，如下面的 App 截图所示:

Answer 1

CPTAxisLabelingPolicyNone 标签策略不会创建任何标签或刻度线。您需要创建位置集并设置 majorTickLocations 和/或 minorTickLocations。

这是 Plot Gallery 示例应用程序中的一些示例代码:

NSSet *majorTickLocations = [NSSet setWithObjects:[NSDecimalNumber zero],
                             [NSDecimalNumber numberWithUnsignedInteger:30],
                             [NSDecimalNumber numberWithUnsignedInteger:50],
                             [NSDecimalNumber numberWithUnsignedInteger:85],
                             [NSDecimalNumber numberWithUnsignedInteger:100],
                             nil];
xAxis.majorTickLocations = majorTickLocations;

刻度位置通常与标签位置相同，但并非必须如此。