ios - Objective C核心图:饼图图例

Question

在核心图中调用UILabel方法时，如何设置与饼图切片颜色相同的sliceWasSelectedAtRecordIndex:对象的颜色？我用这种方法用渐变色填充切片。

-(CPTFill *)sliceFillForPieChart:(CPTPieChart *)pieChart recordIndex:(NSUInteger)index
{
     sectorColour=[[[CPTFill alloc]init]autorelease];//creating a sector color object
     if (index == 0) {
          //creating cptcolor 
          CPTColor *areaColor1 = [CPTColor colorWithComponentRed:0.0 
               green:0.7
                blue:1.0
               alpha:1.0];
          CPTColor *areaColor2 = [CPTColor colorWithComponentRed:0.0 
               green:0.1
                blue:0.2
               alpha:1.0];
          UIColor *color1=[UIColor colorWithRed:0.0 green:0.7 blue:1.0 alpha:1.0];
          UIColor *color2=[UIColor colorWithRed:0.0 green:0.1 blue:0.2 alpha:1.0];

          //filling with gradient color with CPTColor
          CPTGradient *areaGradientUI = [CPTGradient gradientWithBeginningColor:(CPTColor *)color1 endingColor:(CPTColor *)color2];  
          sectorColour=[CPTFill fillWithGradient:areaGradientUI];
    }
}

Answer 1

使用CPTGradient对象而不是CPTColor创建UIColor。

CPTGradient *areaGradientUI = [CPTGradient gradientWithBeginningColor:areaColor1
                                                          endingColor:areaColor2];

您可以将 backgroundColor的 UILabel设置为单个 UIColor。我不确定在不制作自定义子类来绘制背景渐变的情况下如何使用渐变。