ios - 悬停时在 CPTPlotSymbol 上显示工具提示

Question

我正在使用 Core Plot 绘制散点图。它工作正常。但我想在悬停 CPTPlotSymbol 时显示当前值。请看下图:

这是一个示例代码:

- (void)configurePlots
{
[...]
    CPTMutableLineStyle *lineStyle = [myPlot.dataLineStyle mutableCopy];
    lineStyle.lineWidth = 2.5;
    lineStyle.lineColor = [CPTColor greenColor];
    myPlot.dataLineStyle = lineStyle;
    CPTMutableLineStyle *symbolLineStyle = [CPTMutableLineStyle lineStyle];
    symbolLineStyle.lineColor = [CPTColor greenColor];
    CPTPlotSymbol *symbol = [CPTPlotSymbol ellipsePlotSymbol];
    symbol.fill = [CPTFill fillWithColor:[CPTColor greenColor]];
    symbol.lineStyle = symbolLineStyle;
    symbol.size = CGSizeMake(6.0f, 6.0f);
    myPlot.plotSymbol = symbol;
}

Answer 1

如果你想在触摸条/点时显示任何附加信息，你应该实现

    -(void)barPlot:(CPTBarPlot *)plot barWasSelectedAtRecordIndex:(NSUInteger)index {
}

或

-(void)scatterPlot:(CPScatterPlot *)plot plotSymbolWasSelectedAtRecordIndex:    (NSUInteger)index
{
}

委托(delegate)方法(取决于图表类型)。不要忘记设置委托(delegate)。