ios - 在 CPTXYGraph 饼图上获取触摸反馈

Question

我正在使用 Core Plot 中的 CPTXYGraph 绘制饼图。我使用了委托方法

-(void)pieChart:(CPTPieChart *)plot sliceWasSelectedAtRecordIndex:(NSUInteger)index

单击饼图的特定切片时执行一些操作。但是当我触摸饼图时，我需要显示反馈或某种类型的图像更改，以表明特定切片被触摸，就像按钮事件一样。

是否有任何委托方法来实现相同的目标。

Answer 1

会有一些工作要做。

首先，将此实现为饼图委托函数。

-(void)pieChart:(CPTPieChart *)plot sliceWasSelectedAtRecordIndex:(NSUInteger)index
{
    indexOfPieGraphPlot = index; //gives index of pie which is selected.
    isPieGraphPlot = YES;     //boolean. if set to yes, will call rootcontroller function which will add pop up.
}

然后在 .h 文件中添加CPTPlotSpaceDelegate

然后使用这个功能

- (BOOL)plotSpace:(CPTPlotSpace *)space shouldHandlePointingDeviceUpEvent:(id)event atPoint:(CGPoint)point
{
    if(isPieGraphPlot) //if yes call showpopup of rootcontroller
    {
    isPieGraphPlot = NO;
    [rootController showPopUpView:point indexForPlot:indexOfPieGraphPlot];
    // point gives the x,y of the pie over which you want a pop up.
    }
    else    // if no then call remove popup from rootcontroller. this, incase user clicks anywhere else in graph.
    {
        [rootController removePopUp];
    }
    return  YES;
}

Answer 2

Implement the -sliceFillForPieChart:recordIndex: method in your datasource. Keep track of the selected slice (if any) and use that to decide what fill to apply to each slice. Call -reloadData on the plot any time the selection changes to force it to load new slice fills.