在共图中，当某点被触及时，如何获取该点的信息

Question

我在核心地块的分散地块工作。当我触摸图形中任何绘制的点时，我需要显示与该触摸点相关的一些信息。

我怎么才能做到呢?

Answer 1

这些委托方法帮助了我。

-(BOOL)plotSpace:(CPTXYPlotSpace *)space shouldHandlePointingDeviceUpEvent:(id)event atPoint:(CGPoint)point{
 NSLog(@"point.x=%lf,point.y=%lf",point.x,point.y);
 return YES;
}
-(BOOL)plotSpace:(CPTXYPlotSpace *)space shouldHandlePointingDeviceCancelledEvent:(id)event{
 //NSLog(@"point.x=%lf,point.y=%lf",point.x,point.y);
 return YES;
}
 -(BOOL)plotSpace:(CPTXYPlotSpace *)space shouldHandlePointingDeviceDownEvent:(id)event atPoint:(CGPoint)point{
 NSLog(@"point.x=%lf,point.y=%lf",point.x,point.y);
 return YES;
}
-(BOOL)plotSpace:(CPTXYPlotSpace *)space shouldHandlePointingDeviceDraggedEvent:(id)event atPoint:(CGPoint)point{
 NSLog(@"point.x=%lf,point.y=%lf",point.x,point.y);
 return YES;
}

Answer 2

Core Plot包含的示例应用程序展示了几种不同的方法来做到这一点。在Plot Gallery应用程序中，查看梯度散点图或简单散点图。Mac版本的CPTTestApp有一个点选择演示，展示了在选定点上绘制十字准线而不是标签的一种方法。