如何在核心图饼图中启用对部分的触摸选择？ [英] How do you enable touch selection of a section in a Core Plot pie chart?

问题描述

我正在使用Core Plot框架绘制饼图，并且在绘制饼图本身时没有任何问题。

I am using the Core Plot framework to draw a pie chart, and am having no issues in drawing the pie chart itself.

但是，我需要饼图要本质上是交互式的，即，如果我点击饼图中的任何特定部分，它将触发导航到显示该特定部分详细信息的页面。

However, I need the pie chart to be interactive in nature, i.e., if I tap on any particular section in the pie chart, it should trigger the navigation to a page showing details of that particular section.

我尝试使用方法-（void）pieChart：sliceWasSelectedAtRecordIndex：，但是从未调用过该委托方法。我需要什么来启用这种触摸交互？

I tried using the method -(void)pieChart:sliceWasSelectedAtRecordIndex:, but that delegate method was never called. What do I need to enable this touch interaction?

推荐答案

我已经在iPad应用程序中使用CorePlot 0.2.2实现了饼图选择。 。您使用
（void）pieChart：sliceWasSelectedAtRecordIndex：的猜测是正确的，但也许您忘记了
声明以下两件事：

I have implemented pie piece selection in my iPad app with CorePlot 0.2.2. Your guess to use (void)pieChart:sliceWasSelectedAtRecordIndex: is correct, but maybe you have forgotten to declare the following two things:

• 您的控制器是否声明了 CPPieChartDelegate 协议？


• 您是否告诉饼形图，您的控制器就是它的控制器委托？

• Does your controller declares the CPPieChartDelegate protocol?
• Did you tell the pie chart that your controller is its delegate?

我的视图控制器在标头声明中如下所示：

My view controller looks like this in the header declaration:

@interface YourViewController : UIViewController < CPPieChartDataSource,
                                                   CPPieChartDelegate,
                                                   ... >
{
   ...
   CPXYGraph*          pieGraph;
   CPGraphHostingView* pieView;
}

@property (nonatomic, retain) IBOutlet CPGraphHostingView* pieView;

- (void)pieChart:(CPPieChart *)plot sliceWasSelectedAtRecordIndex:(NSUInteger)index;

@end

在（void）viewDidLoad ，在其中设置数据源和饼图的委托：

The creation of the pie chart is called during the (void)viewDidLoad, where I set the data source and the delegate of the pie chart:

-(void)viewDidLoad {
   [self createPie];
}

-(void)createPie {
   pieGraph = [[CPXYGraph alloc] initWithFrame:CGRectZero];
   pieGraph.axisSet = nil;
   self.pieView.hostedGraph = pieGraph;

   CPPieChart *pieChart = [[CPPieChart alloc] init];

   // This is important in order to have your slice selection handler called!
   pieChart.delegate = self;

   pieChart.dataSource = self;

   pieChart.pieRadius = 80.0;
   [pieGraph addPlot:pieChart];
   [pieChart release];
}

- (void)pieChart:(CPPieChart *)plot sliceWasSelectedAtRecordIndex:(NSUInteger)index {
   // Do whatever you need when the pie slice has been selected.
}

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