Question

- (void)viewDidLoad
{
graph = [[CPTXYGraph alloc] initWithFrame: self.view.bounds];   
CPTGraphHostingView *hostingView = (CPTGraphHostingView *)self.view;
hostingView.hostedGraph = graph;
CPTPieChart *pieChart = [[CPTPieChart alloc] init];
pieChart.dataSource = self;
pieChart.pieRadius = 100.0;
pieChart.identifier = @"PieChart1";
pieChart.startAngle = M_PI_4;
pieChart.sliceDirection = CPTPieDirectionCounterClockwise;

self.pieData=   [NSMutableArray arrayWithObjects:[NSNumber numberWithDouble:90.0], 
                [NSNumber numberWithDouble:20.0],
                [NSNumber numberWithDouble:30.0],
                [NSNumber numberWithDouble:40.0],
                [NSNumber numberWithDouble:50.0], 
                [NSNumber numberWithDouble:60.0], nil];

CPTTheme *theme = [CPTTheme themeNamed:kCPTDarkGradientTheme];
[graph applyTheme:theme];
[graph addPlot:pieChart];
[pieChart release];
}

我在网上找到了这个代码。这个代码工作正常，但是在第二天有两个警告 pieChart.dataSource = self;

它说。

警告：类'SOTC_CorePlotExampleViewController'没有   实施'CPTPlotDataSource'协议

警告：语义问题：从'分配'id'   不兼容的类型'SOTC_CorePlotExampleViewController *'

Answer 1

将<CPTPlotDataSource>添加到@interface（.h）文件中自定义视图控制器声明的末尾：

@interface YourViewController  : UIViewController <CPTPlotDataSource>

（将我的示例中的YourViewController更改为视图控制器的名称）

Answer 2

你做到了吗？

@interface viewController : UIViewController <CPTPlotDataSource>

viewController需要实现所述协议

Answer 3

你必须在.h文件“CPTPlotDataSource”中导入协议，如@interface:UIViewController < CPTPlotDataSource >

执行CorePlot代码时发出警告

3 个答案: