Ios CorePlot饼图：如何隐藏X轴和Y轴？

ios中饼图CorePlot的以下代码：

CPTGraphHostingView *hostingView = [[CPTGraphHostingView alloc] initWithFrame:self.view.bounds];
    [self.view addSubview:hostingView];

    graph = [[CPTXYGraph alloc] initWithFrame:self.view.bounds];
    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];
    [graph addPlot:pieChart];
    [pieChart release];

这是在饼图中不隐藏x和y轴的输出。。。。！ 我需要隐藏X轴和y轴。。。！

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救救我

最好的方法是完全移除轴

graph.axisSet = nil;

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@嗨，你能看看我的问题吗？非常感谢你。