Problems Running Core Plot Tutorial

Question

I am following the tutorial here about core plot here.... http://www.switchonthecode.com/tutorials/using-core-plot-in-an-iphone-application

I am getting errors with the following lines of code

//SAYING INCOMPATIBLE TYPE FOR AURGUMENT 1 'setMajorIntervalLength'
axisSet.xAxis.majorIntervalLength = [NSDecimalNumber decimalNumberWithString:@"5"];

// request for member 'axisLabelOffset' in something not a structure or union
axisSet.xAxis.axisLabelOffset = 3.0f;

//request for member 'bounds' in something not a structure or union
CPScatterPlot *xSquaredPlot = [[[CPScatterPlot alloc] initWithFrame:graph.defaultPlotSpace.bounds] autorelease];

Here is my code now I am not getting any compiler errors anymore but its crashing and not loading the view please take a look if you can

  @implementation FirstCorePlotViewController

 (void)viewDidLoad 
{

      [super viewDidLoad];

      graph = [[CPXYGraph alloc] initWithFrame: self.view.bounds];

      CPLayerHostingView *hostingView = (CPLayerHostingView *)self.view;
      hostingView.hostedLayer = graph;
      graph.paddingLeft = 20.0;
      graph.paddingTop = 20.0;
      graph.paddingRight = 20.0;
      graph.paddingBottom = 20.0;

        CPXYPlotSpace *plotSpace = (CPXYPlotSpace *)graph.defaultPlotSpace;
     plotSpace.xRange = [CPPlotRange plotRangeWithLocation:CPDecimalFromFloat(-6)
                                              length:CPDecimalFromFloat(12)];
     plotSpace.yRange = [CPPlotRange plotRangeWithLocation:CPDecimalFromFloat(-5)
                                               length:CPDecimalFromFloat(30)];

      CPXYAxisSet *axisSet = (CPXYAxisSet *)graph.axisSet;

          CPLineStyle *lineStyle = [CPLineStyle lineStyle];
      lineStyle.lineColor = [CPColor blackColor];
          lineStyle.lineWidth = 2.0f;

      axisSet.xAxis.majorIntervalLength =CPDecimalFromString(@"5");
      axisSet.xAxis.minorTicksPerInterval = 4;
      axisSet.xAxis.majorTickLineStyle = lineStyle;
      axisSet.xAxis.minorTickLineStyle = lineStyle;
      axisSet.xAxis.axisLineStyle = lineStyle;
      axisSet.xAxis.minorTickLength = 5.0f;
      axisSet.xAxis.majorTickLength = 7.0f;
      axisSet.xAxis.labelOffset = 3.0f;

      axisSet.yAxis.majorIntervalLength = CPDecimalFromString(@"5");
      axisSet.yAxis.minorTicksPerInterval = 4;
      axisSet.yAxis.majorTickLineStyle = lineStyle;
      axisSet.yAxis.minorTickLineStyle = lineStyle;
      axisSet.yAxis.axisLineStyle = lineStyle;
      axisSet.yAxis.minorTickLength = 5.0f;
      axisSet.yAxis.majorTickLength = 7.0f;
      axisSet.yAxis.labelOffset = 3.0f;

     CPScatterPlot *xSquaredPlot = [[(CPScatterPlot *)[CPScatterPlot alloc] initWithFrame:graph.bounds] autorelease];


        xSquaredPlot.identifier = @"X Squared Plot";
    xSquaredPlot.dataLineStyle.lineWidth = 1.0f;
    xSquaredPlot.dataLineStyle.lineColor = [CPColor redColor];
    xSquaredPlot.dataSource = self;
    [graph addPlot:xSquaredPlot];

    CPPlotSymbol *greenCirclePlotSymbol = [CPPlotSymbol ellipsePlotSymbol];
        greenCirclePlotSymbol.fill = [CPFill fillWithColor:[CPColor greenColor]];
    greenCirclePlotSymbol.size = CGSizeMake(2.0, 2.0);
    //xSquaredPlot.defaultPlotSymbol = greenCirclePlotSymbol;  

    CPScatterPlot *xInversePlot = [[(CPScatterPlot *)[CPScatterPlot alloc] initWithFrame:graph.bounds] autorelease];    
    xInversePlot.identifier = @"X Inverse Plot";
    xInversePlot.dataLineStyle.lineWidth = 1.0f;
    xInversePlot.dataLineStyle.lineColor = [CPColor blueColor];
    xInversePlot.dataSource = self;
    [graph addPlot:xInversePlot];
}

-(NSUInteger)numberOfRecords 
 {

        return 51;
 }

-(NSNumber *)numberForPlot:(CPPlot *)plot field:(NSUInteger)fieldEnum  
           recordIndex:(NSUInteger)index
 {
        double val = (index/5.0)-5;
    if(fieldEnum == CPScatterPlotFieldX)
    { 

             return [NSNumber numberWithDouble:val]; 
     }
    else
    {
       if(plot.identifier == @"X Squared Plot")
       {
                   return [NSNumber numberWithDouble:val*val]; 
        }
       else
       {
                     return [NSNumber numberWithDouble:1/val];
       }
 }
}

 @end

Eric Skroch Eric Skroch · Accepted Answer · 2010-06-10T23:41:52

None of these errors are caused by #import problems. That tutorial is known to be somewhat out of date and some parts of the Core Plot framework have changed.

The majorIntervalLength property expects an NSDecimal, not NSDecimalNumer. Core Plot includes several utility functions that convert other types to NSDecimal such as CPDecimalFromString and CPDecimalFromDouble.

axisSet.xAxis.majorIntervalLength = CPDecimalFromString(@"5");

The axisLabelOffset property has been renamed to labelOffset.
The third error is caused by two things. Both UIView and CPLayer (the root class for all Core Plot layers) having an -initWithFrame: method. Because -alloc returns an id, the compiler doesn't know which -initWithFrame: to use and sometimes guesses wrong. You can fix it with a typecast. Also, plot spaces are not layers; just get the bounds of the graph.

CPScatterPlot *xSquaredPlot = [[(CPScatterPlot *)[CPScatterPlot alloc] initWithFrame:graph.bounds] autorelease];

Problems Running Core Plot Tutorial

4 Answers