Question

I’m posting a lot of code, but the question is relatively simple:
I’m trying to create a CTPXYGraph as a stand-alone object and then use it as a hostedGraph in another ViewController I have.

For some reason, it crashes! (Gets me to assembly code with EXC_BAD_ACCESS signal)

The ViewController:

RealTimePlot *plot = [[RealTimePlot alloc] init];
CTPXYGraph *graph = [plot createGraph];
self.graphHostingView.hostedGraph = graph;

The graphObject:

#import "CorePlot-CocoaTouch.h"

@interface RealTimePlot : NSObject <CPTPlotDataSource>
{  
NSMutableArray *dataForPlot;
}

@property (readwrite, strong) NSMutableArray *dataForPlot;

- (CPTXYGraph *) createGraph;

@end

Implementation:

@implementation RealTimePlot
@synthesize dataForPlot;

- (CPTXYGraph *) createGraph:
// Create graph from theme
CPTXYGraph *graph = [[CPTXYGraph alloc] initWithFrame:CGRectZero];
CPTTheme *theme = [CPTTheme themeNamed:kCPTDarkGradientTheme];
[graph applyTheme:theme];

graph.paddingLeft   = 10.0;
graph.paddingTop    = 10.0;
graph.paddingRight  = 10.0;
graph.paddingBottom = 10.0;

// Setup plot space
CPTXYPlotSpace *plotSpace = (CPTXYPlotSpace *)graph.defaultPlotSpace;
plotSpace.allowsUserInteraction = YES;
plotSpace.xRange                = [CPTPlotRange plotRangeWithLocation:CPTDecimalFromFloat(1.0) length:CPTDecimalFromFloat(2.0)];
plotSpace.yRange                = [CPTPlotRange plotRangeWithLocation:CPTDecimalFromFloat(1.0) length:CPTDecimalFromFloat(3.0)];

// Axes
CPTXYAxisSet *axisSet = (CPTXYAxisSet *)graph.axisSet;
CPTXYAxis *x          = axisSet.xAxis;
x.majorIntervalLength         = CPTDecimalFromString(@"0.5");
x.orthogonalCoordinateDecimal = CPTDecimalFromString(@"2");
x.minorTicksPerInterval       = 2;
NSArray *exclusionRanges = [NSArray arrayWithObjects:
                            [CPTPlotRange plotRangeWithLocation:CPTDecimalFromFloat(1.99) length:CPTDecimalFromFloat(0.02)],
                            [CPTPlotRange plotRangeWithLocation:CPTDecimalFromFloat(0.99) length:CPTDecimalFromFloat(0.02)],
                            [CPTPlotRange plotRangeWithLocation:CPTDecimalFromFloat(2.99) length:CPTDecimalFromFloat(0.02)],
                            nil];
x.labelExclusionRanges = exclusionRanges;

CPTXYAxis *y = axisSet.yAxis;
y.majorIntervalLength         = CPTDecimalFromString(@"0.5");
y.minorTicksPerInterval       = 5;
y.orthogonalCoordinateDecimal = CPTDecimalFromString(@"2");
exclusionRanges               = [NSArray arrayWithObjects:
                                 [CPTPlotRange plotRangeWithLocation:CPTDecimalFromFloat(1.99) length:CPTDecimalFromFloat(0.02)],
                                 [CPTPlotRange plotRangeWithLocation:CPTDecimalFromFloat(0.99) length:CPTDecimalFromFloat(0.02)],
                                 [CPTPlotRange plotRangeWithLocation:CPTDecimalFromFloat(3.99) length:CPTDecimalFromFloat(0.02)],
                                 nil];
y.labelExclusionRanges = exclusionRanges;

// Create a blue plot area
CPTScatterPlot *boundLinePlot  = [[CPTScatterPlot alloc] init];
CPTMutableLineStyle *lineStyle = [CPTMutableLineStyle lineStyle];
lineStyle.miterLimit        = 1.0f;
lineStyle.lineWidth         = 3.0f;
lineStyle.lineColor         = [CPTColor blueColor];
boundLinePlot.dataLineStyle = lineStyle;
boundLinePlot.identifier    = @"Blue Plot";
boundLinePlot.dataSource    = self;
[graph addPlot:boundLinePlot];

// Do a blue gradient
CPTColor *areaColor1       = [CPTColor colorWithComponentRed:0.3 green:0.3 blue:1.0 alpha:0.8];
CPTGradient *areaGradient1 = [CPTGradient gradientWithBeginningColor:areaColor1 endingColor:[CPTColor clearColor]];
areaGradient1.angle = -90.0f;
CPTFill *areaGradientFill = [CPTFill fillWithGradient:areaGradient1];
boundLinePlot.areaFill      = areaGradientFill;
boundLinePlot.areaBaseValue = [[NSDecimalNumber zero] decimalValue];

// Add plot symbols
CPTMutableLineStyle *symbolLineStyle = [CPTMutableLineStyle lineStyle];
symbolLineStyle.lineColor = [CPTColor blackColor];
CPTPlotSymbol *plotSymbol = [CPTPlotSymbol ellipsePlotSymbol];
plotSymbol.fill          = [CPTFill fillWithColor:[CPTColor blueColor]];
plotSymbol.lineStyle     = symbolLineStyle;
plotSymbol.size          = CGSizeMake(10.0, 10.0);
boundLinePlot.plotSymbol = plotSymbol;

// Create a green plot area
CPTScatterPlot *dataSourceLinePlot = [[CPTScatterPlot alloc] init];
lineStyle                        = [CPTMutableLineStyle lineStyle];
lineStyle.lineWidth              = 3.f;
lineStyle.lineColor              = [CPTColor greenColor];
lineStyle.dashPattern            = [NSArray arrayWithObjects:[NSNumber numberWithFloat:5.0f], [NSNumber numberWithFloat:5.0f], nil];
dataSourceLinePlot.dataLineStyle = lineStyle;
dataSourceLinePlot.identifier    = @"Green Plot";
dataSourceLinePlot.dataSource    = self;

// Put an area gradient under the plot above
CPTColor *areaColor       = [CPTColor colorWithComponentRed:0.3 green:1.0 blue:0.3 alpha:0.8];
CPTGradient *areaGradient = [CPTGradient gradientWithBeginningColor:areaColor endingColor:[CPTColor clearColor]];
areaGradient.angle               = -90.0f;
areaGradientFill                 = [CPTFill fillWithGradient:areaGradient];
dataSourceLinePlot.areaFill      = areaGradientFill;
dataSourceLinePlot.areaBaseValue = CPTDecimalFromString(@"1.75");

// Animate in the new plot, as an example
dataSourceLinePlot.opacity = 0.0f;
[graph addPlot:dataSourceLinePlot];

CABasicAnimation *fadeInAnimation = [CABasicAnimation animationWithKeyPath:@"opacity"];
fadeInAnimation.duration            = 1.0f;
fadeInAnimation.removedOnCompletion = NO;
fadeInAnimation.fillMode            = kCAFillModeForwards;
fadeInAnimation.toValue             = [NSNumber numberWithFloat:1.0];
[dataSourceLinePlot addAnimation:fadeInAnimation forKey:@"animateOpacity"];

// Add some initial data
NSMutableArray *contentArray = [NSMutableArray arrayWithCapacity:100];
NSUInteger i;
for ( i = 0; i < 60; i++ ) {
    id x = [NSNumber numberWithFloat:1 + i * 0.05];
    id y = [NSNumber numberWithFloat:1.2 * rand() / (float)RAND_MAX + 1.2];
    [contentArray addObject:[NSMutableDictionary dictionaryWithObjectsAndKeys:x, @"x", y, @"y", nil]];
}
self.dataForPlot = contentArray;

return graph;
}

Answer 1

RealTimePlot *plot = [[RealTimePlot alloc] init];

is getting dealloc-ed.

It turns out CPTGraphHostingView doesn’t retain its hostedGraph ivar.