how to draw multiple plots in coreplot

Question

I need to draw multiple plots in the same graph at different times. Please look at the image below:

Except that the number of plots would change dynamically. Sometimes I would only require only blue and orange datasets some times all four and some times only 3. I am able to manage for one bar plot like this.

CPTScatterPlot *plot = [[[CPTScatterPlot alloc] init] autorelease];
plot.dataSource = self;
plot.identifier = @"mainplot";
plot.dataLineStyle = lineStyle;
plot.plotSymbol = plotSymbol;
[self.graph addPlot:plot];  

In my case I can put them in a for loop and do [self.graph addplot:plot] in each iteration. But how do I manage the datasource. How do I manage the code below, if the number of datasets changes dynamically.

-(NSNumber *)numberForPlot:(CPTPlot *)plot field:(NSUInteger)fieldEnum recordIndex:(NSUInteger)index {
    if ( [plot.identifier isEqual:@"mainplot"] )
    {
        NSValue *value = [self.graphData objectAtIndex:index];
        CGPoint point = [value CGPointValue];

        // FieldEnum determines if we return an X or Y value.
        if ( fieldEnum == CPTScatterPlotFieldX )
        {
            return [NSNumber numberWithFloat:point.x];
        }
        else    // Y-Axis
        {
            return [NSNumber numberWithFloat:point.y];
        }
    }

    return [NSNumber numberWithFloat:0];
}  

Answer 1

I did it before and it worked! You can use an NSArray for plots, and create some plot data and add them as objects into a NSDictionary. for more detail you can see this sample:

NSDictionary *firstLineDic = [NSDictionary dictionaryWithObjectsAndKeys:@"firstLine", PLOT_IDENTIFIER, firstLineData, PLOT_DATA, nil];
NSDictionary *secondLineDic = [NSDictionary dictionaryWithObjectsAndKeys:@"secondLine", PLOT_IDENTIFIER, secondLineData, PLOT_DATA, nil];
NSArray *arrayData = [NSArray arrayWithObjects:firstLineDic, secondLineDic, nil];
scatterPlot = [[ScatterPlot alloc] initWithHostingView:plotView data:arrayData];
[scatterPlot initialisePlot];

Now in ScatterPlot class write these functions:

-(id)initWithHostingView:(CPTGraphHostingView *)_hostingView data:(NSArray *)_data{
    self = [super init];
    if ( self != nil ) {
        self.hostingView = _hostingView;
        data = [[NSArray alloc] initWithArray:_data];
        self.graph = nil;
    }
    return self;
}

-(void)initialisePlot
{

...

    for (NSDictionary *dic in data) {
        CPTScatterPlot *plot = [[[CPTScatterPlot alloc] init] autorelease];
        plot.dataSource = self;
        plot.identifier = [dic objectForKey:PLOT_IDENTIFIER];
        plot.dataLineStyle = [lineStyles objectAtIndex:[dic objectForKey:PLOT_COLOR]];
        plot.plotSymbol = plotSymbol;
        [self.graph addPlot:plot];
    }

...

}

-(NSUInteger)numberOfRecordsForPlot:(CPTPlot *)plot 
{
    for (NSDictionary *dic in data) {
        NSString *identity = [dic objectForKey:PLOT_IDENTIFIER];
        if([plot.identifier isEqual:identity]){
            NSArray *arr = [dic objectForKey:PLOT_DATA];
            return [arr count];
        }
    }
    return 0;
}

Answer 2

Check for different plot identifiers, and return other data then.