Core Plot line not showing up

Question

I have created a simple implementation of the CorePlot framework. The chart shows up fine, but there is no line plotted. I have tried logging out my sample values and indeed do have data. Any and all input on why the line of plotted data does not show up would be appreciated!

Header File:

#import <UIKit/UIKit.h>
#import "PresentedViewControllerDelegate.h"
#import "CorePlot-CocoaTouch.h"

#define NUM_SAMPLES 30

@interface DeviceDetailModal : UIViewController <PresentedViewControllerDelegate, UIWebViewDelegate, UITableViewDataSource, UITableViewDelegate, CPTPlotDataSource>{
CPTXYGraph *graph;
NSMutableArray *samples;

double xxx[NUM_SAMPLES];
double yyy1[NUM_SAMPLES];

}

@property (weak, nonatomic) IBOutlet UITableView *tableView;

@property (nonatomic, weak) id <PresentedViewControllerDelegate> delegate;


@end

Main File

#import <Foundation/Foundation.h>
#import "DeviceDetailModal.h"
#import "DetailCell.h"
#import "CorePlot-CocoaTouch.h"

#define START_POINT 0 // Start at origin
#define END_POINT 15.0 // TODO time is 15 seconds

#define X_VAL @"X_VAL"
#define Y_VAL @"Y_VAL"

@implementation DeviceDetailModal


-(void)viewDidLoad{
UIBarButtonItem *closeButton = [[UIBarButtonItem alloc] initWithTitle:@"Close" style:UIBarButtonItemStylePlain target:self action:@selector(closeView)];
self.navigationItem.leftBarButtonItem = closeButton;

[[UIBarButtonItem appearance] setTintColor:[UIColor lightGrayColor]];

[[UINavigationBar appearance] setBarTintColor:[UIColor blackColor]];


self.tableView.layer.cornerRadius = 10.0;
self.tableView.layer.borderWidth = 0.7;
self.tableView.layer.borderColor = [UIColor whiteColor].CGColor;

[self generateDataSamples];

NSNumber *xAxisStart = [NSNumber numberWithDouble:START_POINT];
NSNumber *xAxisLength = [NSNumber numberWithDouble:END_POINT - START_POINT];

double maxY = [[samples valueForKeyPath:@"@max.Y_VAL"] doubleValue];
NSNumber *yAxisStart = [NSNumber numberWithDouble:-maxY];
NSNumber *yAxisLength = [NSNumber numberWithDouble:2 *maxY];

CGRect hostingRect = CGRectMake(20, 330, 335, 347);


CPTGraphHostingView *hostingView = [[CPTGraphHostingView alloc] initWithFrame:hostingRect];

[self.view addSubview:hostingView];

graph = [[CPTXYGraph alloc] initWithFrame:hostingView.bounds];

hostingView.hostedGraph = graph;

CPTXYPlotSpace *plotSpace = (CPTXYPlotSpace *)graph.defaultPlotSpace;
plotSpace.xRange = [CPTPlotRange plotRangeWithLocation:xAxisStart
                                                length:xAxisLength];

plotSpace.yRange = [CPTPlotRange plotRangeWithLocation:yAxisStart
                                                length:yAxisLength];

CPTScatterPlot *dataSourceLinePlot = [[CPTScatterPlot alloc] init];
dataSourceLinePlot.delegate = self;

// LINE STYLE
CPTMutableLineStyle *mainPlotLineStyle = [[dataSourceLinePlot dataLineStyle] mutableCopy];
[mainPlotLineStyle setLineWidth:2.0f];
[mainPlotLineStyle setLineColor:[CPTColor colorWithCGColor:[[UIColor whiteColor] CGColor]]];

[dataSourceLinePlot setDataLineStyle:mainPlotLineStyle];

// AXIS STYLE

CPTXYAxisSet *axisSet = (CPTXYAxisSet *)[graph axisSet];

CPTXYAxis *xAxis = [axisSet xAxis];
CPTXYAxis *yAxis = [axisSet yAxis];
CPTMutableLineStyle *axisLineStyle = [CPTMutableLineStyle lineStyle];
[axisLineStyle setLineWidth:1];
[axisLineStyle setLineColor:[CPTColor colorWithCGColor:[[UIColor whiteColor] CGColor]]];

[xAxis setAxisLineStyle:axisLineStyle];
[xAxis setMajorTickLineStyle:axisLineStyle];
[yAxis setAxisLineStyle:axisLineStyle];
[yAxis setMajorTickLineStyle:axisLineStyle];


[graph addPlot:dataSourceLinePlot];
NSLog(@"PLOT: %@",dataSourceLinePlot);
[graph reloadData];

}


-(void)generateDataSamples{
double length = (END_POINT - START_POINT);
double delta = length / (NUM_SAMPLES -1);

samples = [[NSMutableArray alloc] initWithCapacity:NUM_SAMPLES];

for (int i = 0; i < NUM_SAMPLES; i++) {
    double x = START_POINT + (delta * i);

    //X^2
    double y = x * x;

    NSDictionary *sample = [NSDictionary dictionaryWithObjectsAndKeys:
                            [NSNumber numberWithDouble:x],X_VAL,
                            [NSNumber numberWithDouble:y],Y_VAL,
                            nil];
    NSLog(@"SAMPLE: %@", sample);
    [samples addObject:sample];
}

[graph reloadData];


}

-(NSUInteger)numberOfRecordsForPlot:(CPTPlot *)plot{
return NUM_SAMPLES;
}

-(NSNumber *)numberForPlot:(CPTPlot *)plot field:(NSUInteger)fieldEnum recordIndex:(NSUInteger)index{
NSDictionary *sample = [samples objectAtIndex:index];

if (fieldEnum == CPTScatterPlotFieldX) {
    return [sample valueForKey:X_VAL];
}else{
    return [sample valueForKey:Y_VAL];
}
}

arcade16 arcade16 · Accepted Answer · 2015-10-27T19:09:25

Found the problem! The data source for the plot was not set, I had to do:

dataSourceLinePlot.dataSource = self;

I found this out when my numberOfRecordsPerPlot method was never being called.

Core Plot line not showing up

2 Answers