Xcode 4.2 中的 iOS 核心图

Question

我正在编译应用程序，但看不到图表。

RaceDetailView.h

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

@interface RaceDetailView : UIView <CPTPlotDataSource, CPTPlotSpaceDelegate>

@property (nonatomic, retain) NSArray *plotData;
@property (nonatomic, retain) NSString *title;
@property (nonatomic, retain) CPTGraphHostingView *layerHostingView;
@property CGFloat labelRotation;

- (void)setTitleDefaultsForGraph:(CPTGraph *)graph withBounds:(CGRect)bounds;
- (void)setPaddingDefaultsForGraph:(CPTGraph *)graph withBounds:(CGRect)bounds;
-(NSUInteger)numberOfRecords;
-(NSNumber *)numberForPlot:(CPTPlot *)plot field:(NSUInteger)fieldEnum recordIndex:(NSUInteger)index;

@end

RaceDetailView.m

#import "RaceDetailView.h"

@implementation RaceDetailView

@synthesize layerHostingView;
@synthesize labelRotation;
@synthesize title;
@synthesize plotData;

- (id)initWithFrame:(CGRect)frame
{
    self = [super initWithFrame:frame];
    if (self) {
        title = @"my race chart";

        plotData = [[NSMutableArray alloc] initWithObjects:
                    [NSNumber numberWithDouble:20.0],
                    [NSNumber numberWithDouble:30.0],
                    [NSNumber numberWithDouble:60.0],
                    nil];

        CPTGraph *graph = [[[CPTXYGraph alloc] initWithFrame:frame] autorelease];
        //[self addGraph:graph toHostingView:layerHostingView];
        layerHostingView.hostedGraph = graph;
        //[self applyTheme:theme toGraph:graph withDefault:[CPTTheme themeNamed:kCPTDarkGradientTheme]];
        [graph applyTheme:[CPTTheme themeNamed:kCPTDarkGradientTheme]];

        [self setTitleDefaultsForGraph:graph withBounds:frame];
        [self setPaddingDefaultsForGraph:graph withBounds:frame];

        // Setup scatter plot space
        CPTXYPlotSpace *plotSpace = (CPTXYPlotSpace *)graph.defaultPlotSpace;
        plotSpace.allowsUserInteraction = YES;
        plotSpace.delegate = self;

        // Grid line styles
        CPTMutableLineStyle *majorGridLineStyle = [CPTMutableLineStyle lineStyle];
        majorGridLineStyle.lineWidth = 0.75;
        majorGridLineStyle.lineColor = [[CPTColor colorWithGenericGray:0.2] colorWithAlphaComponent:0.75];

        CPTMutableLineStyle *minorGridLineStyle = [CPTMutableLineStyle lineStyle];
        minorGridLineStyle.lineWidth = 0.25;
        minorGridLineStyle.lineColor = [[CPTColor whiteColor] colorWithAlphaComponent:0.1];    

        CPTMutableLineStyle *redLineStyle = [CPTMutableLineStyle lineStyle];
        redLineStyle.lineWidth = 10.0;
        redLineStyle.lineColor = [[CPTColor redColor] colorWithAlphaComponent:0.5];

        // Axes
        // Label x axis with a fixed interval policy
        CPTXYAxisSet *axisSet = (CPTXYAxisSet *)graph.axisSet;
        CPTXYAxis *x = axisSet.xAxis;
        x.majorIntervalLength = CPTDecimalFromString(@"0.5");
        x.orthogonalCoordinateDecimal = CPTDecimalFromString(@"1.0");
        x.minorTicksPerInterval = 2;
        x.majorGridLineStyle = majorGridLineStyle;
        x.minorGridLineStyle = minorGridLineStyle;

        x.title = @"X Axis";
        x.titleOffset = 30.0;
        x.titleLocation = CPTDecimalFromString(@"1.25");

        // Label y with an automatic label policy. 
        CPTXYAxis *y = axisSet.yAxis;
        y.labelingPolicy = CPTAxisLabelingPolicyAutomatic;
        y.orthogonalCoordinateDecimal = CPTDecimalFromString(@"1.0");
        y.minorTicksPerInterval = 2;
        y.preferredNumberOfMajorTicks = 8;
        y.majorGridLineStyle = majorGridLineStyle;
        y.minorGridLineStyle = minorGridLineStyle;
        y.labelOffset = 10.0;

        y.title = @"Y Axis";
        y.titleOffset = 30.0;
        y.titleLocation = CPTDecimalFromString(@"1.0");

        // Rotate the labels by 45 degrees, just to show it can be done.
        labelRotation = M_PI * 0.25;

        // Set axes
        //graph.axisSet.axes = [NSArray arrayWithObjects:x, y, y2, nil];
        graph.axisSet.axes = [NSArray arrayWithObjects:x, y, nil];

        // Create a plot that uses the data source method
        CPTScatterPlot *dataSourceLinePlot = [[[CPTScatterPlot alloc] init] autorelease];
        dataSourceLinePlot.identifier = @"Data Source Plot";

        CPTMutableLineStyle *lineStyle = [[dataSourceLinePlot.dataLineStyle mutableCopy] autorelease];
        lineStyle.lineWidth = 3.0;
        lineStyle.lineColor = [CPTColor greenColor];
        dataSourceLinePlot.dataLineStyle = lineStyle;

        dataSourceLinePlot.dataSource = self;
        [graph addPlot:dataSourceLinePlot];

        // Auto scale the plot space to fit the plot data
        // Extend the y range by 10% for neatness
        [plotSpace scaleToFitPlots:[NSArray arrayWithObjects:dataSourceLinePlot, nil]];
        CPTPlotRange *xRange = plotSpace.xRange;
        CPTPlotRange *yRange = plotSpace.yRange;
        [xRange expandRangeByFactor:CPTDecimalFromDouble(1.3)];
        [yRange expandRangeByFactor:CPTDecimalFromDouble(1.3)];
        plotSpace.yRange = yRange;

        // Restrict y range to a global range
        CPTPlotRange *globalYRange = [CPTPlotRange plotRangeWithLocation:CPTDecimalFromFloat(0.0f)
                                                                  length:CPTDecimalFromFloat(2.0f)];
        plotSpace.globalYRange = globalYRange;

        // set the x and y shift to match the new ranges
        CGFloat length = xRange.lengthDouble;
        //xShift = length - 3.0;
        length = yRange.lengthDouble;
        //yShift = length - 2.0;

        // 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);
        dataSourceLinePlot.plotSymbol = plotSymbol;

        // Set plot delegate, to know when symbols have been touched
        // We will display an annotation when a symbol is touched
        dataSourceLinePlot.delegate = self; 
        dataSourceLinePlot.plotSymbolMarginForHitDetection = 5.0f;

        // Add legend
        graph.legend = [CPTLegend legendWithGraph:graph];
        graph.legend.textStyle = x.titleTextStyle;
        graph.legend.fill = [CPTFill fillWithColor:[CPTColor darkGrayColor]];
        graph.legend.borderLineStyle = x.axisLineStyle;
        graph.legend.cornerRadius = 5.0;
        graph.legend.swatchSize = CGSizeMake(25.0, 25.0);
        graph.legendAnchor = CPTRectAnchorBottom;
        graph.legendDisplacement = CGPointMake(0.0, 12.0);
    }
    return self;
}

- (void)setTitleDefaultsForGraph:(CPTGraph *)graph withBounds:(CGRect)bounds
{
    graph.title = title;
    CPTMutableTextStyle *textStyle = [CPTMutableTextStyle textStyle];
    textStyle.color = [CPTColor grayColor];
    textStyle.fontName = @"Helvetica-Bold";
    textStyle.fontSize = round(bounds.size.height / 20.0f);
    graph.titleTextStyle = textStyle;
    graph.titleDisplacement = CGPointMake(0.0f, round(bounds.size.height / 18.0f)); // Ensure that title displacement falls on an integral pixel
    graph.titlePlotAreaFrameAnchor = CPTRectAnchorTop;    
}

- (void)setPaddingDefaultsForGraph:(CPTGraph *)graph withBounds:(CGRect)bounds
{
    float boundsPadding = round(bounds.size.width / 20.0f); // Ensure that padding falls on an integral pixel
    graph.paddingLeft = boundsPadding;

    if (graph.titleDisplacement.y > 0.0) {
        graph.paddingTop = graph.titleDisplacement.y * 2;
    }
    else {
        graph.paddingTop = boundsPadding;
    }

    graph.paddingRight = boundsPadding;
    graph.paddingBottom = boundsPadding;    
}

-(NSUInteger)numberOfRecordsForPlot:(CPTPlot *)plot
{
    return [plotData count];
}

-(NSNumber *)numberForPlot:(CPTPlot *)plot field:(NSUInteger)fieldEnum recordIndex:(NSUInteger)index
{
    NSNumber *num;
    if (fieldEnum == CPTPieChartFieldSliceWidth) {
        num = [plotData objectAtIndex:index];
    }
    else {
        return [NSNumber numberWithInt:index];
    }

    return num;
}

@end

编辑:您可能会注意到，这是来自 CorePlot 示例 SimpleScatterPlot。

Answer 1

为什么这段代码在 UIView 中？此代码通常位于 View Controller (UIViewController) 中。您从中提取示例的 Plot Gallery 应用程序稍微复杂一些，因为它在多个地方使用绘图——在主视图区域中，还为列表或浏览器 View 制作缩略图。

你有没有设置过layerHostingView？它在 View 层次结构中并且可见吗？

按照@danielbeard 的建议检查您的数据源。散点图的正确字段名称是 CPTScatterPlotFieldX 和 CPTScatterPlotFieldY。