ios - 核心情节实时图

Question

我正在使用核心图制作实时图表。这些值来自 Web 服务，但只提供了 45 个值，然后它必须停止。我拿到了core plot 1.4的real time plot sample，差不多可以用了。

我有两个问题，我的图表固定在 0,0 并且我的 y 轴消失了。该图在值数组(X 轴)处正确输入数据。日期数组(Y 轴)与值数组不同。此外，在此之前我得到了没有动画的图表。

到目前为止，这是我的代码，我相信所有需要的都在那里:

#pragma mark - CPTPlotDataSource methods
    -(NSUInteger)numberOfRecordsForPlot:(CPTPlot *)plot {
        return [plotData count];
    }


    -(void)newData:(NSTimer *)theTimer
    {
        //    CPTGraph *theGraph = [self.graphs objectAtIndex:0];
        CPTPlot *thePlot   = [self.hostView.hostedGraph plotWithIdentifier:CPDTickerSymbolGOOG];

    if ( thePlot ) {
        if ( plotData.count >= kMaxDataPoints ) {
            [plotData removeObjectAtIndex:0];
            [thePlot deleteDataInIndexRange:NSMakeRange(0, 1)];

            [dataTimer invalidate];
            return;
        }

        CPTXYPlotSpace *plotSpace = (CPTXYPlotSpace *)self.hostView.hostedGraph.defaultPlotSpace;
        NSUInteger location       = (currentIndex >= kMaxDataPoints ? currentIndex - kMaxDataPoints + 2 : 0);

        CPTPlotRange *newRange = [CPTPlotRange plotRangeWithLocation:CPTDecimalFromUnsignedInteger(location)
                                                              length:CPTDecimalFromUnsignedInteger(kMaxDataPoints - 2)];

        [CPTAnimation animate:plotSpace
                     property:@"xRange"
                fromPlotRange:plotSpace.xRange
                  toPlotRange:newRange
                     duration:(1.0 / kFrameRate)];

        currentIndex++;
        NSLog(@"%@",plotData);

        [plotData addObject:[arrValues lastObject]];
        [arrValues removeObjectAtIndex:[arrValues count] -1];
        [thePlot insertDataAtIndex:plotData.count - 1 numberOfRecords:1];
    }
    }

    -(NSNumber *)numberForPlot:(CPTPlot *)plot field:(NSUInteger)fieldEnum recordIndex:(NSUInteger)index {
        NSInteger valueCount = [[self datesInMonth]count];

    //  switch (fieldEnum) {
    //      case CPTScatterPlotFieldX:
    //          if (index < valueCount) {
    //              return [NSNumber numberWithUnsignedInteger:index];
    //          }
    //          break;
    //          
    //      case CPTScatterPlotFieldY:
    //            
    //          if ([plot.identifier isEqual:CPDTickerSymbolAAPL] == YES) {
    //              return [[[CPDStockPriceStore sharedInstance] monthlyPrices:CPDTickerSymbolAAPL] objectAtIndex:index];
    //          } else if ([plot.identifier isEqual:CPDTickerSymbolGOOG] == YES) {
    //              return [[[CPDStockPriceStore sharedInstance] monthlyPrices:CPDTickerSymbolGOOG] objectAtIndex:index];
    //          } else if ([plot.identifier isEqual:CPDTickerSymbolMSFT] == YES) {
    //              return [[[CPDStockPriceStore sharedInstance] monthlyPrices:CPDTickerSymbolMSFT] objectAtIndex:index];
    //          }
    //          break;
    //  }

    NSNumber *num = nil;

    switch ( fieldEnum ) {
        case CPTScatterPlotFieldX:
            num = [NSNumber numberWithUnsignedInteger:index + currentIndex - plotData.count];
            break;

        case CPTScatterPlotFieldY:
            num = [plotData objectAtIndex:index];
            break;

        default:
            break;
    }

    return num;


    return [NSDecimalNumber zero];
    }

    -(void)configureAxes {

    // 1 - Create styles
    CPTMutableTextStyle *axisTitleStyle = [CPTMutableTextStyle textStyle];
    axisTitleStyle.color = [CPTColor whiteColor];
    axisTitleStyle.fontName = @"Helvetica-Bold";
    axisTitleStyle.fontSize = 16.0f;

    CPTMutableTextStyle *axisTextStyle = [[CPTMutableTextStyle alloc] init];
    axisTextStyle.fontName = @"Helvetica";
    axisTextStyle.fontSize = 12.0f;

    CPTMutableLineStyle *axisLineStyle = [CPTMutableLineStyle lineStyle];
    axisLineStyle.lineWidth = 0.5f;
    axisLineStyle.lineColor = [[CPTColor whiteColor] colorWithAlphaComponent:0.4];

    CPTMutableLineStyle *tickLineStyle = [CPTMutableLineStyle lineStyle];
    tickLineStyle.lineColor = [CPTColor whiteColor];
    tickLineStyle.lineWidth = 0.0f;

    CPTMutableLineStyle *majorGridLineStyle = [CPTMutableLineStyle lineStyle];
    majorGridLineStyle.lineWidth = 1.0;
    majorGridLineStyle.lineColor = [[CPTColor whiteColor] colorWithAlphaComponent:0.4];

    CPTMutableLineStyle *minorGridLineStyle = [CPTMutableLineStyle lineStyle];
    minorGridLineStyle.lineColor = [CPTColor whiteColor];
    minorGridLineStyle.lineWidth = 1.0f;
    // 2 - Get axis set

    CPTXYAxisSet *axisSet = (CPTXYAxisSet *) self.hostView.hostedGraph.axisSet;

    // 3 - Configure x-axis
    CPTXYAxis *x = axisSet.xAxis;
    x.orthogonalCoordinateDecimal = CPTDecimalFromInteger(0);
    //x.title = @"Day of Month";
    x.titleTextStyle = axisTitleStyle;
    x.titleOffset = 15.0f;
    x.axisLineStyle = axisLineStyle;
    //    x.majorGridLineStyle = majorGridLineStyle;


    x.labelingPolicy = CPTAxisLabelingPolicyNone;


    x.majorTickLineStyle = axisLineStyle;
    x.majorTickLength = 30.0f;
    x.tickDirection = CPTSignNegative;
    //x.labelOffset = -25;

    CGFloat dateCount = 1;
    NSMutableSet *xLabels = [NSMutableSet setWithCapacity:dateCount];
    NSMutableSet *xLocations = [NSMutableSet setWithCapacity:dateCount];
    NSInteger i = 0;

    //    NSLog(@"datesInMonth - >%@",[self datesInMonth]);

    NSArray *_weekDays = @[@"", @"D", @"S", @"T", @"Q", @"Q", @"S", @"S"];

    int z = 0;
    for (NSString *date in [self datesInMonth]) {

        int contador = i++;
        NSDateFormatter *df = [[NSDateFormatter alloc] init];
        [df setDateFormat:@"dd/MM/yyyy"];

        NSString *dateTimeString = [date stringByAppendingString:@"12:00:00"];
        const char* dateString = [dateTimeString UTF8String];
        struct tm tm;
        time_t timestamp;
        strptime(dateString, "%d/%m/%Y %H:%M:%S", &tm);
        timestamp = mktime(&tm);

        NSDate *myDate = [NSDate dateWithTimeIntervalSince1970:timestamp];
        NSDateComponents *components = [[NSCalendar currentCalendar] components:NSCalendarUnitDay |
                                                                                NSCalendarUnitMonth |
                                                                                NSCalendarUnitYear fromDate:myDate];

        NSCalendar *calendar = [NSCalendar currentCalendar];
        NSRange weekdayRange = [calendar maximumRangeOfUnit:NSWeekdayCalendarUnit];
        NSDateComponents *_components = [calendar components:NSWeekdayCalendarUnit fromDate:myDate];
        NSUInteger weekdayOfDate = [_components weekday];

        if (weekdayOfDate == weekdayRange.location || weekdayOfDate == weekdayRange.length) {
            axisTextStyle.color = [CPTColor orangeColor];

            CPTPlotRange *bandRange;
            bandRange = [CPTPlotRange plotRangeWithLocation:CPTDecimalFromDouble((double)z-1) length:CPTDecimalFromDouble(1)];

            CPTColor *areaColor       = [CPTColor colorWithComponentRed:1.0 green:1.0 blue:1.0 alpha:0.1];
            CPTColor *areaColorEnd       = [CPTColor colorWithComponentRed:1.0 green:1.0 blue:1.0 alpha:1.0];
            CPTGradient *areaGradient = [CPTGradient gradientWithBeginningColor:areaColor endingColor:areaColorEnd];
            areaGradient.angle = -90.0f;
            CPTFill *areaGradientFill = [CPTFill fillWithGradient:areaGradient];

            areaGradient.angle                = -90.0f;
            areaGradientFill                  = [CPTFill fillWithGradient:areaGradient];

            [x addBackgroundLimitBand:[CPTLimitBand limitBandWithRange:bandRange fill:areaGradientFill]];

        } else {
            axisTextStyle.color = [CPTColor whiteColor];
        }

        axisTextStyle.textAlignment = CPTAlignmentCenter;
        x.labelTextStyle = axisTextStyle;

        CPTAxisLabel *label = [[CPTAxisLabel alloc]
                               initWithText:[NSString stringWithFormat:@"%i\n%@",[components day], _weekDays[weekdayOfDate]]
                                  textStyle:x.labelTextStyle];

        label.alignment = CPTAlignmentRight;
        NSDecimal location = CPTDecimalFromInteger(contador);


        label.tickLocation = CPTDecimalFromCGFloat(contador);
        //label.offset = x.majorTickLength - 10;

        if (label){
            [xLabels addObject:label];
        }

        [xLocations addObject:[NSDecimalNumber decimalNumberWithDecimal:location]];

        z++;
    }

    axisTextStyle.color = [CPTColor whiteColor];
    axisTextStyle.textAlignment = CPTAlignmentCenter;
    x.axisLabels = xLabels;
    x.majorTickLocations = xLocations;

    CPTXYAxis *y = axisSet.yAxis;
    //  y.title = @"";
        y.titleTextStyle = axisTitleStyle;
    //  y.titleOffset = -40.0f;
        y.axisLineStyle = axisLineStyle;
        y.majorTickLineStyle = axisLineStyle;
    //  y.minorTickLineStyle = nil;
        y.majorGridLineStyle = majorGridLineStyle;
    //  y.minorGridLineStyle = minorGridLineStyle;
        y.labelingPolicy = CPTAxisLabelingPolicyNone;
        y.labelTextStyle = axisTextStyle;
        y.labelOffset = 36.0f;
        //y.majorTickLineStyle = axisLineStyle;
        //y.majorTickLength = 4.0f;
        //y.minorTickLength = 1.0f;
        y.gridLinesRange = [CPTPlotRange plotRangeWithLocation:CPTDecimalFromFloat(-1.0f) length:CPTDecimalFromFloat(45.0f)];
        y.tickDirection = CPTSignPositive;

        NSInteger majorIncrement = 10000000;
        NSInteger minorIncrement = 10000000;
        CGFloat yMax = 180000000;  // should determine dynamically based on max price
        NSMutableSet *yLabels = [NSMutableSet set];
    //  NSMutableSet *yMajorLocations = [NSMutableSet set];
    //  NSMutableSet *yMinorLocations = [NSMutableSet set];
        NSMutableSet *yLocations = [NSMutableSet set];

        for (NSInteger j = minorIncrement; j <= yMax; j += minorIncrement) {
            NSUInteger mod = j % majorIncrement;

            NSNumberFormatter *numFormatter = [[NSNumberFormatter alloc] init];
            [numFormatter setNumberStyle:NSNumberFormatterDecimalStyle];

            if (mod == 0) {
                CPTAxisLabel *label = [[CPTAxisLabel alloc] initWithText:[numFormatter stringFromNumber:[NSNumber numberWithInt:j]] textStyle:y.labelTextStyle];
                NSDecimal location = CPTDecimalFromInteger(j);
                label.tickLocation = location;
                label.offset = -y.majorTickLength - y.labelOffset - 60;

                if (label) {
                    [yLabels addObject:label];
                }
                [yLocations addObject:[NSDecimalNumber decimalNumberWithDecimal:location]];

            }
        }
        y.axisLabels = yLabels;
    //  y.majorTickLocations = yMajorLocations;
    //  y.minorTickLocations = yMinorLocations;
        y.majorTickLocations = yLocations;

    }

Answer 1

您应该使用约束来定位 y 轴，使其不会随着图形滚动而移动。

y.axisConstraints = [CPTConstraints constraintWithLowerOffset:0.0];

kMaxDataPoints 的值是多少？如果它大于数据点的数量，图表将不会滚动。