iphone - 核心图 : Updating X Axis range in real time plotting

Question

我已经检查了大多数似乎最相关的问题，但没有一个真正涉及我目前遇到的一些麻烦。我的问题是，虽然我知道无论我如何尝试更新它都需要更新 plotSpace.xRange，但要么什么都没有发生，要么我崩溃了。

我目前正在做的是我在 RealTimeScatterPlot.m 文件中声明了 2 个全局变量(xMinVal，xMaxVal)，这些是我在绘图初始化时用于 plotSpace.xRange 计算的变量。然后，托管绘图 View 的 View Controller 包含一个函数，该函数每秒生成并绘制一个随机点。在这个函数中，我跟踪查看是否有超过 25 个(我的默认 x 轴范围目前是从 0 到 50)点，如果有，我会尝试将 RealTimeScatterPlot.m 中的全局值加一，这理论上应该将我的图形 View 移动 1。第一次增量发生，尽管 View 没有移动，我也不能再次增量，因为值保持不变。如果看到代码有助于让我知道，我会编辑它，但它都非常简单/通用。我在想，这可能不是我应该实现的方式，而不是编码问题。

任何见解将不胜感激!

Answer 1

您可以轻松地做您想做的事情，例如更新 tableview 数据。
这是我所做的部分代码，您可以引用。希望这可以帮助你。

-(void) fetchArrayOffeedback {

    NSFetchRequest *fetchRequest = [[NSFetchRequest alloc] init];

    NSEntityDescription *entity = [NSEntityDescription entityForName:@"Pulse"
                                              inManagedObjectContext:appDelegate.managedObjectContext];
    [fetchRequest setEntity:entity];

    NSPredicate *predictate = [NSPredicate predicateWithFormat:@"sessionKey == %@", appDelegateiPhone.strSessionId];

    [fetchRequest setPredicate:predictate];

    NSSortDescriptor *sort = [[NSSortDescriptor alloc]
                              initWithKey:@"date" ascending:YES];
    [fetchRequest setSortDescriptors:[NSArray arrayWithObject:sort]];
    [sort release];

    NSError *error;

    chartData = (NSMutableArray*)[appDelegate.managedObjectContext
                                            executeFetchRequest:fetchRequest error:&error];

    [chartData retain];
    NSLog(@"array count :%d", [chartData count]);

    [graph reloadData];

    CPXYPlotSpace *plotSpace = (CPXYPlotSpace *)graph.defaultPlotSpace;
    plotSpace.xRange = [CPPlotRange plotRangeWithLocation:CPDecimalFromFloat(0.0) length:CPDecimalFromFloat(fiveHour*3)];   
}

- (void)constructScatterPlotForFeedback
{
    [graph release];

    graph = [[CPXYGraph alloc] initWithFrame:CGRectZero];
    graph.delegate = self;
    CPTheme *theme = [CPTheme themeNamed:kCPPlainWhiteTheme];
    [graph applyTheme:theme];
    feedbackChart.hostedGraph = graph;
    [feedbackChart setBackgroundColor:[UIColor clearColor]];

    graph.paddingLeft = 0.0;
    graph.paddingTop = 0.0;
    graph.paddingRight = 0.0;
    graph.paddingBottom = 0.0;

    graph.plotAreaFrame.paddingLeft = 5.0;
    graph.plotAreaFrame.paddingTop = 10.0;
    graph.plotAreaFrame.paddingRight = 10.0;
    graph.plotAreaFrame.paddingBottom = 10.0;

    NSTimeInterval oneHour =  60 * 60;

    CPXYPlotSpace *plotSpace = (CPXYPlotSpace *)graph.defaultPlotSpace;
    plotSpace.allowsUserInteraction = YES;
    plotSpace.delegate = self;

    float xRange;
    xRange = [chartData count] + 1.0;

    if (xRange>5) {
        xRange = 5.0;
    }
    plotSpace.xRange = [CPPlotRange plotRangeWithLocation:CPDecimalFromFloat(0.0) length:CPDecimalFromFloat(fiveHour*3)];
    plotSpace.yRange = [CPPlotRange plotRangeWithLocation:CPDecimalFromFloat(-20.0) length:CPDecimalFromFloat(40.0)];


    CPLineStyle *gridline = [CPLineStyle lineStyle];
    gridline.lineColor = [CPColor grayColor];
    gridline.lineWidth = 1.0f;  

    CPXYAxisSet *axisSet = (CPXYAxisSet *)graph.axisSet;
    CPXYAxis *x = axisSet.xAxis;
    x.majorIntervalLength = CPDecimalFromFloat(fiveHour);
    x.minorTicksPerInterval = 0;
    x.labelOffset=0;

    NSDate *refDate = [NSDate date];
    NSDateFormatter *dateFormatter = [[[NSDateFormatter alloc] init] autorelease];

    dateFormatter.dateFormat = @"HH:mm:ss";

    CPTimeFormatter *timeFormatter = [[[CPTimeFormatter alloc] initWithDateFormatter:dateFormatter] autorelease];
    timeFormatter.referenceDate = refDate;
    x.labelFormatter = timeFormatter;

    CPXYAxis *y = axisSet.yAxis;

    y.minorTicksPerInterval = 0;
    y.orthogonalCoordinateDecimal = CPDecimalFromString(@"0.0");
    y.majorIntervalLength = CPDecimalFromString(@"5");
    y.majorGridLineStyle = nil;

    y.visibleRange = [CPPlotRange plotRangeWithLocation:CPDecimalFromFloat(-20.0f) length:CPDecimalFromFloat(40.0f)];
    CPConstraints yConstraints = {CPConstraintNone, CPConstraintFixed};
    y.isFloatingAxis=YES;
    y.constraints=yConstraints;

    CPScatterPlot *dataSourceLinePlot = [[[CPScatterPlot alloc] init] autorelease];
    dataSourceLinePlot.identifier = @"FeedBack Plot";
    dataSourceLinePlot.dataLineStyle.lineWidth = 3.f;
    dataSourceLinePlot.dataLineStyle.lineColor = [CPColor blackColor];
    dataSourceLinePlot.dataLineStyle.dashPattern = [NSArray arrayWithObjects:[NSNumber numberWithFloat:1.0f], [NSNumber numberWithFloat:1.0f], nil];
    dataSourceLinePlot.dataSource = self;

    dataSourceLinePlot.opacity = 0.0f;
    dataSourceLinePlot.cachePrecision = CPPlotCachePrecisionDecimal;

    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"];

    CPColor *areaColor1 = [CPColor colorWithComponentRed:0.3 green:0.3 blue:1.0 alpha:0.8];
    CPGradient *areaGradient1 = [CPGradient gradientWithBeginningColor:areaColor1 endingColor:[CPColor clearColor]];
    areaGradient1.angle = -90.0f;

    NSUInteger i;

    [graph addPlot:dataSourceLinePlot];

    NSMutableArray *contentArray1 = [NSMutableArray arrayWithCapacity:100];

    NSMutableArray *customTickLocations = [[NSMutableArray alloc] init];
    NSMutableArray *xAxisLabels = [[NSMutableArray alloc] init];
    for ( i = 0; i < [chartData count]; i++ ) {
    //for ( i = 0; i < 10; i++ ) {  
        [customTickLocations addObject:[NSDecimalNumber numberWithInt:i]];
        [xAxisLabels addObject:[NSString stringWithFormat:@"%0.1f", 5.0 * i]];
        Pulse *objPulse1 = (Pulse *)[chartData objectAtIndex:i];
//      id x = [NSNumber numberWithFloat:i*fiveHour];
        id x = [NSNumber numberWithFloat:i];
        id y = [NSNumber numberWithFloat:[objPulse1.feedBack floatValue]];
        NSLog(@"point of gragh for Performance x:%@, y : %@ ", x, y);
        [contentArray1 addObject:[NSMutableDictionary dictionaryWithObjectsAndKeys:x, @"x", y, @"y", nil]];
    }

    NSLog(@"Axis lable count : %d", [xAxisLabels count]);
    NSMutableArray *customLabels = [NSMutableArray arrayWithCapacity:[chartData count]];
    NSUInteger labelLocation = 0;

    for (NSNumber *tickLocation in customTickLocations) {
        NSLog(@">>>>>>>>>>>>>>>>> tick location");
        CPAxisLabel *newLabel = [[CPAxisLabel alloc] initWithText: [xAxisLabels objectAtIndex:labelLocation++] textStyle:x.labelTextStyle];
        newLabel.tickLocation = [tickLocation decimalValue];
        newLabel.offset = x.labelOffset + x.majorTickLength - 5.0f;
        newLabel.rotation = 0;
        [customLabels addObject:newLabel];
        [newLabel release];
    }

    x.axisLabels =  [NSSet setWithArray:customLabels];

    arrScatter = contentArray1;
    [arrScatter retain];
}

-(NSUInteger)numberOfRecordsForPlot:(CPPlot *)plot 
{

    if ( [(NSString *)plot.identifier isEqualToString:@"FeedBack Plot"] ) {
        return [chartData count];
    }

    return 0;
}

-(NSNumber *)numberForPlot:(CPPlot *)plot field:(NSUInteger)fieldEnum recordIndex:(NSUInteger)index
{
    switch ( fieldEnum ) {
        case CPScatterPlotFieldX:
            return (NSDecimalNumber *)[NSDecimalNumber numberWithUnsignedInteger:index*fiveHour];
        case CPScatterPlotFieldY:
        {
            Pulse *objPulse1 = (Pulse *)[chartData objectAtIndex:index];
            return [NSNumber numberWithFloat:[objPulse1.feedBack floatValue]];          
        }
    }
    return nil;
}

-(CGPoint)plotSpace:(CPPlotSpace *)space willDisplaceBy:(CGPoint)displacement {

    return CGPointMake(displacement.x, 0);
}


/*
-(NSNumber *)numberForPlot:(CPPlot *)plot field:(NSUInteger)fieldEnum recordIndex:(NSUInteger)index 
{
    NSDecimalNumber *num = nil;

    if ( [(NSString *)plot.identifier isEqualToString:@"FeedBack Plot"] ) {
        if ( [arrScatter count] != 0) {
            num = [[arrScatter objectAtIndex:index] valueForKey:(fieldEnum == CPScatterPlotFieldX ? @"x" : @"y")];
        }
    }
    return num;
 }
*/

-(CPLayer *)dataLabelForPlot:(CPPlot *)plot recordIndex:(NSUInteger)index {

        Pulse *objPulse1 = (Pulse *)[chartData objectAtIndex:index];
        float value = [objPulse1.feedBack floatValue];       
        //CPTextLayer *textLayer = [[CPTextLayer alloc] initWithText:[NSString stringWithFormat:@"%d", value]];

        CPTextStyle *textStyle = [CPTextStyle textStyle];
        textStyle.color = [CPColor blackColor];

        CPTextLayer *textLayer = [[CPTextLayer alloc] initWithText:[NSString stringWithFormat:@"%0.1f", value] style:textStyle];
        return textLayer;
}