Question

我有一个绘制散点图的方法，我得到错误[__NSArrayI count]：消息发送到解除分配的实例。

我进行了调试，错误发生在

行

   [plotSpace scaleToFitPlots:[NSArray arrayWithObjects:aaplPlot, googPlot, msftPlot, nil]];

我认为对象被释放存在问题，但我不确切知道如何解决问题。第二次调用该方法时出现错误。

这是方法：

-(void)configurePlots {

    // 1 - Get graph and plot space
    CPTGraph *graph = self.hostView.hostedGraph;
    CPTXYPlotSpace *plotSpace = (CPTXYPlotSpace *) graph.defaultPlotSpace;
    // 2 - Create the three plots
    CPTScatterPlot *aaplPlot = [[CPTScatterPlot alloc] init];
    aaplPlot.dataSource = self;
    aaplPlot.identifier = CPDTickerSymbolAAPL;
    CPTColor *aaplColor = [CPTColor redColor];
    [graph addPlot:aaplPlot toPlotSpace:plotSpace];
    CPTScatterPlot *googPlot = [[CPTScatterPlot alloc] init];
    googPlot.dataSource = self;
    googPlot.identifier = CPDTickerSymbolGOOG;
    CPTColor *googColor = [CPTColor greenColor];
    [graph addPlot:googPlot toPlotSpace:plotSpace];
    CPTScatterPlot *msftPlot = [[CPTScatterPlot alloc] init];
    msftPlot.dataSource = self;
    msftPlot.identifier = CPDTickerSymbolMSFT;
    CPTColor *msftColor = [CPTColor blueColor];
    [graph addPlot:msftPlot toPlotSpace:plotSpace];
    // 3 - Set up plot space
    // Here is the problem//
    [plotSpace scaleToFitPlots:[NSArray arrayWithObjects:aaplPlot, googPlot, msftPlot, nil]];
    CPTMutablePlotRange *xRange = [plotSpace.xRange mutableCopy];
    [xRange expandRangeByFactor:CPTDecimalFromCGFloat(1.1f)];
    plotSpace.xRange = xRange;
    CPTMutablePlotRange *yRange = [plotSpace.yRange mutableCopy];
    [yRange expandRangeByFactor:CPTDecimalFromCGFloat(1.2f)];
    plotSpace.yRange = yRange;
    // 4 - Create styles and symbols
    CPTMutableLineStyle *aaplLineStyle = [aaplPlot.dataLineStyle mutableCopy];
    aaplLineStyle.lineWidth = 2.5;
    aaplLineStyle.lineColor = aaplColor;
    aaplPlot.dataLineStyle = aaplLineStyle;
    CPTMutableLineStyle *aaplSymbolLineStyle = [CPTMutableLineStyle lineStyle];
    aaplSymbolLineStyle.lineColor = aaplColor;
    CPTPlotSymbol *aaplSymbol = [CPTPlotSymbol ellipsePlotSymbol];
    aaplSymbol.fill = [CPTFill fillWithColor:aaplColor];
    aaplSymbol.lineStyle = aaplSymbolLineStyle;
    aaplSymbol.size = CGSizeMake(6.0f, 6.0f);
    aaplPlot.plotSymbol = aaplSymbol;
    CPTMutableLineStyle *googLineStyle = [googPlot.dataLineStyle mutableCopy];
    googLineStyle.lineWidth = 1.0;
    googLineStyle.lineColor = googColor;
    googPlot.dataLineStyle = googLineStyle;
    CPTMutableLineStyle *googSymbolLineStyle = [CPTMutableLineStyle lineStyle];
    googSymbolLineStyle.lineColor = googColor;
    CPTPlotSymbol *googSymbol = [CPTPlotSymbol starPlotSymbol];
    googSymbol.fill = [CPTFill fillWithColor:googColor];
    googSymbol.lineStyle = googSymbolLineStyle;
    googSymbol.size = CGSizeMake(6.0f, 6.0f);
    googPlot.plotSymbol = googSymbol;
    CPTMutableLineStyle *msftLineStyle = [msftPlot.dataLineStyle mutableCopy];
    msftLineStyle.lineWidth = 2.0;
    msftLineStyle.lineColor = msftColor;
    msftPlot.dataLineStyle = msftLineStyle;
    CPTMutableLineStyle *msftSymbolLineStyle = [CPTMutableLineStyle lineStyle];
    msftSymbolLineStyle.lineColor = msftColor;
    CPTPlotSymbol *msftSymbol = [CPTPlotSymbol diamondPlotSymbol];
    msftSymbol.fill = [CPTFill fillWithColor:msftColor];
    msftSymbol.lineStyle = msftSymbolLineStyle;
    msftSymbol.size = CGSizeMake(6.0f, 6.0f);
    msftPlot.plotSymbol = msftSymbol;
}

我做了一些更改：我创建了graph，plotSpace，array，aaplPlot，googPlot和msftPlot属性，并使用散点图分配和初始化数组。

  array = [[NSArray alloc] initWithObjects:aaplPlot, googPlot, msftPlot, nil];
  [plotSpace scaleToFitPlots:array];

当第二次调用该方法时，我得到了同样的错误。

Answer 1

self.hostView.hostedGraph正在发布。将其创建为具有保留值或强值的属性，然后再次检查。由于这发生在第二次运行中，因此只有在您使用它时才会释放您的对象。

@property (nonatomic, strong) CPTGraph *graph;

Answer 2

CPTXYPlotSpace *plotSpace = (CPTXYPlotSpace *) graph.defaultPlotSpace;

上面的plotSpace是一个方法，尝试将其作为静态变量或类属性，以便它不会被释放，并检查它是否再次init - ed。如果是财产。

[__NSArrayI count]：发送给解除分配的实例iPhone的消息

2 个答案: