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編輯：我認爲我的問題更好措詞如下：我怎麼能有一個不從零開始的Y軸？看起來x軸始終位於y = 0處，但我希望x軸在y軸上處於某個正數。爲什麼我的X軸不會在iPhone上顯示核心圖？
下面是與更規則數據的圖...我只希望x軸被設置在最小的y值的曲線圖（約77），而不是在0
這是我用來創建圖形的函數。
這是一大堆代碼，我不太確定哪一部分可能不顯示x軸。
x軸不顯示與我的數據有關嗎？
- (void) showGraph:(SavedDetailScreen*)dataSource {
// create the graph and add it to the view
CPXYGraph *graph = [[CPXYGraph alloc] initWithFrame: CGRectZero];
graph.plotArea.masksToBorder = NO;
CPLayerHostingView *graphView = [[CPLayerHostingView alloc] initWithFrame:CGRectMake(0,0, 280, 240)];
[self addSubview:graphView];
graphView.hostedLayer = graph;
graph.paddingLeft = 50.0;
graph.paddingTop = 20.0;
graph.paddingRight = 10.0;
graph.paddingBottom = 40.0;
// set up the ranges for the graph axis
float minElevation = dataSource.track.tbStats.minAlt;
float maxElevation = dataSource.track.tbStats.maxAlt-dataSource.track.tbStats.minAlt;
float minDistance = 0.0f;
float maxDistance = dataSource.track.tbStats.totalDistance;
CPXYPlotSpace *plotSpace = (CPXYPlotSpace *)graph.defaultPlotSpace;
plotSpace.xRange = [CPPlotRange plotRangeWithLocation:CPDecimalFromFloat(minDistance)
length:CPDecimalFromFloat(maxDistance)];
plotSpace.yRange = [CPPlotRange plotRangeWithLocation:CPDecimalFromFloat(minElevation)
length:CPDecimalFromFloat(maxElevation)];
// style the graph with white text and lines
CPTextStyle *whiteText = [CPTextStyle textStyle];
whiteText.color = [CPColor whiteColor];
CPLineStyle *whiteStyle = [CPLineStyle lineStyle];
whiteStyle.lineColor = [CPColor whiteColor];
whiteStyle.lineWidth = 2.0f;
// set up the axis
CPXYAxisSet *axisSet = (CPXYAxisSet *)graph.axisSet;
CPXYAxis *x = axisSet.xAxis;
CPXYAxis *y = axisSet.yAxis;
x.majorIntervalLength = CPDecimalFromFloat(maxDistance/10.0f);
x.minorTicksPerInterval = 0;
x.majorTickLineStyle = whiteStyle;
x.minorTickLineStyle = whiteStyle;
x.axisLineStyle = whiteStyle;
x.minorTickLength = 5.0f;
x.majorTickLength = 10.0f;
x.labelOffset = 3.0f;
x.labelTextStyle = whiteText;
y.majorIntervalLength = CPDecimalFromFloat(maxElevation/5.0f);
y.minorTicksPerInterval = 0;
y.majorTickLineStyle = whiteStyle;
y.minorTickLineStyle = whiteStyle;
y.axisLineStyle = whiteStyle;
y.minorTickLength = 5.0f;
y.majorTickLength = 10.0f;
y.labelOffset = 3.0f;
y.labelTextStyle = whiteText;
CPScatterPlot *plot = [[[CPScatterPlot alloc] initWithFrame:graph.bounds] autorelease];
plot.dataLineStyle.lineWidth = 2.0f;
plot.dataLineStyle.lineColor = [CPColor blueColor];
plot.dataSource = dataSource;
[graph addPlot:plot];
CPPlotSymbol *greenCirclePlotSymbol = [CPPlotSymbol ellipsePlotSymbol];
greenCirclePlotSymbol.fill = [CPFill fillWithColor:[CPColor greenColor]];
greenCirclePlotSymbol.size = CGSizeMake(2.0, 2.0);
plot.plotSymbol = greenCirclePlotSymbol;
}
的數據是所有罰款。圖形顯示，y軸顯示，y軸標籤顯示，圖顯示...只是x軸不顯示，也沒有標籤。數據唯一的問題是y值有時可能低於最小y值。這會搞砸了嗎？ – 2010-01-13 06:00:37
對不起，不太熟悉這個框架。但是，你有這個方法呢：plotRangeWithLocation：CPDecimalFromFloat（minDistance）length：CPDecimalFromFloat（maxDistance）]; 這是正確的長度值嗎？例如。同時你有maxAlt是你的數據源min和max之間的差異，但是對於距離你有它在0和數據源max之間。 – 2010-01-13 06:40:37
此外，作爲一般觀察，它看起來像整個圖表可能在那裏，但由於一些低y值切斷x軸。你可以創建一個更簡單的虛擬數據集（也許在所有的y都相同的情況下產生一條水平線）來查看x軸是否出現了嗎？ – 2010-01-13 06:41:41