本文介绍了更改索引处的颜色图符号-CorePlot的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！
问题描述
我尝试在用户触摸绘图符号时添加绘图符号的标签。
如何也更改此绘图符号的颜色。
这是我的代码，用于添加绘图符号的标签
I try add label of plot symbol when user touch at plot symbol.How to change color this plot symbol,too.Here i my code to add label of plot symbol
- (void)scatterPlot:(CPTScatterPlot *)plot plotSymbolWasSelectedAtRecordIndex (NSUInteger)index {
if(symbolTextAnnotation) {
[graph.plotAreaFrame.plotArea removeAnnotation:symbolTextAnnotation];
[symbolTextAnnotation release];
symbolTextAnnotation = nil;
}
if ([(NSString *)plot.identifier isEqualToString:@"TOTAL"]) {
// Setup a style for the annotation
CPTMutableTextStyle *hitAnnotationTextStyle = [CPTMutableTextStyle textStyle];
hitAnnotationTextStyle.color = [CPTColor whiteColor];
hitAnnotationTextStyle.fontSize = 14.0f;
hitAnnotationTextStyle.fontName = @"SourceSansPro-Bold";
// Determine point of symbol in plot coordinates
NSNumber *x = [[plotData objectAtIndex:index] valueForKey:@"x"];
NSNumber *y = [[plotData objectAtIndex:index] valueForKey:@"y"];
NSArray *anchorPoint = [NSArray arrayWithObjects:x, y, nil];
// Add annotation
// First make a string for the y value
NSNumberFormatter *formatter = [[[NSNumberFormatter alloc] init] autorelease];
[formatter setMaximumFractionDigits:2];
NSString *yString = [formatter stringFromNumber:y];
// Now add the annotation to the plot area
CPTTextLayer *textLayer = [[[CPTTextLayer alloc] initWithText:[[currencySymbol objectAtIndex:index] stringByAppendingFormat: yString] style:hitAnnotationTextStyle] autorelease];
symbolTextAnnotation = [[CPTPlotSpaceAnnotation alloc] initWithPlotSpace:graph.defaultPlotSpace anchorPlotPoint:anchorPoint];
symbolTextAnnotation.contentLayer = textLayer;
symbolTextAnnotation.displacement = CGPointMake(0.0f, 20.0f);
[graph.plotAreaFrame.plotArea addAnnotation:symbolTextAnnotation];
}
推荐答案
在数据源中实施 -symbolForScatterPlot：recordIndex：方法。为每个要有特殊外观的索引返回一个绘图符号，或者为 nil 返回以绘制标准绘图符号（ plotSymbol 属性）。每当需要更新图解符号时，在图解上调用 -reloadData 。
Implement the -symbolForScatterPlot:recordIndex: method in your datasource. Return a plot symbol for each index that you want to have a special appearance or nil to draw the standard plot symbol (the plotSymbol property) at that index. Call -reloadData on the plot whenever you need to update the plot symbols.
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