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今天在项目中为了实现一个可以显示自定义样式的x轴label，整了我一个下午，搞死我了。先上图：
图中的表格可以左右拖动，不允许上下拖动。而且只允许显示当前三十天的数据，且今天的标签显示白色。
设置corePlot可拖动：
- plotSpace.allowsUserInteraction = YES;
设置x显示的范围：
- plotSpace.xRange = [CPTPlotRange plotRangeWithLocation:CPTDecimalFromInt(8 * oneDay)length:CPTDecimalFromInt(23 * oneDay)];
设置x轴拖动范围：
- plotSpace.globalXRange = [CPTPlotRange plotRangeWithLocation:CPTDecimalFromInt(0) length:CPTDecimalFromInt(31 * oneDay)];
禁止corePlot缩放(Self是CPTGraphHostingView)：
- [self setAllowPinchScaling:NO];//禁止缩放
自定义label：
- x.axisLabels = [self buildLabelTitle];
- x.labelingPolicy = CPTAxisLabelingPolicyNone;
- //构建30天的label样式
- - (NSMutableSet*)buildLabelTitle
- {
- NSMutableSet *newAxisLabels = [NSMutableSet set];
- CPTMutableTextStyle *textStyleB = [CPTMutableTextStyle textStyle];
- textStyleB.color = [CPTColor colorWithComponentRed:CPTFloat((float)0x09/0xFF) green:CPTFloat((float)0x31/0xFF) blue:CPTFloat((float)0x4A/0xFF) alpha:CPTFloat(1.0)];
- NSDateFormatter *dateFormatter = [[[NSDateFormatter alloc] init] autorelease];
- [dateFormatter setDateFormat:@"MM.dd"];
- int n = 1;
- for ( NSUInteger i = 29; i > 0; i--) //从今起前29天
- {
- NSTimeInterval secondsPerDay = 24 * 60 * 60 * i;
- NSDate *ago = [[NSDate alloc] initWithTimeIntervalSinceNow:-secondsPerDay];
- CPTAxisLabel *newLabel = [[CPTAxisLabel alloc] initWithText:[dateFormatter stringFromDate:ago]
- textStyle:textStyleB];
- [ago release];
- newLabel.tickLocation = CPTDecimalFromUnsignedInteger(n++ * oneDay);
- newLabel.offset = 5;
- [self.locationLabels addObject:[NSNumber numberWithInt:(n-1) * oneDay]];
- [newAxisLabels addObject:newLabel];
- [newLabel release];
- }
- //今天
- CPTMutableTextStyle *textStyleW = [CPTMutableTextStyle textStyle];
- textStyleW.color = [CPTColor whiteColor];
- CPTAxisLabel *newLabel = [[CPTAxisLabel alloc] initWithText:@"今日" textStyle:textStyleW];
- newLabel.tickLocation = CPTDecimalFromUnsignedInteger(oneDay * n);
- [self.locationLabels addObject:[NSNumber numberWithInt:(n) * oneDay]];
- newLabel.offset = 5;
- [newAxisLabels addObject:newLabel];
- [newLabel release];
- return newAxisLabels;
- }
但是写好后发现majorGridLine不见了，之后各种折腾后终于找到原因是：
CPTAxisLabelingPolicyNone
No labels provided; user sets labels and tick locations.
设置这个属性是要自己重新定义majorGridLine位置的
所以需要使用：
- x.majorTickLocations = [NSSet setWithArray:locationLabels];
结果为：