前言
今年大数据行业火爆异常，大数据的实用点之一在于数据的统计和加工实现数据的“增值”，方便人们从大量的数据统计中得出结论。
对于一个iOS开发程序猿来说不是专门搞大数据开发的，似乎没有多大关系，但后续iOS开发中，各类APP中必然会加入统计表格的形式展示数据，相对于传统的列表形式+各类查询显示，表格形式直观、简洁、通俗易懂，分析更透彻，必然会成为抢手货。
本文介绍一下简易的柱状图、折线图、扇形图三种统计图的制作，希望能帮助到大家
坐标系
利用CAShapeLayer和UIBezierPath绘制坐标系，坐标系中需要绘制的部分如下图所示：
需要绘制的部分有原点、x坐标轴、y坐标轴、坐标轴末尾的箭头和坐标轴上的标度。需要计算位置和长度，需要根据所在页面的大小计算坐标系的位置和大小。
这里给出代码如下：
CAShapeLayer *layer = [CAShapeLayer layer]; UIBezierPath *path = [UIBezierPath bezierPath]; //坐标轴原点 CGPoint rPoint = CGPointMake(1.3*margin, self.zzHeight-margin); //画y轴 [path moveToPoint:rPoint]; [path addLineToPoint:CGPointMake(1.3*margin, margin)]; //画y轴的箭头 [path moveToPoint:CGPointMake(1.3*margin, margin)]; [path addLineToPoint:CGPointMake(1.3*margin-5, margin+5)]; [path moveToPoint:CGPointMake(1.3*margin, margin)]; [path addLineToPoint:CGPointMake(1.3*margin+5, margin+5)]; //画x轴 [path moveToPoint:rPoint]; [path addLineToPoint:CGPointMake(self.zzWidth-0.8*margin, self.zzHeight-margin)]; //画x轴的箭头 [path moveToPoint:CGPointMake(self.zzWidth-0.8*margin, self.zzHeight-margin)]; [path addLineToPoint:CGPointMake(self.zzWidth-0.8*margin-5, self.zzHeight-margin-5)]; [path moveToPoint:CGPointMake(self.zzWidth-0.8*margin, self.zzHeight-margin)]; [path addLineToPoint:CGPointMake(self.zzWidth-0.8*margin-5, self.zzHeight-margin+5)]; //画x轴上的标度 for (int i=0; i<x_itemarr.count; i++) { [path movetopoint:cgpointmake(1.3*margin+(self.zzwidth-2*margin)="" (x_itemarr.count+1)*(i+1), self.zzheight-margin)];="" [path addlinetopoint:cgpointmake(1.3*margin+(self.zzwidth-2*margin)="" (x_itemarr.count+1)*(i+1), self.zzheight-margin-3)];="" } ="" 画y轴上的标度="" for (int i="0; i<10; i++) {" [path movetopoint:cgpointmake(1.3*margin, margin+(self.zzheight-2*margin)="" 11*(i+1))];="" [path addlinetopoint:cgpointmake(1.3*margin+3, margin+(self.zzheight-2*margin)="" }="" layer.path =" path.CGPath;" layer.fillcolor =" [UIColor clearColor].CGColor;" layer.strokecolor =" [UIColor blackColor].CGColor;" layer.linewidth =" 2.0;" [self.layer addsublayer:layer]; ="" 给y轴加标注="" lab.text =" [NSString stringWithFormat:@"%d", 10*i];" lab.textcolor =" [UIColor blackColor];" lab.font =" [UIFont boldSystemFontOfSize:size];" lab.textalignment =" NSTextAlignmentCenter;" [self addsubview:lab];="" }<="" pre=""><p><span style="font-size: 18px;"><strong>柱状图</strong></span></p><p>在绘制坐标系的基础上，绘制柱状图的原理非常简单，根据x轴的坐标，计算每条柱的高度。</p><p>这里需要注意： </p><p>提供的数据需要转化为自己设定的y轴的刻度单位计算出的高度。另外，柱状图需要占用x轴的宽度，所以柱子的位置需要好好考虑一下放在x轴的什么位置。</p><p>代码如下：</p><pre class="brush:as3;toolbar:false"> //画柱状图 for (int i=0; i<x_itemarr.count; i++) { uibezierpath *path =" [UIBezierPath bezierPathWithRect:CGRectMake(1.3*margin+(self.zzWidth-2*margin)/(x_itemArr.count+1)*(i+0.7), self.zzHeight-margin-(self.zzHeight-2*margin)/11*[y_itemArr[i] floatValue]/10, 0.6*((self.zzWidth-2*margin)/(x_itemArr.count+1)), (self.zzHeight-2*margin)/11*[y_itemArr[i] floatValue]/10-1)];" cashapelayer *layer =" [CAShapeLayer layer];" layer.path =" path.CGPath;" layer.fillcolor =" zzRandomColor.CGColor;" layer.strokecolor =" [UIColor clearColor].CGColor;" [self.layer addsublayer:layer];="" }="" ="" 给x轴加标注="" for (int i="0; i<x_itemArr.count; i++) {" cgfloat xlwidth =" ((self.zzWidth-2*margin)/(x_itemArr.count+1)) <= 25 ? ((self.zzWidth-2*margin)/(x_itemArr.count+1)) : 25;" uilabel *lab =" [[UILabel alloc] initWithFrame:CGRectMake(1.3*margin+(self.zzWidth-2*margin)/(x_itemArr.count+1)*(i+1)-xLWidth/2, self.zzHeight-margin, xLWidth, 20)];" lab.text =" x_itemArr[i];" lab.textcolor =" [UIColor blackColor];" lab.adjustsfontsizetofitwidth =" YES;" lab.textalignment =" NSTextAlignmentCenter;" [self addsubview:lab];="" }<="" pre=""><p>效果图如下：</p><p style="text-align: center;"><img src="http://cc.cocimg.com/api/uploads//20171206/1512520726921727.png" title="iOS后续开发 数据统计表" _src="http://cc.cocimg.com/api/uploads//20171206/1512520726921727.png" alt="iOS后续开发 数据统计表" width="500" height="495" border="0" vspace="0" style="width: 500px; height: 495px;"></p><p><span style="font-size: 18px;"><strong>折线图</strong></span></p><p>在坐标系的基础上，计算绘制对应y轴上的点，然后从第一个点开始，依次连接到最后一个点，可以直线连接，或者用贝塞尔曲线绘制，具体看实际情况实现。</p><p>代码如下：</p><pre class="brush:as3;toolbar:false"> //开始点 CGPoint startPoint = CGPointMake(1.3*margin+(self.zzWidth-2*margin)/(x_itemArr.count+1), self.zzHeight-margin-(self.zzHeight-2*margin)/11*[y_itemArr[0] floatValue]/10); //结束点 CGPoint endPoint; for (int i=0; i<x_itemarr.count; i++) { endpoint =" CGPointMake(1.3*margin+(self.zzWidth-2*margin)/(x_itemArr.count+1)*(i+1), self.zzHeight-margin-(self.zzHeight-2*margin)/11*[y_itemArr[i] floatValue]/10);" uibezierpath *path =" [UIBezierPath bezierPath];" [path movetopoint:startpoint];="" [path addarcwithcenter:endpoint radius:1.5 startangle:0 endangle:2*m_pi clockwise:yes];="" [path addlinetopoint:endpoint]; ="" 绘制连线="" cashapelayer *layer =" [CAShapeLayer layer];" layer.path =" path.CGPath;" layer.strokecolor =" [UIColor redColor].CGColor;" layer.linewidth =" 1.0;" [self.layer addsublayer:layer]; ="" 绘制点="" cashapelayer *layer1 =" [CAShapeLayer layer];" layer1.frame =" CGRectMake(endPoint.x-2, endPoint.y-2, 4, 4);" layer1.backgroundcolor =" [UIColor blackColor].CGColor;" [self.layer addsublayer:layer1]; ="" 绘制虚线="" cashapelayer *shapelayer =" [CAShapeLayer layer];" [shapelayer setstrokecolor:[uicolor blackcolor].cgcolor];="" [shapelayer setlinewidth:1];="" [shapelayer setlinejoin:kcalinejoinround]; ="" 设置虚线的线宽及间距="" [shapelayer setlinedashpattern:[nsarray arraywithobjects:[nsnumber numberwithint:2], [nsnumber numberwithint:3], nil]]; ="" 创建虚线绘制路径="" cgmutablepathref path =" CGPathCreateMutable(); //设置y轴方向的虚线" cgpathmovetopoint(path, null, point.x, point.y);="" cgpathaddlinetopoint(path, null, point.x, self.zzheight-margin); ="" 设置x轴方向的虚线="" cgpathaddlinetopoint(path, null, 1.3*margin, point.y); ="" 设置虚线绘制路径="" [shapelayer setpath:path];="" cgpathrelease(path);="" [self.layer addsublayer:shapelayer];="" startpoint =" endPoint;" } ="" 给x轴加标注="" for (int i="0; i<x_itemArr.count; i++) { CGFloat xLWidth = ((self.zzWidth-2*margin)/(x_itemArr.count+1)) <= 25 ? ((self.zzWidth-2*margin)/(x_itemArr.count+1)) : 25; UILabel *lab = [[UILabel alloc] initWithFrame:CGRectMake(1.3*margin+(self.zzWidth-2*margin)/(x_itemArr.count+1)*(i+1)-xLWidth/2, self.zzHeight-margin, xLWidth, 20)];" lab.text =" x_itemArr[i];" lab.textcolor =" [UIColor blackColor];" lab.adjustsfontsizetofitwidth =" YES;" lab.textalignment =" NSTextAlignmentCenter;" [self addsubview:lab];="" }<="" pre=""><p>效果图如下： </p><p style="text-align: center;"><img src="http://cc.cocimg.com/api/uploads//20171206/1512520769607184.png" title="iOS后续开发 数据统计表" _src="http://cc.cocimg.com/api/uploads//20171206/1512520769607184.png" alt="iOS后续开发 数据统计表" width="500" height="486" border="0" vspace="0" style="width: 500px; height: 486px;"></p><p><span style="font-size: 18px;"><strong>扇形图</strong></span></p><p>扇形图制作需要首先计算每一条数据占数据总和的百分比，然后以页面中心点为中心，指定半径，开始画扇形，每条数据对应一个扇形，起点半径每次都不一样，知道最后一条数据画完，可以正好得到一个整圆。</p><p>代码如下：</p><pre class="brush:as3;toolbar:false"> CGPoint yPoint = CGPointMake(self.zzWidth/2, self.zzHeight/2); CGFloat startAngle = 0; CGFloat endAngle; float r = self.zzHeight/3; //求和 float sum=0; for (NSString *str in y_itemArr) { sum += [str floatValue]; } for (int i=0; i= 45 ? 40 : self.zzHeight/6; CGFloat size = self.zzHeight/6+5 >= 45 ? 9 : 5; CGFloat lab_x = yPoint.x + (r + bLWidth/2) * cos((startAngle + (endAngle - startAngle)/2)) - bLWidth/2; CGFloat lab_y = yPoint.y + (r + bLWidth*3/8) * sin((startAngle + (endAngle - startAngle)/2)) - bLWidth*3/8; UILabel *lab = [[UILabel alloc] initWithFrame:CGRectMake(lab_x, lab_y, bLWidth, bLWidth*3/4)]; lab.text = [NSString stringWithFormat:@"%@%.2f%@",x_itemArr[i],zhanbi*100,@"%"]; lab.textColor = [UIColor blackColor]; lab.numberOfLines = 0; lab.font = [UIFont boldSystemFontOfSize:size]; lab.textAlignment = NSTextAlignmentCenter; [self addSubview:lab]; layer.path = path.CGPath; layer.fillColor = zzRandomColor.CGColor; layer.strokeColor = [UIColor clearColor].CGColor; [self.layer addSublayer:layer]; startAngle = endAngle; }</pre><p>效果图如下： </p><p style="text-align: center;"><img src="http://cc.cocimg.com/api/uploads//20171206/1512520794943194.png" title="iOS后续开发 数据统计表" _src="http://cc.cocimg.com/api/uploads//20171206/1512520794943194.png" alt="iOS后续开发 数据统计表" width="500" height="493" border="0" vspace="0" style="width: 500px; height: 493px;"></p><p><span style="font-size: 18px;"><strong>尾声</strong></span></p><p>简易的三种画法，仅用于展示数据，封装类和Demo已经上传到了GitHub上，地址：<a href="https://github.com/fuzheng0301/DrawChart" target="_blank" _href="https://github.com/fuzheng0301/DrawChart">https://github.com/fuzheng0301/DrawChart</a>，感谢star，希望能给大家带来帮助，也希望能看到大神的更精彩的分享。</p> </x_itemarr.count; i++) {></pre></x_itemarr.count; i++) {></pre></x_itemarr.count; i++) {>