iOS之画饼图

1.效果图如下

2.画饼图实现步骤如下：

• 1.在main.storyboard中拖入一个UIView控件，并设置其Custom Class 为HMPieView。如下图
  

• 2.新建HMPieView类

////  HMPieView.h//  03-饼图//#import <UIKit/UIKit.h>@interface HMPieView : UIView@end

////  HMPieView.m//  03-饼图//#import "HMPieView.h"#import "UIColor+Random.h"@implementation HMPieView- (id)initWithFrame:(CGRect)frame{    self = [super initWithFrame:frame];    if (self) {        // Initialization code    }    return self;}// Only override drawRect: if you perform custom drawing.// An empty implementation adversely affects performance during animation.- (void)drawRect:(CGRect)rect{    // Drawing code    NSArray *data = @[@25,@25,@50];    // 1.获取上下文    CGContextRef ctx = UIGraphicsGetCurrentContext();    // 2.拼接路径    CGPoint center = CGPointMake(125, 125);    CGFloat radius = 120;    CGFloat startA = 0;    CGFloat angle = 0;    CGFloat endA = 0;    for (NSNumber *number in data) {        // 2.拼接路径        startA = endA;        angle = number.intValue / 100.0 * M_PI * 2;        endA = startA + angle;        UIBezierPath *path = [UIBezierPath bezierPathWithArcCenter:center radius:radius startAngle:startA endAngle:endA clockwise:YES];        [path addLineToPoint:center];        [[UIColor randomColor] set];        // 把路径添加上下文        CGContextAddPath(ctx, path.CGPath);        // 渲染        CGContextFillPath(ctx);    }}- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event{    CGFloat a = arc4random_uniform(6);    //CGFloat a =  arc4random()%6;    NSLog(@"随机数--%f",a);    [self setNeedsDisplay];}- (void)drawPie{    // 1.获取上下文    CGContextRef ctx = UIGraphicsGetCurrentContext();    // 2.拼接路径    CGPoint center = CGPointMake(125, 125);    CGFloat radius = 120;    CGFloat startA = 0;    CGFloat angle = 0;    CGFloat endA = 0;    // 第一个扇形    angle = 25 / 100.0 * M_PI * 2;    endA = startA + angle;    UIBezierPath *path = [UIBezierPath bezierPathWithArcCenter:center radius:radius startAngle:startA endAngle:endA clockwise:YES];    [path addLineToPoint:center];    // 添加到上下文    CGContextAddPath(ctx, path.CGPath);    [[UIColor redColor] set];    // 渲染    CGContextFillPath(ctx);    // 第二个扇形    startA = endA;    angle = 25 / 100.0 * M_PI * 2;    endA = startA + angle;    UIBezierPath *path1 = [UIBezierPath bezierPathWithArcCenter:center radius:radius startAngle:startA endAngle:endA clockwise:YES];    [path1 addLineToPoint:center];    // 添加到上下文    CGContextAddPath(ctx, path1.CGPath);    [[UIColor greenColor] set];    // 渲染    CGContextFillPath(ctx);    // 第三个扇形    startA = endA;    angle = 50 / 100.0 * M_PI * 2;    endA = startA + angle;    UIBezierPath *path2 = [UIBezierPath bezierPathWithArcCenter:center radius:radius startAngle:startA endAngle:endA clockwise:YES];    [path2 addLineToPoint:center];    // 添加到上下文    CGContextAddPath(ctx, path2.CGPath);    [[UIColor blueColor] set];    // 渲染    CGContextFillPath(ctx);   }@end

• 3.新建UIColor+Random类

////  UIColor+Random.h//  03-饼图//#import <UIKit/UIKit.h>@interface UIColor (Random)+ (UIColor *)randomColor;@end

////  UIColor+Random.m//  03-饼图//#import "UIColor+Random.h"@implementation UIColor (Random)+ (UIColor *)randomColor{    /*     颜色有两种表现形式 RGB RGBA     RGB 24     R,G,B每个颜色通道8位     8的二进制 255     R,G,B每个颜色取值 0 ~255     120 / 255.0     */    CGFloat r = arc4random_uniform(256) / 255.0;    CGFloat g = arc4random_uniform(256) / 255.0;    CGFloat b = arc4random_uniform(256) / 255.0;    return [UIColor colorWithRed:r green:g blue:b alpha:1];}@end