-(void)drawRect:(CGRect)rect

#import "pieview.h"
//直径，其实radius是半径的意思吧，哈哈 算了先用着，demo都写好了就不改了，你们知道就行了
#define radius 50

@implementation pieview

-(void)drawRect:(CGRect)rect
{
    CGContextRef ctx = UIGraphicsGetCurrentContext();//获取图形上下文
    CGPoint cent=CGPointMake((self.frame.size.width/2)-radius/2, (self.frame.size.height/2)-radius/2);//设置图形开始画的坐标原点,根据实际需要设置，我这是随便写的
    CGContextAddEllipseInRect(ctx, CGRectMake(cent.x, cent.y, 100, 100));这个是核心函数，在这里设置图形的开始从哪里画，画的宽度和高度是多少。如果宽高不一样 可就是椭圆了啊
     [[UIColor greenColor] set];//设置颜色
    CGContextFillPath(ctx);//实心的
    //CGContextStrokePath(ctx);空心的
}

@end

#import "pieViewController.h"
//#import "myview.h"
//#import "JYpieview.h"
#import "pieview.h"
@interface pieViewController ()

@end

@implementation pieViewController

- (void)viewDidLoad {
  [super viewDidLoad];
  pieview *view=[[pieview alloc]init];
  view.frame=CGRectMake(4, 150, 150, 300);
  [self.view addSubview:view];

}
- (void)didReceiveMemoryWarning {
  [super didReceiveMemoryWarning];
  // Dispose of any resources that can be recreated.
}
@end

#import "pieview.h"
//直径
#define radius 50
#define PI 3.14159265358979323846

@implementation pieview
//计算度转弧度
static inline float radians(double degrees) {
  return degrees * PI / 180;
}
-(void)drawRect:(CGRect)rect
{
  CGPoint cent=CGPointMake((self.frame.size.width/2)-radius/2, (self.frame.size.height/2)-radius/2);
  CGContextRef ctx = UIGraphicsGetCurrentContext();
  CGContextClearRect(ctx, rect);

  float angle_start = radians(0.0);
  float angle_end = radians(120.0);
  CGContextMoveToPoint(ctx, cent.x, cent.y);
  CGContextSetFillColor(ctx, CGColorGetComponents( [[UIColor greenColor] CGColor]));
  CGContextAddArc(ctx, cent.x, cent.y, radius, angle_start, angle_end, 0);
  CGContextFillPath(ctx);

  angle_start = angle_end;
  angle_end = radians(360.0);
  CGContextMoveToPoint(ctx, cent.x, cent.y);
  CGContextSetFillColor(ctx, CGColorGetComponents( [[UIColor blueColor] CGColor]));
  CGContextAddArc(ctx, cent.x, cent.y, radius, angle_start, angle_end, 0);
  CGContextFillPath(ctx);
}
@end

#import "pieview.h"
//直径
#define radius 50
#define PI 3.14159265358979323846

@implementation pieview
//计算度转弧度
static inline float radians(double degrees) {
  return degrees * PI / 180;
}
static inline void drawArc(CGContextRef ctx, CGPoint point, float angle_start, float angle_end, UIColor* color) {
  CGContextMoveToPoint(ctx, point.x, point.y);
  CGContextSetFillColor(ctx, CGColorGetComponents( [color CGColor]));
  CGContextAddArc(ctx, point.x, point.y, radius, angle_start, angle_end, 0);
  //CGContextClosePath(ctx);
  CGContextFillPath(ctx);
}
-(void)drawRect:(CGRect)rect
{
  CGPoint cent=CGPointMake((self.frame.size.width/2)-radius/2, (self.frame.size.height/2)-radius/2);
  CGContextRef ctx = UIGraphicsGetCurrentContext();
  CGContextClearRect(ctx, rect);

  float angle_start = radians(0.0);
  float angle_end = radians(121.0);
  drawArc(ctx, cent, angle_start, angle_end, [UIColor yellowColor]);

  angle_start = angle_end;
  angle_end = radians(228.0);
  drawArc(ctx, cent, angle_start, angle_end, [UIColor greenColor]);

  angle_start = angle_end;
  angle_end = radians(260);
  drawArc(ctx, cent, angle_start, angle_end, [UIColor orangeColor]);

  angle_start = angle_end;
  angle_end = radians(360);
  drawArc(ctx, cent, angle_start, angle_end, [UIColor purpleColor]);

}
@end

  //通知自定义的view重新绘制图形
//  [self setNeedsDisplay];

#import <UIKit/UIKit.h>

@interface pieview : UIView
//直径
@property(nonatomic,assign)float radius;
@end

#import "pieview.h"
#define PI 3.14159265358979323846

@implementation pieview
//计算度转弧度
static inline float radians(double degrees) {
  return degrees * PI / 180;
}
static inline void drawArc(CGContextRef ctx, CGPoint point, float angle_start, float angle_end, UIColor* color,float radius) {
  CGContextMoveToPoint(ctx, point.x, point.y);
  CGContextSetFillColor(ctx, CGColorGetComponents( [color CGColor]));
  CGContextAddArc(ctx, point.x, point.y, radius, angle_start, angle_end, 0);
  //CGContextClosePath(ctx);
  CGContextFillPath(ctx);
}
-(void)drawRect:(CGRect)rect
{
  CGPoint cent=CGPointMake((self.frame.size.width/2)-self.radius/2, (self.frame.size.height/2)-self.radius/2);
  CGContextRef ctx = UIGraphicsGetCurrentContext();
  CGContextClearRect(ctx, rect);

  float angle_start = radians(0.0);
  float angle_end = radians(121.0);
  drawArc(ctx, cent, angle_start, angle_end, [UIColor yellowColor],self.radius);

  angle_start = angle_end;
  angle_end = radians(228.0);
  drawArc(ctx, cent, angle_start, angle_end, [UIColor greenColor],self.radius);

  angle_start = angle_end;
  angle_end = radians(260);
  drawArc(ctx, cent, angle_start, angle_end, [UIColor orangeColor],self.radius);

  angle_start = angle_end;
  angle_end = radians(360);
  drawArc(ctx, cent, angle_start, angle_end, [UIColor purpleColor],self.radius);

}
-(void)setRadius:(float)radius
{
  _radius=radius;
  [self setNeedsDisplay];
}
@end

@implementation pieViewController

- (void)viewDidLoad {
  [super viewDidLoad];
  pieview *view=[[pieview alloc]init];
  view.radius=50;
  view.frame=CGRectMake(4, 150, 150, 300);
  [self.view addSubview:view];
  //view.backgroundColor=[UIColor clearColor];
  //模拟5秒后执行这个段代码
  dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(5.0 * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{
    view.radius=20;
  });
}
- (void)didReceiveMemoryWarning {
  [super didReceiveMemoryWarning];
  // Dispose of any resources that can be recreated.
}
@end