iOS之画饼图

iOS之画饼图

1.效果图如下

2.画饼图实现步骤如下：

//
//  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

//
//  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