CoreGraphics--饼状图

//传入数据,饼状图

pieChartView.dataArr = @[@20,@50,@80,@70,@40];

- (void)drawRect:(CGRect)rect {

// Drawing code

#if 0

//贝塞尔路径

UIBezierPath *path = [UIBezierPath bezierPathWithOvalInRect:CGRectMake(50, 50, 100, 100)];

//Oval 椭圆

//线条颜色

[[UIColor redColor] setStroke];

//线条宽度

path.lineWidth = 5;

//开始画

[path stroke];

//设置填充颜色

[[UIColor yellowColor] set];

//开始填充

[path fill];

#endif

//开始

CGFloat startDegress = 0;

//结束

CGFloat endDegress = 0;

for (int i = 0; i < _dataArr.count; i++) {

//终点弧

//计算数据每个元素的值所占的百分比

endDegress += M_PI * 2 *([self.dataArr[i] floatValue]/[self sum]);

//弧 路径

UIBezierPath *path = [UIBezierPath bezierPathWithArcCenter:CGPointMake(self.frame.size.width/2, self.frame.size.height/2) radius:MIN(self.frame.size.width, self.frame.size.height)/2 startAngle:startDegress endAngle:endDegress clockwise:YES];

//更底层(这两句,相当于上面一句)

//        CGMutablePathRef path = CGPathCreateMutable();

//        CGPathAddArc(path, NULL,self.frame.size.width/2,self.frame.size.height/2, MIN(self.frame.size.width, self.frame.size.height)/2, startDegress, endDegress, YES);

//重新修改开始的弧度

//第二个弧的起点 ,是上一个弧的终点

startDegress  = endDegress;

//注意:先画一个弧,然后终点-圆心 画一条线(以便能够填充,否则不能填充)

//坐标为圆心

[path addLineToPoint:CGPointMake(self.frame.size.width/2, self.frame.size.height/2)];

//线条颜色

//        [[self randomColor] setStroke];

//线条宽度

//        path.lineWidth = 5;

//开始画

//        [path stroke];

//设置填充颜色

[[self randomColor] set];

//开始填充

[path fill];

}

}

- (UIColor *)randomColor{

return [UIColor colorWithRed:arc4random()%256/255.0 green:arc4random()%256/255.0 blue:arc4random()%256/255.0 alpha:1];

}

- (void)setDataArr:(NSArray *)dataArr{

_dataArr = dataArr;

//调用drawRect刷新(再走一次上面)

[self setNeedsDisplay];

}

//获取数组中总数

#pragma mark -- 计算数组中 数据的总和

- (CGFloat)sum{

__block CGFloat sum = 0;

[self.dataArr enumerateObjectsUsingBlock:^(id obj, NSUInteger idx, BOOL *stop) {

sum = sum + [obj floatValue];

}];

return sum;

}