本篇文章已授权微信公众号 guolin_blog （郭霖）独家发布

原始图效果

模仿效果

PNG


GIF

流程

1. 绘制中心线，用于计算外层多边形各点的坐标
2. 绘制最外层多边形
3. 分析原型图算出每个多边形之间的间距
4. 绘制里三层多边形
5. 绘制字体

6. 根据进度值绘制等级进度

   
   

难点

关键在于坐标的计算(三角函数的运用，哈哈)，与旋转角度的掌控。

绘制中心线

/**
     * 绘制中心线
     *
     * @param canvas
     */
    private void center(Canvas canvas) {
        //绘制七边形中心线
        canvas.save();//保存当前状态
        canvas.rotate(0, center, center);
        float startY = getPaddingTop() + 2 * str_rect.height();
        float endY = center;
        float du = (float) (360 / 7 + 0.5);
        for (int i = 0; i < 7; i++) {
            canvas.drawLine(center, startY, center, endY, center_paint);
            canvas.rotate(du, center, center);

        }
        canvas.restore();//恢复之前状态
    }

先计算出圆心到A点的坐标，
在计算出旋转的角度（360/7），
然后旋转7次Canvas，绘制7条中心线。
为了加深显示效果，先绘制一个绿色背景作参考。

绘制最外层正七边形

各坐标点的计算主要用到了三角函数。

A点

x ： 对应圆心center。
y ：paddingTop+2个字体高度的距离

B点

x ： A点的x坐标+EB

利用三角函数公式，BE=sin(AB的夹角)*OB

这里有个坑，Math.sin(x)里的x是弧度，而不是角度。

如果要计算角度则需要加上Math.sin(Math.toRadians(x))

center+ Math.sin(Math.toRadians(360/7)) *one_radius

y ：A点的y坐标+AE

同理AE=OA-OE,OE=cos(AB的夹角)*OB

OE=cos(AB的夹角)*OB

Math.abs(Math.cos(Math.toRadians(360/7)) *one_radius

由于余弦有正负值，这里要取绝对值

AE=OA-OE

(getPaddingTop() +2*str_rect.height() +one_radius

• Math.abs(Math.cos(Math.toRadians(360/7)) *one_radius))

C点

x :圆心X+FC
Math.sin(Math.toRadians(360/7+360/7/2)) *one_radius

y: 圆心Y+OF
(Math.cos(Math.toRadians(360/7+360/7/2)) *one_radius) +center

D点

x :圆心x+HD

center+ Math.sin(Math.toRadians(360/7/2)) *one_radius

y：圆心y+OH

Math.cos(Math.toRadians(360/7/2)) *one_radius) +center

右边点绘制完后，左边点自然就简单了，y位置一样，x位置只需要把相加改成相减即可。

绘制内三层正七边形

绘制完最外层七边形后，剩下来的就好办了，只需要计算出每个七边形的间距即可。
由原型图分析，每一个正七边形占半径的四分之一。

 /**
     * 绘制第二层多边形
     *
     * @param canvas
     */
    private void twoPolygons(Canvas canvas) {
        distance = one_radius / 4;
        Path path = new Path();
        path.moveTo(center, getPaddingTop() + 2 * str_rect.height() + distance);                           //起始点
        path.lineTo((float) (center + Math.sin(Math.toRadians(360 / 7)) * (one_radius - distance)), (float) (getPaddingTop() + 2 * str_rect.height() + (one_radius) - Math.abs(Math.cos(Math.toRadians(360 / 7)) * (one_radius - distance))));
        path.lineTo((float) (center + Math.sin(Math.toRadians(360 / 7 + 360 / 7 / 2)) * (one_radius - distance)), (float) (Math.cos(Math.toRadians(360 / 7 + 360 / 7 / 2)) * (one_radius - distance)) + center);
        path.lineTo((float) (center + Math.sin(Math.toRadians(360 / 7 / 2)) * (one_radius - distance)), (float) (Math.cos(Math.toRadians(360 / 7 / 2)) * (one_radius - distance)) + center);
        path.lineTo((float) (center - Math.sin(Math.toRadians(360 / 7 / 2)) * (one_radius - distance)), (float) (Math.cos(Math.toRadians(360 / 7 / 2)) * (one_radius - distance)) + center);
        path.lineTo((float) (center - Math.sin(Math.toRadians(360 / 7 + 360 / 7 / 2)) * (one_radius - distance)), (float) (Math.cos(Math.toRadians(360 / 7 + 360 / 7 / 2)) * (one_radius - distance)) + center);
        path.lineTo((float) (center - Math.sin(Math.toRadians(360 / 7)) * (one_radius - distance)), (float) (getPaddingTop() + 2 * str_rect.height() + (one_radius) - Math.abs(Math.cos(Math.toRadians(360 / 7)) * (one_radius - distance))));
        path.close();
        canvas.drawPath(path, two_paint);
    }

    /**
     * 绘制第三层多边形
     *
     * @param canvas
     */
    private void threePolygons(Canvas canvas) {
        distance = one_radius / 2;
        Path path = new Path();
        path.moveTo(center, getPaddingTop() + 2 * str_rect.height() + distance);                           //起始点
        path.lineTo((float) (center + Math.sin(Math.toRadians(360 / 7)) * (one_radius - distance)), (float) (getPaddingTop() + 2 * str_rect.height() + (one_radius) - Math.abs(Math.cos(Math.toRadians(360 / 7)) * (one_radius - distance))));
        path.lineTo((float) (center + Math.sin(Math.toRadians(360 / 7 + 360 / 7 / 2)) * (one_radius - distance)), (float) (Math.cos(Math.toRadians(360 / 7 + 360 / 7 / 2)) * (one_radius - distance)) + center);
        path.lineTo((float) (center + Math.sin(Math.toRadians(360 / 7 / 2)) * (one_radius - distance)), (float) (Math.cos(Math.toRadians(360 / 7 / 2)) * (one_radius - distance)) + center);
        path.lineTo((float) (center - Math.sin(Math.toRadians(360 / 7 / 2)) * (one_radius - distance)), (float) (Math.cos(Math.toRadians(360 / 7 / 2)) * (one_radius - distance)) + center);
        path.lineTo((float) (center - Math.sin(Math.toRadians(360 / 7 + 360 / 7 / 2)) * (one_radius - distance)), (float) (Math.cos(Math.toRadians(360 / 7 + 360 / 7 / 2)) * (one_radius - distance)) + center);
        path.lineTo((float) (center - Math.sin(Math.toRadians(360 / 7)) * (one_radius - distance)), (float) (getPaddingTop() + 2 * str_rect.height() + (one_radius) - Math.abs(Math.cos(Math.toRadians(360 / 7)) * (one_radius - distance))));

        path.close();
        canvas.drawPath(path, three_paint);
    }

    /**
     * 绘制最内层多边形
     *
     * @param canvas
     */
    private void fourPolygons(Canvas canvas) {
        distance = one_radius / 2 + one_radius / 4;
        Path path = new Path();
        path.moveTo(center, getPaddingTop() + 2 * str_rect.height() + distance);                           //起始点
        path.lineTo((float) (center + Math.sin(Math.toRadians(360 / 7)) * (one_radius - distance)), (float) (getPaddingTop() + 2 * str_rect.height() + (one_radius) - Math.abs(Math.cos(Math.toRadians(360 / 7)) * (one_radius - distance))));
        path.lineTo((float) (center + Math.sin(Math.toRadians(360 / 7 + 360 / 7 / 2)) * (one_radius - distance)), (float) (Math.cos(Math.toRadians(360 / 7 + 360 / 7 / 2)) * (one_radius - distance)) + center);
        path.lineTo((float) (center + Math.sin(Math.toRadians(360 / 7 / 2)) * (one_radius - distance)), (float) (Math.cos(Math.toRadians(360 / 7 / 2)) * (one_radius - distance)) + center);
        path.lineTo((float) (center - Math.sin(Math.toRadians(360 / 7 / 2)) * (one_radius - distance)), (float) (Math.cos(Math.toRadians(360 / 7 / 2)) * (one_radius - distance)) + center);
        path.lineTo((float) (center - Math.sin(Math.toRadians(360 / 7 + 360 / 7 / 2)) * (one_radius - distance)), (float) (Math.cos(Math.toRadians(360 / 7 + 360 / 7 / 2)) * (one_radius - distance)) + center);
        path.lineTo((float) (center - Math.sin(Math.toRadians(360 / 7)) * (one_radius - distance)), (float) (getPaddingTop() + 2 * str_rect.height() + (one_radius) - Math.abs(Math.cos(Math.toRadians(360 / 7)) * (one_radius - distance))));

        path.close();
        canvas.drawPath(path, four_paint);
    }

去掉绿色背景后，显示的效果

绘制字体

根据最外层多边形各点坐标以及字体的长度高度 微调。

privateRectstr_rect;//字体矩形

String[]str= {"击杀","生存","助攻","物理","魔法","防御","金钱"};

 /**
     * 绘制字体
     *
     * @param canvas
     */
    private void PaintFout(Canvas canvas) {
        canvas.drawText(str[0], center - str_rect.width() / 2, (float) (getPaddingTop() + 1.5 * str_rect.height()), str_paint);
        canvas.drawText(str[1], (float) (center + Math.sin(Math.toRadians(360 / 7)) * one_radius + str_rect.height() / 2), (float) ((getPaddingTop() + 2 * str_rect.height() + one_radius - Math.abs(Math.cos(Math.toRadians(360 / 7)) * one_radius))), str_paint);
        canvas.drawText(str[2], (float) (center + Math.sin(Math.toRadians(360 / 7 + 360 / 7 / 2)) * one_radius + str_rect.height() / 2), (float) (Math.cos(Math.toRadians(360 / 7 + 360 / 7 / 2)) * one_radius) + center + str_rect.height() / 2, str_paint);
        canvas.drawText(str[3], (float) (center + Math.sin(Math.toRadians(360 / 7 / 2)) * one_radius - str_rect.height() / 2 + str_rect.width() / 2), (float) ((Math.cos(Math.toRadians(360 / 7 / 2)) * one_radius) + center + str_rect.height()), str_paint);
        canvas.drawText(str[4], (float) (center - Math.sin(Math.toRadians(360 / 7 / 2)) * one_radius + str_rect.height() / 2 - str_rect.width() * 1.5), (float) ((Math.cos(Math.toRadians(360 / 7 / 2)) * one_radius) + center + str_rect.height()), str_paint);
        canvas.drawText(str[5], (float) (center - Math.sin(Math.toRadians(360 / 7 + 360 / 7 / 2)) * one_radius - str_rect.height() / 2 - str_rect.width()), (float) (Math.cos(Math.toRadians(360 / 7 + 360 / 7 / 2)) * one_radius) + center + str_rect.height() / 2, str_paint);
        canvas.drawText(str[6], (float) (center - Math.sin(Math.toRadians(360 / 7)) * one_radius - str_rect.height() / 2 - str_rect.width()), (float) ((getPaddingTop() + 2 * str_rect.height() + one_radius - Math.abs(Math.cos(Math.toRadians(360 / 7)) * one_radius))), str_paint);

    }

绘制各能力值进度

 /**
     * 绘制等级进度
     */
    private void PaintRank(Canvas canvas) {

        Path path = new Path();
        path.moveTo(center, getPaddingTop() + 2 * str_rect.height() + f1);                           //起始点
        path.lineTo((float) (center + Math.sin(Math.toRadians(360 / 7)) * (one_radius - f2)), (float) (getPaddingTop() + 2 * str_rect.height() + (one_radius) - Math.abs(Math.cos(Math.toRadians(360 / 7)) * (one_radius - f2))));
        path.lineTo((float) (center + Math.sin(Math.toRadians(360 / 7 + 360 / 7 / 2)) * (one_radius - f3)), (float) (Math.cos(Math.toRadians(360 / 7 + 360 / 7 / 2)) * (one_radius - f3)) + center);
        path.lineTo((float) (center + Math.sin(Math.toRadians(360 / 7 / 2)) * (one_radius - f4)), (float) (Math.cos(Math.toRadians(360 / 7 / 2)) * (one_radius - f4)) + center);
        path.lineTo((float) (center - Math.sin(Math.toRadians(360 / 7 / 2)) * (one_radius - f5)), (float) (Math.cos(Math.toRadians(360 / 7 / 2)) * (one_radius - f5)) + center);
        path.lineTo((float) (center - Math.sin(Math.toRadians(360 / 7 + 360 / 7 / 2)) * (one_radius - f6)), (float) (Math.cos(Math.toRadians(360 / 7 + 360 / 7 / 2)) * (one_radius - f6)) + center);
        path.lineTo((float) (center - Math.sin(Math.toRadians(360 / 7)) * (one_radius - f7)), (float) (getPaddingTop() + 2 * str_rect.height() + (one_radius) - Math.abs(Math.cos(Math.toRadians(360 / 7)) * (one_radius - f7))));
        path.close();
        canvas.drawPath(path, mPaint);

    }

感兴趣的同学可直接到github下载源码查看。
如果你觉得还不错，可以给个star，支持下，谢谢了！
https://github.com/jiangzehui/polygonsview