前言

纸上得来终觉浅，绝知此事要躬行。

直接上代码

import android.content.Context;

import android.graphics.Canvas;

import android.graphics.Color;

import android.graphics.Paint;

import android.graphics.Path;

import android.support.annotation.Nullable;

import android.util.AttributeSet;

import android.view.View;

public class SpiderView extends View{

private Paint radarPaint,valuePaint;

private float radius;

private int centerX;

private int centerY;

private int count = 6;

private int maxValue = 6;

double[] data = {2,5,1,6,4,5};

private int a = 360/6;

public SpiderView(Context context) {

super(context);

init();

}

public SpiderView(Context context, @Nullable AttributeSet attrs) {

super(context, attrs);

init();

}

public SpiderView(Context context, @Nullable AttributeSet attrs, int defStyleAttr) {

super(context, attrs, defStyleAttr);

init();

}

private void init() {

radarPaint = new Paint();

radarPaint.setStyle(Paint.Style.STROKE);

radarPaint.setColor(Color.GREEN);

valuePaint = new Paint();

valuePaint.setStyle(Paint.Style.FILL);

valuePaint.setColor(Color.BLUE);

}

@Override

protected void onSizeChanged(int w, int h, int oldw, int oldh) {

radius = Math.min(w,h)/2*0.9f;

centerX = w/2;

centerY = h/2;

postInvalidate();

super.onSizeChanged(w, h, oldw, oldh);

}

@Override

protected void onDraw(Canvas canvas) {

super.onDraw(canvas);

drawPolygon(canvas);

drawLine(canvas);

drawRegion(canvas);

}

//画数据区域

private void drawRegion(Canvas canvas) {

Path path = new Path();

valuePaint.setAlpha(127);

for(int i=0;i

double percent = data[i]/maxValue;

float x = (float)(centerX + radius * percent * Math.cos(Math.toRadians(a)*i));

float y = (float)(centerY + radius * percent * Math.sin(Math.toRadians(a)*i));

if(i==0){

path.moveTo(x,y);

}else{

path.lineTo(x,y);

}

canvas.drawCircle(x,y,10,valuePaint);

}

valuePaint.setStyle(Paint.Style.FILL_AND_STROKE);

canvas.drawPath(path,valuePaint);

}

//画角线

private void drawLine(Canvas canvas) {

Path path = new Path();

for(int i=0;i

path.reset();

path.moveTo(centerX,centerY);

float x = (float)(centerX + radius * Math.cos(Math.toRadians(a)*i));

float y = (float)(centerY + radius * Math.sin(Math.toRadians(a)*i));

path.lineTo(x,y);

canvas.drawPath(path,radarPaint);

}

}

//画网格框

private void drawPolygon(Canvas canvas) {

Path path = new Path();

float r = radius/count;

for(int i=1;i<=count;i++){

float curR = r * i;

path.reset();

for(int j=0;j

if(j==0){

path.moveTo(centerX + curR, centerY);

}else{

float x = (float)(centerX + curR * Math.cos(Math.toRadians(a)*j));

float y = (float)(centerY + curR*Math.sin(Math.toRadians(a)*j));

path.lineTo(x,y);

}

}

// path.close();

canvas.drawPath(path,radarPaint);

}

}

}

效果图如下：

缺了一个口.jpg

本来就没有完美的事情，索性就让它缺一个口吧，代码中注释的那句就是解决的方案。

遇到的问题

三角函数的问题，里面一定要用弧度弧度弧度，Math.cos(Math.toRadians(a)i)和Math.sin(Math.toRadians(a)i)，关于弧度还是角度看这里