Android RadarView雷达图（蜘蛛网图）的实现代码

 @Override protected void onDraw(Canvas canvas) {  super.onDraw(canvas);  drawPolygon(canvas);//画边  drawLines(canvas);//画线  drawText(canvas);//描绘文字  drawRegion(canvas);//覆盖区域 }

 private int count = 5; //几边形 private int layerCount = 4; //层数 private float angle; //每条边对应的圆心角 private int centerX; //圆心x private int centerY; //圆心y private float radius; //半径 private Paint polygonPaint; //边框paint private Paint linePaint; //连线paint private Paint txtPaint; //文字paint private Paint circlePaint; //圆点paint private Paint regionColorPaint; //覆盖区域paint private Double[] percents = {0.91, 0.35, 0.12, 0.8, 0.5}; //覆盖区域百分比 private String[] titles = {"dota", "斗地主", "大吉大利，晚上吃鸡", "炉石传说", "跳一跳"};//文字

public RadarView(Context context) {  this(context, null, 0); } public RadarView(Context context, @Nullable AttributeSet attrs) {  this(context, attrs, 0); } public RadarView(Context context, @Nullable AttributeSet attrs, int defStyleAttr) {  super(context, attrs, defStyleAttr);  //计算圆心角  angle = (float) (Math.PI * 2 / count);  polygonPaint = new Paint();  polygonPaint.setColor(ContextCompat.getColor(context, R.color.radarPolygonColor));  polygonPaint.setAntiAlias(true);  polygonPaint.setStyle(Paint.Style.STROKE);  polygonPaint.setStrokeWidth(4f);  linePaint = new Paint();  linePaint.setColor(ContextCompat.getColor(context, R.color.radarLineColor));  linePaint.setAntiAlias(true);  linePaint.setStyle(Paint.Style.STROKE);  linePaint.setStrokeWidth(2f);  txtPaint = new Paint();  txtPaint.setColor(ContextCompat.getColor(context, R.color.radarTxtColor));  txtPaint.setAntiAlias(true);  txtPaint.setStyle(Paint.Style.STROKE);  txtPaint.setTextSize(DensityUtil.dpToPx(context, 12));  circlePaint = new Paint();  circlePaint.setColor(ContextCompat.getColor(context, R.color.radarCircleColor));  circlePaint.setAntiAlias(true);  regionColorPaint = new Paint();  regionColorPaint.setColor(ContextCompat.getColor(context, R.color.radarRegionColor));  regionColorPaint.setStyle(Paint.Style.FILL);  regionColorPaint.setAntiAlias(true); }

 @Override protected void onSizeChanged(int w, int h, int oldw, int oldh) {  super.onSizeChanged(w, h, oldw, oldh);  radius = Math.min(h, w) / 2 * 0.7f;  centerX = w / 2;  centerY = h / 2; }

private void drawPolygon(Canvas canvas) {  Path path = new Path();  float r = radius / layerCount;  for (int i = 1; i <= layerCount; i++) {   float curR = r * i; //当前所在层的半径   for (int j = 0; j < count; j++) {    if (j == 0) {     //每一层第一个点坐标     path.moveTo(centerX, centerY - curR);     } else {     //顺时针记录其余顶角的点坐标     float x = (float) (centerX + Math.sin(angle * j) * curR);     float y = (float) (centerY - Math.cos(angle * j) * curR);     path.lineTo(x, y);    }   }   //最外层的顶角外面的五个小圆点(图中红色部分)   if (i == layerCount) {    for (int j = 0; j < count; j++) {     float x = (float) (centerX + Math.sin(angle * j) * (curR + 12));     float y = (float) (centerY - Math.cos(angle * j) * (curR + 12));     canvas.drawCircle(x, y, 4, circlePaint);    }   }   path.close();   canvas.drawPath(path, polygonPaint);  } }

 private void drawLines(Canvas canvas) {  float r = radius / layerCount;  for (int i = 0; i < count; i++) {   //起始坐标 从中心开始的话 startx=centerX , startY=centerY   float startX = (float) (centerX + Math.sin(angle * i) * r);   float startY = (float) (centerY - Math.cos(angle * i) * r);   //末端坐标   float endX = (float) (centerX + Math.sin(angle * i) * radius);   float endY = (float) (centerY - Math.cos(angle * i) * radius);   canvas.drawLine(startX, startY, endX, endY, linePaint);  } }

 //设置几边形，**注意：设置几边形需要重新计算圆心角** public void setCount(int count){  this.count = count;  angle = (float) (Math.PI * 2 / count);  invalidate(); } //设置层数 public void setLayerCount(int layerCount){  this.layerCount = layerCount;  invalidate(); }

 radarView.setCount(6); radarView.setLayerCount(6);

private void drawText(Canvas canvas) {  for (int i = 0; i < count; i++) {   //获取到雷达图最外边的坐标   float x = (float) (centerX + Math.sin(angle * i) * (radius + 12));   float y = (float) (centerY - Math.cos(angle * i) * (radius + 12));   if (angle * i == 0) {    //第一个文字位于顶角正上方    txtPaint.setTextAlign(Paint.Align.CENTER);    canvas.drawText(titles[i], x, y - 18, txtPaint);    txtPaint.setTextAlign(Paint.Align.LEFT);   } else if (angle * i > 0 && angle * i < Math.PI / 2) {    //微调    canvas.drawText(titles[i], x + 18, y + 10, txtPaint);   } else if (angle * i >= Math.PI / 2 && angle * i < Math.PI) {    //最右下的文字获取到文字的长、宽，按文字长度百分比向左移    String txt = titles[i];    Rect bounds = new Rect();    txtPaint.getTextBounds(txt, 0, txt.length(), bounds);    float height = bounds.bottom - bounds.top;    float width = txtPaint.measureText(txt);    canvas.drawText(txt, x - width * 0.4f, y + height + 18, txtPaint);   } else if (angle * i >= Math.PI && angle * i < 3 * Math.PI / 2) {    //同理最左下的文字获取到文字的长、宽，按文字长度百分比向左移    String txt = titles[i];    Rect bounds = new Rect();    txtPaint.getTextBounds(txt, 0, txt.length(), bounds);    float width = txtPaint.measureText(txt);    float height = bounds.bottom - bounds.top;    canvas.drawText(txt, x - width * 0.6f, y + height + 18, txtPaint);   } else if (angle * i >= 3 * Math.PI / 2 && angle * i < 2 * Math.PI) {    //文字向左移动    String txt = titles[i];    float width = txtPaint.measureText(txt);    canvas.drawText(txt, x - width - 18, y + 10, txtPaint);   }  } }

 private void drawRegion(Canvas canvas) {  Path path = new Path();  float r = radius / layerCount;//每层的间距  for (int i = 0; i < count; i++) {   if (i == 0) {    path.moveTo(centerX, (float) (centerY - r - (radius - r) * percents[i]));   } else {    float x = (float) (centerX + Math.sin(angle * i) * (percents[i] * (radius - r) + r));    float y = (float) (centerY - Math.cos(angle * i) * (percents[i] * (radius - r) + r));    path.lineTo(x, y);   }  }  path.close();  canvas.drawPath(path, regionColorPaint); }