@Override
 protected void onDraw(Canvas canvas) {
 if (!canDraw()) {
 return;
 }
 canvas.translate(width / 2, height / 2);
 computeMaxPoint();
 drawPolygon(canvas);
 drawLine(canvas);
 drawArea(canvas);
 drawText(canvas);
 }

 @Override
 protected void onSizeChanged(int w, int h, int oldw, int oldh) {
 width = w;
 height = h;
 maxRadius = (float) ((width / 2) * 0.8);
 postInvalidate();
 }

 /*
 計(jì)算最大半徑，之后的位置都是基于最大半徑的比例
 */
 public void computeMaxPoint() {
 maxPointXList = new ArrayList<>();
 maxPointYList = new ArrayList<>();
 for (int i = 0; i < eageCount; i++) {
 float currentAngle = i * angle - 90;
 float currentX = (float) (maxRadius * Math.cos((currentAngle / 180) * Math.PI));
 float currentY = (float) (maxRadius * Math.sin((currentAngle / 180) * Math.PI));
 maxPointXList.add(currentX);
 maxPointYList.add(currentY);
 }
 }

 /*
 繪制多邊形和每一層
 */
 private void drawPolygon(Canvas canvas) {
 Path path = new Path();
 for (int i = 0; i < loopCount; i++) {
 path.reset();
 //依據(jù)最大半徑和角度來判斷每一層點(diǎn)的位置
 float rate = computeRate(i + 1, loopCount);
 for (int j = 0; j < eageCount; j++) {
 float currentX = maxPointXList.get(j) * rate;
 float currentY = maxPointYList.get(j) * rate;
 if (j == 0) {
  path.moveTo(currentX, currentY);
 } else {
  path.lineTo(currentX, currentY);
 }
 }
 path.close();
 canvas.drawPath(path, eagePaint);
 }
 }

 /*
 畫出從中心向各頂點(diǎn)的連線
 */
 private void drawLine(Canvas canvas) {
 Path path = new Path();
 for (int i = 0; i < eageCount; i++) {
  path.reset();
  path.lineTo(maxPointXList.get(i), maxPointYList.get(i));
  canvas.drawPath(path, eagePaint);
 }
 }

 /*
 繪制個(gè)方向值覆蓋的區(qū)域
 */
 private void drawArea(Canvas canvas) {
 Path path = new Path();
 //原理就是用path根據(jù)各方向值創(chuàng)建一個(gè)封閉的區(qū)域，然后填充
 for (int i = 0; i < eageCount; i++) {
  float rate = pointValue.get(i);
  float currentX = maxPointXList.get(i) * rate;
  float currentY = maxPointYList.get(i) * rate;
  if (i == 0) {
  path.moveTo(currentX, currentY);
  } else {
  path.lineTo(currentX, currentY);
  }
 }
 path.close();
 canvas.drawPath(path, areaPaint);
 }

 /*
 繪制文字
 */
 private void drawText(Canvas canvas) {
 if (pointName == null) {
  return;
 }
 //繪制文字的難點(diǎn)在于無法最好的適配屏幕的位置，會(huì)發(fā)生難以控制的偏倚
 for (int i = 0; i < pointName.size(); i++) {
  //解決辦法就是讓文字在不同的角度也發(fā)生旋轉(zhuǎn)，并且在x軸上減去一定的數(shù)值來保證正確的位置
  float currentAngle = i * angle;
  //180度需要也別的處理，讓它正著顯示，不然就是倒著的
  if (currentAngle == 180) {
  float currentX = maxPointXList.get(i) * 1.1f;
  float currentY = maxPointYList.get(i) * 1.1f;
  canvas.drawText(pointName.get(i), currentX - (textPaint.getTextSize() / 4)
   * (pointName.get(i).length()), currentY, textPaint);
  } else {
  canvas.save();
  float currentX = maxPointXList.get(0) * 1.1f;
  float currentY = maxPointYList.get(0) * 1.1f;
  //旋轉(zhuǎn)畫布，達(dá)到旋轉(zhuǎn)文字的效果
  canvas.rotate(currentAngle);
  canvas.drawText(pointName.get(i), currentX - (textPaint.getTextSize() / 4)
   * (pointName.get(i).length()), currentY, textPaint);
  canvas.restore();
  }
 }
 }

 /*
 用屬性動(dòng)畫繪制組件
 */
 public void draw() {
 if (canDraw()) {
  final Float[] trueValues = pointValue.toArray(new Float[pointValue.size()]);
  ValueAnimator valueAnimator = ValueAnimator.ofFloat(0, 1);
  valueAnimator.setDuration(1000);
  valueAnimator.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
  @Override
  public void onAnimationUpdate(ValueAnimator animation) {
   float rate = animation.getAnimatedFraction();
   for (int i = 0; i < pointValue.size(); i++) {
   pointValue.set(i, trueValues[i] * rate);
   }
   invalidate();
  }
  });
  valueAnimator.start();
 }
 }

public PolygonView(Context context, @Nullable AttributeSet attrs) {
 super(context, attrs);
 init(context, attrs);
 }
 public PolygonView(Context context, @Nullable AttributeSet attrs, int defStyleAttr) {
 super(context, attrs, defStyleAttr);
 init(context, attrs);
 }

xmlns:app="http://schemas.android.com/apk/res-auto"
<com.totoro.xkf.polygonview.PolygonView
 android:id="@+id/pv_polygon_view"
 android:layout_width="match_parent"
 android:layout_height="match_parent"
 app:areaColor="@android:color/holo_blue_light"
 app:eageColor="@android:color/black"
 app:eageCount="6"
 app:loopCount="4"
 app:textColor="@android:color/black" />

public void init(Context context, AttributeSet attrs) {
 TypedArray typedArray = context.obtainStyledAttributes(attrs, R.styleable.Polygon);
 initPaint();
 setTextColor(typedArray.getColor(R.styleable.Polygon_textColor, Color.BLACK));
 setLoopCount(typedArray.getInteger(R.styleable.Polygon_loopCount, 0));
 setEageCount(typedArray.getInteger(R.styleable.Polygon_eageCount, 0));
 setAreaColor(typedArray.getColor(R.styleable.Polygon_areaColor, Color.BLUE));
 setEageColor(typedArray.getColor(R.styleable.Polygon_eageColor, Color.GRAY));
 typedArray.recycle();
 }

xmlns:app=http://schemas.android.com/apk/res-auto