public class DoughnutView extends View {

  }

 /**
   * 當(dāng)布局為wrap_content時(shí)設(shè)置默認(rèn)長(zhǎng)寬
   *
   * @param widthMeasureSpec
   * @param heightMeasureSpec
   */
  @Override
  protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
    setMeasuredDimension(measure(widthMeasureSpec), measure(heightMeasureSpec));
  }

  private int measure(int origin) {
    int result = DEFAULT_MIN_WIDTH;
    int specMode = MeasureSpec.getMode(origin);
    int specSize = MeasureSpec.getSize(origin);
    if (specMode == MeasureSpec.EXACTLY) {
      result = specSize;
    } else {
      if (specMode == MeasureSpec.AT_MOST) {
        result = Math.min(result, specSize);
      }
    }
    return result;
  }

 //畫背景白色圓環(huán)
 initPaint();
 float doughnutWidth = Math.min(width, height) / 2 * 0.15f;
 paint.setStrokeWidth(doughnutWidth);
 paint.setStyle(Paint.Style.STROKE);
 paint.setColor(Color.WHITE);
 paint.setAntiAlias(true);
 RectF rectF = new RectF((width > height ? Math.abs(width - height) / 2 : 0) + doughnutWidth / 2, (height > width ? Math.abs(height - width) / 2 : 0) + doughnutWidth / 2, width - (width > height ? Math.abs(width - height) / 2 : 0) - doughnutWidth / 2, height - (height > width ? Math.abs(height - width) / 2 : 0) - doughnutWidth / 2);
 canvas.drawArc(rectF, 0, 360, false, paint);

 //畫彩色圓環(huán)
 initPaint();
 canvas.rotate(-90, width / 2, height / 2);
 paint.setStrokeWidth(doughnutWidth);
 paint.setStyle(Paint.Style.STROKE);
 if (doughnutColors.length > 1) {
   paint.setShader(new SweepGradient(width / 2, height / 2, doughnutColors, null));
 } else {
   paint.setColor(doughnutColors[0]);
 }
 canvas.drawArc(rectF, 0, currentValue, false, paint);

 //畫中間數(shù)值的背景
 int fontSize = 50;
 initPaint();
 paint.setStyle(Paint.Style.FILL);
 paint.setColor(Color.WHITE);
 canvas.drawCircle(width / 2, height / 2, fontSize * 2, paint);}

 //畫中間數(shù)值
 canvas.rotate(90, width / 2, height / 2);
 initPaint();
 paint.setColor(ColorUtils.getCurrentColor(currentValue / 360f, doughnutColors));
 paint.setTextSize(fontSize);
 paint.setTextAlign(Paint.Align.CENTER);
 float baseLine = height / 2 - (paint.getFontMetrics().descent + paint.getFontMetrics().ascent) / 2;
 canvas.drawText((int) (currentValue / 360f * 100) + "%", width / 2, baseLine, paint);

 /**
 * 顏色漸變算法
 * 獲取某個(gè)百分比下的漸變顏色值
 *
 * @param percent
 * @param colors
 * @return
 */
 public static int getCurrentColor(float percent, int[] colors) {
   float[][] f = new float[colors.length][3];
   for (int i = 0; i < colors.length; i++) {
     f[i][0] = (colors[i] & 0xff0000) >> 16;
     f[i][1] = (colors[i] & 0x00ff00) >> 8;
     f[i][2] = (colors[i] & 0x0000ff);
   }
   float[] result = new float[3];
   for (int i = 0; i < 3; i++) {
     for (int j = 0; j < f.length; j++) {
       if (f.length == 1 || percent == j / (f.length - 1f)) {
         result = f[j];
       } else {
         if (percent > j / (f.length - 1f) && percent < (j + 1f) / (f.length - 1)) {
           result[i] = f[j][i] - (f[j][i] - f[j + 1][i]) * (percent - j / (f.length - 1f)) * (f.length - 1f);
         }
       }
     }
   }
   return Color.rgb((int) result[0], (int) result[1], (int) result[2]);
 }

public void setValue(float value) {
ValueAnimator valueAnimator = ValueAnimator.ofFloat(currentValue, value);
valueAnimator.setDuration(300);
valueAnimator.setInterpolator(new Interpolator() {
  @Override
  public float getInterpolation(float v) {
    return 1-(1-v)*(1-v)*(1-v);
  }
});
valueAnimator.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
  @Override
  public void onAnimationUpdate(ValueAnimator valueAnimator) {
    currentValue = (float) valueAnimator.getAnimatedValue();
    invalidate();
  }
});
valueAnimator.start();
}

 valueAnimator.setInterpolator(new AccelerateInterpolator());//加速
  valueAnimator.setInterpolator(new DecelerateInterpolator());//減速
  valueAnimator.setInterpolator(new AccelerateDecelerateInterpolator());//加速減速
  valueAnimator.setInterpolator(new LinearInterpolator());//云速

valueAnimator.setInterpolator(new Interpolator() {
  @Override
  public float getInterpolation(float v) {
    return 1-(1-v)*(1-v)*(1-v);
  }
});