/** * 根據fraction值來計算當前的顏色。 */private int getCurrentColor(float fraction, int startColor, int endColor) {  int redCurrent;  int blueCurrent;  int greenCurrent;  int alphaCurrent;  int redStart = Color.red(startColor);  int blueStart = Color.blue(startColor);  int greenStart = Color.green(startColor);  int alphaStart = Color.alpha(startColor);  int redEnd = Color.red(endColor);  int blueEnd = Color.blue(endColor);  int greenEnd = Color.green(endColor);  int alphaEnd = Color.alpha(endColor);  int redDifference = redEnd - redStart;  int blueDifference = blueEnd - blueStart;  int greenDifference = greenEnd - greenStart;  int alphaDifference = alphaEnd - alphaStart;  redCurrent = (int) (redStart + fraction * redDifference);  blueCurrent = (int) (blueStart + fraction * blueDifference);  greenCurrent = (int) (greenStart + fraction * greenDifference);  alphaCurrent = (int) (alphaStart + fraction * alphaDifference);  return Color.argb(alphaCurrent, redCurrent, greenCurrent, blueCurrent);}