Android Color颜色过度计算实现代码
在看自定义TypeEvaluator来计算属性动画的属性值时,用到了对颜色的过度计算,翻看了好多博客,找到了比较有优秀的解决方案,在此记录,以备后用。
实现效果图:
实现代码:
/** * 根据fraction值来计算当前的颜色。 */ 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); }
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