demo链接：github.com/yangSpica27…
code：
class SunriseView : View { constructor(context: Context) : super(context) constructor(context: Context, attrs: AttributeSet) : super(context, attrs) constructor(context: Context, attrs: AttributeSet, defStyleAttr: Int) : super(context, attrs, defStyleAttr) // 完整运动轨迹 private val allPath = Path() // 地平线以上的部分 private val topPath = Path() // 地平线以下的部分[用于绘制阴影] private val topPath2 = Path() private val moveAnim = ObjectAnimator.ofFloat(this, "progress", -1.0f, 2.0f).apply { duration = 1000 } private var currentProgress = 0f @Suppress("unused") fun to(@FloatRange(-1.0, 2.0) progress: Float) { moveAnim.cancel() moveAnim.duration = (abs(progress - currentProgress) / 3f * 800).toLong() moveAnim.setFloatValues(currentProgress, progress) moveAnim.start() } // -1~0: 日出前 // 0~1: 日出中 // 1~2: 日落后 fun setProgress(@FloatRange(-1.0, 2.0) progress: Float) { currentProgress = progress postInvalidateOnAnimation() } // 用于绘制地平线以下部分 private val pathPaint1 = Paint().apply { color = Color.BLACK style = Paint.Style.STROKE strokeWidth = 24f } // 用于绘制地平线以上部分 private val pathPaint2 = Paint().apply { color = Color.BLACK style = Paint.Style.STROKE strokeWidth = 24f } private val sunPaint = Paint().apply { color = Color.YELLOW style = Paint.Style.FILL } private var lineY = 0f private val pathMeasure = PathMeasure() override fun onSizeChanged(w: Int, h: Int, oldw: Int, oldh: Int) { super.onSizeChanged(w, h, oldw, oldh) // 设置颜色渐变 pathPaint1.shader = LinearGradient( 0f, 0f, w * 1f, 0f, intArrayOf( Color.parseColor("#597ef7"), Color.parseColor("#1d39c4"), Color.parseColor("#597ef7") ), floatArrayOf(0f, 0.5f, 1f), Shader.TileMode.CLAMP ) pathPaint2.shader = LinearGradient( 0f, 0f, w * 1f, 0f, intArrayOf( Color.parseColor("#fadb14"), Color.parseColor("#fa8c16"), Color.parseColor("#fadb14") ), floatArrayOf(0f, 0.5f, 1f), Shader.TileMode.CLAMP ) // 重新计算路径 allPath.reset() allPath.moveTo(0f, h * 1f - pathPaint1.strokeWidth - h / 8f) allPath.cubicTo( w / 4f + w / 6f, h - h / 6f, w / 2f - w / 5f, 0 + h / 6f, w / 2f, 0 + h / 6f ) allPath.cubicTo( w / 2f + w / 5f, 0 + h / 6f, w - (w / 4f + w / 6f), h - h / 6f, w * 1f, h * 1f - pathPaint1.strokeWidth - h / 8f ) pathMeasure.setPath(allPath, false) // 确定地平线锚点的位置 val floatArray = FloatArray(2) pathMeasure.getPosTan(pathMeasure.length / 6, floatArray, null) // 左边的锚点 val leftPoint = PointF(floatArray[0], floatArray[1]) pathMeasure.getPosTan(pathMeasure.length / 6 * 5, floatArray, null) // 右边的锚点 val rightPoint = PointF(floatArray[0], floatArray[1]) // 地平线Y坐标 lineY = (leftPoint.y + rightPoint.y) / 2 // 截取地平线以上的部分 topPath.reset() pathMeasure.getSegment(pathMeasure.length / 6, pathMeasure.length / 6 * 5, topPath, true) topPath2.reset() pathMeasure.getSegment(pathMeasure.length / 6, pathMeasure.length / 6 * 5, topPath2, true) topPath2.close() sunLightPaint.shader = LinearGradient( 0f, 0f, 0f, h * 1f, intArrayOf( Color.parseColor("#ffffb8"), Color.TRANSPARENT ), floatArrayOf(0f, 1f), Shader.TileMode.CLAMP ) } private val sunLightPaint = Paint().apply { color = Color.YELLOW style = Paint.Style.FILL } private val sunPointXY = FloatArray(2) private val xf = PorterDuffXfermode(PorterDuff.Mode.CLEAR) override fun onDraw(canvas: Canvas) { super.onDraw(canvas) // 绘制地平线 sunPaint.color = ContextCompat.getColor(context, R.color.line_color) sunPaint.strokeWidth = 12f canvas.drawLine(0f, lineY, width * 1f, lineY, sunPaint) // 前1/4为日出前段 if (currentProgress < 0) { // 日出前段 val progress = currentProgress - (-1) / 1f pathMeasure.getPosTan(pathMeasure.length / 6 * progress, sunPointXY, null) } else if (currentProgress < 1) { // 中间段 val progress = currentProgress / 1f pathMeasure.getPosTan(pathMeasure.length / 6 + pathMeasure.length / 2 * progress, sunPointXY, null) // 绘制阴影 val id = canvas.saveLayer(0f, 0f, width * 1f, height * 1f, null) sunPaint.color = Color.BLACK canvas.drawPath(topPath2, sunLightPaint) sunLightPaint.xfermode = xf sunPaint.color = Color.YELLOW canvas.drawRect(sunPointXY[0], 0f, width * 1f, height * 1f, sunLightPaint) canvas.restoreToCount(id) sunLightPaint.xfermode = null } else { // 日落后段 val progress = currentProgress - 1 / 1f pathMeasure.getPosTan(pathMeasure.length / 6 * 5 + pathMeasure.length / 6 * progress, sunPointXY, null) // 绘制阴影 val id = canvas.saveLayer(0f, 0f, width * 1f, height * 1f, null) sunPaint.color = Color.BLACK canvas.drawPath(topPath2, sunLightPaint) sunLightPaint.xfermode = xf sunPaint.color = Color.YELLOW canvas.drawRect(sunPointXY[0], 0f, width * 1f, height * 1f, sunLightPaint) canvas.restoreToCount(id) sunLightPaint.xfermode = null } // 绘制背景 canvas.drawPath(allPath, pathPaint1) // 绘制地平线以上的部分 canvas.drawPath(topPath, pathPaint2) sunPaint.color = Color.parseColor("#fafafa") canvas.drawCircle(sunPointXY[0], sunPointXY[1], 55f, sunPaint) sunPaint.color = ContextCompat.getColor(context, R.color.yellow) canvas.drawCircle(sunPointXY[0], sunPointXY[1], 40f, sunPaint) }}
