利用PathMeasure来实现自定义的动画

源码地址

https://github.com/SHPDZY/AndroidUiDemo

效果展示

1630377136826.gif

代码实现

主要使用PathMeasure绘制View动画的执行路径，成功/失败的动画使用贝塞尔实现。

设置view路径

//边框路径
val path = Path()
path.moveTo(lineStartX, lineTopY)
path.lineTo(lineStopX, lineTopY)
arcRectF.left = mW - mH + padding
arcRectF.top = padding
arcRectF.right = mW - padding
arcRectF.bottom = mH - padding
path.arcTo(arcRectF, arcRtStartAng, arcSweepAng)
pathMeasureStrokeTop = PathMeasure(path, false)
pathMeasureStrokeLen = pathMeasureStrokeTop.length
path.reset()
path.moveTo(lineStopX, lineBtmY)
path.lineTo(lineStartX, lineBtmY)
arcRectF.left = padding
arcRectF.top = padding
arcRectF.right = mH + padding
arcRectF.bottom = mH - padding
path.arcTo(arcRectF, arcLtStartAng, arcSweepAng)
pathMeasureStrokeBtm = PathMeasure(path, false)

//对钩的路径
path.reset()
path.moveTo(tickLtStartX, tickLtStartY)
path.quadTo(tickLtControlX, tickLtControlY, tickLtEndX, tickLtEndY)
path.quadTo(tickCenX, tickCenY, tickCenEndX, tickCenEndY)
path.quadTo(tickRtControlX, tickRtControlY, tickRtEdX, tickRtEdY)
mPathMeasureTick = PathMeasure(path, false)
pathMeasureTickLen = mPathMeasureTick.length

// X的路径
path.reset()
path.moveTo(xLfStartX, xLfStartY)
path.lineTo(xLfEdX, xLfEdY)
pathMeasureXL = PathMeasure(path, false)
pathMeasureXLen = pathMeasureXL.length
path.reset()

path.moveTo(xRfStartX, xRfStartY)
path.lineTo(xRfEdX, xRfEdY)
pathMeasureXR = PathMeasure(path, false)

根据路径和动画执行进度绘制

/**
 * 绘制边框
 */
private fun drawStroke(canvas: Canvas) {
    getStrokePaint()
    pathMeasurePath.reset()
    pathMeasureStrokeLenRatio = pathMeasureStrokeLen * strokeRatio
    if (strokeMode == MODE_STROKE_AROUND) {
        pathMeasureStrokeLenRatio *= 2f
    }
    pathMeasureStrokeTop.getSegment(pathMeasureStrokeLenRatio, pathMeasureStrokeLen, pathMeasurePath, true)
    canvas.drawPath(pathMeasurePath, paint)
    if (strokeMode == MODE_STROKE_AROUND) {
        pathMeasureStrokeLenRatio = pathMeasureStrokeLen * max((strokeRatio - 0.5f), 0f) * 2f
    }
    pathMeasurePath.reset()
    pathMeasureStrokeBtm.getSegment(pathMeasureStrokeLenRatio, pathMeasureStrokeLen, pathMeasurePath, true)
    canvas.drawPath(pathMeasurePath, paint)
}

/**
 * 绘制成功或失败的图案
 */
private fun drawComplete(canvas: Canvas) {
    getTickAndXPaint()
    pathMeasurePath.reset()
    if (isSuccess) {
        mPathMeasureTick.getSegment(0f, pathMeasureTickLen * tickAndXRatio, pathMeasurePath, true)
        canvas.drawPath(pathMeasurePath, paint)
        return
    }
    pathMeasureXLenRatio = pathMeasureXLen * tickAndXRatio
    pathMeasureXL.getSegment(0f, pathMeasureXLenRatio, pathMeasurePath, true)
    canvas.drawPath(pathMeasurePath, paint)
    pathMeasurePath.reset()
    pathMeasureXLenRatio = pathMeasureXLen * max(tickAndXRatio - 0.5f, 0f) * 2f
    pathMeasureXR.getSegment(0f, pathMeasureXLenRatio, pathMeasurePath, true)
    canvas.drawPath(pathMeasurePath, paint)
}

/**
 * 绘制背景
 */
private fun drawBackground(canvas: Canvas) {
    getBacPaint()
    if (isSuccess) {
        paint.color = getColor(bacColorStart, bacColorSuccess, (strokeRatio + tickAndXRatio) / 2f)
    } else {
        paint.color = getColor(bacColorStart, bacColorError, (strokeRatio + tickAndXRatio) / 2f)
    }
    canvas.drawRoundRect(0f, 0f, mW, mH, 200f, 200f, paint)
}

/**
 * 绘制文字
 */
private fun drawText(canvas: Canvas) {
    getTextPaint()
    val fontMetrics: Paint.FontMetrics = paint.fontMetrics
    textY = mH / 2f - (fontMetrics.ascent + fontMetrics.descent) / 2f
    paint.color = getColor(textColor, 1f - strokeRatio)
    canvas.drawText(if (strokeRatio == 0f) text else textLoading, textX, textY, paint)
}