什么是Kotlin
Kotlin，它是JetBrains開發的基于JVM的面向對象的語言。2017年的時候被Google推薦Android的官方語言，同時Android studio 3.0正式支持這門語言，在這個編譯器上創建一個Kotlin項目，非常方便，甚至可以Java轉為Kotlin。
引言
早上看到有個童鞋在群里面發牢騷,說這個自定義view怎么畫,不太會,ok,正好我也沒事,那我就花兩個小時幫你搞定他吧,先看下他要的效果;
再來看下我實現的效果
實現過程
主要分為x軸和y軸,由效果圖可以看出,x軸主要分為7份,y軸主要分為4份,這樣劃分就比較簡單的知道每條線的位置,每個位置的位置了,繪制起來就很簡單;
先繪制y軸的四條線和文字
文字有三個,放到一個list里面,然后我們均分高度,然后遍歷文字集合,根絕不同的高度繪制文字和橫線
看下代碼:
/** * 繪制邊框線和邊框文本 */ private fun drawBorderLineAndText(canvas: Canvas) { when { valueTextY.size > 0 -> { val averageHeight = mNeedDrawHeight / (valueTextY.size + 1) (1..valueTextY.size + 1).forEach { i -> val nowadayHeight = averageHeight * (valueTextY.size + 1 - i) canvas.drawLine(mBrokenLineLeft, nowadayHeight + mBrokenLineTop, mNeedDrawWidth, nowadayHeight + mBrokenLineTop, mBorderLinePaint) if (i < valueTextY.size + 1) { val fm = mTextPaint.fontMetrics val mTxtHeight = Math.ceil((fm.leading - fm.ascent).toDouble()).toInt() canvas.drawText(valueTextY[valueTextY.size - i].toString() + "萬", mBrokenLineLeft, nowadayHeight + mBrokenLineTop - averageHeight / 2 + mTxtHeight / 2, mTextPaint) } } } } }然后繪制x軸的文字
由于文字有6個,我們分為七份,從第一份之后開始繪制:
代碼如下:
private fun drawMonthText(canvas: Canvas) { when { valueOld.size > 0 -> { var month = defaultStartMonth for (i in 1..valueOld.size) { val averageWidth = (mNeedDrawWidth / (valueOld.size + 1)).toInt() val fm = mTextPaint.fontMetrics val mTxtHeight = Math.ceil((fm.leading - fm.ascent).toDouble()).toInt() canvas.drawText(month.toString() + "月", (averageWidth * i).toFloat(), mNeedDrawHeight - mTxtHeight / 2, mTextPaint) month++ } } } }最后繪制折線和折現上面的小球
這里我們需要把數據放進兩個集合傳入,然后根據數據算出每個點的坐標,最后根據path把每個點連接起來就ok了;
代碼如下:
/** * 設置點的值 */ fun setPointValues(valueNew: ArrayList<Int>, valueOld: ArrayList<Int>) { this.valueNew = valueNew this.valueOld = valueOld } /** * 根據值計算在該值的 x，y坐標 */ fun getPoints(list: ArrayList<Int>): ArrayList<Point> { val avaregwidth = mNeedDrawWidth / (list.size + 1) val points = ArrayList<Point>(list.size) list.indices.forEach { i -> val valueY = list[i].toFloat() val averaHeight = (mNeedDrawHeight * 3 / 4 / maxValue).toDouble() val drawHeight = mNeedDrawHeight * 3 / 4 - (valueY * averaHeight).toFloat() + mBrokenLineTop val pointY = drawHeight.toInt() val pointX = ((avaregwidth * (i + 1)).toInt() + mBrokenLineLeft).toInt() val point = Point(pointX, pointY) points.add(point) } return points }/** * 根據值繪制折線 */ private fun drawBrokenLine(canvas: Canvas) { when { valueOld.size > 0 && valueNew.size > 0 -> { val mPathOld = Path() val mPathNew = Path() val mPathOldshadow = Path() val mPathNewshadow = Path() val pointsOld = getPoints(valueOld) val pointsNew = getPoints(valueNew) for (i in 0 until mAnimatorValue) { val pointOld = pointsOld[i] val pointNew = pointsNew[i] if (i == 0) { mPathOld.moveTo(pointOld.x.toFloat(), pointOld.y.toFloat()) mPathNew.moveTo(pointNew.x.toFloat(), pointNew.y.toFloat()) mPathOldshadow.moveTo(pointOld.x.toFloat(), pointOld.y.toFloat()) mPathNewshadow.moveTo(pointNew.x.toFloat(), pointNew.y.toFloat()) } else { mPathOld.lineTo(pointOld.x.toFloat(), pointOld.y.toFloat()) mPathNew.lineTo(pointNew.x.toFloat(), pointNew.y.toFloat()) mPathOldshadow.lineTo(pointOld.x.toFloat(), pointOld.y.toFloat()) mPathNewshadow.lineTo(pointNew.x.toFloat(), pointNew.y.toFloat()) } } mBrokenLinePaint.color = Color.parseColor("#ff5400") canvas.drawPath(mPathOld, mBrokenLinePaint) mBrokenLinePaint.color = Color.parseColor("#ffff00") canvas.drawPath(mPathNew, mBrokenLinePaint) } } } /** * 繪制線上的圓 */ private fun drawLineCircle(canvas: Canvas) { when { valueOld.size > 0 && valueNew.size > 0 -> { val pointsOld = getPoints(valueOld) val pointsNew = getPoints(valueNew) for (i in 0 until mAnimatorValue) { val pointOld = pointsOld[i] val pointNew = pointsNew[i] mCirclePaint.color = Color.parseColor("#ff5400") canvas.drawCircle(pointOld.x.toFloat(), pointOld.y.toFloat(), radius, mCirclePaint) mCirclePaint.color = Color.parseColor("#ffff00") canvas.drawCircle(pointNew.x.toFloat(), pointNew.y.toFloat(), radius, mCirclePaint) } } } }最后就是添加動畫了,可有可無,看需求吧
代碼如下:
private fun initAnimator( size:Int) { valueAnimator = ValueAnimator.ofInt(0, size).setDuration(defaultDuration.toLong()) mUpdateListener = ValueAnimator.AnimatorUpdateListener { animation -> mAnimatorValue = animation.animatedValue as Int invalidate() } valueAnimator.addUpdateListener(mUpdateListener) valueAnimator.start() } fun setPointValues(valueNew: ArrayList<Int>, valueOld: ArrayList<Int>) { this.valueNew = valueNew this.valueOld = valueOld initAnimator(valueNew.size) }這樣大體效果就已經實現了,最后加陰影,就更簡單了,就直接給畫筆設置陰影就行了
喜歡請到github點個贊啦
地址:github
總結
以上就是這篇文章的全部內容了，希望本文的內容對大家的學習或者工作具有一定的參考學習價值，如果有疑問大家可以留言交流，謝謝大家對VeVb武林網的支持。
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