文章目錄

• • 前言
  • 思考
  • 代碼
  • 總結

前言

無論是線上推廣，還是線下營銷，轉盤游戲都是非常吸引人的一項活動，就像電視劇《贅婿》中的“拼刀刀”，達到的是萬人空巷的影響力。其實，這是一種賭徒心理。每個人都希望不勞而獲，這是賭徒心理的成長的肥沃土壤，不幸的是，千百萬年的成長中，人已經形成了避難趨易的本性。轉盤是一種傻瓜式的操作，只需要手指點一下，不過幾秒鐘，就可以收到反饋。而想要立即得到結果，害怕未知依然是每個人的本質。所以，轉盤游戲有其滋生的土壤。

思考

怎么樣實現一個轉盤那？首先：轉盤是一個圓，然后把圓等分成幾份，每一份都是一個扇形區域，在扇形區域中畫出我們先展示的內容，接著，中間可能有裝飾(圖片)，最后，按照層級一層層畫。
想必大家都對自定義View的過程了熟于心，這里就不過多介紹了。下面我們進入代碼。

代碼

自定義轉盤
這里沒有給出全部的代碼，而是抽取了一些關鍵步驟，文章的最后有給出全部代碼。

class LuckySpinView : View {constructor(context: Context?) : super(context) {initPaint()}// 初始化畫筆。自定義View前先想好需要哪些畫筆，對實現View有神奇效果private fun initPaint() {mArcPaint = Paint()mArcPaint.isAntiAlias = truemArcPaint.isDither = truemTextPaint = TextPaint()mTextPaint.style = Paint.Style.FILLmTextPaint.isAntiAlias = truemTextPaint.isDither = truemTextPaint.color = mTextColormTextPaint.textSize = mTextSizemTextPaint.typeface = ResourcesCompat.getFont(context, R.font.impact)mTextStrokePaint = TextPaint(mTextPaint)mTextStrokePaint.style = Paint.Style.STROKEmTextStrokePaint.strokeWidth = TEXT_STROKE_WIDTHmBackgroundPaint = Paint()mBackgroundPaint.isAntiAlias = truemBackgroundPaint.isDither = true}// 測量階段。自定義View必要的階段，用來規范我們View的展示大小override fun onMeasure(widthMeasureSpec: Int, heightMeasureSpec: Int) {super.onMeasure(widthMeasureSpec, heightMeasureSpec)val width = measuredWidth.coerceAtMost(measuredHeight)mPadding = paddingLeftif (mOutRadius == 0) mOutRadius = width / 2if (mInnerRadius == 0) mInnerRadius = width / 2setMeasuredDimension(mOutRadius * 2, mOutRadius * 2)}// 繪畫階段。自定義View必要的階段，畫布承載我們想要的效果，畫筆將我們的想法變成現實/*** @param canvas*/@SuppressLint("DrawAllocation")override fun onDraw(canvas: Canvas) {super.onDraw(canvas)drawArc(canvas) // 畫扇形區域drawCenterImg(canvas) //畫中間的區域drawOutBoundImg(canvas) // 畫外圍的裝飾}@SuppressLint("UseCompatLoadingForDrawables")private fun drawCenterImg(canvas: Canvas) {if (mCenterImageId == 0) returnif (mCenterBitmap == null) {val drawable = resources.getDrawable(mCenterImageId, null)val bitmap = Utils.drawableToBitmap(drawable)mCenterBitmap = Bitmap.createScaledBitmap(bitmap,drawable!!.intrinsicWidth,drawable.intrinsicHeight,false)}val bitmap = mCenterBitmap!!canvas.drawBitmap(bitmap, mCenterPoint.x - bitmap.width / 2.toFloat(),mCenterPoint.y - bitmap.height / 2.toFloat(), null)}@SuppressLint("UseCompatLoadingForDrawables")private fun drawOutBoundImg(canvas: Canvas) {val drawable = resources.getDrawable(mBackgroundImgId, null)drawable.bounds = Rect(mOutRange.left.toInt() ,mOutRange.top.toInt() ,mOutRange.right.toInt() ,mOutRange.bottom.toInt())drawable.draw(canvas)}private fun drawArc(canvas: Canvas) {var tmpAngle = mStartAngleval sweepAngle = 360f / mRewardList.sizefor (i in mRewardList.indices) {fillArc(canvas, tmpAngle, sweepAngle, i)drawArcBorder(canvas, tmpAngle, sweepAngle)drawItemContentWithoutIcon(i, canvas, tmpAngle, sweepAngle)tmpAngle += sweepAngle}}private fun rotateTo(index: Int) {HandlerUtils.runOnUiThread {val rand = Random()rotateTo(index, rand.nextInt() and 1, true)}}// 執行旋轉fun rotateTo(index: Int, rotation: Int, startShow: Boolean) {if (isRunning) {return}val rotationAssess = if (rotation <= 0) 1 else -1var roundOfNumber = mRoundOfNumberval accDuration = 1500Lvar decDuration = 1500Lvar interpolator: TimeInterpolator// 從上一次轉盤最終的位置處旋轉if (getRotation() != 0.0f) {setRotation(getRotation() % 360f)interpolator = AccelerateInterpolator()animate().setInterpolator(interpolator).setDuration(accDuration).setListener(object : Animator.AnimatorListener {override fun onAnimationStart(animation: Animator) {isRunning = true}override fun onAnimationEnd(animation: Animator) {isRunning = falsesetRotation(0f) // 加速到角度為0的水平軸， 接著再減速到目標角度rotateTo(index, rotation, false)}override fun onAnimationCancel(animation: Animator) {}override fun onAnimationRepeat(animation: Animator) {}}).rotation(360f * roundOfNumber * rotationAssess).start()return}interpolator = DecelerateInterpolator()// 進入轉盤后的第一次玩轉盤, 先加速再減速if (startShow) {roundOfNumber = roundOfNumber shl 1decDuration = accDuration shl 1interpolator = AccelerateDecelerateInterpolator()}val targetAngle =360f * roundOfNumber * rotationAssess + 270f - getAngleOfIndexTarget(index) - 360f / mRewardList.size / 2animate().setInterpolator(interpolator).setDuration(decDuration + 500L).setListener(object : Animator.AnimatorListener {override fun onAnimationStart(animation: Animator) {isRunning = true}override fun onAnimationEnd(animation: Animator) {isRunning = falsesetRotation(getRotation() % 360f)if (mRotateListener != null) {mRotateListener!!.rotateDone(index)}}override fun onAnimationCancel(animation: Animator) {}override fun onAnimationRepeat(animation: Animator) {}}).rotation(targetAngle).start()}fun setTargetIndex(index: Int) {targetIndex = index}// 開始旋轉fun startLuckyWheelWithTargetIndex(index: Int) {this.rotateTo(index)}fun startLuckyWheelWithRandomTarget() {val r = Random()this.rotateTo(r.nextInt(this.rewardListSize - 1))}// 取消旋轉fun cancelRotate() {animate().cancel()} }

這里有全部的代碼，歡迎查看，LuckySpin

總結

在實現轉盤游戲的過程中，總會碰到一些攔路虎。如果避其鋒芒，不敢與之對抗，那么此消彼長，它會一步步成長，直到你覺得不能再逃避想要面對它時，它已經是個龐然大物，此時便會有心無力。碰到困難，最簡單也是最有效的方法，直接面對它，將它分解成你能解決的許多小塊，這就是分治算法的核心：分而治之。

總結

以上是生活随笔為你收集整理的Android--大转盘的全部內容，希望文章能夠幫你解決所遇到的問題。

如果覺得生活随笔網站內容還不錯，歡迎將生活随笔推薦給好友。