自定義View系列之kotlin繪制手勢設置溫度控件的方法

2024-07-21 23:03:49

字體：大中小

來源：轉載

供稿：網友

引言

最近公司接了一個車聯網的項目，主要是新能源汽車的一些控制功能，其中涉及到一個是溫度的調節功能，產品的意思是做一個手勢滑動調節溫度,大概意思我是明白的。就是要手勢調節唄，沒辦法，誰讓我是搬磚的呢，人為刀俎,我為魚肉，只有搞了；

最后搞出來的效果大概如下，不過還沒確定，

kotlin,溫度控件

思路

在這里我先說下自己的實現思路，這個控件的難點主要是手勢控制，其他的都很簡單，沒有什么好說的，控制的一些具體的數值我是寫死的，沒有做自定義拓展，主要是閑麻煩，如果有需要可以自己的實現；

具體的實現步奏

首先繪制圓盤，刻度，陰影（需要關閉硬件加速），文字
然后根據劃過的角度繪制進度條
最后根絕touch事件重新繪制，并設置數據回調

代碼實現

1，繪制前的準備

首先kotlin提供了init方法，我們需要在這個方法里面初始化我們需要的畫筆和一些數據

注：這里涉及到陰影的繪制，所以必須關閉硬件加速

 init {  //關閉硬件加速  setLayerType(View.LAYER_TYPE_SOFTWARE, null)  mInCirclePaint.color = Color.WHITE  mInCirclePaint.strokeWidth = 1f  mInCirclePaint.style = Paint.Style.FILL  mInCirclePaint.setShadowLayer(25f, 0f, 0f, Color.GRAY)  mGrayLinePaint.color = Color.parseColor("#00EEEE")  mGrayLinePaint.strokeWidth = dp2px(1f).toFloat()  mGrayLinePaint.style = Paint.Style.STROKE  mGrayLinePaint.setShadowLayer(15f, 0f, 0f, Color.GRAY)  mTempTextPaint.textSize = sp2px(32f).toFloat()  mTempTextPaint.style = Paint.Style.FILL  mTempTextPaint.color = Color.parseColor("#7CCD7C")  mTempTextPaint.textAlign = Paint.Align.CENTER  mTempTextPaint.isFakeBoldText = true  mTempTextPaint.setShadowLayer(5f, 0f, 0f, Color.GRAY)  mTextPaint.textSize = sp2px(18f).toFloat()  mTextPaint.style = Paint.Style.FILL  mTextPaint.color = Color.parseColor("#aaaaaa")  mTextPaint.textAlign = Paint.Align.CENTER//  mTextPaint.setShadowLayer(5f, 0f, 0f, Color.GRAY)  mLineProgressPaint.style = Paint.Style.STROKE  mLineProgressPaint.strokeWidth = dp2px(10f).toFloat()  mLineProgressPaint.color = Color.parseColor("#7CCD7C")//  mLineProgressPaint.setShadowLayer(5f, 0f, 0f, Color.GRAY)  mProgressCirclePaint.style = Paint.Style.FILL//  mProgressCirclePaint.setShadowLayer(15f, 0f, 0f, Color.GRAY)  mProgressPaint.style = Paint.Style.FILL  mProgressPaint.color = Color.parseColor("#436EEE")  mProgressPaint.strokeCap = Paint.Cap.ROUND//  mProgressPaint.setShadowLayer(5f, 0f, 0f, Color.GRAY)  mPaintTriangle.style = Paint.Style.FILL  mPaintTriangle.color = Color.parseColor("#436EEE") }

然后我們需要重寫onMeasure()方法，因為這個控件必須是正方形的，所以我們必須保證寬和高一致；

 override fun onMeasure(widthMeasureSpec: Int, heightMeasureSpec: Int) {  val width = View.MeasureSpec.getSize(widthMeasureSpec)  val height = View.MeasureSpec.getSize(heightMeasureSpec)  val imageSize = if (width < height) width else height  setMeasuredDimension(imageSize, imageSize) }

再之后我們需要知道一些具體的寬高值，從而設置半徑的大小，一般是在onSizeChanged()方法里面拿到

 override fun onSizeChanged(w: Int, h: Int, oldw: Int, oldh: Int) {  super.onSizeChanged(w, h, oldw, oldh)  mHeight = Math.min(h, w)  mWidth = height  dialRadius = (width / 2 - dp2px(10f))  arcRadius = dialRadius / 2  mBgRectf = RectF(-dialRadius * 1f / 2 - dp2px(5f), -dialRadius * 1f / 2 - dp2px(5f), dialRadius * 1f / 2 + dp2px(5f), dialRadius * 1f / 2 + dp2px(5f)) }

2，繪制

接下來就開始繪制視圖了，繪制之前需要把視圖的原心移動到中心位置

 canvas.translate(mWidth * 1f / 2, mHeight * 1f / 2);

接著就開始繪制，首先我們繪制最外邊源的線，這里繪制180根線，其中30根長線

 private var beginAngle = 0f private val drawLine = { canvas: Canvas ->  beginAngle = 0f  canvas.save()  for (i in 0..180) {   canvas.save()   canvas.rotate(beginAngle)   mGrayLinePaint.setARGB(180, (0.7 * i * 2).toInt(), ((255 - 0.7 * i * 2).toInt()), ((255 - 0.7 * i * 2).toInt()))   if (beginAngle % 12 == 0f) {    canvas.drawLine(dialRadius * 7f / 9 - dp2px(5f), 0f, dialRadius * 8f / 9, 0f, mGrayLinePaint)   } else {    canvas.drawLine(dialRadius * 7f / 9, 0f, dialRadius * 8f / 9, 0f, mGrayLinePaint)   }   beginAngle += 2f   canvas.restore()  }  canvas.restore() }

效果如下

kotlin,溫度控件

接著開始繪制中心的文字，如果如下

 private val drawText = { canvas: Canvas ->  val baseLineY = Math.abs(mTempTextPaint.ascent() + mTempTextPaint.descent()) / 2  mTempTextPaint.setARGB(180, (0.7 * currentAngle).toInt(), (255 - 0.7 * currentAngle).toInt(), (255 - 0.7 * currentAngle).toInt())  if (temText == 30 || temText == 29) {   mTempTextPaint.setARGB(255, 255, 0, 0)  } else if (temText == 15) {   mTempTextPaint.setARGB(255, 0, 255, 255)  }  canvas.drawText("${temText}°", 0f, baseLineY + dp2px(20f), mTempTextPaint)  canvas.drawText("最大溫度設置", 0f, baseLineY - dp2px(20f), mTextPaint) }

kotlin,溫度控件

接下來就開始繪制進度條和陰影部分

 private val drawPointCircle = { canvas: Canvas ->  canvas.save()  canvas.rotate(rotateAngle + 2)  mProgressPaint.setARGB(255, (0.7 * currentAngle).toInt(), (260 - 0.7 * currentAngle).toInt(), (260 - 0.7 * currentAngle).toInt())  mPaintTriangle.setARGB(255, (0.7 * currentAngle).toInt(), (260 - 0.7 * currentAngle).toInt(), (260 - 0.7 * currentAngle).toInt())  if (temText == 30 || temText == 29) {   mProgressPaint.setARGB(255, 255, 0, 0)   mPaintTriangle.setARGB(255, 255, 0, 0)  } else if (temText == 15) {   mProgressPaint.setARGB(255, 0, 255, 255)   mPaintTriangle.setARGB(255, 0, 255, 255)  }  val path = Path()  path.moveTo(dialRadius * 1f / 2 + dp2px(5f), (-dp2px(10f)).toFloat())  path.lineTo(dialRadius * 1f / 2 + dp2px(5f), dp2px(10f).toFloat())  path.lineTo(dialRadius * 1f / 2 - dp2px(10f), 0f)  path.close()  canvas.drawPath(path, mPaintTriangle)  val point = dialRadius * 1f / 2 + dp2px(5f)  canvas.drawCircle(point, 0f, dp2px(10f).toFloat(), mProgressPaint)  canvas.restore() } private val drawProgress = { canvas: Canvas ->  if (rotateAngle > 0) {   mProgressCirclePaint.color = Color.parseColor("#00ffff")   canvas.drawCircle(dialRadius * 1f / 2 + dp2px(5f), 0f, dp2px(5f).toFloat(), mProgressCirclePaint)  }  val colors = intArrayOf(Color.parseColor("#00ffff"), Color.parseColor("#ff0000"))  val mShader = SweepGradient(0f, 0f, colors, null)  mLineProgressPaint.shader = mShader  canvas.drawArc(mBgRectf, 0f, rotateAngle, false, mLineProgressPaint) }

kotlin,溫度控件

2，手勢

繪制視圖結束，現在開始手勢的處理，主要就是處理touch事件，我們以圓心為坐標圓點，建立坐標系，求出(targetX, targetY)坐標與x軸的夾角，顯現代碼如下

private val calcAngle = { targetX: Float, targetY: Float ->  val x = targetX - width / 2  val y = targetY - height / 2  val radian: Double  if (x != 0f) {   val tan = Math.abs(y / x)   if (x > 0) {    if (y >= 0) {     radian = Math.atan(tan.toDouble())    } else {     radian = 2 * Math.PI - Math.atan(tan.toDouble())    }   } else {    if (y >= 0) {     radian = Math.PI - Math.atan(tan.toDouble())    } else {     radian = Math.PI + Math.atan(tan.toDouble())    }   }  } else {   if (y > 0) {    radian = Math.PI / 2   } else {    radian = -Math.PI / 2   }  }  (radian * 180 / Math.PI).toFloat() }

然后在touch事件中進行處理，主要代碼如下

override fun onTouchEvent(event: MotionEvent): Boolean {  when (event.action) {   MotionEvent.ACTION_DOWN -> {    isDown = true    downX = event.x    downY = event.y    currentAngle = calcAngle(downX, downY)   }   MotionEvent.ACTION_MOVE -> {    isMove = true    val targetX: Float = event.x    val targetY: Float = event.y    val angle = calcAngle(targetX, targetY)    // 滑過的角度增量    var angleIncreased = angle - currentAngle    if (angleIncreased < -180) {     angleIncreased += 360    } else if (angleIncreased > 180) {     angleIncreased -= 360    }    increaseAngle(angleIncreased)    currentAngle = angle    invalidate()    // 滑過的角度增量   }   MotionEvent.ACTION_CANCEL, MotionEvent.ACTION_UP -> {    if (isDown) {     if (isMove) {      temparetureChangeListner?.invoke(temText)      isMove = false     }     isDown = false    }   }  }  return true }

計算出當前角度對應的溫度值

 /**  * 增加旋轉角度  */ private val increaseAngle = { angle: Float ->  rotateAngle += angle  if (rotateAngle < 0) {   rotateAngle = 0f  } else if (rotateAngle > 360f) {   rotateAngle = 360f  }  temText = (rotateAngle / 360 * 15).toInt() + 15 }

這樣一個溫度控件就做好了，喜歡的話麻煩點個贊哦

項目也傳到了github，有興趣可以去下載玩一下

github項目地址（本地下載）

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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