概述
样式效果
还是先来看效果:
这是一个仿雷达扫描的效果,是之前在做地图sdk接入时就想实现的效果,但之前由于赶着毕业设计,就没有亲手去实现,不过现在自己撸一个发现还是挺简单的。
这里主要分享一下我的做法。
目录
主体轮廓的实现(雷达的结构)
动画的实现(雷达扫描的效果)
目标点的加入(图片/点)
主体轮廓实现
不难分析得出,这个View主要由外部的一个圆,中间的锚点圆以及扇形旋转区域组成。而且每个部分理应由不同的Paint去绘制,以方便去定制各部分的样式。
外部圆以及锚点圆的绘制较为简单,主要的点还是要对整个View的宽高进行一定的限制,例如宽高必须相等且在某种模式下,取小的那个值来限定整个RadarView的最大值。那么该如何去控制呢?
onMeasure(widthMeasureSpec: Int, heightMeasureSpec: Int)
由于我们继承自View,在onMeasure方法中,我们可以根据两个参数来获取Mode,并且根据Mode来指定宽/高对应的值,再通过setMeasuredDimension去指定控件主体的宽高即可。
override fun onMeasure(widthMeasureSpec: Int, heightMeasureSpec: Int) { super.onMeasure(widthMeasureSpec, heightMeasureSpec) val vWidth = measureDimension(widthMeasureSpec) val vHeight = measureDimension(heightMeasureSpec) val size = min(vWidth, vHeight) setMeasuredDimension(size, size) } private fun measureDimension(spec: Int) = when (MeasureSpec.getMode(spec)) { MeasureSpec.EXACTLY -> { // exactly number or match_parent MeasureSpec.getSize(spec) } MeasureSpec.AT_MOST -> { // wrap_content min(mDefaultSize, MeasureSpec.getSize(spec)) } else -> { mDefaultSize } }
测量工作完成了,我们自然可以去绘制了。为了不让中间的小圆看起来那么突兀(偏大或偏小),这里设置了一个scaleFactor的缩放因子,使其能根据外圆的尺寸来进行缩放。
override fun onDraw(canvas: Canvas?) { super.onDraw(canvas) // draw outside circle (background) canvas?.drawCircle(measuredWidth.toFloat() / 2, measuredHeight.toFloat() / 2, measuredWidth.toFloat() / 2, mOutlinePaint) if (mBorderWidth > 0F && mOutlinePaint.shader == null) { drawBorder(canvas) } // mOutlineRect = Rect(0, 0, measuredWidth, measuredHeight) canvas?.drawArc(mOutlineRect.toRectF(), mStartAngle, mSweepAngle, true, mSweepPaint) // draw center circle // scaleFactor = 30F canvas?.drawCircle(measuredWidth.toFloat() / 2, measuredHeight.toFloat() / 2, measuredWidth.toFloat() / 2 / mScaleFactor, mPaint) } private fun drawBorder(canvas: Canvas?) { Log.i("RadarView", "drawBorder") mOutlinePaint.style = Paint.Style.STROKE mOutlinePaint.color = mBorderColor mOutlinePaint.strokeWidth = mBorderWidth canvas?.drawCircle(measuredWidth.toFloat() / 2, measuredHeight.toFloat() / 2, (measuredWidth.toFloat() - mBorderWidth) / 2, mOutlinePaint) // 还原 mOutlinePaint.style = Paint.Style.FILL_AND_STROKE mOutlinePaint.color = mBackgroundColor }
绘制了基准圆以后,要实现雷达扫描时那种渐变的效果,我们可以通过SweepGradient来操作。通过指定中心点,渐变颜色,以及颜色的分布,来定制扫描渐变的样式,默认的即时开头时gif展示的那种。由于这里是从第一象限开始旋转,因此将旋转的起点通过matrix逆时针旋转90度,从而达到由浅入深的效果。
private fun setShader(size: Int) { val shader = SweepGradient(size.toFloat() / 2, size.toFloat() / 2, mScanColors?: mDefaultScanColors, // 可通过setScanColors()来定制颜色 floatArrayOf(0F, 0.5F, 1F)) // 这里默认走平均分布 val matrix = Matrix() // 逆时针旋转90度 matrix.setRotate(-90F, size.toFloat() / 2, size.toFloat() / 2) shader.setLocalMatrix(matrix) mSweepPaint.shader = shader }
这里完成了测量与绘制的工作,那么我们在布局里引用以后,就会看到这样的效果:
这时,由于我们之前在测量的时候,将宽高最小值作为绘制的基准大小给予了RadarView,因此measuredWidth和measuredHeight是相等的,但是由于在布局中指定了match_parent属性,那么实际的控件宽高还是和父布局一致(在这里即占满屏幕宽高,由于宽比高小,所以看到绘制的图形会偏向上方;如果设置了高比宽小,那么绘制的图形就会位于左侧)。一般的雷达控件应该都是居中显示的,所以我在这里也重写了onLayout方法,来实现居中的效果。
override fun onLayout(changed: Boolean, left: Int, top: Int, right: Int, bottom: Int) { // 设置默认居中 var l = left var r = right var t = top var b = bottom when { width > height -> { // 宽度比高度大 那么要设置默认居中就得把left往右移 right往左移 l = (width - measuredWidth) / 2 r = width - l layout(l, t, r, b) } height > width -> { // 高度比宽度大 那么要设置默认居中就得把top往下移 bottom往上移 t = (height - measuredHeight) / 2 b = height - t layout(l, t, r, b) } else -> super.onLayout(changed, left, top, right, bottom) } }
动画的实现
完成了绘制,接下来就是思考该如何让他动起来了。由绘制的代码不难想到,我这里考虑的是通过mStartAngle的变化来控制绘制的角度旋转,而ValueAnimator则正好能获取到每次更新时value的值,因此这里我选用了这个方案。
fun start() { Log.i("RadarView", "animation start") mIsAnimating = true mAnimator.duration = 2000 mAnimator.repeatCount = ValueAnimator.INFINITE mAnimator.addUpdateListener { val angle = it.animatedValue as Float mStartAngle = angle // Log.i("RadarView", "mStartAngle = $mStartAngle and curValue = ${it.animatedValue}") postInvalidate() } mAnimator.start() }
坑
这里就需要注意一个点,就是canvas在绘制时,后绘制的会覆盖在前绘制的图像上,所以需要注意绘制的顺序。当然,这里也可以把mOutlineRect的宽高设置为measuredWidth - mBorderWidth,那么就能保证绘制填充角度时,不会把边界覆盖。
至此,动画的效果便完成了。
目标点的加入
首先,前两点已经能满足大多的雷达扫描需求了。这里这个添加目标点(target)纯粹是我自己想加入的功能,因为觉得可以结合地图sdk的MapView来共同使用,目前也只是开发阶段,扩展性可能考虑得还不是特别充足,也还没应用到具体项目中。但是,总觉得自己想的功能也该试着去实践一下~
这里主要运用的圆的计算公式:
由于Android的坐标系的原点是在左上角,y轴过顶点向下延伸。由我们的绘制可知,此绘制图像在坐标系中的位置大概如下图所示:
那么,对应的公式就为:
要注意的是,这里r的计算会根据图/点的设置来动态计算,具体例子通过代码来进行分析。
// 随机落点 fun addTarget(size: Int, type: TYPE = TYPE.RANDOM) { val list = ArrayList<PointF>() val r = measuredWidth.toFloat() / 2 val innerRect = Rect((r - r / mScaleFactor).toInt(), (r - r / mScaleFactor).toInt(), (r + r / mScaleFactor).toInt(), (r + r / mScaleFactor).toInt()) // 圆的中心点 val circle = PointF(measuredWidth.toFloat() / 2, measuredHeight.toFloat() / 2) while (list.size < size) { val ranX = Random.nextDouble(0.0, r * 2.0).toFloat() val ranY = Random.nextDouble(0.0, r * 2.0).toFloat() val ranPointF = PointF(ranX, ranY) if (innerRect.contains(ranPointF.toPoint())) { continue } // 圆公式 if (!mNeedBitmap && (ranX - circle.x).pow(2) + (ranY - circle.y).pow(2) < (r - mTargetRadius - mBorderWidth).toDouble().pow(2.0)) { // 普通点 addTargetFromType(type, list, ranX, ranY, r, ranPointF) } else if (mNeedBitmap && (ranX - circle.x).pow(2) + (ranY - circle.y).pow(2) < (r - mBorderWidth - max(mBitmap.width, mBitmap.height) / 2).toDouble().pow(2)) { // 图 addTargetFromType(type, list, ranX, ranY, r, ranPointF) } else { continue } } mTargetList = list for (target in list) { Log.i("RadarView", "target = [${target.x}, ${target.y}]") } invalidate() }
可以看到,当target为普通点时,r的计算还要减去targetRadius,即目标点的半径,同时还要减去边界的宽度,如图所示:
当target为图时,由于宽高不定,故除了边界外,还要减去大的边,那么r的计算则为:
同时为了避免图片的尺寸过大,这里同样采取了一个默认值与一个缩放因子,从而保证图的完整性以及避免过大而引起的视觉丑化。
关于落点的位置,目前采取的是随机落点,如果应用到地图扫点的话,可以通过地图sdk内的距离计算工具再与RadarView的坐标做一个比例转换,从而达到雷达内显示该点具体方位。
关于落点的分布,目前提供了5种类型:分别是全象限随机、第一象限、第二象限、第三象限与第四象限随机。
Github
若须直接调用,可移步至 https://github.com/CarsonWoo/RadarView
完整代码
class RadarView : View { enum class TYPE { RANDOM, FIRST, SECOND, THIRD, FOURTH } private val mPaint by lazy { Paint(Paint.ANTI_ALIAS_FLAG) } private val mSweepPaint by lazy { Paint(Paint.ANTI_ALIAS_FLAG) } private val mOutlinePaint by lazy { Paint(Paint.ANTI_ALIAS_FLAG) } private val mTargetPaint by lazy { Paint(Paint.ANTI_ALIAS_FLAG) } private val mDefaultSize = 120// px // limit the size of bitmap private var mBitmapMaxSize = 0F private var mBitmapWHRatio = 0F private val mScaleFactor = 30F private var mStartAngle = 0F private val mSweepAngle = -60F private var mScanColors: IntArray? = null private val mDefaultScanColors = intArrayOf(Color.parseColor("#0F7F7F7F"), Color.parseColor("#7F7F7F7F"), Color.parseColor("#857F7F7F")) private val mDefaultBackgroundColor = Color.WHITE private var mBackgroundColor: Int = mDefaultBackgroundColor private var mBorderColor: Int = Color.BLACK private var mBorderWidth = 0F private var mTargetColor: Int = Color.RED private var mTargetRadius = 10F private lateinit var mOutlineRect: Rect private val mAnimator = ValueAnimator.ofFloat(0F, 360F) private var mTargetList: ArrayList<PointF>? = null private var mIsAnimating = false private var mNeedBitmap = false private var mBitmap = BitmapFactory.decodeResource(resources, R.mipmap.ic_launcher) constructor(context: Context): this(context, null) constructor(context: Context, attributeSet: AttributeSet?) : super(context, attributeSet) init { mPaint.color = Color.GRAY mPaint.strokeWidth = 10F mPaint.style = Paint.Style.FILL_AND_STROKE mPaint.strokeJoin = Paint.Join.ROUND mPaint.strokeCap = Paint.Cap.ROUND mSweepPaint.style = Paint.Style.FILL mOutlinePaint.style = Paint.Style.FILL_AND_STROKE mOutlinePaint.color = mBackgroundColor mTargetPaint.style = Paint.Style.FILL mTargetPaint.color = mTargetColor mTargetPaint.strokeWidth = 10F } override fun onMeasure(widthMeasureSpec: Int, heightMeasureSpec: Int) { super.onMeasure(widthMeasureSpec, heightMeasureSpec) val vWidth = measureDimension(widthMeasureSpec) val vHeight = measureDimension(heightMeasureSpec) val size = min(vWidth, vHeight) setShader(size) setMeasuredDimension(size, size) setParamUpdate() } override fun onLayout(changed: Boolean, left: Int, top: Int, right: Int, bottom: Int) { // 设置默认居中 var l = left var r = right var t = top var b = bottom when { width > height -> { // 宽度比高度大 那么要设置默认居中就得把left往右移 right往左移 l = (width - measuredWidth) / 2 r = width - l layout(l, t, r, b) } height > width -> { // 高度比宽度大 那么要设置默认居中就得把top往下移 bottom往上移 t = (height - measuredHeight) / 2 b = height - t layout(l, t, r, b) } else -> super.onLayout(changed, left, top, right, bottom) } } private fun setShader(size: Int) { val shader = SweepGradient(size.toFloat() / 2, size.toFloat() / 2, mScanColors?: mDefaultScanColors, floatArrayOf(0F, 0.5F, 1F)) val matrix = Matrix() matrix.setRotate(-90F, size.toFloat() / 2, size.toFloat() / 2) shader.setLocalMatrix(matrix) mSweepPaint.shader = shader } fun setScanColors(colors: IntArray) { this.mScanColors = colors setShader(measuredWidth) invalidate() } fun setRadarColor(@ColorInt color: Int) { this.mBackgroundColor = color this.mOutlinePaint.color = color invalidate() } fun setRadarColor(colorString: String) { if (!colorString.startsWith("#") || colorString.length != 7 || colorString.length != 9) { Log.e("RadarView", "colorString parse error, please check your enter param") return } val color = Color.parseColor(colorString) setRadarColor(color) } fun setBorderColor(@ColorInt color: Int) { this.mBorderColor = color invalidate() } fun setBorderColor(colorString: String) { if (!colorString.startsWith("#") || colorString.length != 7 || colorString.length != 9) { Log.e("RadarView", "colorString parse error, please check your enter param") return } val color = Color.parseColor(colorString) setBorderColor(color) } fun setRadarGradientColor(colors: IntArray) { val shader = SweepGradient(measuredWidth.toFloat() / 2, measuredHeight.toFloat() / 2, colors, null) mOutlinePaint.shader = shader invalidate() } fun setBorderWidth(width: Float) { this.mBorderWidth = width invalidate() } private fun setParamUpdate() { mOutlineRect = Rect(0, 0, measuredWidth, measuredHeight) mBitmapMaxSize = measuredWidth.toFloat() / mScaleFactor } private fun measureDimension(spec: Int) = when (MeasureSpec.getMode(spec)) { MeasureSpec.EXACTLY -> { // exactly number or match_parent MeasureSpec.getSize(spec) } MeasureSpec.AT_MOST -> { // wrap_content min(mDefaultSize, MeasureSpec.getSize(spec)) } else -> { mDefaultSize } } override fun setBackground(background: Drawable?) { // 取消传统背景设置 // super.setBackground(background) } override fun onDraw(canvas: Canvas?) { super.onDraw(canvas) // draw outside circle (background) canvas?.drawCircle(measuredWidth.toFloat() / 2, measuredHeight.toFloat() / 2, measuredWidth.toFloat() / 2, mOutlinePaint) if (mBorderWidth > 0F && mOutlinePaint.shader == null) { drawBorder(canvas) } canvas?.drawArc(mOutlineRect.toRectF(), mStartAngle, mSweepAngle, true, mSweepPaint) if (!mTargetList.isNullOrEmpty() && !mIsAnimating) { drawTarget(canvas) } // draw center circle canvas?.drawCircle(measuredWidth.toFloat() / 2, measuredHeight.toFloat() / 2, measuredWidth.toFloat() / 2 / mScaleFactor, mPaint) } private fun drawBorder(canvas: Canvas?) { Log.i("RadarView", "drawBorder") mOutlinePaint.style = Paint.Style.STROKE mOutlinePaint.color = mBorderColor mOutlinePaint.strokeWidth = mBorderWidth canvas?.drawCircle(measuredWidth.toFloat() / 2, measuredHeight.toFloat() / 2, (measuredWidth.toFloat() - mBorderWidth) / 2, mOutlinePaint) // 还原 mOutlinePaint.style = Paint.Style.FILL_AND_STROKE mOutlinePaint.color = mBackgroundColor } private fun drawTarget(canvas: Canvas?) { mTargetList?.let { Log.e("RadarView", "draw target") for (target in it) { if (mNeedBitmap) { canvas?.drawBitmap(mBitmap, target.x - mBitmap.width / 2, target.y - mBitmap.height / 2, mTargetPaint) } else { canvas?.drawCircle(target.x, target.y, mTargetRadius, mTargetPaint) } } } } fun setBitmapEnabled(enabled: Boolean, drawable: Drawable) { // 这里是为了防止界面还未获取到宽高时 会导致onMeasure走不到 那么maxSize就会为0 post { this.mNeedBitmap = enabled this.mBitmapWHRatio = drawable.intrinsicWidth.toFloat() / drawable.intrinsicHeight.toFloat() mBitmap = if (mBitmapWHRatio >= 1) { // 宽比高大 drawable.toBitmap( width = min(mBitmapMaxSize, drawable.intrinsicWidth.toFloat()).toInt(), height = (min(mBitmapMaxSize, drawable.intrinsicWidth.toFloat()) / mBitmapWHRatio).toInt(), config = Bitmap.Config.ARGB_8888) } else { // 高比宽大 drawable.toBitmap( height = min(mBitmapMaxSize, drawable.intrinsicHeight.toFloat()).toInt(), width = (min(mBitmapMaxSize, drawable.intrinsicHeight.toFloat()) * mBitmapWHRatio).toInt(), config = Bitmap.Config.ARGB_8888 ) } } } // 随机落点 fun addTarget(size: Int, type: TYPE = TYPE.RANDOM) { val list = ArrayList<PointF>() val r = measuredWidth.toFloat() / 2 val innerRect = Rect((r - r / mScaleFactor).toInt(), (r - r / mScaleFactor).toInt(), (r + r / mScaleFactor).toInt(), (r + r / mScaleFactor).toInt()) // 圆的中心点 val circle = PointF(measuredWidth.toFloat() / 2, measuredHeight.toFloat() / 2) while (list.size < size) { val ranX = Random.nextDouble(0.0, r * 2.0).toFloat() val ranY = Random.nextDouble(0.0, r * 2.0).toFloat() val ranPointF = PointF(ranX, ranY) if (innerRect.contains(ranPointF.toPoint())) { continue } // 圆公式 if (!mNeedBitmap && (ranX - circle.x).pow(2) + (ranY - circle.y).pow(2) < (r - mTargetRadius - mBorderWidth).toDouble().pow(2.0)) { // 在圆内 addTargetFromType(type, list, ranX, ranY, r, ranPointF) } else if (mNeedBitmap && (ranX - circle.x).pow(2) + (ranY - circle.y).pow(2) < (r - mBorderWidth - max(mBitmap.width, mBitmap.height) / 2).toDouble().pow(2)) { addTargetFromType(type, list, ranX, ranY, r, ranPointF) } else { continue } } mTargetList = list for (target in list) { Log.i("RadarView", "target = [${target.x}, ${target.y}]") } invalidate() } private fun addTargetFromType(type: TYPE, list: ArrayList<PointF>, ranX: Float, ranY: Float, r: Float, ranPointF: PointF) { when (type) { TYPE.RANDOM -> { list.add(ranPointF) } TYPE.FOURTH -> { if (ranX in r.toDouble()..2 * r.toDouble() && ranY in r.toDouble()..2 * r.toDouble()) { list.add(ranPointF) } } TYPE.THIRD -> { if (ranX in 0.0..r.toDouble() && ranY in r.toDouble()..2 * r.toDouble()) { list.add(ranPointF) } } TYPE.SECOND -> { if (ranX in 0.0..r.toDouble() && ranY in 0.0..r.toDouble()) { list.add(ranPointF) } } TYPE.FIRST -> { if (ranX in r.toDouble()..2 * r.toDouble() && ranY in 0.0..r.toDouble()) { list.add(ranPointF) } } } } fun start() { Log.i("RadarView", "animation start") mIsAnimating = true mAnimator.duration = 2000 mAnimator.repeatCount = ValueAnimator.INFINITE mAnimator.addUpdateListener { val angle = it.animatedValue as Float mStartAngle = angle Log.i("RadarView", "mStartAngle = $mStartAngle and curValue = ${it.animatedValue}") postInvalidate() } mAnimator.start() } fun start(startVal: Float, endVal: Float) { mIsAnimating = true mAnimator.setFloatValues(startVal, endVal) mAnimator.duration = 2000 mAnimator.repeatCount = ValueAnimator.INFINITE mAnimator.addUpdateListener { mStartAngle = it.animatedValue as Float Log.i("RadarView", "mStartAngle = $mStartAngle and curValue = ${it.animatedValue}") postInvalidate() } mAnimator.start() } fun stop() { mIsAnimating = false if (mAnimator.isRunning) { mAnimator.cancel() mAnimator.removeAllListeners() } mStartAngle = 0F } }
调用方式
override fun onCreate(savedInstanceState: Bundle?) { super.onCreate(savedInstanceState) setContentView(R.layout.activity_main) radar_view.setBorderWidth(5F) radar_view.setRadarColor(Color.TRANSPARENT) radar_view.setBitmapEnabled(true, resources.getDrawable(R.mipmap.ic_launcher_round)) // radar_view.setScanColors(intArrayOf(Color.RED, Color.LTGRAY, Color.CYAN)) // radar_view.setRadarGradientColor(intArrayOf(Color.RED, Color.GREEN, Color.BLUE)) btn_start.setOnClickListener { radar_view.start() // workThreadAndCallback() } btn_stop.setOnClickListener { radar_view.stop() radar_view.addTarget(7) } }
总结
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