1 val dialog = AlertDialog.Builder(this).setView(R.layout.dialogbox).create()
 2         //设置对话框宽度尺寸
 3         val windowManager = windowManager
 4         val display = windowManager.defaultDisplay
 5         val lp = dialog.window!!.attributes
 6         lp.width = display.width
 7         dialog.window!!.attributes = lp
 8         //设置背景高斯模糊
 9         this.setBlurredBackground(true)
10         dialog.show()

设置ActivityA背景

 private fun setBlurredBackground(blurry:Boolean){
         if (blurry){
             //高斯模糊背景
             val overlay= GaussianBlur.setFastblur(GaussianBlur.takeScreenShot(this))
             //  设置背景图片
             window.setBackgroundDrawable(BitmapDrawable(this.resources, overlay))
            // findViewById<LinearLayout>(R.id.dialog).setBackgroundDrawable(BitmapDrawable(this.resources, overlay))
             setHideView(false)
         }else{
             // 还原背景颜色
             window.setBackgroundDrawable(resources.getDrawable(R.color.color_main))
             setHideView(true)
隐藏View方法
 1 //隐藏View
 2     private fun setHideView(hide:Boolean){
 3      if (hide){
 4          ButSearch.visibility = View.VISIBLE
 5          ButAdd.visibility = View.VISIBLE
 6          bnView.visibility= View.VISIBLE
 7          title.visibility=View.VISIBLE
 8          findViewById<LinearLayout>(R.id.lin_lay_fragment).visibility=View.VISIBLE
10       }else{
11          ButSearch.visibility = View.GONE
12          ButAdd.visibility = View.GONE
13          bnView.visibility= View.GONE
14          title.visibility=View.GONE
15          findViewById<LinearLayout>(R.id.lin_lay_fragment).visibility=View.GONE
16      }
截取ActivityA方法
 1 /**
 2      * 截屏
 3      * @param activity 截屏的activity
 4      * @return 截屏图片
 5      */
 6     fun takeScreenShot(activity: Activity): Bitmap {
 7         val view = activity.window.decorView
 8         view.isDrawingCacheEnabled = true
 9         view.buildDrawingCache()
10         val b1 = view.drawingCache
11         // 获取屏幕长和高
12         val width = activity.resources.displayMetrics.widthPixels
13         val height = activity.resources.displayMetrics.heightPixels
14         val bmp = Bitmap.createBitmap(b1, 0, 0, width, height)
15         view.destroyDrawingCache()
16         return bmp
高斯模糊工具类具体代码
object GaussianBlur {
     * @param activity 截屏的activity
     * @return 截屏图片
    fun takeScreenShot(activity: Activity): Bitmap {
        val view = activity.window.decorView
        view.isDrawingCacheEnabled = true
        view.buildDrawingCache()
        val b1 = view.drawingCache
        // 获取屏幕长和高
        val width = activity.resources.displayMetrics.widthPixels
        val height = activity.resources.displayMetrics.heightPixels
        val bmp = Bitmap.createBitmap(b1, 0, 0, width, height)
        view.destroyDrawingCache()
        return bmp
    fun setFastblur(bitmap: Bitmap): Bitmap?{
        var bit = small(bitmap)?.let {
            blurry(
                it,6)
        return bit?.let { big(it) }
     * 放大图片
     * @param bitmap 需要放大的图片
     * @return 放大的图片
    private  fun big(bitmap: Bitmap): Bitmap? {
        val matrix = Matrix()
        matrix.postScale(4f, 4f)
        return Bitmap.createBitmap(bitmap, 0, 0, bitmap.width, bitmap.height, matrix, true)
     * 缩小图片
     * @param bitmap 需要缩小的图片
     * @return 缩小的图片
    private  fun small(bitmap: Bitmap): Bitmap? {
        val matrix = Matrix()
        matrix.postScale(0.25f, 0.25f)
        return Bitmap.createBitmap(bitmap, 0, 0, bitmap.width, bitmap.height, matrix, true)
    /**  将图片模糊化
    @param sentBitmap 需要模糊的图片
    @param radius  模糊程度
    @return 模糊后的图片
    private  fun blurry(sentBitmap: Bitmap, radius: Int): Bitmap? {
        val bitmap = sentBitmap.copy(sentBitmap.config, true)
        if (radius < 1) {
            return null
        val w = bitmap.width
        val h = bitmap.height
        val pix = IntArray(w * h)
        bitmap.getPixels(pix, 0, w, 0, 0, w, h)
        val wm = w - 1
        val hm = h - 1
        val wh = w * h
        val div = radius + radius + 1
        val r = IntArray(wh)
        val g = IntArray(wh)
        val b = IntArray(wh)
        var rsum: Int
        var gsum: Int
        var bsum: Int
        var x: Int
        var y: Int
        var i: Int
        var p: Int
        var yp: Int
        var yi: Int
        var yw: Int
        val vmin = IntArray(w.coerceAtLeast(h))
        var divsum = div + 1 shr 1
        divsum *= divsum
        val dv = IntArray(256 * divsum)
        i = 0
        while (i < 256 * divsum) {
            dv[i] = i / divsum
        yi = 0
        yw = yi
        val stack =
            Array(div) { IntArray(3) }
        var stackpointer: Int
        var stackstart: Int
        var sir: IntArray
        var rbs: Int
        val r1 = radius + 1
        var routsum: Int
        var goutsum: Int
        var boutsum: Int
        var rinsum: Int
        var ginsum: Int
        var binsum: Int
        y = 0
        while (y < h) {
            bsum = 0
            gsum = bsum
            rsum = gsum
            boutsum = rsum
            goutsum = boutsum
            routsum = goutsum
            binsum = routsum
            ginsum = binsum
            rinsum = ginsum
            i = -radius
            while (i <= radius) {
                p = pix[yi + wm.coerceAtMost(i.coerceAtLeast(0))]
                sir = stack[i + radius]
                sir[0] = p and 0xff0000 shr 16
                sir[1] = p and 0x00ff00 shr 8
                sir[2] = p and 0x0000ff
                rbs = r1 - abs(i)
                rsum += sir[0] * rbs
                gsum += sir[1] * rbs
                bsum += sir[2] * rbs
                if (i > 0) {
                    rinsum += sir[0]
                    ginsum += sir[1]
                    binsum += sir[2]
                } else {
                    routsum += sir[0]
                    goutsum += sir[1]
                    boutsum += sir[2]
            stackpointer = radius
            x = 0
            while (x < w) {
                r[yi] = dv[rsum]
                g[yi] = dv[gsum]
                b[yi] = dv[bsum]
                rsum -= routsum
                gsum -= goutsum
                bsum -= boutsum
                stackstart = stackpointer - radius + div
                sir = stack[stackstart % div]
                routsum -= sir[0]
                goutsum -= sir[1]
                boutsum -= sir[2]
                if (y == 0) {
                    vmin[x] = (x + radius + 1).coerceAtMost(wm)
                p = pix[yw + vmin[x]]
                sir[0] = p and 0xff0000 shr 16
                sir[1] = p and 0x00ff00 shr 8
                sir[2] = p and 0x0000ff
                rinsum += sir[0]
                ginsum += sir[1]
                binsum += sir[2]
                rsum += rinsum
                gsum += ginsum
                bsum += binsum
                stackpointer = (stackpointer + 1) % div
                sir = stack[stackpointer % div]
                routsum += sir[0]
                goutsum += sir[1]
                boutsum += sir[2]
                rinsum -= sir[0]
                ginsum -= sir[1]
                binsum -= sir[2]
                yi++
            yw += w
        x = 0
        while (x < w) {
            bsum = 0
            gsum = bsum
            rsum = gsum
            boutsum = rsum
            goutsum = boutsum
            routsum = goutsum
            binsum = routsum
            ginsum = binsum
            rinsum = ginsum
            yp = -radius * w
            i = -radius
            while (i <= radius) {
                yi = 0.coerceAtLeast(yp) + x
                sir = stack[i + radius]
                sir[0] = r[yi]
                sir[1] = g[yi]
                sir[2] = b[yi]
                rbs = r1 - abs(i)
                rsum += r[yi] * rbs
                gsum += g[yi] * rbs
                bsum += b[yi] * rbs
                if (i > 0) {
                    rinsum += sir[0]
                    ginsum += sir[1]
                    binsum += sir[2]
                } else {
                    routsum += sir[0]
                    goutsum += sir[1]
                    boutsum += sir[2]
                if (i < hm) {
                    yp += w
            yi = x
            stackpointer = radius
            y = 0
            while (y < h) {
                pix[yi] =
                    -0x1000000 and pix[yi] or (dv[rsum] shl 16) or (dv[gsum] shl 8) or dv[bsum]
                rsum -= routsum
                gsum -= goutsum
                bsum -= boutsum
                stackstart = stackpointer - radius + div
                sir = stack[stackstart % div]
                routsum -= sir[0]
                goutsum -= sir[1]
                boutsum -= sir[2]
                if (x == 0) {
                    vmin[y] = (y + r1).coerceAtMost(hm) * w
                p = x + vmin[y]
                sir[0] = r[p]
                sir[1] = g[p]
                sir[2] = b[p]
                rinsum += sir[0]
                ginsum += sir[1]
                binsum += sir[2]
                rsum += rinsum
                gsum += ginsum
                bsum += binsum
                stackpointer = (stackpointer + 1) % div
                sir = stack[stackpointer]
                routsum += sir[0]
                goutsum += sir[1]
                boutsum += sir[2]
                rinsum -= sir[0]
                ginsum -= sir[1]
                binsum -= sir[2]
                yi += w
        bitmap.setPixels(pix, 0, w, 0, 0, w, h)
        return bitmap