可直接使用的Bitmap保存至手机图库（Kotlin 版）适配Android8.0

  fun saveToPicDir(context: Context, bitmap: Bitmap): String {
        var result = ""

        val imageFileType = when (bitmap.hasAlpha()) {
            true -> "png"
            false -> "jpeg"
        }
        val bitmapFormat = when (bitmap.hasAlpha()) {
            true -> Bitmap.CompressFormat.PNG
            false -> Bitmap.CompressFormat.JPEG
        }
        val fileName =
            "${System.currentTimeMillis()}.$imageFileType"



        ContentValues().apply {
            put(MediaStore.Images.Media.TITLE, fileName)
            put(MediaStore.Images.Media.DISPLAY_NAME, fileName)
            put(MediaStore.Images.Media.DESCRIPTION, "描述文件")

            if (Build.VERSION.SDK_INT >= 29) {
                put(MediaStore.Images.Media.RELATIVE_PATH, "Pictures/${MissBearConst.MB_DIR_SAVE}")
            }
            put(MediaStore.Images.Media.MIME_TYPE, "image/$imageFileType")
            val uri =
                context.contentResolver.insert(MediaStore.Images.Media.EXTERNAL_CONTENT_URI, this)
            var outputStream: OutputStream? = null
            try {
                outputStream = context.contentResolver.openOutputStream(uri!!)
                bitmap.compress(bitmapFormat, 100, outputStream)
                uri.path?.let { result = it }
            } catch (e: java.lang.Exception) {
                e.printStackTrace()
            } finally {
                outputStream?.let {
                    it.flush()
                    it.close()
                }
            }
            if (Build.VERSION.SDK_INT >= 26) {
                if (uri != null) {
                    sendBroadcastToPic(context, uri)
                }
            }
        }

        return result
    }

/**
* 适配Android 8.0 出现保存之后不通知图库更新的问题
*/
    private fun sendBroadcastToPic(context: Context, imageUri: Uri) {

        var path = ""
        val query = context.contentResolver.query(
            imageUri,
            arrayOf(MediaStore.Images.ImageColumns.DATA),
            null,
            null,
            null
        )

        if (query == null) {
            path = imageUri.path!!
        } else {
            query.moveToFirst()
            val name: Int = query.getColumnIndex(MediaStore.Images.ImageColumns.DATA)
            path = query.getString(name)
            query.close()
        }
        MediaScannerConnection.scanFile(context, arrayOf(path), null, null);
    }