RecyclerViewScreenShot.kt

fun BaseQuickAdapter<*, BaseViewHolder>.shotRecyclerView(
    recyclerView: RecyclerView, bgColor: Int? = null): Bitmap {
    val size = itemCount
    var height = 0
    val maxMemory: Int = ((Runtime.getRuntime().maxMemory() / 1024).toInt())
    // Use 1/8th of the available memory for this memory cache.
    val cacheSize = maxMemory / 8
    val bitmapCache: LruCache<String, Bitmap> = LruCache(cacheSize)
    for (i in 0 until size) {
        var itemView: View?
        itemView = when (getItemViewType(i)) {
            BaseQuickAdapter.HEADER_VIEW -> headerLayout
            else -> {
                val holder = createViewHolder(recyclerView, getItemViewType(i))
                onBindViewHolder(holder, i)
                holder.itemView
            }
        }
        itemView?.run {
            measure(
                View.MeasureSpec.makeMeasureSpec(recyclerView.width, View.MeasureSpec.EXACTLY),
                View.MeasureSpec.makeMeasureSpec(0, View.MeasureSpec.UNSPECIFIED))
            layout(left, top, measuredWidth, measuredHeight)
            isDrawingCacheEnabled = true
            buildDrawingCache()
            var bitmap: Bitmap? = drawingCache
            if (getItemViewType(i) == BaseQuickAdapter.HEADER_VIEW) {
                // header需要特殊处理，因为在滑动时header的top会变成负数，导致截图其和第一条item之间会有空隙，所以要把空隙裁掉
                fun cropBitmap(bmp: Bitmap?): Bitmap? {
                    return bmp?.let {
                        Bitmap.createBitmap(
                            bmp, 0, 0, width, it.height + headerLayout.top, null, false)
                    }
                }
                bitmap = cropBitmap(bitmap)
            }
            bitmapCache.put("$i", bitmap)
            height += measuredHeight
//            isDrawingCacheEnabled = false
//            destroyDrawingCache()
        }
    }
    val bigBitmap = Bitmap.createBitmap(recyclerView.measuredWidth, height, Bitmap.Config.ARGB_8888)
    val bigCanvas = Canvas(bigBitmap)
    // draw background if necessary
    val lBackground: Drawable? = recyclerView.background
    if (bgColor == null && lBackground == null) {
        bigCanvas.drawColor(Color.WHITE)
    } else if (lBackground != null && lBackground is ColorDrawable) {
        bigCanvas.drawColor(lBackground.color)
    } else {
        bgColor?.let { bigCanvas.drawColor(it) }
    }
    // drawBitmap
    var iHeight = 0f
    for (i in 0 until size) {
        val bitmap: Bitmap? = bitmapCache.get("$i")
        bitmap?.run {
            bigCanvas.drawBitmap(bitmap, 0f, iHeight, Paint())
            iHeight += this.height
        }
        // 如果recycle掉了，第二次点击截图的时候会报错Canvas: trying to use a recycled bitmap android.graphics.Bitmap@xxx
//        bitmap.recycle()
    }
    return bigBitmap
}

fun BaseQuickAdapter<*, BaseViewHolder>.shotRecyclerView(recyclerView: RecyclerView): Bitmap {
    return shotRecyclerView(recyclerView, null)
}

fun BaseQuickAdapter<*, BaseViewHolder>.shotRecyclerViewHeader(): Bitmap {
    return shotRecyclerViewHeader(null)
}

fun BaseQuickAdapter<*, BaseViewHolder>.shotRecyclerViewHeader(bgColor: Int? = null): Bitmap {
    val bigBitmap = Bitmap.createBitmap(
        headerLayout.measuredWidth, headerLayout.measuredHeight, Bitmap.Config.ARGB_8888)
    headerLayout?.run {
        val bigCanvas = Canvas(bigBitmap)
        // draw background if necessary
        val lBackground: Drawable? = background
        if (bgColor == null && lBackground == null) {
            bigCanvas.drawColor(Color.WHITE)
        } else if (lBackground != null && lBackground is ColorDrawable) {
            bigCanvas.drawColor(lBackground.color)
        } else {
            bgColor?.let { bigCanvas.drawColor(it) }
        }
        // drawBitmap
        draw(bigCanvas)
    }
    return bigBitmap
}