自定義Glide的Transformation實(shí)現(xiàn)部分圓角的文章和代碼在網(wǎng)上有很多阅羹，原本我也是隨便在網(wǎng)上找一份Glide 加載部分圓角圖片在項(xiàng)目中直接使用，但在使用過(guò)程居然遇到Bug，所以去查看了官方文檔卓箫，發(fā)現(xiàn)自定義的Transformation忘掉了最關(guān)鍵的部分,即重寫(xiě)equals()/hashCode()兩個(gè)函數(shù)淑倾，雖然在一般場(chǎng)景下可以正常使用鸥鹉，但在RecyclerView這種會(huì)加載大量圖片的場(chǎng)景下撑帖，自定義的transform且未重寫(xiě)equals()/hashCode()會(huì)導(dǎo)致Bug筐眷。

(emmm，具體是什么Bug我忘了垒手，大概是滑動(dòng)卡頓蒜焊？因?yàn)槭呛芫弥坝龅降膯?wèn)題，現(xiàn)在補(bǔ)的文章)

先來(lái)看看官方文檔：

官方文檔

最后附上修改后的RoundedCornersTransform优妙，目前可以正常使用：

//Koltin版本
class RoundedCornersTransform(
    context: Context?,
    var radius: Float,
    var leftTop: Boolean = true,
    var rightTop: Boolean = true,
    var leftBottom: Boolean = true,
    var rightBottom: Boolean = true
) :
    Transformation<Bitmap?> {
    private val mBitmapPool: BitmapPool = Glide.get(context!!).bitmapPool

    private val id = javaClass.name
    private val idBytes = id.toByteArray(Charsets.UTF_8);

    override fun transform(
        context: Context,
        resource: Resource<Bitmap?>,
        outWidth: Int,
        outHeight: Int
    ): Resource<Bitmap?> {
        val source: Bitmap = resource.get()
        var finalWidth: Int
        var finalHeight: Int
        //輸出目標(biāo)的寬高或高寬比例
        var scale: Float
        if (outWidth > outHeight) {
            //如果 輸出寬度 > 輸出高度 求高寬比
            scale = outHeight.toFloat() / outWidth.toFloat()
            finalWidth = source.width
            //固定原圖寬度,求最終高度
            finalHeight = (source.width.toFloat() * scale).toInt()
            if (finalHeight > source.height) {
                //如果 求出的最終高度 > 原圖高度 求寬高比
                scale = outWidth.toFloat() / outHeight.toFloat()
                finalHeight = source.height
                //固定原圖高度,求最終寬度
                finalWidth = (source.height.toFloat() * scale).toInt()
            }
        } else if (outWidth < outHeight) {
            //如果 輸出寬度 < 輸出高度 求寬高比
            scale = outWidth.toFloat() / outHeight.toFloat()
            finalHeight = source.height
            //固定原圖高度,求最終寬度
            finalWidth = (source.height.toFloat() * scale).toInt()
            if (finalWidth > source.width) {
                //如果 求出的最終寬度 > 原圖寬度 求高寬比
                scale = outHeight.toFloat() / outWidth.toFloat()
                finalWidth = source.width
                finalHeight = (source.width.toFloat() * scale).toInt()
            }
        } else {
            //如果 輸出寬度=輸出高度
            finalHeight = source.height
            finalWidth = finalHeight
        }

        //修正圓角
        radius *= finalHeight.toFloat() / outHeight.toFloat()
        val outBitmap: Bitmap = mBitmapPool[finalWidth, finalHeight, Bitmap.Config.ARGB_8888]
        val canvas = Canvas(outBitmap)
        val paint = Paint()
        //關(guān)聯(lián)畫(huà)筆繪制的原圖bitmap
        val shader = BitmapShader(source, Shader.TileMode.CLAMP, Shader.TileMode.CLAMP)
        //計(jì)算中心位置,進(jìn)行偏移
        val width: Int = (source.width - finalWidth) / 2
        val height: Int = (source.height - finalHeight) / 2
        if (width != 0 || height != 0) {
            val matrix = Matrix()
            matrix.setTranslate((-width).toFloat(), (-height).toFloat())
            shader.setLocalMatrix(matrix)
        }
        paint.shader = shader
        paint.isAntiAlias = true
        val rectF = RectF(0.0f, 0.0f, canvas.width.toFloat(), canvas.height.toFloat())
        //先繪制圓角矩形
        canvas.drawRoundRect(rectF, radius, radius, paint)

        //左上角圓角
        if (!leftTop) {
            canvas.drawRect(0f, 0f, radius, radius, paint)
        }
        //右上角圓角
        if (!rightTop) {
            canvas.drawRect(canvas.width - radius, 0f, canvas.width.toFloat(), radius, paint)
        }
        //左下角圓角
        if (!leftBottom) {
            canvas.drawRect(0f, canvas.height - radius, radius, canvas.height.toFloat(), paint)
        }
        //右下角圓角
        if (!rightBottom) {
            canvas.drawRect(
                canvas.width - radius,
                canvas.height - radius,
                canvas.width.toFloat(),
                canvas.height.toFloat(),
                paint
            )
        }
        return BitmapResource.obtain(outBitmap, mBitmapPool)!!
    }

    /** must override */
    override fun equals(other: Any?): Boolean {
        return other is RoundedCornersTransform
    }

    /** must override */
    override fun hashCode(): Int {
        return id.hashCode()
    }

    /** must override */
    override fun updateDiskCacheKey(messageDigest: MessageDigest) {
        messageDigest.update(idBytes)
    }
}

RoundedCornersTransform使用：

//默認(rèn)裁剪四個(gè)圓角，不需要設(shè)置圓角憎账，對(duì)應(yīng)參數(shù)設(shè)為false
Glide.with(context)
            .load(item.coverUrl)
            .apply(
                RequestOptions().transform(
                    CenterCrop(), RoundedCornersTransform(
                        context, 8f,
                        leftBottom = false,
                        rightBottom = false
                    )
                )
            )
            .into(holder.getView(R.id.img_icon))