Question

我有以下自定义转换（kotlin）：

private class IconTransformation : BitmapTransformation() {
    companion object {
        private const val ID = "com.example.widget.IconView\$IconTransformation"
        private val ID_BYTES = ID.toByteArray()

        private const val PAINT_FLAGS = Paint.DITHER_FLAG or Paint.FILTER_BITMAP_FLAG
        private const val CIRCLE_CROP_PAINT_FLAGS = PAINT_FLAGS or Paint.ANTI_ALIAS_FLAG
        private val CIRCLE_CROP_SHAPE_PAINT = Paint(CIRCLE_CROP_PAINT_FLAGS)
        private val CIRCLE_CROP_BITMAP_PAINT = Paint(CIRCLE_CROP_PAINT_FLAGS).apply {
            xfermode = PorterDuffXfermode(PorterDuff.Mode.SRC_IN)
        }
        private val CLEAR_PAINT = Paint().apply {
            xfermode = PorterDuffXfermode(PorterDuff.Mode.CLEAR)
        }
    }

    override fun updateDiskCacheKey(messageDigest: MessageDigest) {
        messageDigest.update(ID_BYTES)
    }

    override fun transform(pool: BitmapPool, toTransform: Bitmap, outWidth: Int,
            outHeight: Int): Bitmap {
        val img = TransformationUtils.fitCenter(pool, toTransform, outWidth, outHeight)
        val result = pool.get(outWidth, outHeight, Bitmap.Config.ARGB_8888)
        val left = (result.width - img.width) / 2f
        val top = (result.height - img.height) / 2f
        result.setHasAlpha(true)
        Canvas(result).apply {
            drawColor(Color.TRANSPARENT)
            drawCircle(outWidth / 2f, outHeight / 2f,
                    Math.min(outWidth, outHeight) / 2f, CIRCLE_CROP_SHAPE_PAINT)
            drawBitmap(img, left, top, CIRCLE_CROP_BITMAP_PAINT)
            if (left > 0f) {
                drawRect(0f, 0f, left, outHeight.toFloat(), CLEAR_PAINT)
                drawRect(left + img.width - 1, 0f,
                        outWidth.toFloat(), outHeight.toFloat(), CLEAR_PAINT)
            }
            if (top > 0f) {
                drawRect(0f, 0f, outWidth.toFloat(), top, CLEAR_PAINT)
                drawRect(0f, top + img.height - 1,
                        outWidth.toFloat(), outHeight.toFloat(), CLEAR_PAINT)
            }
        }
        pool.put(img)
        return result
    }

    override fun hashCode(): Int = ID.hashCode()

    override fun equals(other: Any?): Boolean = other is IconTransformation
}

当我在回收者视图中使用它时，图像会闪烁并反弹。从我阅读的所有内容来看，它与不正当地实施updateDiskCacheKey，hashCode和equals有关。从AFAIK我完全按照BitmapTransformation中的说明进行操作。

    Glide.with(icon)
            .load(url)
            .apply(RequestOptions()
                    .transform(IconTransformation())
                    .error(errorDrawableRes))
            .into(icon)

Answer 1

问题出在pool.put(img)行中，以下问题解决了这个问题：

if (img != toTransform) {
    pool.put(img)
}

Answer 2

我的评论here可能会有帮助。

我使用占位符解决闪烁问题。 dontTransform确实在我的应用中不起作用。在搜索Glide的源代码之后，我发现问题可能来自ImageViewTarget：
/**
   * Sets the given {@link android.graphics.drawable.Drawable} on the view using {@link
   * android.widget.ImageView#setImageDrawable(android.graphics.drawable.Drawable)}.
   *
   * @param placeholder {@inheritDoc}
   */
  @Override
  public void onLoadStarted(@Nullable Drawable placeholder) {
    super.onLoadStarted(placeholder);
    setResourceInternal(null);
    setDrawable(placeholder);
  }
因此，如果占位符为null，ImageView将在之后立即变为空白每次加载。所以我将最后一张图片缓存在ImageView中并进行设置作为下一次加载的占位符。这是代码
// init
mGlideOpt = new RequestOptions().dontAnimate().skipMemoryCache(false);
mGlideRB = Glide.with(imageView).asBitmap();

// loading
Drawable drawable = mImageView.getDrawable();
if (drawable != null) {
    mGlideOpt = mGlideOpt.placeholder(drawable);
}
mGlideRB.apply(mGlideOpt).load(mCacheFile).into(mImageView);
只需解决。希望对您有所帮助。

Glide 4.6.1自定义转换时的图像闪烁

2 个答案: