Android Fresco调优实践｜得物技术

图片的加载体验对于交易、社区为核心的社交电商类应用来说可以说是生命线，好的图片加载体验决定了用户分享欲、购买欲。

二

图片拉伸优化

本地图拉伸

private void updatePaint() {    if (mLastBitmap == null || mLastBitmap.get() != mBitmap) {        mLastBitmap = new WeakReference<>(mBitmap);        mPaint.setShader(new BitmapShader(mBitmap, Shader.TileMode.CLAMP, Shader.TileMode.CLAMP));        mIsShaderTransformDirty = true;    }    if (mIsShaderTransformDirty) {        mPaint.getShader().setLocalMatrix(mTransform);        mIsShaderTransformDirty = false;    }    mPaint.setFilterBitmap(getPaintFilterBitmap());}

//设置path的核心代码if (mIsCircle) {  mPath.addCircle(      mRootBounds.centerX(),      mRootBounds.centerY(),      Math.min(mRootBounds.width(), mRootBounds.height()) / 2,      Path.Direction.CW);} else if (mScaleDownInsideBorders) {  if (mInsideBorderRadii == null) {    mInsideBorderRadii = new float[8];  }  for (int i = 0; i < mBorderRadii.length; i++) {    mInsideBorderRadii[i] = mCornerRadii[i] - mBorderWidth;  }  mPath.addRoundRect(mRootBounds, mInsideBorderRadii, Path.Direction.CW);} else {  mPath.addRoundRect(mRootBounds, mCornerRadii, Path.Direction.CW);}


//设置RootBounds的核心代码if (mTransformCallback != null) {  mTransformCallback.getTransform(mParentTransform);  mTransformCallback.getRootBounds(mRootBounds);} else {  mParentTransform.reset();  mRootBounds.set(getBounds());}

.9图拉伸

@JvmStatic fun loadNinePatchBackground(image: ImageView, url: String) {    //获取.9图的cdn下载文件    loadImageAsFile(url, {        //通过BitmapFactory进行解码 获取bitmap        val bitmap = BitmapFactory.decodeFile(it.path) ?: return@loadImageAsFile        val chunk = bitmap.ninePatchChunk        image.resources?.apply {           //将bitmap数据封装到NinePatchDrawable中            val defaultDrawable = if (NinePatch.isNinePatchChunk(chunk)) {                NinePatchDrawable(this, bitmap, chunk, Rect(), null)            } else {                BitmapDrawable(this, bitmap)            }            //设置核心图片背景            image.background = defaultDrawable        }    })}

问题.9图仍旧为xxhdpi的标准图片BitmapDensity为480。

网络图取决于手机实际分辨率情况，问题设备上为640。

网络图FIT_CENTER拉伸

网络图CENTER_CROP拉伸

//重写测量宽高的实现@Overridepublic int getIntrinsicHeight() {    Bitmap bitmap = this.mBitmap;    if (bitmap != null) {        return bitmap.getHeight();    }    return super.getIntrinsicHeight();}

@Overridepublic int getIntrinsicWidth() {    Bitmap bitmap = this.mBitmap;    if (bitmap != null) {        return bitmap.getWidth();    }    return super.getIntrinsicWidth();}

三

本地相册加载优化

缩略图获取

旋转参数兼容

//cursor 获取具体的pathNamefinal String pathname = cursor.getString(cursor.getColumnIndex(MediaStore.Images.ImageColumns.DATA));if (pathname != null) {    try {       //通过ExifInterface获取图片的旋转角度        ExifInterface exif = new ExifInterface(pathname);        orientation = exif.getAttributeInt(ExifInterface.TAG_ORIENTATION, ExifInterface.ORIENTATION_NORMAL);        rotationAngle = JfifUtil.getAutoRotateAngleFromOrientation(orientation);    } catch (IOException ioe) {        FLog.e(PRODUCER_NAME, ioe, "Unable to retrieve thumbnail rotation for %s", pathname);    }}..... //此处省略部分代码实现
//构造CloseableStaticBitmap时，传入旋转的角度与方向CloseableStaticBitmap closeableStaticBitmap =new CloseableStaticBitmap(        loadThumbnail,        SimpleBitmapReleaser.getInstance(),        ImmutableQualityInfo.FULL_QUALITY,        rotationAngle, orientation)

异常读取兜底

try {    loadThumbnail = mContentResolver.loadThumbnail(imageRequest.getSourceUri(), new Size(imageRequest.getPreferredWidth(), imageRequest.getPreferredHeight()), cancellationSignal);} catch (IOException exception) {    if (exception.getMessage() != null && exception.getMessage().contains("Failed to create thumbnail")) {        if (imageRequest.getMimeType() != null && HEIF_MIME_TYPE.contains(imageRequest.getMimeType())) {            String path = getRealPathFromUri(mContentResolver, imageRequest.getSourceUri());            if (path != null) {                File file = new File(path);                FileInputStream fileInputStream = new FileInputStream(file);                //读取头文件 做实际的判断                String type = ImageFormatChecker.getInstance().determineImageFormat(fileInputStream).getFileExtension();                //暂时只判断heif, avif格式的误判 暂时没做头文件 format检测                if (type != null && !type.equals(HEIF_FORMAT_EXTENSION)) {                    loadThumbnail = createImageThumbnail(file, new Size(imageRequest.getPreferredWidth(), imageRequest.getPreferredHeight()), cancellationSignal);
                    if (loadThumbnail != null) {                        //补充异常兜底事件抛到业务层                        producerContext.getProducerListener().onProducerEvent(producerContext, PRODUCER_NAME, THUMBNAIL_FALL_BACK_EVENT);                    }                }            }        } else {            //此处抛出异常 会被onProducerFailed 处理 上层能监控到            throw exception;        }    }}

视频缩略图兼容 & 大图压缩

if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.Q) {    loadThumbnail = mContentResolver.loadThumbnail(imageRequest.getSourceUri(), new Size(imageRequest.getPreferredWidth(), imageRequest.getPreferredHeight()), null);} else {    long videoId = -1;    try {        videoId = ContentUris.parseId(imageRequest.getSourceUri());    } catch (Exception e) {        FLog.w(PRODUCER_NAME, imageRequest.getSourceUri().toString() + " find exception " + e.getLocalizedMessage());    }    if (videoId > 0) {        loadThumbnail = MediaStore.Video.Thumbnails.getThumbnail(                mContentResolver,                videoId,                calculateKind(imageRequest),                null        );    }}

if (imageRequest.isResizingThumbnail() && imageRequest.getResizeOptions() != null) {    if (bitmap.getHeight() <= 0 || bitmap.getWidth() <= 0) return;    ResizeOptions resizeOptions = imageRequest.getResizeOptions();    int resizeWidth = resizeOptions.width;    int resizeHeight = resizeOptions.height;    if (resizeWidth <= 0 || resizeHeight <= 0 ) return;    //计算缩略图的宽高比    float radio = (float) bitmap.getWidth() / bitmap.getHeight();
    float tempWidth = resizeWidth;    float tempHeight = resizeHeight;    // 如果 resize的宽高比 大于 实际原图的话,那就需要对图片做调整    if (tempWidth / tempHeight > radio) {        resizeHeight = (int) (tempWidth / radio);    } else {        resizeWidth = (int) (tempHeight * radio);    }    bitmap = Bitmap.createScaledBitmap(bitmap, resizeWidth, resizeHeight, true);}

四

动图缓存、闪烁优化

private void prepareFrame(final int frameNumber) {    // 先从缓存中取    BitmapFrameCache mBitmapFrameCache = mAnimationBackend.mBitmapFrameCache;    CloseableReference<Bitmap> bitmapReference = mBitmapFrameCache.getCachedFrame(frameNumber);    if (bitmapReference == null || !bitmapReference.isValid()) {        // 缓存中没有，new Bitmap并保存        try {            bitmapReference = mAnimationBackend.mPlatformBitmapFactory.createBitmap(mAnimationBackend.getIntrinsicWidth(), mAnimationBackend.getIntrinsicHeight(), Bitmap.Config.ARGB_8888);        } catch (OutOfMemoryError e) {           //埋点上报逻辑        }        // 新建出来的对象也不可用  丢弃当前帧        if (bitmapReference == null || !bitmapReference.isValid()) {            return;        }        Bitmap bitmap = bitmapReference.get();        if (bitmap.isRecycled()) {            return;        }        mAnimationBackend.mAnimatedImageCompositor.renderFrame(frameNumber, bitmap);        // 动图不再写入内存缓存        mBitmapFrameCache.onFrameRendered(frameNumber, bitmapReference, BitmapAnimationBackend.FRAME_TYPE_CACHED);    }    mAnimationBackend.mCurrentFrame.put(frameNumber, bitmapReference);}

动图cacheKey重写

@Overridepublic boolean equals(Object obj) {  if (this == obj) {    return true;  }  if (obj == null || getClass() != obj.getClass()) {    return false;  }  AnimationFrameCacheKey that = (AnimationFrameCacheKey) obj;  //equals 仅对比mAnimationUriString   return mAnimationUriString.equals(that.mAnimationUriString);}
@Overridepublic int hashCode() {  //hashCode 仅对比mAnimationUriString的hashCode 即 anim:// + 图片URI hashcode  return mAnimationUriString.hashCode();}

private BitmapFrameCache createBitmapFrameCache(AnimatedImageResult animatedImageResult) {    int cacheKeyHash;    if (DuImageGlobalConfig.isEnableAnimatedCompareOnlyUri() && animatedImageResult.getSourceUri() != null && !animatedImageResult.getSourceUri().isEmpty()) {        //动图cacheKeyHash 仅采用SourceUri        cacheKeyHash = animatedImageResult.getSourceUri().hashCode();    } else {        //原有逻辑        cacheKeyHash = animatedImageResult.hashCode();    }    return new FrescoFrameCache(new AnimatedFrameCache(new AnimationFrameCacheKey(cacheKeyHash, DuImageGlobalConfig.isEnableNewAnimatedCache()), mBackingCache), DuImageGlobalConfig.isEnableNewAnimatedCache());}

支持重用帧配置

 // 先从内存缓存中取 BitmapFrameCache mBitmapFrameCache = mAnimationBackend.mBitmapFrameCache; CloseableReference<Bitmap> bitmapReference = mBitmapFrameCache.getCachedFrame(frameNumber);if (DuImageGlobalConfig.isEnableNewAnimatedCache() && (bitmapReference == null || !bitmapReference.isValid())) {    //从无引用的缓存中在尝试取一次    bitmapReference = mBitmapFrameCache.getBitmapToReuseForFrame(frameNumber, mAnimationBackend.getIntrinsicWidth(), mAnimationBackend.getIntrinsicHeight());    //获取到后重新写入内存缓存    mBitmapFrameCache.onFramePrepared(frameNumber, bitmapReference, BitmapAnimationBackend.FRAME_TYPE_CACHED);}

绑定view加载Tag

//当前view的tag 与 加载url不相等if(view.tag != image.url){  view.loadwith(image.url).apply  view.tag=image.url}

五

未来展望

六

总结