Android 开发——优化 Glide 加载超大 gif 图
// If we couldn't decode the GIF, we will end up with a frame count of 0.
return null
}
//进行采样设置
val sampleSize = getSampleSize(header, width, height)
//创建解析器构建模式
val builder = GifDrawableBuilder()
builder.from(byteBuffer)
builder.sampleSize(sampleSize)
builder.isRenderingTriggeredOnDraw = true
// pl.droidsonroids.gif.GifOptions gifOptions = new pl.droidsonroids.gif.GifOptions();
// DES: 不含透明层可以加速渲染 但是透明的 gif 会渲染黑色背景
// gifOptions.setInIsOpaque();
val gifDrawable = builder.build()
val loopCount = gifDrawable.loopCount
if (loopCount <= 1) {
//循环一次的则矫正为无限循环
Log.v(TAG, "Decoded GIF LOOP COUNT WARN $loopCount")
gifDrawable.loopCount = 0
}
GifLibDrawableResource(gifDrawable, byteBuffer)
} catch (e: IOException) {
Log.v(TAG, "Decoded GIF Error" + e.message)
null
} finally {
Log.v(TAG, "Decoded GIF from stream in " + LogTime.getElapsedMillis(startTime))
}
}
}
序列化类：
class GifLibEncoder : ResourceEncoder<GifDrawable?> {
override fun getEncodeStrategy(options: Options): EncodeStrategy {
return EncodeStrategy.SOURCE
}
override fun encode(data: Resource<GifDrawable?>, file: File, options: Options): Boolean {
var success = false
if (data is GifLibDrawableResource) {
val byteBuffer = data.buffer
try {
ByteBufferUtil.toFile(byteBuffer, file)
success = true
} catch (e: IOException) {
e.printStackTrace()
}
// DES: 将 resource 编码成文件
Log.d(TAG, "GifLibEncoder -> {file.absolutePath}")
}
return success
}
}
注册组件，注解注册类继承 AppGlideModule 并在 registerComponents 中调用如下 fun：
@JvmStatic
fun registerGifLib(glide: Glide, registry: Registry) {
//优先使用 gifLib-Gif
val bufferDecoder = GifLibByteBufferDecoder(registry.imageHeaderParsers)
val gifLibTranscoder = GifLibBytesTranscoder()
val bitmapBytesTranscoder = BitmapBytesTranscoder()
val gifTranscoder = GifDrawableBytesTranscoder()
registry.prepend(
Registry.BUCKET_GIF, java.io.InputStream::class.java, GifDrawable::class.java,
GifLibDecoder(registry.imageHeaderParsers, bufferDecoder, glide.arrayPool)
).prepend(
Registry.BUCKET_GIF,
java.nio.ByteBuffer::class.java,
GifDrawable::class.java, bufferDecoder
).prepend(
GifDrawable::class.java, GifLibEncoder()
).register(
Drawable::class.java, ByteArray::class.java,
DrawableBytesTranscoder(
glide.bitmapPool,
bitmapBytesTranscoder,
gifTranscoder,
gifLibTranscoder
)
).register(
GifDrawable::class.java, ByteArray::class.java, gifLibTranscoder
)
}
Registry api 说明
append(..)追加到最后，当内部的组件在handles()返回 false 或失败时候使用追加组件prepend(..)最佳到前面，当你的组件在失败时候使用原生提供组件replace(..)替换组件
验证组件是否注册成功
IGlideModule.with(view).load(url)
.placeholder(R.color.colorAccent)
.listener(object : RequestListener<Drawable> {
override fun onResourceReady(
resource: Drawable?, model: Any?,
target: Target<Drawable>?, dataSource: DataSource?, isFirstResource: Boolean
): Boolean {
if (resource is pl.droidsonroids.gif.GifDrawable) {
Log.d("TAG", "giflib 的 Gifdrawable")
} else if (resource is com.bumptech.glide.load.resource.gif.GifDrawable) {
Log.d("TAG", "glide 的 Gifdrawable")
}
return false
}
override fun onLoadFailed(
e: GlideException?, model: Any?,
target: Target<Drawable>?, isFirstResource: Boolean
): Boolean = false
})
.into(view)
log: com.example.mydemo
D/TAG: giflib 的 Gifdrawable
这样做看起来侵入性很低的替换了 Glide 的 gif 支持，并且还可以兼容 giflib 出错后使用原生组件，那么缺点呢？缺点也是非常头疼，通常我们会对一些图片加载需求做一些圆角或者圆形等等处理。glide 自己的 GifDrawable 支持的很好，几乎所有的 BitmapTransformation 都支持，而我们的缺失效了，究其原因是源码中所有 transform 设置最终调用到如下：
class BaseRequestOptions...
@NonNull
T transform(@NonNull Transformation<Bitmap> transformation, boolean isRequired) {
...省略
DrawableTransformation drawableTransformation =
new DrawableTransformation(transformation, isRequired);
transform(Bitmap.class, transformation, isRequired);
transform(Drawable.class, drawableTransformation, isRequired);
transform(BitmapDrawable.class, drawableTransformation.asBitmapDrawable(), isRequired);
//对 gifdrawble 的 Transformation 支持缘由
transform(GifDrawable.class, new GifDrawableTransformation(transformation), isRequired);
return selfOrThrowIfLocked();
}
}
由于源码已经固定了次转换注入口，除非我们自己修改源码编译或者 asm 手段。如何解决呢?先依旧照猫画虎GifLibDrawableTransformation然后实现
class GifLibDrawableTransformation(wrapped: Transformation<Bitmap>) : Transformation<GifDrawable> {
private val wrapped: Transformation<Bitmap> = Preconditions.checkNotNull(wrapped)
override fun transform(
context: Context, resource: Resource<GifDrawable?>, outWidth: Int, outHeight: Int
): Resource<GifDrawable?> {
val drawable = resource.get()
drawable.transform = object : Transform {
private val mDstRectF = RectF()
override fun onBoundsChange(rct: Rect) = mDstRectF.set(rct)
override fun onDraw(canvas: Canvas, paint: Paint, bitmap: Bitmap) {
val bitmapPool = Glide.get(context).bitmapPool
val bitmapResource: Resource<Bitmap> = BitmapResource(bitmap, bitmapPool)
val transformed = wrapped.transform(context, bitmapResource, outWidth, outHeight)
val transformedFrame = transformed.get()
canvas.drawBitmap(transformedFrame, null, mDstRectF, paint)
}
}
return resource
}
override fun equals(o: Any?): Boolean {
if (o is GifLibDrawableTransformation) {
return wrapped == o.wrapped
}
return false
}
override fun hashCode(): Int {
return wrapped.hashCode()
}
override fun updateDiskCacheKey(messageDigest: MessageDigest) {
wrapped.updateDiskCacheKey(messageDigest)
}
}
//每次调用 transform 时候注入下
val circleCrop = CircleCrop()
IGlideModule.with(this)
.load("http://tva2.sinaimg.cn/large/005CjUdnly1g6lwmq0fijg30rs0zu4qp.gif")
.transform(GifDrawable::class.java, GifLibDrawableTransformation(circleCrop))
.transform(circleCrop)
.into(iv_2)
缺陷攻克了？其实还没有完美解决，一来这样的书写方式不是很方便，二来目前对ScaleType.CENTER_CROP等支持还是有问题，如果你有更好的建议或者可以修复请提交 pr.
glide已经非常优秀了，如果是仅仅少量使用 gif 完全可以胜任了，而且随着 android 版和硬件的升级，这些性能问题越来越少，但是如果你发现项目中因为 gif 的使用导致 oom 的问题较多可以尝试次优化，另外也可以降低手机发热耗电问题。生命不息折腾不止啊。
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