Using Facebook's Fresco to load a bitmap

Question

I\'m trying to replace Picasso in my android app with Fresco. However I am unsure of how to simply load a bitmap using Fresco.

With Picasso I would just do the foll

Answer 1

Starting from this answer I created a quick implementation that uses Kotlin extensions and RxJava to get a ClosableBitmap from an ImageRequest:

fun ImageRequest.getBitmap(context: Context): Maybe> {
    val dataSource = Fresco.getImagePipeline().fetchDecodedImage(this, context)
    return Maybe.create { emitter ->
        dataSource.subscribe(
            object : BaseDataSubscriber>() {
                override fun onFailureImpl(dataSource: DataSource>) {
                    emitter.onComplete()
                }

                override fun onNewResultImpl(dataSource: DataSource>) {
                    if (!dataSource.isFinished) {
                        return
                    }

                    dataSource.result
                        ?.takeIf { it.get() is CloseableBitmap }
                        ?.let {
                            @Suppress("UNCHECKED_CAST")
                            emitter.onSuccess(it as CloseableReference)
                        }

                    emitter.onComplete()
                }
            },
            DefaultExecutorSupplier(1).forBackgroundTasks()
        )
    }
}

Since by contract it is required to close the reference once the bitmap has been used, I created this util function:

/**
 * The bitmap passed into [block] is only valid during the execution of the method.
 */
fun  CloseableReference.useBitmap(block: (Bitmap?) -> T): T? {
    return try {
        this.get()?.underlyingBitmap?.let { block(it) }
    } finally {
        CloseableReference.closeSafely(this)
    }
}