cloud storage post published and glide updated

Author: maciej-nowak

_drafts/2019-06-17-glide.md

@@ -7,7 +7,7 @@ image: libraries/glide
 github: libraries/tree/master/glide
 description: "Biblioteki"
 version: Glide 4.9
-keywords: "glide, image, imageview, bitmap, network, resources, memory, cache, disk, loader, imageloader, gif, transition, transformation, android, programowanie, programming"
+keywords: "glide, image, imageview, bitmap, network, resources, memory, cache, disk, loader, imageloader, gif, transition, transformation, glideapp, glidemodule, glideextension, glideoption, glidetype, recyclerview, android, programowanie, programming"
 ---
 
 ## Wstęp
@@ -208,4 +208,81 @@ private fun loadImageByCustomModule() {
         .smallCircle() //new custom option
         .into(imageView)
 }
+{% endhighlight %}
+
+## RecyclerView
+Glide ułatwia współpracę z `RecyclerView` (obrazy są ładowane wcześniej zgodnie z kierunkiem przesuwania) poprzez użycie `RecyclerViewPreloader` jako obiektu słuchacza dla akcji przesuwania `addOnScrollListener`. W połączeniu z odpowiednim rozmiarem obrazu i optymalną strategią pamięci pozwala na zmniejszenie liczby ładowanych obrazów dostarczając je wcześniej.
+
+{% highlight kotlin %}
+//usage of RecyclerViewPreloader in RecyclerView
+class RecyclerViewActivity : AppCompatActivity() {
+
+    private lateinit var recyclerView: RecyclerView
+    private lateinit var preloader: RecyclerViewPreloader<Any>
+    private val urls = listOf("url1", "url2", "url3") //mock some url
+
+    override fun onCreate(savedInstanceState: Bundle?) {
+        super.onCreate(savedInstanceState)
+        setContentView(R.layout.activity_recyclerView)
+
+        initPreloader()
+        initRecyclerView()
+    }
+
+    private fun initPreloader() {
+        val size = 100
+        val maxPreload = 10
+        val sizeProvider: ListPreloader.PreloadSizeProvider<Any> = FixedPreloadSizeProvider(size, size)
+        val modelProvider = CustomPreloadModelProvider(urls, this) //own implementation of PreloadModelProvider
+        preloader = RecyclerViewPreloader(this, modelProvider, sizeProvider, maxPreload)
+    }
+
+    private fun initRecyclerView() {
+        recyclerView = findViewById(R.id.recyclerView)
+        recyclerView.apply {
+            layoutManager = LinearLayoutManager(this@MainActivity)
+            adapter = CustomAdapter(urls, this@MainActivity)
+            addOnScrollListener(preloader) //set RecyclerViewPreloader as scroll listener
+        }
+    }
+}
+
+//implement PreloadModelProvider
+class CustomPreloadModelProvider(val urls: List<String>, val context: Context) : ListPreloader.PreloadModelProvider<Any> {
+
+    override fun getPreloadItems(position: Int): MutableList<Any> {
+        val url = urls[position]
+        if (TextUtils.isEmpty(url)) {
+            return Collections.emptyList()
+        }
+        return Collections.singletonList(url)
+    }
+
+    override fun getPreloadRequestBuilder(item: Any): RequestBuilder<*>? {
+        return GlideApp.with(context).load(item)
+    }
+}
+
+//just simple adapter
+class CustomAdapter(val urls: List<String>, val context: Context) : RecyclerView.Adapter<CustomAdapter.CustomViewHolder>() {
+
+    class CustomViewHolder(view: View) : RecyclerView.ViewHolder(view) {
+        val imageView: ImageView
+        init {
+            imageView = view.findViewById(R.id.imageView)
+        }
+    }
+
+    override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): CustomViewHolder {
+        val view = LayoutInflater.from(parent.context).inflate(R.layout.item_layout, parent, false)
+        return CustomViewHolder(view)
+    }
+
+    override fun onBindViewHolder(holder: CustomViewHolder, position: Int) {
+        //set some data on item
+        GlideApp.with(context).load(urls[position]).into(holder.imageView) //standard Glide loading
+    }
+
+    override fun getItemCount(): Int = urls.size
+}
 {% endhighlight %}