Android Glide预加载RecyclerViewPreloader,ViewPreloadSizeProvider，kotlin

快来打我* 2023-10-13 13:21 58阅读 0赞

implementation 'com.github.bumptech.glide:glide:4.15.1'
        implementation ("com.github.bumptech.glide:recyclerview-integration:4.14.2") {
            // Excludes the support library because it's already included by Glide.
            transitive = false
        }

<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />
        <uses-permission android:name="android.permission.READ_MEDIA_IMAGES" />

import android.content.Context
    import android.os.Bundle
    import android.provider.MediaStore
    import android.util.Log
    import android.view.LayoutInflater
    import android.view.View
    import android.view.ViewGroup
    import android.widget.ImageView
    import androidx.appcompat.app.AppCompatActivity
    import androidx.recyclerview.widget.GridLayoutManager
    import androidx.recyclerview.widget.RecyclerView
    import com.bumptech.glide.Glide
    import com.bumptech.glide.ListPreloader
    import com.bumptech.glide.RequestBuilder
    import com.bumptech.glide.integration.recyclerview.RecyclerViewPreloader
    import com.bumptech.glide.util.ViewPreloadSizeProvider
    import kotlinx.coroutines.CoroutineScope
    import kotlinx.coroutines.Dispatchers
    import kotlinx.coroutines.launch
    import kotlinx.coroutines.withContext
    import java.io.File
    
    
    class MainActivity : AppCompatActivity() {
        companion object {
            const val TAG = "fly"
        }
    
        override fun onCreate(savedInstanceState: Bundle?) {
            super.onCreate(savedInstanceState)
            setContentView(R.layout.activity_main)
    
            var recyclerView: RecyclerView = findViewById(R.id.recycler_view)
            recyclerView?.layoutManager = GridLayoutManager(this, 3).apply {
                orientation = GridLayoutManager.VERTICAL
            }
    
            val adapter = MyAdapter()
            recyclerView?.adapter = adapter
    
            CoroutineScope(Dispatchers.IO).launch {
                val items = readAllImage(applicationContext)
                withContext(Dispatchers.Main) {
                    adapter.onChange(items)
                }
            }
    
            var preloadSizeProvider = ViewPreloadSizeProvider<MyData>()
            val preloadModelProvider = MyPreloadModelProvider(adapter, this)
            val preloader = RecyclerViewPreloader(
                this,
                preloadModelProvider,
                preloadSizeProvider,
                100 //maxPreload预加载数量
            )
    
            recyclerView?.addOnScrollListener(preloader)
        }
    
        class MyPreloadModelProvider(
            private val adapter: MyAdapter,
            private val context: Context
        ) : ListPreloader.PreloadModelProvider<MyData> {
            // 从当前屏幕结束的位置开始，再加载maxPreload条item，
            // 不可见的item即为屏幕外的position位置
            // 如果对于一个给定的位置不需要加载任何东西，getPreloadItems 可以返回一个空表。
            override fun getPreloadItems(position: Int): MutableList<MyData> {
                val data: MyData = adapter.getItems()[position]
                Log.d(TAG, "getPreloadItems pos:$position index:${data.index}")
                return mutableListOf(data)
            }
    
            override fun getPreloadRequestBuilder(item: MyData): RequestBuilder<*>? {
                Log.d(TAG, "getPreloadRequestBuilder ${item.index}")
                return Glide.with(context).load(File(item.path))
            }
        }
    
        class MyAdapter : RecyclerView.Adapter<MyViewHolder>() {
            private var items: ArrayList<MyData>? = null
    
            fun onChange(items: ArrayList<MyData>?) {
                this.items = items
                notifyDataSetChanged()
            }
    
            fun getItems(): ArrayList<MyData> {
                return items!!
            }
    
            override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): MyViewHolder {
                val view = LayoutInflater.from(parent.context)
                    .inflate(R.layout.item, parent, false)
                return MyViewHolder(view)
            }
    
            override fun onBindViewHolder(holder: MyViewHolder, position: Int) {
                Glide.with(holder.itemView.context).load(File(items?.get(position)?.path))
                    .into(holder.image)
            }
    
            override fun getItemCount(): Int {
                return items?.size ?: 0
            }
        }
    
        class MyViewHolder(itemView: View) : RecyclerView.ViewHolder(itemView) {
            val image: ImageView = itemView.findViewById(R.id.image)
        }
    
        private fun readAllImage(context: Context): ArrayList<MyData> {
            val photos = ArrayList<MyData>()
    
            //读取手机图片
            val cursor = context.contentResolver.query(
                MediaStore.Images.Media.EXTERNAL_CONTENT_URI,
                null,
                null,
                null,
                null
            )
            var index = 0
            while (cursor!!.moveToNext()) {
                //图片路径
                val path = cursor.getString(cursor.getColumnIndexOrThrow(MediaStore.Images.Media.DATA))
    
                //图片名称
                //val name = cursor.getString(cursor.getColumnIndexOrThrow(MediaStore.Images.Media.DISPLAY_NAME))
    
                //图片大小
                //val size = cursor.getLong(cursor.getColumnIndexOrThrow(MediaStore.Images.Media.SIZE))
    
                photos.add(MyData(path, index++))
            }
            cursor.close()
    
            return photos
        }
    
        class MyData(var path: String, val index: Int)
    }

<?xml version="1.0" encoding="utf-8"?>
    <androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
        xmlns:app="http://schemas.android.com/apk/res-auto"
        xmlns:tools="http://schemas.android.com/tools"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        tools:context=".MainActivity">
    
        <androidx.recyclerview.widget.RecyclerView
            android:id="@+id/recycler_view"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            tools:context=".MainActivity" />
    
    </androidx.constraintlayout.widget.ConstraintLayout>

<?xml version="1.0" encoding="utf-8"?>
    <ImageView xmlns:android="http://schemas.android.com/apk/res/android"
        android:id="@+id/image"
        android:layout_width="100dp"
        android:layout_height="100dp" />

[Android Glide自定义AppGlideModule，让Glide在app启动后基于定制化GlideModule加载，kotlin\_zhangphil的博客-CSDN博客在实际的开发中，虽然Glide解决了快速加载图片的问题，但还有一个问题悬而未决：比如用户的头像，往往用户的头像是从服务器端读出的一个普通矩形图片，但是现在的设计一般要求在APP端的用户头像显示成圆形头像，那么此时虽然Glide可以加载，但加载出来的是一个矩形，如果要Glide\_android 毛玻璃圆角。《Android图片加载与缓存开源框架：Android Glide》Android Glide是一个开源的图片加载和缓存处理的第三方框架。![favicon32.ico][]https://blog.csdn.net/zhangphil/article/details/131592226][Android Glide_AppGlideModule_Glide_app_GlideModule_kotlin_zhangphil_-CSDN_Glide_APP_Glide_Glide_android _Android_Android Glide_Android Glide_favicon32.ico_https_blog.csdn.net_zhangphil_article_details_131592226][Android load all photos into RecyclerView,pinch to zoom by ScaleGestureDetector,kotlin(4)\_zhangphil的博客-CSDN博客Android RecyclerView的StaggeredGridLayoutManager实现交错排列的子元素分组先看实现的结果如图：设计背景：现在的产品对设计的需求越来越多样化，如附录文章2是典型的联系人分组RecyclerView，子元素排列到一个相同的组，但是有些时候，UI要求把这些元素不是垂直方向的，而是像本文开头的图中所示样式排列，这就需要用StaggeredGridLayoutMa。在处理大图的浏览查看动作过程中，往往还有其他额外的事情需要处理，典型的以微信。![favicon32.ico][]https://blog.csdn.net/zhangphil/article/details/131296499][Android load all photos into RecyclerView_pinch to zoom by ScaleGestureDetector_kotlin_4_zhangphil_-CSDN_Android RecyclerView_StaggeredGridLayoutManager_2_RecyclerView_UI_StaggeredGridLayoutMa_favicon32.ico_https_blog.csdn.net_zhangphil_article_details_131296499]

[Android RecyclerView AsyncListUtil手动刷新fillData，kotlin\_zhangphil的博客-CSDN博客基于Android官方Paging Library的RecyclerView分页加载框架我之前写了一篇RecyclerView分页加载机制的文章，是基于Android官方的AsyncListUtil实现的，详情见附录文章1。基于Android官方Paging Library的RecyclerView分页加载框架我之前写了一篇RecyclerView分页加载机制的文章，是基于Android官方的AsyncListUtil实现的，详情见附录文章1。【代码】Android Paging 3,kotlin（1）![favicon32.ico][]https://blog.csdn.net/zhangphil/article/details/131519811][Android RecyclerView AsyncListUtil_fillData_kotlin_zhangphil_-CSDN_Android_Paging Library_RecyclerView_RecyclerView_Android_AsyncListUtil_1_Android_Paging Library_RecyclerView_RecyclerView_Android_AsyncListUtil_1_Android Paging 3_kotlin_1_favicon32.ico_https_blog.csdn.net_zhangphil_article_details_131519811]

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