Android 优雅封装Glide

核心思想

使用策略模式实现不同图片加载框架的切换，使用建造者设计模式处理不同参数，最后通过 ImageLoader 进行管理。

定义策略接口

interface ILoaderStrategy {fun loadImage(configs: ImageOptions)fun clearDiskCache(context: Context)fun clearMemoryCache(context: Context)fun clearAll(context: Context) {clearDiskCache(context)clearMemoryCache(context)}fun clear(imageView: ImageView)
}

定义图片选项

class ImageOptions private constructor() {var targetObj: Any? = null // 生命周期对象var targetView: ImageView? = null // 目标ImageViewvar resource: Any? = null // 加载资源var width = -1 // 指定宽度var height = -1 // 指定高度var isDiskCache = true // 磁盘缓存var isMemoryCache = true // 内存缓存@DrawableResvar placeholder: Int = -1 // 占位图资源@DrawableResvar error: Int = -1 // 失败图资源var listener: Listener? = nullcompanion object {fun create(): ImageOptions {return ImageOptions()}}fun with(targetObj: Any): ImageOptions {this.targetObj = targetObjreturn this}fun loadResource(resource: Any): ImageOptions {this.resource = resourcereturn this}fun size(size: Int): ImageOptions {return size(width, height)}fun size(width: Int, height: Int): ImageOptions {this.width = widththis.height = heightreturn this}fun placeholder(@DrawableRes placeholder: Int): ImageOptions {this.placeholder = placeholderreturn this}fun error(@DrawableRes error: Int): ImageOptions {this.error = errorreturn this}fun setDiskCache(isCache: Boolean): ImageOptions {isDiskCache = isCachereturn this}fun setMemoryCache(isCache: Boolean): ImageOptions {isMemoryCache = isCachereturn this}fun setListener(listener: Listener): ImageOptions {this.listener = listenerreturn this}fun into(imageView: ImageView) {this.targetView = imageViewImageLoader.loadOptions(this)}interface Listener {fun onSuccess(model: Any?)fun onFail(model: Any?)}
}

实现Glide策略

class GlideLoader : ILoaderStrategy {private lateinit var requestManager: RequestManageroverride fun loadImage(options: ImageOptions) {requestManager = getRequestManager(options.targetObj)var requestBuilder: RequestBuilder<Drawable>? = nulloptions.resource?.let {requestBuilder = generateRequestBuilder(it)}requestBuilder?.let {if (options.placeholder != -1) {it.placeholder(options.placeholder)}if (options.error != -1) {it.error(options.error)}if (options.width != -1 || options.height != -1) {it.override(options.width, options.height)}it.skipMemoryCache(options.isMemoryCache)it.diskCacheStrategy(if (options.isDiskCache) DiskCacheStrategy.AUTOMATIC else DiskCacheStrategy.NONE)options.listener?.let { listener ->it.addListener(object : RequestListener<Drawable> {override fun onLoadFailed(e: GlideException?,model: Any?,target: Target<Drawable>?,isFirstResource: Boolean): Boolean {listener.onFail(model)return false}override fun onResourceReady(resource: Drawable?,model: Any?,target: Target<Drawable>?,dataSource: DataSource?,isFirstResource: Boolean): Boolean {listener.onSuccess(model)return false}})}if (options.targetView == null) {throw IllegalArgumentException("targetView cannot be null");}it.into(options.targetView!!)}}private fun getRequestManager(targetObj: Any?): RequestManager {return if (targetObj is FragmentActivity) {Glide.with(targetObj)} else if (targetObj is Context) {Glide.with(targetObj)} else if (targetObj is View) {Glide.with(targetObj)} else if (targetObj is Fragment) {Glide.with(targetObj)} else {throw IllegalArgumentException("You cannot start a load on a null Context");}}private fun generateRequestBuilder(res: Any): RequestBuilder<Drawable>? {return if (res is String) {requestManager.load(res)} else if (res is File) {requestManager.load(res)} else {return null}}override fun clearDiskCache(context: Context) {thread {Glide.get(context).clearDiskCache()}}override fun clearMemoryCache(context: Context) {Glide.get(context).clearMemory()}override fun clear(imageView: ImageView) {Glide.with(imageView.context).clear(imageView)}
}

图片管理类

object ImageLoader {private var imageLoader: ILoaderStrategy? = nullfun setImageLoader(imageLoader: ILoaderStrategy) {this.imageLoader = imageLoader}fun with(targetObj: Any): ImageOptions {val options = ImageOptions.create()options.with(targetObj)return options}fun loadOptions(options: ImageOptions) {imageLoader!!.loadImage(options)}fun clearDiskCache(context: Context){imageLoader!!.clearDiskCache(context)}fun clearMemoryCache(context: Context){imageLoader!!.clearMemoryCache(context)}fun clearAll(context:Context){imageLoader!!.clearAll(context)}fun clear(imageView: ImageView){imageLoader!!.clear(imageView)}}

使用

override fun onCreate(savedInstanceState: Bundle?) {super.onCreate(savedInstanceState)setContentView(R.layout.activity_image_loader)imageView0 = findViewById(R.id.imageView0)imageView1 = findViewById(R.id.imageView1)imageView2 = findViewById(R.id.imageView2)ImageLoader.setImageLoader(GlideLoader())val url = "https://i-blog.csdnimg.cn/blog_migrate/de6e3262387d57977e53af596a87f582.png"ImageLoader.with(this).loadResource(url).size(100).placeholder(R.mipmap.ic_launcher).error(R.mipmap.ic_launcher).into(imageView1)ImageLoader.with(this).loadResource(File(cacheDir, "aaa.png")).placeholder(R.mipmap.ic_launcher).error(R.mipmap.ic_launcher).into(imageView2)
} 

ImageLoader.clear(imageView1)
ImageLoader.clearAll(this)
ImageLoader.clearMemoryCache(this)
ImageLoader.clearDiskCache(this)