依賴庫(kù)
implementation 'com.github.bumptech.glide:glide:4.9.0'
基本用法
Glide.with(this)
.load(url)
.into(imageView);
過(guò)程
- 創(chuàng)建request
- 執(zhí)行加載
- 回調(diào)刷新UI
源碼分析
Glide#with
獲得RequestManager：請(qǐng)求管理類,創(chuàng)建RequestBuilder。控制整個(gè)界面的生命周期監(jiān)聽。
傳入不同的Context處理
- applicationContext
不做任何特殊處理，通過(guò)RequestManagerFactory來(lái)build出一個(gè)RequestManager。Application對(duì)象的生命周期即應(yīng)用程序的生命周期，因此Glide并不需要做什么特殊的處理，它自動(dòng)就是和應(yīng)用程序的生命周期是同步的，如果應(yīng)用程序關(guān)閉的話，Glide的加載也會(huì)同時(shí)終止。 - Activity
public RequestManager get(@NonNull Activity activity) {
if (Util.isOnBackgroundThread()) {
return get(activity.getApplicationContext());
} else {
assertNotDestroyed(activity);
android.app.FragmentManager fm = activity.getFragmentManager();
return fragmentGet(
activity, fm, /*parentHint=*/ null, isActivityVisible(activity));
}
}
RequestManagerRetriever#fragmentGet
@Deprecated
@NonNull
private RequestManager fragmentGet(@NonNull Context context,
@NonNull android.app.FragmentManager fm,
@Nullable android.app.Fragment parentHint,
boolean isParentVisible) {
RequestManagerFragment current = getRequestManagerFragment(fm, parentHint, isParentVisible);
RequestManager requestManager = current.getRequestManager();
if (requestManager == null) {
Glide glide = Glide.get(context);
requestManager =
factory.build(
glide, current.getGlideLifecycle(), current.getRequestManagerTreeNode(), context);
// RequestManagerFragment和RequestManager綁定起來(lái)
//監(jiān)聽Activity的生命周期來(lái)管理圖片加載
current.setRequestManager(requestManager);
}
return requestManager;
}
Activity中添加沒(méi)有UI的Fragment。需要這個(gè)Fragment來(lái)監(jiān)聽Activity的生命周期。Fragment的生命周期和Activity是同步的，如果Activity被銷毀了，F(xiàn)ragment是可以監(jiān)聽到的，這樣Glide就可以捕獲這個(gè)事件并停止圖片加載了。
3.非主線程使用Glide
如果我們是在非主線程當(dāng)中使用的Glide，那么不管你是傳入的Activity還是Fragment，都會(huì)被強(qiáng)制當(dāng)成Application來(lái)處理。
如何進(jìn)行生命周期綁定的
RequestManagerFragment中ActivityFragmentLifecycle管理生命周期，注冊(cè)了一些回調(diào)接口，當(dāng)Activity，F(xiàn)ragment調(diào)用回調(diào)方法，去處理圖片加載請(qǐng)求。當(dāng)圖片加載到一半，Activity切走，就會(huì)停止加載。
@Override
public void onStop() {
super.onStop();
lifecycle.onStop();
}
Glide#load
public RequestBuilder<Drawable> load(@Nullable String string) {
return asDrawable().load(string);
}
RequestManager#asDrawable
@NonNull
@CheckResult
public RequestBuilder<Drawable> asDrawable() {
return as(Drawable.class);
}
return new RequestBuilder<>(glide, this, resourceClass, context);
RequestBuilder#load
@NonNull
private RequestBuilder<TranscodeType> loadGeneric(@Nullable Object model) {
this.model = model;
isModelSet = true;
return this;
}
Glide#into
RequestBuilder#into
@NonNull
public ViewTarget<ImageView, TranscodeType> into(@NonNull ImageView view) {
// into要在主線程中調(diào)用
Util.assertMainThread();
// 對(duì)傳進(jìn)來(lái)的ImageView做是否為空的判斷
Preconditions.checkNotNull(view);
// 配置圖片加載設(shè)置
BaseRequestOptions<?> requestOptions = this;
if (!requestOptions.isTransformationSet()
&& requestOptions.isTransformationAllowed()
&& view.getScaleType() != null) {
// options保存四種scaleType規(guī)格
switch (view.getScaleType()) {
case CENTER_CROP:
requestOptions = requestOptions.clone().optionalCenterCrop();
break;
case CENTER_INSIDE:
requestOptions = requestOptions.clone().optionalCenterInside();
break;
case FIT_CENTER:
case FIT_START:
case FIT_END:
requestOptions = requestOptions.clone().optionalFitCenter();
break;
case FIT_XY:
requestOptions = requestOptions.clone().optionalCenterInside();
break;
case CENTER:
case MATRIX:
default:
}
}
// 這個(gè)transcodeClass是指的drawable或bitmap
// glideContext#buildImageViewTarget，這個(gè)方法會(huì)構(gòu)建出一個(gè)Target對(duì)象，Target對(duì)象則是用來(lái)最終展示圖片用的
return into(
glideContext.buildImageViewTarget(view, transcodeClass),
/*targetListener=*/ null,
requestOptions,
Executors.mainThreadExecutor());
}
GlideContext#buildImageViewTarget
實(shí)際里面調(diào)用了ImageViewTargetFactory#buildTarget
public class ImageViewTargetFactory {
@NonNull
@SuppressWarnings("unchecked")
// 返回展示Bimtap/Drawable資源的目標(biāo)對(duì)象
// 這個(gè)Class是之前l(fā)oad方法，調(diào)用as(Class class)傳入的
public <Z> ViewTarget<ImageView, Z> buildTarget(@NonNull ImageView view,
@NonNull Class<Z> clazz) {
if (Bitmap.class.equals(clazz)) {
return (ViewTarget<ImageView, Z>) new BitmapImageViewTarget(view);
} else if (Drawable.class.isAssignableFrom(clazz)) {
return (ViewTarget<ImageView, Z>) new DrawableImageViewTarget(view);
} else {
throw new IllegalArgumentException(
"Unhandled class: " + clazz + ", try .as*(Class).transcode(ResourceTranscoder)");
}
}
}
RequestBuilder#into
/**
* 將資源加載到傳入的target
*/
private <Y extends Target<TranscodeType>> Y into(
@NonNull Y target,
@Nullable RequestListener<TranscodeType> targetListener,
BaseRequestOptions<?> options,
Executor callbackExecutor) {
Preconditions.checkNotNull(target);
// 這個(gè)變量load時(shí)置
if (!isModelSet) {
throw new IllegalArgumentException("You must call #load() before calling #into()");
}
// 創(chuàng)建Request，request是用來(lái)發(fā)出加載圖片請(qǐng)求的
// 實(shí)例化對(duì)象是SingleRequest
Request request = buildRequest(target, targetListener, options, callbackExecutor);
// 獲取當(dāng)前target所綁定的request對(duì)象，舊的request
Request previous = target.getRequest();
// 當(dāng)前請(qǐng)求和上次請(qǐng)求一致的話就返回相應(yīng)的target對(duì)象
// isSkipMemoryCacheWithCompletePreviousRequest看options中是否設(shè)置不支持內(nèi)存緩存以及之前的請(qǐng)求是否以及完成。
if (request.isEquivalentTo(previous)
&& !isSkipMemoryCacheWithCompletePreviousRequest(options, previous)) {
request.recycle();
if (!Preconditions.checkNotNull(previous).isRunning()) {
previous.begin();
}
return target;
}
// 清除舊的Target
requestManager.clear(target);
// target綁定新的request對(duì)象
target.setRequest(request);
// 執(zhí)行request
requestManager.track(target, request);
return target;
}
1.創(chuàng)建加載圖片的Request
2.對(duì)舊的Target綁定進(jìn)行刪除
3.交給requestManager進(jìn)行相應(yīng)的request處理
RequestBuilder#buildRequest
最終執(zhí)行到buildThumbnailRequestRecursive方法。
buildRequest - buildRequestRecursive - buildThumbnailRequestRecursive
buildThumbnailRequestRecursive有多個(gè)分支前面都是和縮略圖有關(guān)，實(shí)際創(chuàng)建Request請(qǐng)求是最后一行調(diào)用obtainRequest方法。
private Request obtainRequest(
Target<TranscodeType> target,
RequestListener<TranscodeType> targetListener,
BaseRequestOptions<?> requestOptions,
RequestCoordinator requestCoordinator,
TransitionOptions<?, ? super TranscodeType> transitionOptions,
Priority priority,
int overrideWidth,
int overrideHeight,
Executor callbackExecutor) {
// 進(jìn)行初始化，返回Request對(duì)象
return SingleRequest.obtain(
context,
glideContext,
model,
transcodeClass,
requestOptions,
overrideWidth,
overrideHeight,
priority,
target,
targetListener,
requestListeners,
requestCoordinator,
glideContext.getEngine(),
transitionOptions.getTransitionFactory(),
callbackExecutor);
}
RequestManager#track
synchronized void track(@NonNull Target<?> target, @NonNull Request request) {
// 添加target進(jìn)目標(biāo)集合
targetTracker.track(target);
requestTracker.runRequest(request);
}
RequestTraker#runRequest
public void runRequest(@NonNull Request request) {
requests.add(request);
// 是否有正在進(jìn)行的request請(qǐng)求
if (!isPaused) {
request.begin();
} else {
// 加入待執(zhí)行隊(duì)列
request.clear();
pendingRequests.add(request);
}
}
SingleRequest#begin
@Override
public synchronized void begin() {
assertNotCallingCallbacks();
stateVerifier.throwIfRecycled();
startTime = LogTime.getLogTime();
// model就是我們?cè)趌oad()方法中傳入的資源
// 會(huì)先去獲取一個(gè)error的占位圖，如果獲取不到的話會(huì)再去獲取一個(gè)loading占位圖，然后調(diào)用target.onLoadFailed(error)方法并將占位圖傳入
if (model == null) {
if (Util.isValidDimensions(overrideWidth, overrideHeight)) {
width = overrideWidth;
height = overrideHeight;
}
int logLevel = getFallbackDrawable() == null ? Log.WARN : Log.DEBUG;
onLoadFailed(new GlideException("Received null model"), logLevel);
return;
}
...
status = Status.WAITING_FOR_SIZE;
// 是否使用了override() API為圖片指定了一個(gè)固定的寬高
if (Util.isValidDimensions(overrideWidth, overrideHeight)) {
onSizeReady(overrideWidth, overrideHeight);
} else {
target.getSize(this);
}
if ((status == Status.RUNNING || status == Status.WAITING_FOR_SIZE)
&& canNotifyStatusChanged()) {
target.onLoadStarted(getPlaceholderDrawable());
}
if (IS_VERBOSE_LOGGABLE) {
logV("finished run method in " + LogTime.getElapsedMillis(startTime));
}
}
SingleRequest#onSizeReady
public synchronized void onSizeReady(int width, int height) {
...
/**
* 當(dāng)前圖片需要裁剪的倍數(shù)，得出需要加載圖片的寬，高
*/
float sizeMultiplier = requestOptions.getSizeMultiplier();
this.width = maybeApplySizeMultiplier(width, sizeMultiplier);
this.height = maybeApplySizeMultiplier(height, sizeMultiplier);
// 根據(jù)給定的配置進(jìn)行加載，engine是一個(gè)負(fù)責(zé)加載、管理活躍和緩存資源的引擎類
loadStatus =
engine.load(...);
...
}
Engine#load
/**
* 該方法負(fù)責(zé)管理活動(dòng)和緩存資源
*/
public synchronized <R> LoadStatus load(...) {
// 生成緩存key
EngineKey key = keyFactory.buildKey(model, signature, width, height, transformations,
resourceClass, transcodeClass, options);
// 內(nèi)存采用了一個(gè)HashMap進(jìn)行內(nèi)存的緩存，使用了弱引用ResourceWeakReference持有了Resource
// 從Map<Key, ResourceWeakReference> activeEngineResources這個(gè)緩存中取EngineResource里面主要維護(hù)了acquire int，資源被使用加1，被釋放-1，資源沒(méi)有被使用時(shí)，則會(huì)調(diào)用onResourceReleased，將資源存儲(chǔ)到MemoryCache中。
EngineResource<?> active = loadFromActiveResources(key, isMemoryCacheable);
if (active != null) {
cb.onResourceReady(active, DataSource.MEMORY_CACHE);
if (VERBOSE_IS_LOGGABLE) {
logWithTimeAndKey("Loaded resource from active resources", startTime, key);
}
return null;
}
// 沒(méi)有再?gòu)拇疟P內(nèi)存中查找,有的話會(huì)取出并放到ActiveResources（內(nèi)部維護(hù)的弱引用緩存map）里面
EngineResource<?> cached = loadFromCache(key, isMemoryCacheable);
if (cached != null) {
cb.onResourceReady(cached, DataSource.MEMORY_CACHE);
if (VERBOSE_IS_LOGGABLE) {
logWithTimeAndKey("Loaded resource from cache", startTime, key);
}
return null;
}
// 當(dāng)前Request是否正在執(zhí)行
EngineJob<?> current = jobs.get(key, onlyRetrieveFromCache);
if (current != null) {
current.addCallback(cb, callbackExecutor);
if (VERBOSE_IS_LOGGABLE) {
logWithTimeAndKey("Added to existing load", startTime, key);
}
return new LoadStatus(cb, current);
}
// 創(chuàng)建engineJob，創(chuàng)建后臺(tái)任務(wù)執(zhí)行
EngineJob<R> engineJob =
engineJobFactory.build(
key,
isMemoryCacheable,
useUnlimitedSourceExecutorPool,
useAnimationPool,
onlyRetrieveFromCache);
// 創(chuàng)建解析工作對(duì)象
DecodeJob<R> decodeJob =
decodeJobFactory.build(
glideContext,
model,
key,
signature,
width,
height,
resourceClass,
transcodeClass,
priority,
diskCacheStrategy,
transformations,
isTransformationRequired,
isScaleOnlyOrNoTransform,
onlyRetrieveFromCache,
options,
engineJob);
// 放在Jobs內(nèi)部維護(hù)的HashMap中
jobs.put(key, engineJob);
engineJob.addCallback(cb, callbackExecutor);
// 內(nèi)部開啟線程去執(zhí)行decodeJob的run方法
engineJob.start(decodeJob);
if (VERBOSE_IS_LOGGABLE) {
logWithTimeAndKey("Started new load", startTime, key);
}
// 開始一個(gè)新加載
return new LoadStatus(cb, engineJob);
}
EngineJob#start
public synchronized void start(DecodeJob<R> decodeJob) {
this.decodeJob = decodeJob;
// //這里根據(jù)緩存策略，決定使用哪個(gè)Executor。默認(rèn)情況返回diskCacheExecutor。
//共三種執(zhí)行器：diskCacheExecutor、sourceExecutor、sourceUnlimitedExecutor
GlideExecutor executor = decodeJob.willDecodeFromCache()
? diskCacheExecutor
: getActiveSourceExecutor();
// 正式開啟子線程進(jìn)行資源加載，線程也從主線程切換到子線程
executor.execute(decodeJob);
}
DecodeJob#run
里面執(zhí)行到runWrapped方法
private void runWrapped() {
switch (runReason) {
// 第一次加載，DecodeJob調(diào)用init方法就會(huì)置成這個(gè)狀態(tài)
case INITIALIZE:
// 獲取下一階段狀態(tài)
stage = getNextStage(Stage.INITIALIZE);
// 獲取下一階段的Generator對(duì)象
currentGenerator = getNextGenerator();
// 內(nèi)部會(huì)調(diào)用相應(yīng)Generator的startNext()
// 真正的去加載網(wǎng)絡(luò)資源
runGenerators();
break;
case SWITCH_TO_SOURCE_SERVICE:
runGenerators();
break;
case DECODE_DATA:
// 將獲取的數(shù)據(jù)解碼成對(duì)應(yīng)的資源
decodeFromRetrievedData();
break;
default:
throw new IllegalStateException("Unrecognized run reason: " + runReason);
}
}
DecodeJob#getNextStage
INITIALIZE：初始化、RESOURCE_CACHE：讀取轉(zhuǎn)換后的緩存、DATA_CACHE：讀取原文件緩存、SOURCE：原文件加載、FINISHED：結(jié)束狀態(tài)。
private Stage getNextStage(Stage current) {
switch (current) {
case INITIALIZE:
return diskCacheStrategy.decodeCachedResource()
? Stage.RESOURCE_CACHE : getNextStage(Stage.RESOURCE_CACHE);
case RESOURCE_CACHE:
return diskCacheStrategy.decodeCachedData()
? Stage.DATA_CACHE : getNextStage(Stage.DATA_CACHE);
case DATA_CACHE:
return onlyRetrieveFromCache ? Stage.FINISHED : Stage.SOURCE;
case SOURCE:
case FINISHED:
return Stage.FINISHED;
default:
throw new IllegalArgumentException("Unrecognized stage: " + current);
}
}
DecodeJob#getNextGenerator
private DataFetcherGenerator getNextGenerator() {
switch (stage) {
case RESOURCE_CACHE:
//從轉(zhuǎn)換后的緩存中讀取文件
return new ResourceCacheGenerator(decodeHelper, this);
case DATA_CACHE:
//從原文件緩存中讀取文件
return new DataCacheGenerator(decodeHelper, this);
case SOURCE:
//沒(méi)有緩存，重新加載資源（比如：網(wǎng)絡(luò)圖片、本地文件）
return new SourceGenerator(decodeHelper, this);
case FINISHED:
return null;
default:
throw new IllegalStateException("Unrecognized stage: " + stage);
}
}
SourceGenerator#startNext
@Override
public boolean startNext() {
...
while (!started && hasNextModelLoader()) {
// getLoadData()方法內(nèi)部會(huì)在modelLoaders里面找到ModelLoder對(duì)象
// 并使用modelLoader.buildLoadData方法返回一個(gè)loadData列表
loadData = helper.getLoadData().get(loadDataListIndex++);
if (loadData != null
&& (helper.getDiskCacheStrategy().isDataCacheable(loadData.fetcher.getDataSource())
|| helper.hasLoadPath(loadData.fetcher.getDataClass()))) {
started = true;
// 通過(guò)loadData對(duì)象的fetcher對(duì)象的loadData方法來(lái)獲取圖片數(shù)據(jù)
// 最終是通過(guò)HttpUrlFetcher調(diào)用loadData方法獲取數(shù)據(jù)
// 內(nèi)部是通過(guò)HttpURLConnection網(wǎng)絡(luò)請(qǐng)求數(shù)據(jù)
loadData.fetcher.loadData(helper.getPriority(), this);
}
}
return started;
}
DecodeHelper#getLoadData
List<LoadData<?>> getLoadData() {
if (!isLoadDataSet) {
isLoadDataSet = true;
loadData.clear();
// Registry類是一個(gè)組件管理類，它的主要用途是擴(kuò)展和替換Glide組件，這些組件包括加載，編碼，解碼等邏輯。
// Registry并不是承當(dāng)所有模塊的注冊(cè)工作，而是把各個(gè)模塊分配的不同的Registry當(dāng)中。
// ModelLoader主要工作是將復(fù)雜數(shù)據(jù)模型轉(zhuǎn)通過(guò)DataFetcher轉(zhuǎn)換成需要的Data
List<ModelLoader<Object, ?>> modelLoaders = glideContext.getRegistry().getModelLoaders(model);
//noinspection ForLoopReplaceableByForEach to improve perf
for (int i = 0, size = modelLoaders.size(); i < size; i++) {
ModelLoader<Object, ?> modelLoader = modelLoaders.get(i);
// 注意：這里最終是通過(guò)HttpGlideUrlLoader的buildLoadData獲取到實(shí)際的loadData對(duì)象
LoadData<?> current =
modelLoader.buildLoadData(model, width, height, options);
if (current != null) {
loadData.add(current);
}
}
}
return loadData;
}
HttpGlideUrlLoader#buildLoadData
@Override
public LoadData<InputStream> buildLoadData(@NonNull GlideUrl model, int width, int height,
@NonNull Options options) {
// GlideUrls memoize parsed URLs so caching them saves a few object instantiations and time
// spent parsing urls.
GlideUrl url = model;
if (modelCache != null) {
url = modelCache.get(model, 0, 0);
if (url == null) {
// 使用LruCache來(lái)對(duì)解析后的url來(lái)進(jìn)行緩存，以便后續(xù)可以省去解析url的時(shí)間
modelCache.put(model, 0, 0, model);
url = model;
}
}
int timeout = options.get(TIMEOUT);
// HttpUrlFetcher實(shí)際上就是最終的請(qǐng)求執(zhí)行者
return new LoadData<>(url, new HttpUrlFetcher(url, timeout));
}
HttpUrlFetcher#load
@Override
public void loadData(@NonNull Priority priority,@NonNull DataCallback<? super InputStream> callback) {
long startTime = LogTime.getLogTime();
try {
// loadDataWithRedirects內(nèi)部是通過(guò)HttpURLConnection網(wǎng)絡(luò)請(qǐng)求數(shù)據(jù)
// 當(dāng)code是2xx，會(huì)調(diào)用getStreamForSuccessfulRequest()方法獲取到了最終的圖片流
InputStream result = loadDataWithRedirects(glideUrl.toURL(), 0, null, glideUrl.getHeaders());
callback.onDataReady(result);
} catch (IOException e) {
if (Log.isLoggable(TAG, Log.DEBUG)) {
Log.d(TAG, "Failed to load data for url", e);
}
callback.onLoadFailed(e);
} finally {
if (Log.isLoggable(TAG, Log.VERBOSE)) {
Log.v(TAG, "Finished http url fetcher fetch in " + LogTime.getElapsedMillis(startTime));
}
}
}
DecodeJob#runWrapped
得到數(shù)據(jù)流需要將其變成我們想要的資源。最終調(diào)用到decodeFromRetrievedData。
private void decodeFromRetrievedData() {
Resource<R> resource = null;
try {
// 從數(shù)據(jù)中解碼得到資源
resource = decodeFromData(currentFetcher, currentData, currentDataSource);
} catch (GlideException e) {
e.setLoggingDetails(currentAttemptingKey, currentDataSource);
throwables.add(e);
}
if (resource != null) {
// //通知外界資源獲取成功
notifyEncodeAndRelease(resource, currentDataSource);
} else {
runGenerators();
}
}
解碼得到資源
DecodeJob#decodeFromData方法 - DecodeJob#decodeFromFetcher方法 - DecodeJob#runLoadPath方法 - LoadPath#load方法 - LoadPath#loadWithExceptionList方法 - DecodePath#decode方法 - DecodePath#decodeResource方法 - DecodePath#decodeResourceWithList方法
public Resource<Transcode> decode(DataRewinder<DataType> rewinder, int width, int height,
@NonNull Options options, DecodeCallback<ResourceType> callback) throws GlideException {
//獲取到Resource<Bitmap>對(duì)象
Resource<ResourceType> decoded = decodeResource(rewinder, width, height, options);
//將資源轉(zhuǎn)化為目標(biāo)效果，如在構(gòu)建request時(shí)設(shè)置的CenterCrop
Resource<ResourceType> transformed = callback.onResourceDecoded(decoded);
//將數(shù)據(jù)轉(zhuǎn)化為目標(biāo)格式，將Resource<Bitmap>轉(zhuǎn)換為L(zhǎng)azyBitmapDrawableResource對(duì)象
//可通過(guò)LazyBitmapDrawableResource的get獲取到BitmapDrawable對(duì)象
//該transcoder為BitmapDrawableTranscoder
return transcoder.transcode(transformed, options);
}
將結(jié)果設(shè)置到對(duì)應(yīng)的ImageView
DecodeJob#notifyEncodeAndRelease
private void notifyEncodeAndRelease(Resource<R> resource, DataSource dataSource) {
...
notifyComplete(result, dataSource);
...
}
EngineJob#onResourceReady -> EngineJob#notifyCallbacksOfResult
void notifyCallbacksOfResult() {
ResourceCallbacksAndExecutors copy;
Key localKey;
EngineResource<?> localResource;
synchronized (this) {
...
copy = cbs.copy();
...
}
//通知上層Engine的任務(wù)完成了
listener.onEngineJobComplete(this, localKey, localResource);
for (final ResourceCallbackAndExecutor entry : copy) {
// //回調(diào)給ImageViewTarget來(lái)展示資源
entry.executor.execute(new CallResourceReady(entry.cb));
}
decrementPendingCallbacks();
}
EngineJob#CallResourceReady#run
@Override
public void run() {
synchronized (EngineJob.this) {
if (cbs.contains(cb)) {
// Acquire for this particular callback.
engineResource.acquire();
callCallbackOnResourceReady(cb);
removeCallback(cb);
}
decrementPendingCallbacks();
}
}
EngineJob#callCallbackOnResourceReady -> SingleRequest#onResourceReady
private synchronized void onResourceReady(Resource<R> resource, R result, DataSource dataSource) {
// 第一次加載
boolean isFirstResource = isFirstReadyResource();
status = Status.COMPLETE;
this.resource = resource;
isCallingCallbacks = true;
try {
boolean anyListenerHandledUpdatingTarget = false;
if (requestListeners != null) {
for (RequestListener<R> listener : requestListeners) {
anyListenerHandledUpdatingTarget |=
listener.onResourceReady(result, model, target, dataSource, isFirstResource);
}
}
anyListenerHandledUpdatingTarget |=
targetListener != null
&& targetListener.onResourceReady(result, model, target, dataSource, isFirstResource);
if (!anyListenerHandledUpdatingTarget) {
Transition<? super R> animation =
animationFactory.build(dataSource, isFirstResource);
//展示照片
//此時(shí)的target為DrawableImageViewTarget
target.onResourceReady(result, animation);
}
} finally {
isCallingCallbacks = false;
}
//通知加載成功
notifyLoadSuccess();
}
ImageViewTarget#onResourceReady
@Override
public void onResourceReady(@NonNull Z resource, @Nullable Transition<? super Z> transition) {
//是否有動(dòng)畫效果
if (transition == null || !transition.transition(resource, this)) {
// 靜態(tài)圖
// 內(nèi)部調(diào)用setResource來(lái)展示照片
setResourceInternal(resource);
} else {
// gif
maybeUpdateAnimatable(resource);
}
}
總結(jié)
with:
1.獲取RequestManager用來(lái)管理請(qǐng)求
2.Gradle綁定組件生命周期，通過(guò)不同生命周期來(lái)進(jìn)行相應(yīng)處理
load:
在RequestBuilder中設(shè)置要請(qǐng)求的url，并置狀態(tài)。返回RequestBuilder對(duì)象
into:
1.創(chuàng)建加載圖片請(qǐng)求Request，ViewTarget對(duì)象
2.生成唯一的緩存key，在內(nèi)存緩存，磁盤緩存中按順序查找，查找到哪一步有緩存就直接返回圖片，否則繼續(xù)檢查下一步。如果都沒(méi)有緩存，則 Glide會(huì)從原始資源（File、Uri、遠(yuǎn)程圖片 url 等）中解碼，變換，緩存，加載圖片。
參考
Glide4.0源碼全解析
Android圖片加載框架最全解析（二），從源碼的角度理解Glide的執(zhí)行流程
Glide 4.0源碼解析
Android主流三方庫(kù)源碼分析（三、深入理解Glide源碼）
