Android开源库——Glide
Glide是什么？
Android的图像加载和缓存库，专注于平滑滚动
Glide的用法?
依赖
implementation 'com.github.bumptech.glide:glide:5.0.0-rc01'
使用过程
public class MainActivity extends AppCompatActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
ImageView iv = findViewById(R.id.iv);
Glide.with(this)
.load("https://img2.baidu.com/it/u=618715884,3279759230&fm=253&fmt=auto&app=138&f=JPEG?w=800&h=1200")
.into(iv);
}
}
Glide源码解析
GeneratedAppGlideModule
用于自定义创建RequestManagerRetriever.RequestManagerFactory
abstract class GeneratedAppGlideModule extends AppGlideModule {
@NonNull
Set<Class<?>> getExcludedModuleClasses() {
return new HashSet<>();
}
@Nullable
RequestManagerRetriever.RequestManagerFactory getRequestManagerFactory() {
return null;
}
}
Glide
Glide是单例的，get()通过双重检验锁获取实例
- getAnnotationGeneratedGlideModules()通过反射创建"com.bumptech.glide.GeneratedAppGlideModuleImpl"
- 调用checkAndInitializeGlide()创建Glide
public class Glide implements ComponentCallbacks2 {
private static volatile Glide glide;
Glide(......) {}
public static Glide get(@NonNull Context context) {
if (glide == null) {
GeneratedAppGlideModule annotationGeneratedModule =
getAnnotationGeneratedGlideModules(context.getApplicationContext());
synchronized (Glide.class) {
if (glide == null) {
checkAndInitializeGlide(context, annotationGeneratedModule);
}
}
}
return glide;
}
private static GeneratedAppGlideModule getAnnotationGeneratedGlideModules(Context context) {
GeneratedAppGlideModule result = null;
try {
Class<GeneratedAppGlideModule> clazz =
(Class<GeneratedAppGlideModule>)
Class.forName("com.bumptech.glide.GeneratedAppGlideModuleImpl");
result =
clazz.getDeclaredConstructor(Context.class).newInstance(context.getApplicationContext());
}.....
return result;
}
}
checkAndInitializeGlide()调用initializeGlide()通过GlideBuilder创建Glide，若上面无GeneratedAppGlideModuleImpl则requestManagerFactory为空
public class Glide implements ComponentCallbacks2 {
static void checkAndInitializeGlide(
@NonNull Context context, @Nullable GeneratedAppGlideModule generatedAppGlideModule) {
......
try {
initializeGlide(context, generatedAppGlideModule);
} finally {
isInitializing = false;
}
}
private static void initializeGlide(
@NonNull Context context, @Nullable GeneratedAppGlideModule generatedAppGlideModule) {
initializeGlide(context, new GlideBuilder(), generatedAppGlideModule);
}
private static void initializeGlide(
@NonNull Context context,
@NonNull GlideBuilder builder,
@Nullable GeneratedAppGlideModule annotationGeneratedModule) {
.....
RequestManagerRetriever.RequestManagerFactory factory =
annotationGeneratedModule != null
? annotationGeneratedModule.getRequestManagerFactory()
: null;
builder.setRequestManagerFactory(factory);
Glide glide = builder.build(applicationContext, manifestModules, annotationGeneratedModule);
applicationContext.registerComponentCallbacks(glide);
Glide.glide = glide;
}
}
GlideBuilder的build()创建RequestManagerRetriever（上面说了传参为null）等对象构造Gilde和GlideContext
public class Glide implements ComponentCallbacks2 {
@NonNull
Glide build(
@NonNull Context context,
List<GlideModule> manifestModules,
AppGlideModule annotationGeneratedGlideModule) {
......
RequestManagerRetriever requestManagerRetriever =
new RequestManagerRetriever(requestManagerFactory);
return new Glide(
context,
engine,
memoryCache,
bitmapPool,
arrayPool,
requestManagerRetriever,
connectivityMonitorFactory,
logLevel,
defaultRequestOptionsFactory,
defaultTransitionOptions,
defaultRequestListeners,
manifestModules,
annotationGeneratedGlideModule,
experiments);
}
Glide(......) {
......
GlideSupplier<Registry> registry =
RegistryFactory.lazilyCreateAndInitializeRegistry(
this, manifestModules, annotationGeneratedModule);
ImageViewTargetFactory imageViewTargetFactory = new ImageViewTargetFactory();
glideContext =
new GlideContext(
context,
arrayPool,
registry,
imageViewTargetFactory,
defaultRequestOptionsFactory,
defaultTransitionOptions,
defaultRequestListeners,
engine,
experiments,
logLevel);
}
}
RequestManagerRetriever
DEFAULT_FACTORY为匿名内部类RequestManagerFactory，其build()创建RequestManager，并传给LifecycleRequestManagerRetriever
public class RequestManagerRetriever implements Handler.Callback {
public RequestManagerRetriever(@Nullable RequestManagerFactory factory) {
this.factory = factory != null ? factory : DEFAULT_FACTORY;
lifecycleRequestManagerRetriever = new LifecycleRequestManagerRetriever(this.factory);
frameWaiter = buildFrameWaiter();
}
public interface RequestManagerFactory {
@NonNull
RequestManager build(
@NonNull Glide glide,
@NonNull Lifecycle lifecycle,
@NonNull RequestManagerTreeNode requestManagerTreeNode,
@NonNull Context context);
}
private static final RequestManagerFactory DEFAULT_FACTORY =
new RequestManagerFactory() {
@NonNull
@Override
public RequestManager build(
@NonNull Glide glide,
@NonNull Lifecycle lifecycle,
@NonNull RequestManagerTreeNode requestManagerTreeNode,
@NonNull Context context) {
return new RequestManager(glide, lifecycle, requestManagerTreeNode, context);
}
};
}
LifecycleLifecycle
将Acitivty的生命周期事件传给自己的LifecycleListener
final class LifecycleLifecycle implements Lifecycle, LifecycleObserver {
@NonNull
private final Set<LifecycleListener> lifecycleListeners = new HashSet<LifecycleListener>();
@NonNull private final androidx.lifecycle.Lifecycle lifecycle;
LifecycleLifecycle(androidx.lifecycle.Lifecycle lifecycle) {
this.lifecycle = lifecycle;
lifecycle.addObserver(this);
}
@OnLifecycleEvent(Event.ON_START)
public void onStart(@NonNull LifecycleOwner owner) {
for (LifecycleListener lifecycleListener : Util.getSnapshot(lifecycleListeners)) {
lifecycleListener.onStart();
}
}
@OnLifecycleEvent(Event.ON_STOP)
public void onStop(@NonNull LifecycleOwner owner) {
for (LifecycleListener lifecycleListener : Util.getSnapshot(lifecycleListeners)) {
lifecycleListener.onStop();
}
}
@OnLifecycleEvent(Event.ON_DESTROY)
public void onDestroy(@NonNull LifecycleOwner owner) {
for (LifecycleListener lifecycleListener : Util.getSnapshot(lifecycleListeners)) {
lifecycleListener.onDestroy();
}
owner.getLifecycle().removeObserver(this);
}
@Override
public void addListener(@NonNull LifecycleListener listener) {
lifecycleListeners.add(listener);
if (lifecycle.getCurrentState() == State.DESTROYED) {
listener.onDestroy();
} else if (lifecycle.getCurrentState().isAtLeast(State.STARTED)) {
listener.onStart();
} else {
listener.onStop();
}
}
@Override
public void removeListener(@NonNull LifecycleListener listener) {
lifecycleListeners.remove(listener);
}
}
RequestManager
实现了LifecycleListener可以监听到Acitivity的生命周期，创建RequestTracker
public class RequestManager
implements ComponentCallbacks2, LifecycleListener, ModelTypes<RequestBuilder<Drawable>> {
public RequestManager(
@NonNull Glide glide,
@NonNull Lifecycle lifecycle,
@NonNull RequestManagerTreeNode treeNode,
@NonNull Context context) {
this(
glide,
lifecycle,
treeNode,
new RequestTracker(),
glide.getConnectivityMonitorFactory(),
context);
}
@SuppressWarnings("PMD.ConstructorCallsOverridableMethod")
RequestManager(
Glide glide,
Lifecycle lifecycle,
RequestManagerTreeNode treeNode,
RequestTracker requestTracker,
ConnectivityMonitorFactory factory,
Context context) {
this.glide = glide;
this.lifecycle = lifecycle;
this.treeNode = treeNode;
this.requestTracker = requestTracker;
this.context = context;
connectivityMonitor =
factory.build(
context.getApplicationContext(),
new RequestManagerConnectivityListener(requestTracker));
glide.registerRequestManager(this);
if (Util.isOnBackgroundThread()) {
Util.postOnUiThread(addSelfToLifecycle);
} else {
lifecycle.addListener(this);
}
lifecycle.addListener(connectivityMonitor);
defaultRequestListeners =
new CopyOnWriteArrayList<>(glide.getGlideContext().getDefaultRequestListeners());
setRequestOptions(glide.getGlideContext().getDefaultRequestOptions());
}
}
即
- Glide包含RequestManagerRetriever
- RequestManagerRetriever中的RequestManagerFactory的build()创建RequestManager
- RequestManager包含RequestTracker
with()过程
Glide的with()通过getRetriever()获取Glide中的RequestManagerRetriever，调用get()获取RequestManager
public static RequestManager with(@NonNull FragmentActivity activity) {
return getRetriever(activity).get(activity);
}
private static RequestManagerRetriever getRetriever(@Nullable Context context) {
return Glide.get(context).getRequestManagerRetriever();
}
RequestManagerRetriever的get()通过lifecycleRequestManagerRetriever的getOrCreate()返回RequestManager
public class RequestManagerRetriever implements Handler.Callback {
@NonNull
public RequestManager get(@NonNull FragmentActivity activity) {
if (Util.isOnBackgroundThread()) {
return get(activity.getApplicationContext());
}
.......
frameWaiter.registerSelf(activity);
boolean isActivityVisible = isActivityVisible(activity);
Glide glide = Glide.get(activity.getApplicationContext());
return lifecycleRequestManagerRetriever.getOrCreate(
activity,
glide,
activity.getLifecycle(),
activity.getSupportFragmentManager(),
isActivityVisible);
}
}
LifecycleRequestManagerRetriever
- 通过HashMap管理Activity的Lifecycle和RequestManager的映射，Activity在onDestroy()时移除RequestManager
- getOrCreate()调用getOnly()判断是否在map中，不在则通过DEFAULT_FACTORY的build()创建RequestManager
- 若Activity当前已经可见则调用RequestManager的onStart()
final class LifecycleRequestManagerRetriever {
@Synthetic final Map<Lifecycle, RequestManager> lifecycleToRequestManager = new HashMap<>();
@NonNull private final RequestManagerFactory factory;
LifecycleRequestManagerRetriever(@NonNull RequestManagerFactory factory) {
this.factory = factory;
}
RequestManager getOnly(Lifecycle lifecycle) {
Util.assertMainThread();
return lifecycleToRequestManager.get(lifecycle);
}
RequestManager getOrCreate(
Context context,
Glide glide,
final Lifecycle lifecycle,
FragmentManager childFragmentManager,
boolean isParentVisible) {
Util.assertMainThread();
RequestManager result = getOnly(lifecycle);
if (result == null) {
LifecycleLifecycle glideLifecycle = new LifecycleLifecycle(lifecycle);
result =
factory.build(
glide,
glideLifecycle,
new SupportRequestManagerTreeNode(childFragmentManager),
context);
lifecycleToRequestManager.put(lifecycle, result);
glideLifecycle.addListener(
new LifecycleListener() {
@Override
public void onStart() {}
@Override
public void onStop() {}
@Override
public void onDestroy() {
lifecycleToRequestManager.remove(lifecycle);
}
});
if (isParentVisible) {
result.onStart();
}
}
return result;
}
}
load()过程
RequestManager的load()调用asDrawable()获取RequestBuilder，调用其load()方法
public class RequestManager
implements ComponentCallbacks2, LifecycleListener, ModelTypes<RequestBuilder<Drawable>> {
public RequestBuilder<Drawable> load(@Nullable String string) {
return asDrawable().load(string);
}
public RequestBuilder<Drawable> asDrawable() {
return as(Drawable.class);
}
public <ResourceType> RequestBuilder<ResourceType> as(
@NonNull Class<ResourceType> resourceClass) {
return new RequestBuilder<>(glide, this, resourceClass, context);
}
}
RequestBuilder的load()将url设置到model返回自身
public class RequestBuilder<TranscodeType> extends BaseRequestOptions<RequestBuilder<TranscodeType>>
implements Cloneable, ModelTypes<RequestBuilder<TranscodeType>> {
protected RequestBuilder(
@NonNull Glide glide,
RequestManager requestManager,
Class<TranscodeType> transcodeClass,
Context context) {
this.glide = glide;
this.requestManager = requestManager;
this.transcodeClass = transcodeClass;
this.context = context;
this.transitionOptions = requestManager.getDefaultTransitionOptions(transcodeClass);
this.glideContext = glide.getGlideContext();
initRequestListeners(requestManager.getDefaultRequestListeners());
apply(requestManager.getDefaultRequestOptions());
}
public RequestBuilder<TranscodeType> load(@Nullable String string) {
return loadGeneric(string);
}
private RequestBuilder<TranscodeType> loadGeneric(@Nullable Object model) {
if (isAutoCloneEnabled()) {
return clone().loadGeneric(model);
}
this.model = model;
isModelSet = true;
return selfOrThrowIfLocked();
}
}
into()过程
RequestBuilder的into()
- 通过glideContext的buildImageViewTarget()返回DrawableImageViewTarget（transcodeClass即是上面创建RequestBuilder时传递的Drawable.class）
- Executors.mainThreadExecutor()返回Executor，其execute()将runnable交给主线程的handler
public class RequestBuilder<TranscodeType> extends BaseRequestOptions<RequestBuilder<TranscodeType>>
implements Cloneable, ModelTypes<RequestBuilder<TranscodeType>> {
public ViewTarget<ImageView, TranscodeType> into(@NonNull ImageView view) {
BaseRequestOptions<?> requestOptions = this;
......
return into(
glideContext.buildImageViewTarget(view, transcodeClass),
/* targetListener= */ null,
requestOptions,
Executors.mainThreadExecutor());
}
}
public class GlideContext extends ContextWrapper {
@NonNull
public <X> ViewTarget<ImageView, X> buildImageViewTarget(
@NonNull ImageView imageView, @NonNull Class<X> transcodeClass) {
return imageViewTargetFactory.buildTarget(imageView, transcodeClass);
}
}
public class ImageViewTargetFactory {
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);
}......
}
}
public final class Executors {
private static final Executor MAIN_THREAD_EXECUTOR =
new Executor() {
@Override
public void execute(@NonNull Runnable command) {
Util.postOnUiThread(command);
}
};
public static Executor mainThreadExecutor() {
return MAIN_THREAD_EXECUTOR;
}
}
public final class Util {
public static void postOnUiThread(Runnable runnable) {
getUiThreadHandler().post(runnable);
}
private static Handler getUiThreadHandler() {
if (mainThreadHandler == null) {
synchronized (Util.class) {
if (mainThreadHandler == null) {
mainThreadHandler = new Handler(Looper.getMainLooper());
}
}
}
return mainThreadHandler;
}
}
RequestBuilder的into()
- 调用buildRequest()创建Request的实现类SingleRequest
- 调用RequestManager的clear()
- 调用DrawableImageViewTarget的父类ViewTarget的setRequest()将requset设置到View的tag中
- 调用RequestManager的track()
public class RequestBuilder<TranscodeType> extends BaseRequestOptions<RequestBuilder<TranscodeType>>
implements Cloneable, ModelTypes<RequestBuilder<TranscodeType>> {
private <Y extends Target<TranscodeType>> Y into(
@NonNull Y target,
@Nullable RequestListener<TranscodeType> targetListener,
BaseRequestOptions<?> options,
Executor callbackExecutor) {
......
Request request = buildRequest(target, targetListener, options, callbackExecutor);
......
requestManager.clear(target);
target.setRequest(request);
requestManager.track(target, request);
return target;
}
private Request buildRequest(......) {
return buildRequestRecursive(
/* requestLock= */ new Object(),
target,
targetListener,
/* parentCoordinator= */ null,
transitionOptions,
requestOptions.getPriority(),
requestOptions.getOverrideWidth(),
requestOptions.getOverrideHeight(),
requestOptions,
callbackExecutor);
}
private Request buildRequestRecursive(......) {
......
Request mainRequest =
buildThumbnailRequestRecursive(
requestLock,
target,
targetListener,
parentCoordinator,
transitionOptions,
priority,
overrideWidth,
overrideHeight,
requestOptions,
callbackExecutor);
if (errorRequestCoordinator == null) {
return mainRequest;
}
......
}
private Request buildThumbnailRequestRecursive(......) {
.....
if (thumbnailBuilder != null) {
.....
} else if (thumbSizeMultiplier != null) {
.....
} else {
return obtainRequest(
requestLock,
target,
targetListener,
requestOptions,
parentCoordinator,
transitionOptions,
priority,
overrideWidth,
overrideHeight,
callbackExecutor);
}
}
private Request obtainRequest(......) {
return SingleRequest.obtain(
context,
glideContext,
requestLock,
model,
transcodeClass,
requestOptions,
overrideWidth,
overrideHeight,
priority,
target,
targetListener,
requestListeners,
requestCoordinator,
glideContext.getEngine(),
transitionOptions.getTransitionFactory(),
callbackExecutor);
}
}
public abstract class ViewTarget<T extends View, Z> extends BaseTarget<Z> {
public void setRequest(@Nullable Request request) {
setTag(request);
}
private void setTag(@Nullable Object tag) {
isTagUsedAtLeastOnce = true;
view.setTag(tagId, tag);
}
}
RequestManager的track()调用requestTracker的runRequest()
public class RequestManager
implements ComponentCallbacks2, LifecycleListener, ModelTypes<RequestBuilder<Drawable>> {
synchronized void track(@NonNull Target<?> target, @NonNull Request request) {
......
requestTracker.runRequest(request);
}
}
RequestTracker的runRequest()调用request的begin()
public class RequestTracker {
public void runRequest(@NonNull Request request) {
requests.add(request);
if (!isPaused) {
request.begin();
} else {
request.clear();
......
}
}
}
调用其实现类SingleRequest的begin()，判断当时state
- 若overrideWidth和overrideHeight存在则调用onSizeReady()，否则调用ViewTarget的getSize()，最终还是调用onSizeReady()
- 若state == RUNNING则调用ImageViewTarget的onLoadStarted()先设置placeholder
public final class SingleRequest<R> implements Request, SizeReadyCallback, ResourceCallback {
@Override
public void begin() {
synchronized (requestLock) {
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());
}
}
}
public abstract class ViewTarget<T extends View, Z> extends BaseTarget<Z> {
public void getSize(@NonNull SizeReadyCallback cb) {
sizeDeterminer.getSize(cb);
}
static final class SizeDeterminer {
void getSize(@NonNull SizeReadyCallback cb) {
int currentWidth = getTargetWidth();
int currentHeight = getTargetHeight();
if (isViewStateAndSizeValid(currentWidth, currentHeight)) {
cb.onSizeReady(currentWidth, currentHeight);
return;
}
......
}
}
}
public abstract class ImageViewTarget<Z> extends ViewTarget<ImageView, Z>
implements Transition.ViewAdapter {
public void onLoadStarted(@Nullable Drawable placeholder) {
super.onLoadStarted(placeholder);
setResourceInternal(null);
setDrawable(placeholder);
}
}
SingleRequest的onSizeReady()将状态设置为RUNNING，调用Engine的load()，注意这里将this传给Engine的cb域
public final class SingleRequest<R> implements Request, SizeReadyCallback, ResourceCallback {
@Override
public void onSizeReady(int width, int height) {
stateVerifier.throwIfRecycled();
synchronized (requestLock) {
......
status = Status.RUNNING;
......
loadStatus =
engine.load(
glideContext,
model,
requestOptions.getSignature(),
this.width,
this.height,
requestOptions.getResourceClass(),
transcodeClass,
priority,
requestOptions.getDiskCacheStrategy(),
requestOptions.getTransformations(),
requestOptions.isTransformationRequired(),
requestOptions.isScaleOnlyOrNoTransform(),
requestOptions.getOptions(),
requestOptions.isMemoryCacheable(),
requestOptions.getUseUnlimitedSourceGeneratorsPool(),
requestOptions.getUseAnimationPool(),
requestOptions.getOnlyRetrieveFromCache(),
this,
callbackExecutor);
.....
}
}
}
Engine的load()先从内存中获取，若存在直接调用SingleRequest的onResourceReady()否则调用waitForExistingOrStartNewJob()
public class Engine
implements EngineJobListener,
MemoryCache.ResourceRemovedListener,
EngineResource.ResourceListener {
public <R> LoadStatus load(......) {
long startTime = VERBOSE_IS_LOGGABLE ? LogTime.getLogTime() : 0;
EngineKey key =
keyFactory.buildKey(
model,
signature,
width,
height,
transformations,
resourceClass,
transcodeClass,
options);
EngineResource<?> memoryResource;
synchronized (this) {
memoryResource = loadFromMemory(key, isMemoryCacheable, startTime);
if (memoryResource == null) {
return waitForExistingOrStartNewJob(
glideContext,
model,
signature,
width,
height,
resourceClass,
transcodeClass,
priority,
diskCacheStrategy,
transformations,
isTransformationRequired,
isScaleOnlyOrNoTransform,
options,
isMemoryCacheable,
useUnlimitedSourceExecutorPool,
useAnimationPool,
onlyRetrieveFromCache,
cb,
callbackExecutor,
key,
startTime);
}
}
cb.onResourceReady(
memoryResource, DataSource.MEMORY_CACHE, /* isLoadedFromAlternateCacheKey= */ false);
return null;
}
}
Engine的waitForExistingOrStartNewJob()创建EngineJob、DecodeJob，addCallback()设置SingleRequest和callbackExecutor，调用start()启动
- 这里的cbs为ResourceCallbackAndExecutor（包含SingleRequest和callbackExecutor）的list
public class Engine
implements EngineJobListener,
MemoryCache.ResourceRemovedListener,
EngineResource.ResourceListener {
private <R> LoadStatus waitForExistingOrStartNewJob(.....) {
.....
EngineJob<R> engineJob =
engineJobFactory.build(
key,
isMemoryCacheable,
useUnlimitedSourceExecutorPool,
useAnimationPool,
onlyRetrieveFromCache);
DecodeJob<R> decodeJob =
decodeJobFactory.build(
glideContext,
model,
key,
signature,
width,
height,
resourceClass,
transcodeClass,
priority,
diskCacheStrategy,
transformations,
isTransformationRequired,
isScaleOnlyOrNoTransform,
onlyRetrieveFromCache,
options,
engineJob);
jobs.put(key, engineJob);
engineJob.addCallback(cb, callbackExecutor);
engineJob.start(decodeJob);
if (VERBOSE_IS_LOGGABLE) {
logWithTimeAndKey("Started new load", startTime, key);
}
return new LoadStatus(cb, engineJob);
}
}
class EngineJob<R> implements DecodeJob.Callback<R>, Poolable {
final ResourceCallbacksAndExecutors cbs = new ResourceCallbacksAndExecutors();
synchronized void addCallback(final ResourceCallback cb, Executor callbackExecutor) {
stateVerifier.throwIfRecycled();
cbs.add(cb, callbackExecutor);
......
}
}
static final class ResourceCallbacksAndExecutors
implements Iterable<ResourceCallbackAndExecutor> {
ResourceCallbacksAndExecutors() {
this(new ArrayList<ResourceCallbackAndExecutor>(2));
}
void add(ResourceCallback cb, Executor executor) {
callbacksAndExecutors.add(new ResourceCallbackAndExecutor(cb, executor));
}
}
}
EngineJob的start()创建GlideExecutor执行DecodeJob
class EngineJob<R> implements DecodeJob.Callback<R>, Poolable {
public synchronized void start(DecodeJob<R> decodeJob) {
this.decodeJob = decodeJob;
GlideExecutor executor =
decodeJob.willDecodeFromCache() ? diskCacheExecutor : getActiveSourceExecutor();
executor.execute(decodeJob);
}
}
DecodeJob的run()调用runWrapped()、decodeFromRetrievedData()、decodeFromData()解析资源，将resouce传给notifyEncodeAndRelease()，回调EngineJob的onResourceReady()
class DecodeJob<R>
implements DataFetcherGenerator.FetcherReadyCallback,
Runnable,
Comparable<DecodeJob<?>>,
Poolable {
@Override
public void run() {
.......
try {
.......
runWrapped();
}.......
}
private void runWrapped() {
switch (runReason) {
.......
case DECODE_DATA:
decodeFromRetrievedData();
break;
default:
throw new IllegalStateException("Unrecognized run reason: " + runReason);
}
}
private void decodeFromRetrievedData() {
......
Resource<R> resource = null;
try {
resource = decodeFromData(currentFetcher, currentData, currentDataSource);
}......
if (resource != null) {
notifyEncodeAndRelease(resource, currentDataSource, isLoadingFromAlternateCacheKey);
}......
}
private void notifyEncodeAndRelease(
Resource<R> resource, DataSource dataSource, boolean isLoadedFromAlternateCacheKey) {
Resource<R> result = resource;
......
notifyComplete(result, dataSource, isLoadedFromAlternateCacheKey);
......
}
}
private void notifyComplete(
Resource<R> resource, DataSource dataSource, boolean isLoadedFromAlternateCacheKey) {
setNotifiedOrThrow();
callback.onResourceReady(resource, dataSource, isLoadedFromAlternateCacheKey);
}
}
EngineJob的onResourceReady()调用notifyCallbacksOfResult()，遍历ResourceCallbackAndExecutor
- entry.executor为在上面的addCallback()中添加的包含主线程hander的线程池
- entry.cb为SingleRequset
- 主线程调用run()、callCallbackOnResourceReady，最终回调SingleRequest的onResourceReady()
class EngineJob<R> implements DecodeJob.Callback<R>, Poolable {
@Override
public void onResourceReady(
Resource<R> resource, DataSource dataSource, boolean isLoadedFromAlternateCacheKey) {
......
notifyCallbacksOfResult();
}
void notifyCallbacksOfResult() {
synchronized (this) {
.....
copy = cbs.copy();
.....
}
for (final ResourceCallbackAndExecutor entry : copy) {
entry.executor.execute(new CallResourceReady(entry.cb));
}
.....
}
private class CallResourceReady implements Runnable {
......
@Override
public void run() {
synchronized (cb.getLock()) {
synchronized (EngineJob.this) {
if (cbs.contains(cb)) {
engineResource.acquire();
callCallbackOnResourceReady(cb);
removeCallback(cb);
}
decrementPendingCallbacks();
}
}
}
}
void callCallbackOnResourceReady(ResourceCallback cb) {
try {
cb.onResourceReady(engineResource, dataSource, isLoadedFromAlternateCacheKey);
}......
}
}
SingleRequest的onResourceReady()调用ImageViewTarget的onResourceReady()
public final class SingleRequest<R> implements Request, SizeReadyCallback, ResourceCallback {
public void onResourceReady(
Resource<?> resource, DataSource dataSource, boolean isLoadedFromAlternateCacheKey) {
......
try {
synchronized (requestLock) {
......
onResourceReady(
(Resource<R>) resource, (R) received, dataSource, isLoadedFromAlternateCacheKey);
}
}
......
}
private void onResourceReady(
Resource<R> resource, R result, DataSource dataSource, boolean isAlternateCacheKey) {
......
if (!anyListenerHandledUpdatingTarget) {
Transition<? super R> animation = animationFactory.build(dataSource, isFirstResource);
target.onResourceReady(result, animation);
}
......
}
}
ImageViewTarget的onResourceReady()调用setResource()
public abstract class ImageViewTarget<Z> extends ViewTarget<ImageView, Z>
implements Transition.ViewAdapter {
@Override
public void onResourceReady(@NonNull Z resource, @Nullable Transition<? super Z> transition) {
if (transition == null || !transition.transition(resource, this)) {
setResourceInternal(resource);
} else {
maybeUpdateAnimatable(resource);
}
}
private void setResourceInternal(@Nullable Z resource) {
setResource(resource);
maybeUpdateAnimatable(resource);
}
}
根据多态调用子类DrawableImageViewTarget的setResource()设置到view中
public class DrawableImageViewTarget extends ImageViewTarget<Drawable> {
@Override
protected void setResource(@Nullable Drawable resource) {
view.setImageDrawable(resource);
}
}