Fresco學習中文地址：Fresco中文學習
Fresco Javadoc地址：Javadoc
Fresco初始化分析：
在Application中加入：
Fresco.initialize(this);
請看我的注釋：
/*
* Copyright (c) 2015-present, Facebook, Inc.
* All rights reserved.
*
* This source code is licensed under the BSD-style license found in the
* LICENSE file in the root directory of this source tree. An additional grant
* of patent rights can be found in the PATENTS file in the same directory.
*/
package com.facebook.drawee.backends.pipeline;
import *
/**
* Fresco entry point.(總體入口點)
*
* <p/> You must initialize this class before use. The simplest way is to just do
* {#code Fresco.initialize(Context)}.
* （指明了一個簡單例子）
*/
public class Fresco {
private static PipelineDraweeControllerBuilderSupplier sDraweeControllerBuilderSupplier; //業(yè)務邏輯工廠
private Fresco() {}
/** Initializes Fresco with the default config. */
public static void initialize(Context context) {
ImagePipelineFactory.initialize(context); // 關系圖片下載邏輯處理和緩存處理
initializeDrawee(context);
}
/** Initializes Fresco with the specified config. */
public static void initialize(Context context, ImagePipelineConfig imagePipelineConfig) {
ImagePipelineFactory.initialize(imagePipelineConfig); // 關系圖片下載邏輯處理和緩存處理
initializeDrawee(context);
}
private static void initializeDrawee(Context context) {
sDraweeControllerBuilderSupplier = new PipelineDraweeControllerBuilderSupplier(context);
SimpleDraweeView.initialize(sDraweeControllerBuilderSupplier); // 這個SimpleDraweeView是在布局中使用的代理Imageview，掛在一堆轉換邏輯
}
/** Gets the supplier of Fresco Drawee controller builders. */
public static PipelineDraweeControllerBuilderSupplier getDraweeControllerBuilderSupplier() {
return sDraweeControllerBuilderSupplier; // 這貨給外部使用，看需求而定
}
/** Returns a new instance of Fresco Drawee controller builder. */
public static PipelineDraweeControllerBuilder newDraweeControllerBuilder() {
return sDraweeControllerBuilderSupplier.get(); // 給外部需求所用，拿到一個新的業(yè)務邏輯工廠對象
}
public static ImagePipelineFactory getImagePipelineFactory() {
return ImagePipelineFactory.getInstance(); // 外部使用的管道類，這貨檢查是否初始化
}
/** Gets the image pipeline instance. */
public static ImagePipeline getImagePipeline() {
return getImagePipelineFactory().getImagePipeline();// 外部使用的管道類，這貨檢查是否初始化，沒有給你個新的，工廠模式
}
/** Shuts Fresco down. */
public static void shutDown() { //Application 退出調用，避免內存泄露
sDraweeControllerBuilderSupplier = null;
SimpleDraweeView.shutDown();
ImagePipelineFactory.shutDown();
}
}
初始化翻譯就這樣：
Fresco.initialize() ===> Fresco.initializeDrawee() ===> SimpleDraweeView.initialize();
請繼續(xù)看我的注釋：
/*
* Copyright (c) 2015-present, Facebook, Inc.
* All rights reserved.
*
* This source code is licensed under the BSD-style license found in the
* LICENSE file in the root directory of this source tree. An additional grant
* of patent rights can be found in the PATENTS file in the same directory.
*/
package com.facebook.drawee.view;
import *
/**
* This view takes a uri as input and internally builds and sets a controller.(這個類就是掛載url和control準備)
*
* <p>This class must be statically initialized in order to be used. If you are using the Fresco
* image pipeline, use {@link com.facebook.drawee.backends.pipeline.Fresco#initialize} to do this.
* （官方教育你，先初始化Fresco.initialize）
*/
public class SimpleDraweeView extends GenericDraweeView { // 這個繼承有點深，慢慢來，最終爸爸肯定是ImageView，但每個繼承做了深度定制
private static Supplier<? extends SimpleDraweeControllerBuilder> sDraweeControllerBuilderSupplier;// 這貨就是前面初始化進來的業(yè)務邏輯提供者
/** Initializes {@link SimpleDraweeView} with supplier of Drawee controller builders. */
public static void initialize( // 初始化傳值
Supplier<? extends SimpleDraweeControllerBuilder> draweeControllerBuilderSupplier) {
sDraweeControllerBuilderSupplier = draweeControllerBuilderSupplier;
}
/** Shuts {@link SimpleDraweeView} down. */
public static void shutDown() { // 關閉
sDraweeControllerBuilderSupplier = null;
}
private SimpleDraweeControllerBuilder mSimpleDraweeControllerBuilder; // 真正的業(yè)務邏輯對象，從sDraweeControllerBuilderSupplier拿出
public SimpleDraweeView(Context context, GenericDraweeHierarchy hierarchy) {
super(context, hierarchy);
init(context, null);
}
public SimpleDraweeView(Context context) {
super(context);
init(context, null);
}
public SimpleDraweeView(Context context, AttributeSet attrs) {
super(context, attrs);
init(context, attrs);
}
public SimpleDraweeView(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
init(context, attrs);
}
@TargetApi(Build.VERSION_CODES.LOLLIPOP)
public SimpleDraweeView(Context context, AttributeSet attrs, int defStyleAttr, int defStyleRes) {
super(context, attrs, defStyleAttr, defStyleRes);
init(context, attrs);
}
private void init(Context context, @Nullable AttributeSet attrs) {
if (isInEditMode()) { // 來自view，是否控件可以編輯
return;
}
Preconditions.checkNotNull(
sDraweeControllerBuilderSupplier,
"SimpleDraweeView was not initialized!"); // 檢查sDraweeControllerBuilderSupplier
mSimpleDraweeControllerBuilder = sDraweeControllerBuilderSupplier.get(); // 拿到對應的業(yè)務邏輯（正常來說都是PipelineDraweeControllerBuilder，如果自己沒有外部定制需求）
// 拿布局屬性，基本無用，可以是個默認圖uri
if (attrs != null) {
TypedArray gdhAttrs = context.obtainStyledAttributes(
attrs,
R.styleable.SimpleDraweeView);
try {
if (gdhAttrs.hasValue(R.styleable.SimpleDraweeView_actualImageUri)) {
setImageURI(Uri.parse(gdhAttrs.getString(R.styleable.SimpleDraweeView_actualImageUri)), null);
}
} finally {
gdhAttrs.recycle();
}
}
}
protected SimpleDraweeControllerBuilder getControllerBuilder() { // 給外部使用，沒有什么好說的
return mSimpleDraweeControllerBuilder;
}
/**
* Displays an image given by the uri.
*
* @param uri uri of the image
* @undeprecate
*/
@Override
public void setImageURI(Uri uri) { // 定制網絡圖片url
setImageURI(uri, null);
}
/**
* Displays an image given by the uri string.
*
* @param uriString uri string of the image
*/
public void setImageURI(@Nullable String uriString) {
setImageURI(uriString, null);
}
/**
* Displays an image given by the uri.
*
* @param uri uri of the image
* @param callerContext caller context
*/
public void setImageURI(Uri uri, @Nullable Object callerContext) { // builder模式建立DraweeController
DraweeController controller = mSimpleDraweeControllerBuilder
.setCallerContext(callerContext)// 這貨如果沒有指定，都是null，一直傳到所有的生產者中
.setUri(uri)
.setOldController(getController())// 這貨首次是null
.build();
setController(controller);
}
/**
* Displays an image given by the uri string.
*
* @param uriString uri string of the image
* @param callerContext caller context
*/
public void setImageURI(@Nullable String uriString, @Nullable Object callerContext) { // 多態(tài)
Uri uri = (uriString != null) ? Uri.parse(uriString) : null;
setImageURI(uri, callerContext);
}
}
SimpleDraweeView 的繼承先不看，控件處理而已，先看完關心request流程。
流程：SimpleDraweeView.setImageURI() ===> PipelineDraweeControllerBuilder.build(),然后SimpleDraweeView 再持有PipelineDraweeController這個對象
接著看注釋，這個build類：
package com.facebook.drawee.backends.pipeline;
import *
/**
* Concrete implementation of ImagePipeline Drawee controller builder. （業(yè)務邏輯實現類）
* <p/> See {@link AbstractDraweeControllerBuilder} for more details.
*/
public class PipelineDraweeControllerBuilder extends AbstractDraweeControllerBuilder<
PipelineDraweeControllerBuilder,
ImageRequest,
CloseableReference<CloseableImage>,
ImageInfo> { // 很多實現在基類AbstractDraweeControllerBuilder完成，如果你需要定制自己DraweeController，繼承這個基類
private final ImagePipeline mImagePipeline; // 各種緩存和策略，維護臟活的就是它
private final PipelineDraweeControllerFactory mPipelineDraweeControllerFactory;// 這貨持有uiThread，用來回掉更新，配合ImagePipeline 完成請求
public PipelineDraweeControllerBuilder(
Context context,
PipelineDraweeControllerFactory pipelineDraweeControllerFactory,
ImagePipeline imagePipeline,
Set<ControllerListener> boundControllerListeners) {
super(context, boundControllerListeners);
mImagePipeline = imagePipeline;
mPipelineDraweeControllerFactory = pipelineDraweeControllerFactory;
}
@Override
public PipelineDraweeControllerBuilder setUri(Uri uri) { // 轉換成一個ImageRequest
return super.setImageRequest(ImageRequest.fromUri(uri));
}
@Override
public PipelineDraweeControllerBuilder setUri(@Nullable String uriString) { // 轉換成一個ImageRequest
return super.setImageRequest(ImageRequest.fromUri(uriString));
}
// 這個函數來自SimpleDraweeView:setImageURI():PipelineDraweeControllerBuilder.build()
@Override
protected PipelineDraweeController obtainController() { // 父類會回掉，首次會走else，為了重復使用，把新數據更新到controller中
DraweeController oldController = getOldController();
PipelineDraweeController controller;
if (oldController instanceof PipelineDraweeController) {
controller = (PipelineDraweeController) oldController;
controller.initialize(
obtainDataSourceSupplier(),
generateUniqueControllerId(),
getCacheKey(),
getCallerContext());
} else {
controller = mPipelineDraweeControllerFactory.newController(
obtainDataSourceSupplier(),
generateUniqueControllerId(),
getCacheKey(),
getCallerContext());
}
return controller;
}
private CacheKey getCacheKey() { // 根據imageRequest 拿到對應的Cache策略，這貨從ImagePipeline 拿到Cache
final ImageRequest imageRequest = getImageRequest();
final CacheKeyFactory cacheKeyFactory = mImagePipeline.getCacheKeyFactory();
CacheKey cacheKey = null;
if (cacheKeyFactory != null && imageRequest != null) {
if (imageRequest.getPostprocessor() != null) {
cacheKey = cacheKeyFactory.getPostprocessedBitmapCacheKey(
imageRequest,
getCallerContext());
} else {
cacheKey = cacheKeyFactory.getBitmapCacheKey(
imageRequest,
getCallerContext());
}
}
return cacheKey;
}
// 數據Bean，帶有回掉數據接口（成功或者失敗）,利用執(zhí)行ImagePipeline request
@Override
protected DataSource<CloseableReference<CloseableImage>> getDataSourceForRequest(
ImageRequest imageRequest,
Object callerContext,
boolean bitmapCacheOnly) {
if (bitmapCacheOnly) {
return mImagePipeline.fetchImageFromBitmapCache(imageRequest, callerContext);
} else {
return mImagePipeline.fetchDecodedImage(imageRequest, callerContext);
}
}
.......
}
好了大致知道了Cache類和Executor類了，都來自ImagePipeline。
ImagePipeline 負責圖片的獲取和管理。圖片可以來自遠程服務器，本地文件，或者Content Provider，本地資源。壓縮后的文件緩存在本地存儲中，Bitmap數據緩存在內存中。
obtainController(),這個函數比較重要，構造了業(yè)務邏輯，有點像MVC，這里創(chuàng)建后生成回掉，給后面view，addWindow()后，收集WMS和IMS(WindowManagerService和InputeManagerService)產生的生命周期回掉或者輸入事件綁定。
在5.0系統以下，Image Pipeline 使用 pinned purgeables 將Bitmap數據避開Java堆內存，存在ashmem中。這要求圖片不使用時，要顯式地釋放內存。
SimpleDraweeView自動處理了這個釋放過程，所以沒有特殊情況，盡量使用SimpleDraweeView，在特殊的場合，如果有需要，也可以直接控制Image Pipeline。
Paste_Image.png
ImagePipeline介紹來自
關于ImagePipeline后面文章介紹里面策略和緩存詳細，先看主request
那執(zhí)行Requst代碼在哪，在前面SimpleDraweeView.setImageURI()里面是執(zhí)行
package com.facebook.drawee.backends.pipeline;
import *
/**
* Drawee controller that bridges the image pipeline with {@link SettableDraweeHierarchy}. <p> The
* hierarchy's actual image is set to the image(s) obtained by the provided data source. The data
* source is automatically obtained and closed based on attach / detach calls.
*/
public class PipelineDraweeController
extends AbstractDraweeController<CloseableReference<CloseableImage>, ImageInfo> {
// Components
private final Resources mResources;
private final AnimatedDrawableFactory mAnimatedDrawableFactory;
private @Nullable MemoryCache<CacheKey, CloseableImage> mMemoryCache;
private static Experiment sExperiment; // 這貨相當于一個對象鎖
private CacheKey mCacheKey;
// Constant state (non-final because controllers can be reused)
private Supplier<DataSource<CloseableReference<CloseableImage>>> mDataSourceSupplier;
public PipelineDraweeController( // 初始化和傳值一堆，為了基類使用
Resources resources,
DeferredReleaser deferredReleaser,
AnimatedDrawableFactory animatedDrawableFactory,
Executor uiThreadExecutor,
MemoryCache<CacheKey, CloseableImage> memoryCache,
Supplier<DataSource<CloseableReference<CloseableImage>>> dataSourceSupplier,
String id,
CacheKey cacheKey,
Object callerContext) {
super(deferredReleaser, uiThreadExecutor, id, callerContext);
mResources = resources;
mAnimatedDrawableFactory = animatedDrawableFactory;
mMemoryCache = memoryCache;
mCacheKey = cacheKey;
init(dataSourceSupplier);
}
public void initialize(
Supplier<DataSource<CloseableReference<CloseableImage>>> dataSourceSupplier,
String id,
CacheKey cacheKey,
Object callerContext) {
super.initialize(id, callerContext);
init(dataSourceSupplier);
mCacheKey = cacheKey;
}
private void init(Supplier<DataSource<CloseableReference<CloseableImage>>> dataSourceSupplier) {
mDataSourceSupplier = dataSourceSupplier;
}
// 這個函數比較重要，利用DataSourceSupplier提供model接口數據接口（MVC模式）
@Override
protected DataSource<CloseableReference<CloseableImage>> getDataSource() { // 更新數據的接口，有成功和失敗
if (FLog.isLoggable(FLog.VERBOSE)) {
FLog.v(TAG, "controller %x: getDataSource", System.identityHashCode(this));
}
return mDataSourceSupplier.get();
}
@Override
protected Drawable createDrawable(CloseableReference<CloseableImage> image) {// 創(chuàng)建Drawable的策略回掉
Preconditions.checkState(CloseableReference.isValid(image));
CloseableImage closeableImage = image.get();
if (closeableImage instanceof CloseableStaticBitmap) {
CloseableStaticBitmap closeableStaticBitmap = (CloseableStaticBitmap) closeableImage;
Drawable bitmapDrawable = new BitmapDrawable(
mResources,
closeableStaticBitmap.getUnderlyingBitmap());
if (closeableStaticBitmap.getRotationAngle() == 0 ||
closeableStaticBitmap.getRotationAngle() == EncodedImage.UNKNOWN_ROTATION_ANGLE) {
return bitmapDrawable;
} else {
return new OrientedDrawable(bitmapDrawable, closeableStaticBitmap.getRotationAngle());
}
} else if (mAnimatedDrawableFactory != null) {
return mAnimatedDrawableFactory.create(closeableImage);
} else {
throw new UnsupportedOperationException("Unrecognized image class: " + closeableImage);
}
}
.......
@Override
protected void releaseImage(@Nullable CloseableReference<CloseableImage> image) { // 釋放引用策略
CloseableReference.closeSafely(image);
}
@Override
protected void releaseDrawable(@Nullable Drawable drawable) { // 釋放引用策略
if (drawable instanceof DrawableWithCaches) {
((DrawableWithCaches) drawable).dropCaches();
}
}
@Override
protected CloseableReference<CloseableImage> getCachedImage() { // 關閉引用策略
if (!getExperiment().mIsFastCheckEnabled) {
return null;
}
if (mMemoryCache == null || mCacheKey == null) {
return null;
}
// We get the CacheKey
CloseableReference<CloseableImage> closeableImage = mMemoryCache.get(mCacheKey);
if (closeableImage != null && !closeableImage.get().getQualityInfo().isOfFullQuality()) {
closeableImage.close();
return null;
}
return closeableImage;
}
/**
* @return The Experiment object
*/
protected static Experiment getExperiment() {
if (sExperiment == null) {
sExperiment = new Experiment();
}
return sExperiment;
}
protected static class Experiment { // 檢查類
private boolean mIsFastCheckEnabled;
public Experiment setFastCheckEnabled(final boolean fastCheckEnabled) {
mIsFastCheckEnabled = fastCheckEnabled;
return this;
}
}
}
上面只是實力類，真正調用在基類, 比較重要的就是getDataSource()和createDrawable()的實現了，其它都是釋放資源和回收，后面再講這個資源回收和回掉過程
接下來看基類指明干活
package com.facebook.drawee.controller;
import *
/**
* Abstract Drawee controller that implements common functionality
* regardless of the backend used to fetch the image.
*
* All methods should be called on the main UI thread.
*
*/
@NotThreadSafe
public abstract class AbstractDraweeController<T, INFO> implements
DraweeController,
DeferredReleaser.Releasable,
GestureDetector.ClickListener {
/**
* This class is used to allow an optimization of not creating a ForwardingControllerListener
* when there is only a single controller listener.
* 這貨也比較重要，但尼瑪你沒有定制自己controllistener，默認為null，沒有什么卵用
*/
private static class InternalForwardingListener<INFO> extends ForwardingControllerListener<INFO> {
public static <INFO> InternalForwardingListener<INFO> createInternal(
ControllerListener<? super INFO> listener1,
ControllerListener<? super INFO> listener2) {
InternalForwardingListener<INFO> forwarder = new InternalForwardingListener<INFO>();
forwarder.addListener(listener1);
forwarder.addListener(listener2);
return forwarder;
}
}
// Components
private final DraweeEventTracker mEventTracker = DraweeEventTracker.newInstance(); // 日志追蹤
private final DeferredReleaser mDeferredReleaser; // 賴加載，延遲安排任務
private final Executor mUiThreadImmediateExecutor; // ui線程從PipelineDraweeControllerBuilder ：PipelineDraweeControllerFactory 來的
// Optional components
private @Nullable RetryManager mRetryManager; // 重試機制
private @Nullable GestureDetector mGestureDetector; // 手勢
private @Nullable ControllerListener<INFO> mControllerListener; // 業(yè)務邏輯回掉監(jiān)聽
// Hierarchy
private @Nullable SettableDraweeHierarchy mSettableDraweeHierarchy; // view對象樹， 用于組織和維護最終繪制和呈現的 Drawable 對象
private @Nullable Drawable mControllerOverlay; // view對象
// Constant state (non-final because controllers can be reused)
private String mId;
private Object mCallerContext;
// Mutable state
private boolean mIsAttached; // 是否view添加到window上
private boolean mIsRequestSubmitted; // 是否已經開始request
private boolean mHasFetchFailed;// 當前request更新失敗flag
private boolean mRetainImageOnFailure;// 設置是否顯示最新的可用的圖片（默認圖），在失敗的時候
private @Nullable String mContentDescription; // 描述
private @Nullable DataSource<T> mDataSource; // 子類data策略
private @Nullable T mFetchedImage; // 獲取到當前image
private @Nullable Drawable mDrawable; // 圖片資源
public AbstractDraweeController(
DeferredReleaser deferredReleaser,
Executor uiThreadImmediateExecutor,
String id,
Object callerContext) {
mDeferredReleaser = deferredReleaser;
mUiThreadImmediateExecutor = uiThreadImmediateExecutor;
init(id, callerContext, true);
}
protected void initialize(String id, Object callerContext) {
init(id, callerContext, false);
}
private void init(String id, Object callerContext, boolean justConstructed) {
mEventTracker.recordEvent(Event.ON_INIT_CONTROLLER);
// cancel deferred release
if (!justConstructed && mDeferredReleaser != null) {
mDeferredReleaser.cancelDeferredRelease(this);
}
// reinitialize mutable state (fetch state)
mIsAttached = false;
releaseFetch();
mRetainImageOnFailure = false;
// reinitialize optional components
if (mRetryManager != null) {
mRetryManager.init();
}
if (mGestureDetector != null) {
mGestureDetector.init();
mGestureDetector.setClickListener(this);
}
if (mControllerListener instanceof InternalForwardingListener) {
((InternalForwardingListener) mControllerListener).clearListeners();
} else {
mControllerListener = null;
}
// clear hierarchy and controller overlay
if (mSettableDraweeHierarchy != null) {
mSettableDraweeHierarchy.reset();
mSettableDraweeHierarchy.setControllerOverlay(null);
mSettableDraweeHierarchy = null;
}
mControllerOverlay = null;
// reinitialize constant state
if (FLog.isLoggable(FLog.VERBOSE)) {
FLog.v(TAG, "controller %x %s -> %s: initialize", System.identityHashCode(this), mId, id);
}
mId = id;
mCallerContext = callerContext;
}
@Override
public void release() {
mEventTracker.recordEvent(Event.ON_RELEASE_CONTROLLER);
if (mRetryManager != null) {
mRetryManager.reset();
}
if (mGestureDetector != null) {
mGestureDetector.reset();
}
if (mSettableDraweeHierarchy != null) {
mSettableDraweeHierarchy.reset();
}
releaseFetch();
}
private void releaseFetch() { // 釋放hold的image和data，為request做準備
boolean wasRequestSubmitted = mIsRequestSubmitted;
mIsRequestSubmitted = false;
mHasFetchFailed = false;
if (mDataSource != null) {
mDataSource.close();
mDataSource = null;
}
if (mDrawable != null) {
releaseDrawable(mDrawable);
}
if (mContentDescription != null) {
mContentDescription = null;
}
mDrawable = null;
if (mFetchedImage != null) {
logMessageAndImage("release", mFetchedImage);
releaseImage(mFetchedImage);
mFetchedImage = null;
}
if (wasRequestSubmitted) {
getControllerListener().onRelease(mId);
}
}
public Object getCallerContext() { // 默認情況都是null，基本無卵用，如果你有特殊要求，這個上下文能起到很大重要，如，日志追蹤
return mCallerContext;
}
protected @Nullable RetryManager getRetryManager() { // 重試機制
return mRetryManager;
}
.......
/** Gets gesture detector. */
protected @Nullable GestureDetector getGestureDetector() {
return mGestureDetector;
}
/** Sets gesture detector. */
protected void setGestureDetector(@Nullable GestureDetector gestureDetector) {
mGestureDetector = gestureDetector;
if (mGestureDetector != null) {
mGestureDetector.setClickListener(this);
}
}
// 這貨有意思了，這貨給你個flag，需要set進來，作用是你下載完后，失敗需要重新下載標志
protected void setRetainImageOnFailure(boolean enabled) {
mRetainImageOnFailure = enabled;
}
.......
// 基本無用，默認是null，為了完成你自己定制的回掉監(jiān)聽設置
/** Adds controller listener. */
public void addControllerListener(ControllerListener<? super INFO> controllerListener) {
Preconditions.checkNotNull(controllerListener);
if (mControllerListener instanceof InternalForwardingListener) {
((InternalForwardingListener<INFO>) mControllerListener).addListener(controllerListener);
return;
}
if (mControllerListener != null) {
mControllerListener = InternalForwardingListener.createInternal(
mControllerListener,
controllerListener);
return;
}
// Listener only receives <INFO>, it never produces one.
// That means if it can accept <? super INFO>, it can very well accept <INFO>.
mControllerListener = (ControllerListener<INFO>) controllerListener;
}
.......
/** Gets controller listener for internal use. */
protected ControllerListener<INFO> getControllerListener() {
if (mControllerListener == null) {
return BaseControllerListener.getNoOpListener();
}
return mControllerListener;
}
/** Gets the hierarchy */
@Override
public @Nullable
DraweeHierarchy getHierarchy() {
return mSettableDraweeHierarchy;
}
// 這函數比較屌，維護view樹，以后再講
@Override
public void setHierarchy(@Nullable DraweeHierarchy hierarchy) {
if (FLog.isLoggable(FLog.VERBOSE)) {
FLog.v(
TAG,
"controller %x %s: setHierarchy: %s",
System.identityHashCode(this),
mId,
hierarchy);
}
mEventTracker.recordEvent(
(hierarchy != null) ? Event.ON_SET_HIERARCHY : Event.ON_CLEAR_HIERARCHY);
// force release in case request was submitted
if (mIsRequestSubmitted) {
mDeferredReleaser.cancelDeferredRelease(this);
release();
}
// clear the existing hierarchy
if (mSettableDraweeHierarchy != null) {
mSettableDraweeHierarchy.setControllerOverlay(null);
mSettableDraweeHierarchy = null;
}
// set the new hierarchy
if (hierarchy != null) {
Preconditions.checkArgument(hierarchy instanceof SettableDraweeHierarchy);
mSettableDraweeHierarchy = (SettableDraweeHierarchy) hierarchy;
mSettableDraweeHierarchy.setControllerOverlay(mControllerOverlay);
}
}
/** Sets the controller overlay */
protected void setControllerOverlay(@Nullable Drawable controllerOverlay) {
mControllerOverlay = controllerOverlay;
if (mSettableDraweeHierarchy != null) {
mSettableDraweeHierarchy.setControllerOverlay(mControllerOverlay);
}
}
/** Gets the controller overlay */
protected @Nullable Drawable getControllerOverlay() {
return mControllerOverlay;
}
@Override
public void onAttach() { // 回調
if (FLog.isLoggable(FLog.VERBOSE)) {
FLog.v(
TAG,
"controller %x %s: onAttach: %s",
System.identityHashCode(this),
mId,
mIsRequestSubmitted ? "request already submitted" : "request needs submit");
}
mEventTracker.recordEvent(Event.ON_ATTACH_CONTROLLER);
Preconditions.checkNotNull(mSettableDraweeHierarchy);
mDeferredReleaser.cancelDeferredRelease(this);
mIsAttached = true;
if (!mIsRequestSubmitted) {
submitRequest();
}
}
@Override
public void onDetach() { // 回調
if (FLog.isLoggable(FLog.VERBOSE)) {
FLog.v(TAG, "controller %x %s: onDetach", System.identityHashCode(this), mId);
}
mEventTracker.recordEvent(Event.ON_DETACH_CONTROLLER);
mIsAttached = false;
mDeferredReleaser.scheduleDeferredRelease(this);
}
@Override
public boolean onTouchEvent(MotionEvent event) { // 回調
if (FLog.isLoggable(FLog.VERBOSE)) {
FLog.v(TAG, "controller %x %s: onTouchEvent %s", System.identityHashCode(this), mId, event);
}
if (mGestureDetector == null) {
return false;
}
if (mGestureDetector.isCapturingGesture() || shouldHandleGesture()) {
mGestureDetector.onTouchEvent(event);
return true;
}
return false;
}
/** Returns whether the gesture should be handled by the controller */
protected boolean shouldHandleGesture() {
return shouldRetryOnTap();
}
private boolean shouldRetryOnTap() {
// We should only handle touch event if we are expecting some gesture.
// For example, we expect click when fetch fails and tap-to-retry is enabled.
return mHasFetchFailed && mRetryManager != null && mRetryManager.shouldRetryOnTap(); // shouldRetryOnTap 判斷是否超過重新的最大值（MAX：4次）
}
@Override
public boolean onClick() {// 回調
if (FLog.isLoggable(FLog.VERBOSE)) {
FLog.v(TAG, "controller %x %s: onClick", System.identityHashCode(this), mId);
}
if (shouldRetryOnTap()) { // mRetryManager去通知重新request準備
mRetryManager.notifyTapToRetry();
mSettableDraweeHierarchy.reset();
submitRequest();
return true;
}
return false;
}
protected void submitRequest() { // 這貨就是干活的
final T closeableImage = getCachedImage(); // 拿到子類的Cache圖片
if (closeableImage != null) { // 如果有，直接刷新成功
mDataSource = null;
mIsRequestSubmitted = true;
mHasFetchFailed = false;
mEventTracker.recordEvent(Event.ON_SUBMIT_CACHE_HIT);
getControllerListener().onSubmit(mId, mCallerContext);
onNewResultInternal(mId, mDataSource, closeableImage, 1.0f, true, true);
return;
}
mEventTracker.recordEvent(Event.ON_DATASOURCE_SUBMIT); // 日志
getControllerListener().onSubmit(mId, mCallerContext); // 給監(jiān)聽器去干活，一個id一個坑
mSettableDraweeHierarchy.setProgress(0, true);// 對象樹準備
mIsRequestSubmitted = true;// 已經提交
mHasFetchFailed = false;// 重置
mDataSource = getDataSource(); // 獲取子類data策略
if (FLog.isLoggable(FLog.VERBOSE)) {
FLog.v(
TAG,
"controller %x %s: submitRequest: dataSource: %x",
System.identityHashCode(this),
mId,
System.identityHashCode(mDataSource));
}
final String id = mId;
final boolean wasImmediate = mDataSource.hasResult();
final DataSubscriber<T> dataSubscriber =
new BaseDataSubscriber<T>() {
@Override
public void onNewResultImpl(DataSource<T> dataSource) {
// isFinished must be obtained before image, otherwise we might set intermediate result
// as final image.
boolean isFinished = dataSource.isFinished();
float progress = dataSource.getProgress();
T image = dataSource.getResult();
if (image != null) {
onNewResultInternal(id, dataSource, image, progress, isFinished, wasImmediate);
} else if (isFinished) {
onFailureInternal(id, dataSource, new NullPointerException(), /* isFinished */ true);
}
}
@Override
public void onFailureImpl(DataSource<T> dataSource) {
onFailureInternal(id, dataSource, dataSource.getFailureCause(), /* isFinished */ true);
}
@Override
public void onProgressUpdate(DataSource<T> dataSource) {
boolean isFinished = dataSource.isFinished();
float progress = dataSource.getProgress();
onProgressUpdateInternal(id, dataSource, progress, isFinished);
}
};
mDataSource.subscribe(dataSubscriber, mUiThreadImmediateExecutor); // 在ui線程訂閱，開始刷新
}
private void onNewResultInternal( // 成功
String id,
DataSource<T> dataSource,
@Nullable T image,
float progress,
boolean isFinished,
boolean wasImmediate) {
// ignore late callbacks (data source that returned the new result is not the one we expected)
if (!isExpectedDataSource(id, dataSource)) { // 略過老data
logMessageAndImage("ignore_old_datasource @ onNewResult", image);
releaseImage(image);
dataSource.close();
return;
}
mEventTracker.recordEvent( // 日志追蹤
isFinished ? Event.ON_DATASOURCE_RESULT : Event.ON_DATASOURCE_RESULT_INT);
// create drawable
Drawable drawable;
try {
drawable = createDrawable(image); //調用子類策略創(chuàng)建drawable
} catch (Exception exception) { // 失敗打印和釋放資源
logMessageAndImage("drawable_failed @ onNewResult", image);
releaseImage(image);
onFailureInternal(id, dataSource, exception, isFinished);
return;
}
T previousImage = mFetchedImage; // 完成新老數據交換
Drawable previousDrawable = mDrawable;
mFetchedImage = image; // 給hold的當前image進行策略釋放
mDrawable = drawable;
try {
// set the new image
if (isFinished) { // 完成后，刷新，監(jiān)聽回掉，改干嘛干嘛
logMessageAndImage("set_final_result @ onNewResult", image);
mDataSource = null;
mSettableDraweeHierarchy.setImage(drawable, 1f, wasImmediate);
getControllerListener().onFinalImageSet(id, getImageInfo(image), getAnimatable());
// IMPORTANT: do not execute any instance-specific code after this point
} else {
logMessageAndImage("set_intermediate_result @ onNewResult", image);
mSettableDraweeHierarchy.setImage(drawable, progress, wasImmediate);
getControllerListener().onIntermediateImageSet(id, getImageInfo(image));
// IMPORTANT: do not execute any instance-specific code after this point
}
} finally { // 釋放當前請求資源
if (previousDrawable != null && previousDrawable != drawable) {
releaseDrawable(previousDrawable);
}
if (previousImage != null && previousImage != image) {
logMessageAndImage("release_previous_result @ onNewResult", previousImage);
releaseImage(previousImage);
}
}
}
private void onFailureInternal( // 更新失敗數據
String id,
DataSource<T> dataSource,
Throwable throwable,
boolean isFinished) {
// ignore late callbacks (data source that failed is not the one we expected)
if (!isExpectedDataSource(id, dataSource)) { // 判斷是否是自己感興趣的data
logMessageAndFailure("ignore_old_datasource @ onFailure", throwable);
dataSource.close();
return;
}
mEventTracker.recordEvent( // 日志追蹤
isFinished ? Event.ON_DATASOURCE_FAILURE : Event.ON_DATASOURCE_FAILURE_INT);
// fail only if the data source is finished
if (isFinished) { //刷新失敗流程
logMessageAndFailure("final_failed @ onFailure", throwable);
mDataSource = null;
mHasFetchFailed = true;
// Set the previously available image if available.
if (mRetainImageOnFailure && mDrawable != null) {
mSettableDraweeHierarchy.setImage(mDrawable, 1f, true);
} else if (shouldRetryOnTap()) {
mSettableDraweeHierarchy.setRetry(throwable);
} else {
mSettableDraweeHierarchy.setFailure(throwable);
}
getControllerListener().onFailure(mId, throwable);
// IMPORTANT: do not execute any instance-specific code after this point
} else {
logMessageAndFailure("intermediate_failed @ onFailure", throwable);
getControllerListener().onIntermediateImageFailed(mId, throwable);
// IMPORTANT: do not execute any instance-specific code after this point
}
}
private void onProgressUpdateInternal( // 更新實時數據
String id,
DataSource<T> dataSource,
float progress,
boolean isFinished) {
// ignore late callbacks (data source that failed is not the one we expected)
if (!isExpectedDataSource(id, dataSource)) {
logMessageAndFailure("ignore_old_datasource @ onProgress", null);
dataSource.close();
return;
}
if (!isFinished) {
mSettableDraweeHierarchy.setProgress(progress, false);
}
}
private boolean isExpectedDataSource(String id, DataSource<T> dataSource) { // 判斷當前提交狀態(tài)的dataSource 釋放為新的，持有id老dataSource 不再感興趣
if (dataSource == null && mDataSource == null) {
// DataSource is null when we use directly the Bitmap from the MemoryCache. In this case
// we don't have to close the DataSource.
return true;
}
// There are several situations in which an old data source might return a result that we are no
// longer interested in. To verify that the result is indeed expected, we check several things:
return id.equals(mId) && dataSource == mDataSource && mIsRequestSubmitted;
}
........
@Override
public @Nullable Animatable getAnimatable() {
return (mDrawable instanceof Animatable) ? (Animatable) mDrawable : null;
}
// 下面都是回掉子類接口 PipelineDraweeController
protected abstract DataSource<T> getDataSource();
protected abstract Drawable createDrawable(T image);
protected abstract @Nullable INFO getImageInfo(T image);
protected String getImageClass(@Nullable T image) {
return (image != null) ? image.getClass().getSimpleName() : "<null>";
}
protected int getImageHash(@Nullable T image) {
return System.identityHashCode(image);
}
protected abstract void releaseImage(@Nullable T image);
protected abstract void releaseDrawable(@Nullable Drawable drawable);
........
}
屬性：SettableDraweeHierarchy 你可以認為這貨就是你的drawable的修飾類所需要維護的樹形結構，相當于drawable是衣服的話，DraweeHierarchy就是衣服上的線條結構和底色配色，和XML中布局默認屬性差不多
這個類比較長，所有request是從attach開始submit，onDetach停止和釋放資源維護。
attach和onDetach事件來自于DraweeHierarchy中toplevel，Drawable的DraweeHold，它實現了監(jiān)聽和派發(fā)回掉
好了你大致也看懂了submit這個函數中，先準備一些flag，然后給Listener去實現submit，然后自己訂閱回掉在ui線程，開始刷新界面。
這個大多數人都有個誤區(qū)，認為Listener是實現提交請求，其實不是，這貨只是監(jiān)聽回調，真正在跑網絡數據得是這個訂閱得datasrouce,而這個datasrouce來自getDataSource(),這個來自AbstractDraweeControllerBuilder:getDataSourceSupplierForRequest(),一路追蹤最后來自PipelineDraweeControllerBuilder:getDataSourceForRequest(),好了這個主線來了，ImagePipeline要開始干活了，往上面翻，自己再總結理解下。
接著看：Fresco源碼分析（二）
