Fresco学习中文地址：Fresco中文学习
Fresco Javadoc地址：Javadoc
Fresco初始化分析：
在Application中加入：
Fresco.initialize(this);
请看我的注释：
/*
* 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.(总体入口点)
*
* You must initialize this class before use. The simplest way is to just do
* {#code Fresco.initialize(Context)}.
* （指明了一个简单例子）
*/
public class Fresco {
private static PipelineDraweeControllerBuilderSupplier sDraweeControllerBuilderSupplier; //业务逻辑工厂
private Fresco() {}
/** Initializes Fresco with the default config. */
public static void initialize(Context context) {
ImagePipelineFactory.initialize(context); // 关系图片下载逻辑处理和缓存处理
initializeDrawee(context);
}
/** Initializes Fresco with the specified config. */
public static void initialize(Context context, ImagePipelineConfig imagePipelineConfig) {
ImagePipelineFactory.initialize(imagePipelineConfig); // 关系图片下载逻辑处理和缓存处理
initializeDrawee(context);
}
private static void initializeDrawee(Context context) {
sDraweeControllerBuilderSupplier = new PipelineDraweeControllerBuilderSupplier(context);
SimpleDraweeView.initialize(sDraweeControllerBuilderSupplier); // 这个SimpleDraweeView是在布局中使用的代理Imageview，挂在一堆转换逻辑
}
/** Gets the supplier of Fresco Drawee controller builders. */
public static PipelineDraweeControllerBuilderSupplier getDraweeControllerBuilderSupplier() {
return sDraweeControllerBuilderSupplier; // 这货给外部使用，看需求而定
}
/** Returns a new instance of Fresco Drawee controller builder. */
public static PipelineDraweeControllerBuilder newDraweeControllerBuilder() {
return sDraweeControllerBuilderSupplier.get(); // 给外部需求所用，拿到一个新的业务逻辑工厂对象
}
public static ImagePipelineFactory getImagePipelineFactory() {
return ImagePipelineFactory.getInstance(); // 外部使用的管道类，这货检查是否初始化
}
/** Gets the image pipeline instance. */
public static ImagePipeline getImagePipeline() {
return getImagePipelineFactory().getImagePipeline();// 外部使用的管道类，这货检查是否初始化，没有给你个新的，工厂模式
}
/** Shuts Fresco down. */
public static void shutDown() { //Application 退出调用，避免内存泄露
sDraweeControllerBuilderSupplier = null;
SimpleDraweeView.shutDown();
ImagePipelineFactory.shutDown();
}
}
初始化翻译就这样：
Fresco.initialize() ===> Fresco.initializeDrawee() ===> SimpleDraweeView.initialize();
请继续看我的注释：
/*
* 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.(这个类就是挂载url和control准备)
*
* 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 { // 这个继承有点深，慢慢来，最终爸爸肯定是ImageView，但每个继承做了深度定制
private static Supplier sDraweeControllerBuilderSupplier;// 这货就是前面初始化进来的业务逻辑提供者
/** Initializes {@link SimpleDraweeView} with supplier of Drawee controller builders. */
public static void initialize( // 初始化传值
Supplier draweeControllerBuilderSupplier) {
sDraweeControllerBuilderSupplier = draweeControllerBuilderSupplier;
}
/** Shuts {@link SimpleDraweeView} down. */
public static void shutDown() { // 关闭
sDraweeControllerBuilderSupplier = null;
}
private SimpleDraweeControllerBuilder mSimpleDraweeControllerBuilder; // 真正的业务逻辑对象，从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()) { // 来自view，是否控件可以编辑
return;
}
Preconditions.checkNotNull(
sDraweeControllerBuilderSupplier,
"SimpleDraweeView was not initialized!"); // 检查sDraweeControllerBuilderSupplier
mSimpleDraweeControllerBuilder = sDraweeControllerBuilderSupplier.get(); // 拿到对应的业务逻辑（正常来说都是PipelineDraweeControllerBuilder，如果自己没有外部定制需求）
// 拿布局属性，基本无用，可以是个默认图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() { // 给外部使用，没有什么好说的
return mSimpleDraweeControllerBuilder;
}
/**
* Displays an image given by the uri.
*
* @param uri uri of the image
* @undeprecate
*/
@Override
public void setImageURI(Uri uri) { // 定制网络图片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)// 这货如果没有指定，都是null，一直传到所有的生产者中
.setUri(uri)
.setOldController(getController())// 这货首次是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) { // 多态
Uri uri = (uriString != null) ? Uri.parse(uriString) : null;
setImageURI(uri, callerContext);
}
}
SimpleDraweeView 的继承先不看，控件处理而已，先看完关心request流程。
流程：SimpleDraweeView.setImageURI() ===> PipelineDraweeControllerBuilder.build(),然后SimpleDraweeView 再持有PipelineDraweeController这个对象
接着看注释，这个build类：
package com.facebook.drawee.backends.pipeline;
import *
/**
* Concrete implementation of ImagePipeline Drawee controller builder. （业务逻辑实现类）
* See {@link AbstractDraweeControllerBuilder} for more details.
*/
public class PipelineDraweeControllerBuilder extends AbstractDraweeControllerBuilder<
PipelineDraweeControllerBuilder,
ImageRequest,
CloseableReference,
ImageInfo> { // 很多实现在基类AbstractDraweeControllerBuilder完成，如果你需要定制自己DraweeController，继承这个基类
private final ImagePipeline mImagePipeline; // 各种缓存和策略，维护脏活的就是它
private final PipelineDraweeControllerFactory mPipelineDraweeControllerFactory;// 这货持有uiThread，用来回掉更新，配合ImagePipeline 完成请求
public PipelineDraweeControllerBuilder(
Context context,
PipelineDraweeControllerFactory pipelineDraweeControllerFactory,
ImagePipeline imagePipeline,
Set boundControllerListeners) {
super(context, boundControllerListeners);
mImagePipeline = imagePipeline;
mPipelineDraweeControllerFactory = pipelineDraweeControllerFactory;
}
@Override
public PipelineDraweeControllerBuilder setUri(Uri uri) { // 转换成一个ImageRequest
return super.setImageRequest(ImageRequest.fromUri(uri));
}
@Override
public PipelineDraweeControllerBuilder setUri(@Nullable String uriString) { // 转换成一个ImageRequest
return super.setImageRequest(ImageRequest.fromUri(uriString));
}
// 这个函数来自SimpleDraweeView:setImageURI():PipelineDraweeControllerBuilder.build()
@Override
protected PipelineDraweeController obtainController() { // 父类会回掉，首次会走else，为了重复使用，把新数据更新到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() { // 根据imageRequest 拿到对应的Cache策略，这货从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;
}
// 数据Bean，带有回掉数据接口（成功或者失败）,利用执行ImagePipeline request
@Override
protected DataSource> 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类和Executor类了，都来自ImagePipeline。
ImagePipeline 负责图片的获取和管理。图片可以来自远程服务器，本地文件，或者Content Provider，本地资源。压缩后的文件缓存在本地存储中，Bitmap数据缓存在内存中。
obtainController(),这个函数比较重要，构造了业务逻辑，有点像MVC，这里创建后生成回掉，给后面view，addWindow()后，收集WMS和IMS(WindowManagerService和InputeManagerService)产生的生命周期回掉或者输入事件绑定。
在5.0系统以下，Image Pipeline 使用 pinned purgeables 将Bitmap数据避开Java堆内存，存在ashmem中。这要求图片不使用时，要显式地释放内存。
SimpleDraweeView自动处理了这个释放过程，所以没有特殊情况，尽量使用SimpleDraweeView，在特殊的场合，如果有需要，也可以直接控制Image Pipeline。
ImagePipeline介绍来自
关于ImagePipeline后面文章介绍里面策略和缓存详细，先看主request
那执行Requst代码在哪，在前面SimpleDraweeView.setImageURI()里面是执行
package com.facebook.drawee.backends.pipeline;
import *
/**
* Drawee controller that bridges the image pipeline with {@link SettableDraweeHierarchy}. 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, ImageInfo> {
// Components
private final Resources mResources;
private final AnimatedDrawableFactory mAnimatedDrawableFactory;
private @Nullable MemoryCache mMemoryCache;
private static Experiment sExperiment; // 这货相当于一个对象锁
private CacheKey mCacheKey;
// Constant state (non-final because controllers can be reused)
private Supplier>> mDataSourceSupplier;
public PipelineDraweeController( // 初始化和传值一堆，为了基类使用
Resources resources,
DeferredReleaser deferredReleaser,
AnimatedDrawableFactory animatedDrawableFactory,
Executor uiThreadExecutor,
MemoryCache memoryCache,
Supplier>> 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>> dataSourceSupplier,
String id,
CacheKey cacheKey,
Object callerContext) {
super.initialize(id, callerContext);
init(dataSourceSupplier);
mCacheKey = cacheKey;
}
private void init(Supplier>> dataSourceSupplier) {
mDataSourceSupplier = dataSourceSupplier;
}
// 这个函数比较重要，利用DataSourceSupplier提供model接口数据接口（MVC模式）
@Override
protected DataSource> getDataSource() { // 更新数据的接口，有成功和失败
if (FLog.isLoggable(FLog.VERBOSE)) {
FLog.v(TAG, "controller %x: getDataSource", System.identityHashCode(this));
}
return mDataSourceSupplier.get();
}
@Override
protected Drawable createDrawable(CloseableReference image) {// 创建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 image) { // 释放引用策略
CloseableReference.closeSafely(image);
}
@Override
protected void releaseDrawable(@Nullable Drawable drawable) { // 释放引用策略
if (drawable instanceof DrawableWithCaches) {
((DrawableWithCaches) drawable).dropCaches();
}
}
@Override
protected CloseableReference getCachedImage() { // 关闭引用策略
if (!getExperiment().mIsFastCheckEnabled) {
return null;
}
if (mMemoryCache == null || mCacheKey == null) {
return null;
}
// We get the CacheKey
CloseableReference 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 { // 检查类
private boolean mIsFastCheckEnabled;
public Experiment setFastCheckEnabled(final boolean fastCheckEnabled) {
mIsFastCheckEnabled = fastCheckEnabled;
return this;
}
}
}
上面只是实力类，真正调用在基类, 比较重要的就是getDataSource()和createDrawable()的实现了，其它都是释放资源和回收，后面再讲这个资源回收和回掉过程
接下来看基类指明干活
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 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.
* 这货也比较重要，但尼玛你没有定制自己controllistener，默认为null，没有什么卵用
*/
private static class InternalForwardingListener extends ForwardingControllerListener {
public static InternalForwardingListener createInternal(
ControllerListener listener1,
ControllerListener listener2) {
InternalForwardingListener forwarder = new InternalForwardingListener();
forwarder.addListener(listener1);
forwarder.addListener(listener2);
return forwarder;
}
}
// Components
private final DraweeEventTracker mEventTracker = DraweeEventTracker.newInstance(); // 日志追踪
private final DeferredReleaser mDeferredReleaser; // 赖加载，延迟安排任务
private final Executor mUiThreadImmediateExecutor; // ui线程从PipelineDraweeControllerBuilder ：PipelineDraweeControllerFactory 来的
// Optional components
private @Nullable RetryManager mRetryManager; // 重试机制
private @Nullable GestureDetector mGestureDetector; // 手势
private @Nullable ControllerListener mControllerListener; // 业务逻辑回掉监听
// Hierarchy
private @Nullable SettableDraweeHierarchy mSettableDraweeHierarchy; // view对象树， 用于组织和维护最终绘制和呈现的 Drawable 对象
private @Nullable Drawable mControllerOverlay; // view对象
// 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; // 是否已经开始request
private boolean mHasFetchFailed;// 当前request更新失败flag
private boolean mRetainImageOnFailure;// 设置是否显示最新的可用的图片（默认图），在失败的时候
private @Nullable String mContentDescription; // 描述
private @Nullable DataSource mDataSource; // 子类data策略
private @Nullable T mFetchedImage; // 获取到当前image
private @Nullable Drawable mDrawable; // 图片资源
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() { // 释放hold的image和data，为request做准备
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() { // 默认情况都是null，基本无卵用，如果你有特殊要求，这个上下文能起到很大重要，如，日志追踪
return mCallerContext;
}
protected @Nullable RetryManager getRetryManager() { // 重试机制
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);
}
}
// 这货有意思了，这货给你个flag，需要set进来，作用是你下载完后，失败需要重新下载标志
protected void setRetainImageOnFailure(boolean enabled) {
mRetainImageOnFailure = enabled;
}
.......
// 基本无用，默认是null，为了完成你自己定制的回掉监听设置
/** Adds controller listener. */
public void addControllerListener(ControllerListener controllerListener) {
Preconditions.checkNotNull(controllerListener);
if (mControllerListener instanceof InternalForwardingListener) {
((InternalForwardingListener) mControllerListener).addListener(controllerListener);
return;
}
if (mControllerListener != null) {
mControllerListener = InternalForwardingListener.createInternal(
mControllerListener,
controllerListener);
return;
}
// Listener only receives , it never produces one.
// That means if it can accept , it can very well accept .
mControllerListener = (ControllerListener) controllerListener;
}
.......
/** Gets controller listener for internal use. */
protected ControllerListener getControllerListener() {
if (mControllerListener == null) {
return BaseControllerListener.getNoOpListener();
}
return mControllerListener;
}
/** Gets the hierarchy */
@Override
public @Nullable
DraweeHierarchy getHierarchy() {
return mSettableDraweeHierarchy;
}
// 这函数比较屌，维护view树，以后再讲
@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() { // 回调
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() { // 回调
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) { // 回调
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 判断是否超过重新的最大值（MAX：4次）
}
@Override
public boolean onClick() {// 回调
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准备
mRetryManager.notifyTapToRetry();
mSettableDraweeHierarchy.reset();
submitRequest();
return true;
}
return false;
}
protected void submitRequest() { // 这货就是干活的
final T closeableImage = getCachedImage(); // 拿到子类的Cache图片
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); // 给监听器去干活，一个id一个坑
mSettableDraweeHierarchy.setProgress(0, true);// 对象树准备
mIsRequestSubmitted = true;// 已经提交
mHasFetchFailed = false;// 重置
mDataSource = getDataSource(); // 获取子类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 dataSubscriber =
new BaseDataSubscriber() {
@Override
public void onNewResultImpl(DataSource 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 dataSource) {
onFailureInternal(id, dataSource, dataSource.getFailureCause(), /* isFinished */ true);
}
@Override
public void onProgressUpdate(DataSource dataSource) {
boolean isFinished = dataSource.isFinished();
float progress = dataSource.getProgress();
onProgressUpdateInternal(id, dataSource, progress, isFinished);
}
};
mDataSource.subscribe(dataSubscriber, mUiThreadImmediateExecutor); // 在ui线程订阅，开始刷新
}
private void onNewResultInternal( // 成功
String id,
DataSource 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)) { // 略过老data
logMessageAndImage("ignore_old_datasource @ onNewResult", image);
releaseImage(image);
dataSource.close();
return;
}
mEventTracker.recordEvent( // 日志追踪
isFinished ? Event.ON_DATASOURCE_RESULT : Event.ON_DATASOURCE_RESULT_INT);
// create drawable
Drawable drawable;
try {
drawable = createDrawable(image); //调用子类策略创建drawable
} catch (Exception exception) { // 失败打印和释放资源
logMessageAndImage("drawable_failed @ onNewResult", image);
releaseImage(image);
onFailureInternal(id, dataSource, exception, isFinished);
return;
}
T previousImage = mFetchedImage; // 完成新老数据交换
Drawable previousDrawable = mDrawable;
mFetchedImage = image; // 给hold的当前image进行策略释放
mDrawable = drawable;
try {
// set the new image
if (isFinished) { // 完成后，刷新，监听回掉，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 { // 释放当前请求资源
if (previousDrawable != null && previousDrawable != drawable) {
releaseDrawable(previousDrawable);
}
if (previousImage != null && previousImage != image) {
logMessageAndImage("release_previous_result @ onNewResult", previousImage);
releaseImage(previousImage);
}
}
}
private void onFailureInternal( // 更新失败数据
String id,
DataSource dataSource,
Throwable throwable,
boolean isFinished) {
// ignore late callbacks (data source that failed is not the one we expected)
if (!isExpectedDataSource(id, dataSource)) { // 判断是否是自己感兴趣的data
logMessageAndFailure("ignore_old_datasource @ onFailure", throwable);
dataSource.close();
return;
}
mEventTracker.recordEvent( // 日志追踪
isFinished ? Event.ON_DATASOURCE_FAILURE : Event.ON_DATASOURCE_FAILURE_INT);
// fail only if the data source is finished
if (isFinished) { //刷新失败流程
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( // 更新实时数据
String id,
DataSource 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 dataSource) { // 判断当前提交状态的dataSource 释放为新的，持有id老dataSource 不再感兴趣
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;
}
// 下面都是回掉子类接口 PipelineDraweeController
protected abstract DataSource 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() : "";
}
protected int getImageHash(@Nullable T image) {
return System.identityHashCode(image);
}
protected abstract void releaseImage(@Nullable T image);
protected abstract void releaseDrawable(@Nullable Drawable drawable);
........
}
属性：SettableDraweeHierarchy 你可以认为这货就是你的drawable的修饰类所需要维护的树形结构，相当于drawable是衣服的话，DraweeHierarchy就是衣服上的线条结构和底色配色，和XML中布局默认属性差不多
这个类比较长，所有request是从attach开始submit，onDetach停止和释放资源维护。
attach和onDetach事件来自于DraweeHierarchy中toplevel，Drawable的DraweeHold，它实现了监听和派发回掉
好了你大致也看懂了submit这个函数中，先准备一些flag，然后给Listener去实现submit，然后自己订阅回掉在ui线程，开始刷新界面。
这个大多数人都有个误区，认为Listener是实现提交请求，其实不是，这货只是监听回调，真正在跑网络数据得是这个订阅得datasrouce,而这个datasrouce来自getDataSource(),这个来自AbstractDraweeControllerBuilder:getDataSourceSupplierForRequest(),一路追踪最后来自PipelineDraweeControllerBuilder:getDataSourceForRequest(),好了这个主线来了，ImagePipeline要开始干活了，往上面翻，自己再总结理解下。
接着看：Fresco源码分析（二）