Glide源码分析和时序图

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使用就不介绍了

Glide.with(this)源码分析

分析下重要的源码:看下第3步

  SupportRequestManagerFragment getSupportRequestManagerFragment(final FragmentManager fm) {
        SupportRequestManagerFragment current = (SupportRequestManagerFragment) fm.findFragmentByTag(
           FRAGMENT_TAG);
        if (current == null) {
            current = pendingSupportRequestManagerFragments.get(fm);
            if (current == null) {
            //主要看这个，最终呢new 一个ActivityFragmentLifecycle()
                current = new SupportRequestManagerFragment();
                pendingSupportRequestManagerFragments.put(fm, current);
                fm.beginTransaction().add(current, FRAGMENT_TAG).commitAllowingStateLoss();
                handler.obtainMessage(ID_REMOVE_SUPPORT_FRAGMENT_MANAGER, fm).sendToTarget();
            }
        }
        return current;
    }

ActivityFragmentLifecycle它是继承于Lifecycle，所以会复写addListener的方法

    @Override
    public void addListener(LifecycleListener listener) {
        lifecycleListeners.add(listener);

        if (isDestroyed) {
            listener.onDestroy();
        } else if (isStarted) {
            listener.onStart();
        } else {
            listener.onStop();
        }
    }

看第二步源码分析

 RequestManager supportFragmentGet(Context context, FragmentManager fm) {
        //这是第三步
        SupportRequestManagerFragment current = getSupportRequestManagerFragment(fm);
        RequestManager requestManager = current.getRequestManager();//第一次肯定是空
        if (requestManager == null) {
        //将刚才设置的ActivityFragmentLifecycle获取并设置到RequsetManager
            requestManager = new RequestManager(context, current.getLifecycle(), current.getRequestManagerTreeNode());
            current.setRequestManager(requestManager);
        }
        return requestManager;
    }

requestManager中的构造方法

  RequestManager(Context context, final Lifecycle lifecycle, RequestManagerTreeNode treeNode,
            RequestTracker requestTracker, ConnectivityMonitorFactory factory) {
        //设置参数
        this.context = context.getApplicationContext();
        this.lifecycle = lifecycle;
        this.treeNode = treeNode;
        this.requestTracker = requestTracker;
        this.glide = Glide.get(context);
        this.optionsApplier = new OptionsApplier();

        ConnectivityMonitor connectivityMonitor = factory.build(context,
                new RequestManagerConnectivityListener(requestTracker));


        if (Util.isOnBackgroundThread()) {
            new Handler(Looper.getMainLooper()).post(new Runnable() {
                @Override
                public void run() {
     //这个方法实际调用的是ActivityFragmentLifecycle中的addListener而RequstManager也是实现了LifecycleListener，它会调用自己的onstart,onDestory等方法
                    lifecycle.addListener(RequestManager.this);
                }
            });
        } else {
            lifecycle.addListener(this);
        }

        lifecycle.addListener(connectivityMonitor);
    }

SupportRequestManagerFragment的onstart

 @Override
    public void onStart() {
        super.onStart();
        lifecycle.onStart();
    }

    @Override
    public void onStop() {
        super.onStop();
        lifecycle.onStop();
    }

    @Override
    public void onDestroy() {
        super.onDestroy();
        lifecycle.onDestroy();
    }

Glide.with:最终会返回一个RequestManager对象，会去 创建一个 Fragment 绑定到 Activity 上面，Fragment 又会调用 setRequestManager() 方法，ActivityFragmentLifecycle会和Fragment生命周期绑定,即RequestManager和Fragment生命周期进行绑定，依次推到Glide.with会和Fragment进行生命周期绑定

接口类对应的类

loadProvider -> FixedLoadProvider
modelLoader -> ImageVideoModelLoader
dataFetcher -> ImageVideoFetcher
streamLoader -> StreamStringLoader -> getResourceFetcher()
uriLoader -> StreamUriLoader -> getResourceFetcher()
urlLoader -> HttpUrlGlideUrlLoader -> getResourceFetcher()
streamFetcher -> HttpUrlFetcher
dataLoadProvider -> ImageVideoGifDrawableLoadProvider -> getSourceDecoder()
sourceDecoder -> GifBitmapWrapperResourceDecoder
bitmapProvider -> ImageVideoDataLoadProvider -> getSourceDecoder() bitmapDecoder -> ImageVideoBitmapDecoder
图片：InputStream ,BitmapFactory.decodeStream() 不能直接解析，图片大小 

Glide.into时序图，源码就不进行分析了，我之前写过一篇文章是Glide源码分析：
https://blog.csdn.net/qq_24675479/article/details/79498250