Glide系列 -- 與Activity關(guān)聯(lián)關(guān)系

分析版本為glide:4.9.0

時序圖

Glide與Activity生命周期相關(guān)聯(lián)

with方法

with(Context context)
with(Activity activity)
with(FragmentActivity activity)
with(android.app.Fragment fragment)
with(Fragment fragment)// v4包下
with(View view)

所有這些with方法，首先都會根據(jù)傳入的值獲取到ApplicationContext,生成Glide對象悔雹，并獲取RequestManagerRetriever對象

根據(jù)代碼分析下

首先得到Glide對象 --initializeGlide(@NonNull Context context, @NonNull GlideBuilder builder)方法

 @SuppressWarnings("deprecation")
  private static void initializeGlide(@NonNull Context context, @NonNull GlideBuilder builder) {
    // with方法根據(jù)不同的傳值獲取其上下文 獲取到全局的上下文
    Context applicationContext = context.getApplicationContext();
    // 獲取注解GlideModule的類 如果沒有自定義的GlideModule則表蝙，返回null
    GeneratedAppGlideModule annotationGeneratedModule = getAnnotationGeneratedGlideModules();
    List<com.bumptech.glide.module.GlideModule> manifestModules = Collections.emptyList();
    // 獲取AndroidManifest.xml中meta-data中配置的GlideModule
    if (annotationGeneratedModule == null || annotationGeneratedModule.isManifestParsingEnabled()) {
      manifestModules = new ManifestParser(applicationContext).parse();
    }
    // 刪除manifestModules中與注解GlideModule重復(fù)的module
    if (annotationGeneratedModule != null
        && !annotationGeneratedModule.getExcludedModuleClasses().isEmpty()) {
      Set<Class<?>> excludedModuleClasses =
          annotationGeneratedModule.getExcludedModuleClasses();
      Iterator<com.bumptech.glide.module.GlideModule> iterator = manifestModules.iterator();
      while (iterator.hasNext()) {
        com.bumptech.glide.module.GlideModule current = iterator.next();
        if (!excludedModuleClasses.contains(current.getClass())) {
          continue;
        }
        if (Log.isLoggable(TAG, Log.DEBUG)) {
          Log.d(TAG, "AppGlideModule excludes manifest GlideModule: " + current);
        }
        iterator.remove();
      }
    }
    ... // 輸出log,無關(guān)代碼
    // 獲取RequestManagerFactory對象 如果沒有自定義的GlideModule則為null
    RequestManagerRetriever.RequestManagerFactory factory =
        annotationGeneratedModule != null
            ? annotationGeneratedModule.getRequestManagerFactory() : null;
    builder.setRequestManagerFactory(factory);
    for (com.bumptech.glide.module.GlideModule module : manifestModules) {
      module.applyOptions(applicationContext, builder);
    }
    if (annotationGeneratedModule != null) {
      annotationGeneratedModule.applyOptions(applicationContext, builder);
    }
    // 生成Glide對象
    Glide glide = builder.build(applicationContext);
    for (com.bumptech.glide.module.GlideModule module : manifestModules) {
      module.registerComponents(applicationContext, glide, glide.registry);
    }
    if (annotationGeneratedModule != null) {
      annotationGeneratedModule.registerComponents(applicationContext, glide, glide.registry);
    }
    applicationContext.registerComponentCallbacks(glide);
    Glide.glide = glide;
  }

第二步一屋，獲取RequestManagerRetriever對象
這步很簡單逢享，我們在生成Glide對象的時候就已經(jīng)生成的RequestManagerRetriever對象
GlideBuilder的build方法

...
// 根據(jù)上面分析芙扎，我們?nèi)绻麤]有寫自定義GlideModule方法，requestManagerFactory為null
 RequestManagerRetriever requestManagerRetriever =
        new RequestManagerRetriever(requestManagerFactory);
 return new Glide(
        context,
        engine,
        memoryCache,
        bitmapPool,
        arrayPool,
        requestManagerRetriever,
        connectivityMonitorFactory,
        logLevel,
        defaultRequestOptions.lock(),
        defaultTransitionOptions,
        defaultRequestListeners,
        isLoggingRequestOriginsEnabled);
  }

RequestManagerRetriever.java

public RequestManagerRetriever(@Nullable RequestManagerFactory factory) {
    // 如果factory為空，使用默認(rèn)的RequestManagerFactory
    this.factory = factory != null ? factory : DEFAULT_FACTORY;
    // 此處愧薛，我覺得很重要
    handler = new Handler(Looper.getMainLooper(), this /* Callback */);
  }

第三步，獲取RequestManager對象

根據(jù)我們調(diào)用with方法傳入的對象獲取RequestManager對象

如果當(dāng)前是后臺線程诊赊，直接獲取ApplicationContext處理

我們先來分析在當(dāng)前UI線程

 @NonNull
  public RequestManager get(@NonNull Activity activity) {
    if (Util.isOnBackgroundThread()) {
      return get(activity.getApplicationContext());
    } else {
      assertNotDestroyed(activity);
      android.app.FragmentManager fm = activity.getFragmentManager();
      return fragmentGet(
          activity, fm, /*parentHint=*/ null, isActivityVisible(activity));
    }
  }

@Deprecated
  @NonNull
  private RequestManager fragmentGet(@NonNull Context context,
      @NonNull android.app.FragmentManager fm,
      @Nullable android.app.Fragment parentHint,
      boolean isParentVisible) {
      // 獲取RequestManagerFragment
    RequestManagerFragment current = getRequestManagerFragment(fm, parentHint, isParentVisible);
    // 獲取fragment中的requestManager
    RequestManager requestManager = current.getRequestManager();
    if (requestManager == null) {
      // TODO(b/27524013): Factor out this Glide.get() call.
      Glide glide = Glide.get(context);
      // 如果沒有厚满，則新建一個，并設(shè)置到fragment中
      // factory 如果我們沒有自定的module設(shè)置的話碧磅，使用的是默認(rèn)的factory
      requestManager =
          factory.build(
              glide, current.getGlideLifecycle(), current.getRequestManagerTreeNode(), context);
      current.setRequestManager(requestManager);
    }
    return requestManager;
  }

獲取RequestManagerFragment

 @NonNull
  private RequestManagerFragment getRequestManagerFragment(
      @NonNull final android.app.FragmentManager fm,
      @Nullable android.app.Fragment parentHint,
      boolean isParentVisible) {
      // 先從FragmentManager中找看是否已經(jīng)存在該fragment
    RequestManagerFragment current = (RequestManagerFragment) fm.findFragmentByTag(FRAGMENT_TAG);
    if (current == null)
    // 如果沒有碘箍，則從我們自己的Map中找
      current = pendingRequestManagerFragments.get(fm);
      if (current == null) {
        // 如果都沒有，則新建一個fragment 
        current = new RequestManagerFragment();
        current.setParentFragmentHint(parentHint);
        // 如果當(dāng)前Activity沒有isFinishing則isParentVisible為true
        if (isParentVisible) {
            // 觸發(fā)lifecycle的onStart方法
          current.getGlideLifecycle().onStart();
        }
        //放入自己的map中
        pendingRequestManagerFragments.put(fm, current);
        // 開啟事物鲸郊，加tag 顯示fragment
        fm.beginTransaction().add(current, FRAGMENT_TAG).commitAllowingStateLoss();
        handler.obtainMessage(ID_REMOVE_FRAGMENT_MANAGER, fm).sendToTarget();
      }
    }
    return current;
  }

獲取requestManager對象最終調(diào)用RequestManager的構(gòu)造方法

RequestManager(
      Glide glide,
      Lifecycle lifecycle,
      RequestManagerTreeNode treeNode,
      RequestTracker requestTracker,
      ConnectivityMonitorFactory factory,
      Context context) {
    this.glide = glide;
    // lifecycle 為fragment中的ActivityFragmenLifecycle對象
    this.lifecycle = lifecycle;
    this.treeNode = treeNode;
    // 請求追蹤器  requestTracker = new RequestTracker()
    this.requestTracker = requestTracker;
    this.context = context;
    // 連接的監(jiān)聽器
    connectivityMonitor =
        factory.build(
            context.getApplicationContext(),
            new RequestManagerConnectivityListener(requestTracker));

    // If we're the application level request manager, we may be created on a background thread.
    // In that case we cannot risk synchronously pausing or resuming requests, so we hack around the
    // issue by delaying adding ourselves as a lifecycle listener by posting to the main thread.
    // This should be entirely safe.
    if (Util.isOnBackgroundThread()) {
      mainHandler.post(addSelfToLifecycle);
    } else {
        // 如果不是后臺線程丰榴，則添加listener
      lifecycle.addListener(this);
    }
    // 添加連接監(jiān)聽器
    lifecycle.addListener(connectivityMonitor);

    defaultRequestListeners =
        new CopyOnWriteArrayList<>(glide.getGlideContext().getDefaultRequestListeners());
    setRequestOptions(glide.getGlideContext().getDefaultRequestOptions());
    
    // 把requestManager注冊到glide中
    glide.registerRequestManager(this);
  }

當(dāng)我們所在的Activity執(zhí)行onStop()方法之后，所關(guān)聯(lián)的fragment也會執(zhí)行onStop()方法

RequestManagerFragment.java

public void onStop() {
    super.onStop();
    // lifecycle為ActivityFragmentLifecycle
    lifecycle.onStop();
  }

ActivityFragmentLifecycle.java

void onStop() {
    isStarted = false;
    //迭代注冊的listener 執(zhí)行onStop方法
    // 一個listener為RequestManager
    // 一個為connectivityMonitor
    for (LifecycleListener lifecycleListener : Util.getSnapshot(lifecycleListeners)) {
      lifecycleListener.onStop();
    }
  }

RequestManager.java

public synchronized void onStop() {
    pauseRequests();
    targetTracker.onStop();
  }
  
  public synchronized void pauseRequests() {
    // requestTracker 為RequestTracker對象 在RequestManager構(gòu)造函數(shù)中創(chuàng)建
    requestTracker.pauseRequests();
  }

RequestTracker.java

/**
   * Stops any in progress requests. 停止任何正在進(jìn)行的請求
   */
public void pauseRequests() {
    isPaused = true;
    for (Request request : Util.getSnapshot(requests)) {
      if (request.isRunning()) {
        request.clear();
        // 將請求加入list
        pendingRequests.add(request);
      }
    }
  }

到此秆撮，頁面onStop后四濒，Glide不在加載

同理頁面onStart()恢復(fù)之后
RequestTracker.java

/**
   * Starts any not yet completed or failed requests. 
   * 開始沒有完成或者失敗的請求
   */
  public void resumeRequests() {
    isPaused = false;
    for (Request request : Util.getSnapshot(requests)) {
      // We don't need to check for cleared here. Any explicit clear by a user will remove the
      // Request from the tracker, so the only way we'd find a cleared request here is if we cleared
      // it. As a result it should be safe for us to resume cleared requests.
      if (!request.isComplete() && !request.isRunning()) {
        request.begin();
      }
    }
    // 清空列表
    pendingRequests.clear();
  }

onDestory()

/**
   * Lifecycle callback that cancels all in progress requests and clears and recycles resources for
   * all completed requests.
   * 清空所有的請求，glide與RequestManager解除關(guān)系
   */
  @Override
  public synchronized void onDestroy() {
    targetTracker.onDestroy();
    for (Target<?> target : targetTracker.getAll()) {
      clear(target);
    }
    targetTracker.clear();
    requestTracker.clearRequests();
    lifecycle.removeListener(this);
    lifecycle.removeListener(connectivityMonitor);
    mainHandler.removeCallbacks(addSelfToLifecycle);
    glide.unregisterRequestManager(this);
  }