Glide

Glide.with(this).load(R.drawable.xx).into(xxImageView);

with()

with()方法是Glide类中的一组静态方法，它有好几个方法重载

  public static RequestManager with(Context context) {
    return getRetriever(context).get(context);
  }

  public static RequestManager with(Activity activity) {
    return getRetriever(activity).get(activity);
  }

  public static RequestManager with(FragmentActivity activity) {
    return getRetriever(activity).get(activity);
  }

  public static RequestManager with(android.app.Fragment fragment) {
    return getRetriever(fragment.getActivity()).get(fragment);
  }

  // v4
  public static RequestManager with(Fragment fragment) {
    return getRetriever(fragment.getActivity()).get(fragment);
  }

  public static RequestManager with(View view) {
    return getRetriever(view.getContext()).get(view);
  }

获取 Context 后调用 RequestManagerRetriever 的 get() 方法

public class RequestManagerRetriever implements Handler.Callback {}

public RequestManager get(Context context) {
    if (context == null) {
      throw new IllegalArgumentException("You cannot start a load on a null Context");
    } else if (Util.isOnMainThread() && !(context instanceof Application)) {
      if (context instanceof FragmentActivity) {
        return get((FragmentActivity) context);
      } else if (context instanceof Activity) {
        return get((Activity) context);
      } else if (context instanceof ContextWrapper) {
        return get(((ContextWrapper) context).getBaseContext());
      }
    }

    return getApplicationManager(context);
  }

  public RequestManager get(FragmentActivity activity) {
    if (Util.isOnBackgroundThread()) {
      return get(activity.getApplicationContext());
    } else {
      assertNotDestroyed(activity);
      FragmentManager fm = activity.getSupportFragmentManager();
      return supportFragmentGet(activity, fm, null /*parentHint*/);
    }
  }

  public RequestManager get(Fragment fragment) {
    Preconditions.checkNotNull(fragment.getActivity(),
          "You cannot start a load on a fragment before it is attached or after it is destroyed");
    if (Util.isOnBackgroundThread()) {
      return get(fragment.getActivity().getApplicationContext());
    } else {
      FragmentManager fm = fragment.getChildFragmentManager();
      return supportFragmentGet(fragment.getActivity(), fm, fragment);
    }
  }

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

  public RequestManager get(View view) {
    if (Util.isOnBackgroundThread()) {
      return get(view.getContext().getApplicationContext());
    }

    Preconditions.checkNotNull(view);
    Preconditions.checkNotNull(view.getContext(),
        "Unable to obtain a request manager for a view without a Context");
    Activity activity = findActivity(view.getContext());
    // The view might be somewhere else, like a service.
    if (activity == null) {
      return get(view.getContext().getApplicationContext());
    }

get方法处理后调用 fragmentGet()

private RequestManager fragmentGet(Context context, android.app.FragmentManager fm,
      android.app.Fragment parentHint) {
    RequestManagerFragment current = getRequestManagerFragment(fm, parentHint);
    RequestManager requestManager = current.getRequestManager();
    if (requestManager == null) {
      // TODO(b/27524013): Factor out this Glide.get() call.
      Glide glide = Glide.get(context);
      requestManager =
          factory.build(
              glide, current.getGlideLifecycle(), current.getRequestManagerTreeNode(), context);
      current.setRequestManager(requestManager);
    }
    return requestManager;
  }

Application 的声明周期 : 非主线程和 Application 的上下文
非Application 的声明周期

// 创建一个 隐藏的Fragment
SupportRequestManagerFragment getSupportRequestManagerFragment(
      final FragmentManager fm, Fragment parentHint) {
     // 从 Map<FragmentManager, SupportRequestManagerFragment> 管理 隐藏的Fragment
    SupportRequestManagerFragment current =
        (SupportRequestManagerFragment) fm.findFragmentByTag(FRAGMENT_TAG);
    if (current == null) {
      current = pendingSupportRequestManagerFragments.get(fm);
      if (current == null) {
        // public class SupportRequestManagerFragment extends Fragment {}
        current = new SupportRequestManagerFragment();
        current.setParentFragmentHint(parentHint);
        pendingSupportRequestManagerFragments.put(fm, current);
        fm.beginTransaction().add(current, FRAGMENT_TAG).commitAllowingStateLoss();
        // 从 map 中移除 该fragment ,下次初始化为空
        handler.obtainMessage(ID_REMOVE_SUPPORT_FRAGMENT_MANAGER, fm).sendToTarget();
      }
    }
    return current;
  }

SupportRequestManagerFragment
在 SupportRequestManagerFragment 中初始化一个 ActivityFragmentLifecycle
ActivityFragmentLifecycle 负责管理 LifecycleListener ，内部使用遍历接口的方式调用 onStart(),onStop(),onDestroy()方法

public SupportRequestManagerFragment() {
    // glide 管理生命周期的类并实现了Lifecycle 接口
    this(new ActivityFragmentLifecycle());
  }

  // For testing only.
  @SuppressLint("ValidFragment")
  public SupportRequestManagerFragment(ActivityFragmentLifecycle lifecycle) {
    this.lifecycle = lifecycle;
  }

  // 将 ActivityFragmentLifecycle 提供给 RequestManager
  ActivityFragmentLifecycle getGlideLifecycle() {
    return lifecycle;
  }

    @Override
  public void onDetach() {
    super.onDetach();
    parentFragmentHint = null;
    unregisterFragmentWithRoot();
  }

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

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

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

ActivityFragmentLifecycle 在该类中管理 Lifecycle 的接口
Lifecycle 处理 LifecycleListener 的添加删除

public interface Lifecycle {
  void addListener(LifecycleListener listener);
  void removeListener(LifecycleListener listener);
}
private final Set<LifecycleListener> lifecycleListeners =
      Collections.newSetFromMap(new WeakHashMap<LifecycleListener, Boolean>());

public class RequestManager implements LifecycleListener {｝实现 LifecycleListener 并将自己添加到 ActivityFragmentLifecycle 中，hook 到 SupportRequestManagerFragment 的生命周期
RequestManager 中 SupportRequestManagerFragment 的生命周期处理

if (Util.isOnBackgroundThread()) {
      mainHandler.post(addSelfToLifecycle);
    } else {
      lifecycle.addListener(this);
    }

 @Override
  public void onStart() {
    resumeRequests();
    targetTracker.onStart();
  }

  @Override
  public void onStop() {
    pauseRequests();
    targetTracker.onStop();
  }

  @Override
  public 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);
  }

RequestTracker requestTracker; 请求(url)
TargetTracker targetTracker = new TargetTracker(); 目标(imageview)
Glide().load().into()
load() 准备加载的资源

 public RequestBuilder<TranscodeType> load(@Nullable Object model) {
    return loadGeneric(model);
  }

  private RequestBuilder<TranscodeType> loadGeneric(@Nullable Object model) {
    this.model = model;
    isModelSet = true;
    return this;
  }

into() 加载资源到 target
Request request = buildRequest(target, targetListener, options); 创建 Request

private Request obtainRequest(
      Target<TranscodeType> target,
      RequestListener<TranscodeType> targetListener,
      RequestOptions requestOptions,
      RequestCoordinator requestCoordinator,
      TransitionOptions<?, ? super TranscodeType> transitionOptions,
      Priority priority,
      int overrideWidth,
      int overrideHeight) {
    return SingleRequest.obtain(
        context,
        glideContext,
        model,
        transcodeClass,
        requestOptions,
        overrideWidth,
        overrideHeight,
        priority,
        target,
        targetListener,
        requestListener,
        requestCoordinator,
        glideContext.getEngine(),
        transitionOptions.getTransitionFactory());
  }

链接：http://blog.csdn.net/guolin_blog/article/details/53939176/

Glide 生命周期Hook

Glide

with()

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