Configuration Change派发到App进程

整体时序

// DisplayContent.java
boolean updateDisplayOverrideConfigurationLocked(Configuration values,
        ActivityRecord starting, boolean deferResume,
        ActivityTaskManagerService.UpdateConfigurationResult result) {

    int changes = 0;
    boolean kept = true;

    mAtmService.deferWindowLayout();
    try {
        if (values != null) {
            if (mDisplayId == DEFAULT_DISPLAY) {
                // 先触发进程相关的Configuration变化
                changes = mAtmService.updateGlobalConfigurationLocked(values,
                        false /* initLocale */, false /* persistent */,
                        UserHandle.USER_NULL /* userId */);
            } else {
                changes = performDisplayOverrideConfigUpdate(values);
            }
        }

        if (!deferResume) {
            // 再触发Activity相关的Configuration的变化
            kept = mAtmService.ensureConfigAndVisibilityAfterUpdate(starting, changes);
        }
    } finally {
        mAtmService.continueWindowLayout();
    }
    .....
}

进程级别ConfigurationChangeItem

主要是更新app进程的Resource中的Configuration并触发Application/Service/Provider等的onConfigurationChanged回调。

System server

// ATMS.java
int updateGlobalConfigurationLocked(@NonNull Configuration values, boolean initLocale,
        boolean persistent, int userId) {

    ......
    Slog.i(TAG, "Config changes=" + Integer.toHexString(changes) + " " + mTempConfig);
   ......
    SparseArray<WindowProcessController> pidMap = mProcessMap.getPidMap();
    for (int i = pidMap.size() - 1; i >= 0; i--) {
        final int pid = pidMap.keyAt(i);
        final WindowProcessController app = pidMap.get(pid);
        ProtoLog.v(WM_DEBUG_CONFIGURATION, "Update process config of %s to new "
                + "config %s", app.mName, mTempConfig);
        app.onConfigurationChanged(mTempConfig);
    }
    ......
}

// WindowProcessController.java
private void scheduleConfigurationChange(IApplicationThread thread, Configuration config) {
    ProtoLog.v(WM_DEBUG_CONFIGURATION, "Sending to proc %s new config %s", mName,
            config);
    ......
    mHasCachedConfiguration = false;
    try {
        mAtm.getLifecycleManager().scheduleTransaction(thread,
                ConfigurationChangeItem.obtain(config, mLastTopActivityDeviceId));
    } catch (Exception e) {
        Slog.e(TAG_CONFIGURATION, "Failed to schedule configuration change: " + mOwner, e);
    }
}

App

// ConfigurationController.java
void handleConfigurationChanged(@Nullable Configuration config,
        @Nullable CompatibilityInfo compat) {
   ......
    synchronized (mResourcesManager) {
        ......
        // 先更新Resource中的Configuration的值
        mResourcesManager.applyConfigurationToResources(config, compat);
        ......
    }
    final ArrayList<ComponentCallbacks2> callbacks =
            mActivityThread.collectComponentCallbacks(false /* includeUiContexts */);

    freeTextLayoutCachesIfNeeded(configDiff);

    if (callbacks != null) {
        final int size = callbacks.size();
        for (int i = 0; i < size; i++) {
            ComponentCallbacks2 cb = callbacks.get(i);
            if (!equivalent) {
                // 再触发Application/Service/Provider等的回调
                performConfigurationChanged(cb, config);
            }
        }
    }
}

Activity级别

处理的两种方式

针对Activity级别的处理，relaunch当前Activity或触发当前Actiivty回调onConfigurationChanged方法，只会发生其一。

• app在AndroidManifest.xml中配置对应的configChanges，则触发Activity回调onConfigurationChanged方法
• 否则直接执行relaunch操作

ActivityRelaunchItem

如果app未在AndroidManifest.xml中配置对应的configChanges，则当configuration更改时会触发当前top页面的relaunch，对应的event log如下：

10-10 16:12:05.951  3972  8346 I configuration_changed: 512
10-10 16:12:06.021  3972  8346 I wm_relaunch_resume_activity: [0,237413577,21,com.miui.gallery/.activity.MapActivity,200]
10-10 16:12:06.022  3972  8346 I wm_relaunch_activity: [0,218943334,21,com.miui.gallery/.activity.HomePageActivity,200]
// top resume的页面重建后仍然停留在onResume的状态
10-10 16:12:06.244 20930 20930 I wm_on_top_resumed_lost_called: [237413577,com.miui.gallery.activity.MapActivity,pausing]
10-10 16:12:06.284 20930 20930 I wm_on_paused_called: [0,237413577,com.miui.gallery.activity.MapActivity,performPause,39]
10-10 16:12:06.294 20930 20930 I wm_on_stop_called: [0,237413577,com.miui.gallery.activity.MapActivity,handleRelaunchActivity,2]
10-10 16:12:06.328 20930 20930 I wm_on_destroy_called: [0,237413577,com.miui.gallery.activity.MapActivity,performDestroy,32]
10-10 16:12:06.461 20930 20930 I wm_on_create_called: [0,237413577,com.miui.gallery.activity.MapActivity,performCreate,29]
10-10 16:12:06.599 20930 20930 I wm_on_start_called: [0,237413577,com.miui.gallery.activity.MapActivity,handleStartActivity,135]
10-10 16:12:06.603 20930 20930 I wm_on_resume_called: [0,237413577,com.miui.gallery.activity.MapActivity,RESUME_ACTIVITY,2]
10-10 16:12:06.603 20930 20930 I wm_on_top_resumed_gained_called: [237413577,com.miui.gallery.activity.MapActivity,topWhenResuming]

// 可见但是pause的页面重建后最终状态仍然是onPause
10-10 16:12:06.625 20930 20930 I wm_on_stop_called: [0,218943334,com.miui.gallery.activity.HomePageActivity,handleRelaunchActivity,6]
10-10 16:12:06.649 20930 20930 I wm_on_destroy_called: [0,218943334,com.miui.gallery.activity.HomePageActivity,performDestroy,13]
10-10 16:12:06.701 20930 20930 I wm_on_create_called: [0,218943334,com.miui.gallery.activity.HomePageActivity,performCreate,34]
10-10 16:12:06.903 20930 20930 I wm_on_start_called: [0,218943334,com.miui.gallery.activity.HomePageActivity,handleStartActivity,199]
10-10 16:12:06.910 20930 20930 I wm_on_resume_called: [0,218943334,com.miui.gallery.activity.HomePageActivity,LIFECYCLER_RESUME_ACTIVITY,5]
10-10 16:12:06.926 20930 20930 I wm_on_paused_called: [0,218943334,com.miui.gallery.activity.HomePageActivity,performPause,1]

传送一个ClientTransaction到app进程：

• 如果应该resume：ActivityRelaunchItem（处理Activity重建） & ResumeActivityItem （处理最终生命周期）
• 否则：ActivityRelaunchItem & PauseActivityItem

void relaunchActivityLocked(boolean preserveWindow) {
    ......
    if (andResume) {
        EventLogTags.writeWmRelaunchResumeActivity(mUserId, System.identityHashCode(this),
                task.mTaskId, shortComponentName, Integer.toHexString(configChangeFlags));
    } else {
        EventLogTags.writeWmRelaunchActivity(mUserId, System.identityHashCode(this),
                task.mTaskId, shortComponentName, Integer.toHexString(configChangeFlags));
    }

    startFreezingScreenLocked(0);

    try {
       ......
        final ClientTransactionItem callbackItem = ActivityRelaunchItem.obtain(pendingResults,
                pendingNewIntents, configChangeFlags,
                new MergedConfiguration(getProcessGlobalConfiguration(),
                        getMergedOverrideConfiguration()),
                preserveWindow);
        final ActivityLifecycleItem lifecycleItem;
        if (andResume) {
            lifecycleItem = ResumeActivityItem.obtain(isTransitionForward(),
                    shouldSendCompatFakeFocus());
        } else {
            lifecycleItem = PauseActivityItem.obtain();
        }
        final ClientTransaction transaction = ClientTransaction.obtain(app.getThread(), token);
        transaction.addCallback(callbackItem);
        transaction.setLifecycleStateRequest(lifecycleItem);
        mAtmService.getLifecycleManager().scheduleTransaction(transaction);
    } catch (RemoteException e) {
        ProtoLog.i(WM_DEBUG_STATES, "Relaunch failed %s", e);
    }
   ......
}

然后根据ResumeActivityItem和PauseActivityItem执行相应的生命周期，一般top Activity执行onResume，底下的执行onPause。

ActivityConfigurationChangeItem

如果没有在功能清单文件配置对应的configChanges，则会触发app当前的Activity执行onConfigurationChanged方法，主要是post一个ActivityConfigurationChangeItem到app进程（区分于进程级别的ConfigurationChangeItem）。

更新top Activity的Configuration

10-10 16:12:05.951  3972  8346 I configuration_changed: 512
10-10 16:12:06.021  3972  8346 I wm_relaunch_resume_activity: [0,237413577,21,com.miui.gallery/.activity.MapActivity,200]
// top resume的页面重建后仍然停留在onResume的状态
10-10 16:12:06.244 20930 20930 I wm_on_top_resumed_lost_called: [237413577,com.miui.gallery.activity.MapActivity,pausing]
10-10 16:12:06.284 20930 20930 I wm_on_paused_called: [0,237413577,com.miui.gallery.activity.MapActivity,performPause,39]
10-10 16:12:06.294 20930 20930 I wm_on_stop_called: [0,237413577,com.miui.gallery.activity.MapActivity,handleRelaunchActivity,2]
10-10 16:12:06.328 20930 20930 I wm_on_destroy_called: [0,237413577,com.miui.gallery.activity.MapActivity,performDestroy,32]
10-10 16:12:06.461 20930 20930 I wm_on_create_called: [0,237413577,com.miui.gallery.activity.MapActivity,performCreate,29]
10-10 16:12:06.599 20930 20930 I wm_on_start_called: [0,237413577,com.miui.gallery.activity.MapActivity,handleStartActivity,135]
10-10 16:12:06.603 20930 20930 I wm_on_resume_called: [0,237413577,com.miui.gallery.activity.MapActivity,RESUME_ACTIVITY,2]
10-10 16:12:06.603 20930 20930 I wm_on_top_resumed_gained_called: [237413577,com.miui.gallery.activity.MapActivity,topWhenResuming]

// ATMS.java
/** Applies latest configuration and/or visibility updates if needed. */
boolean ensureConfigAndVisibilityAfterUpdate(ActivityRecord starting, int changes) {
    boolean kept = true;
    final Task mainRootTask = mRootWindowContainer.getTopDisplayFocusedRootTask();
    // mainRootTask is null during startup.
    if (mainRootTask != null) {
        if (changes != 0 && starting == null) {
            // If the configuration changed, and the caller is not already
            // in the process of starting an activity, then find the top
            // activity to check if its configuration needs to change.
            starting = mainRootTask.topRunningActivity();
        }

        if (starting != null) {
            // 更新top running页面的configuration
            kept = starting.ensureActivityConfiguration(changes,
                    false /* preserveWindow */);
            // And we need to make sure at this point that all other activities
            // are made visible with the correct configuration.
            // 更新其它可见的Activity的configuration
            mRootWindowContainer.ensureActivitiesVisible(starting, changes,
                    !PRESERVE_WINDOWS);
        }
    }

    return kept;
}

更新其它可见的Activity的Configuration

// EnsureActivitiesVisibleHelper.java
private void setActivityVisibilityState(ActivityRecord r, ActivityRecord starting,
        final boolean resumeTopActivity) {
    .....
    final boolean reallyVisible = r.shouldBeVisibleUnchecked();
    ......
    // 如果可见且不是top
    if (reallyVisible) {
       .....
        // First: if this is not the current activity being started, make
        // sure it matches the current configuration.
        if (r != mStarting && mNotifyClients) {
            r.ensureActivityConfiguration(0 /* globalChanges */, mPreserveWindows,
              true /* ignoreVisibility */);
        }

10-10 16:12:05.951  3972  8346 I configuration_changed: 512
10-10 16:12:06.022  3972  8346 I wm_relaunch_activity: [0,218943334,21,com.miui.gallery/.activity.HomePageActivity,200]
// 可见但是pause的页面重建后最终状态仍然是onPause
10-10 16:12:06.625 20930 20930 I wm_on_stop_called: [0,218943334,com.miui.gallery.activity.HomePageActivity,handleRelaunchActivity,6]
10-10 16:12:06.649 20930 20930 I wm_on_destroy_called: [0,218943334,com.miui.gallery.activity.HomePageActivity,performDestroy,13]
10-10 16:12:06.701 20930 20930 I wm_on_create_called: [0,218943334,com.miui.gallery.activity.HomePageActivity,performCreate,34]
10-10 16:12:06.903 20930 20930 I wm_on_start_called: [0,218943334,com.miui.gallery.activity.HomePageActivity,handleStartActivity,199]
10-10 16:12:06.910 20930 20930 I wm_on_resume_called: [0,218943334,com.miui.gallery.activity.HomePageActivity,LIFECYCLER_RESUME_ACTIVITY,5]
10-10 16:12:06.926 20930 20930 I wm_on_paused_called: [0,218943334,com.miui.gallery.activity.HomePageActivity,performPause,1]

更新其它不可见Activity的Configuration

其它Activity会在下次resume的时候再触发relaunch，跟上面两个不在同一线程以及同一时间执行，如果想查找relaunch的具体原因，需要向前时间查找对应的configuration_changed的log，具体参考https://blog.csdn.net/xiaoyantan/article/details/126292133

10-11 10:58:57.071  3998 11823 I wm_set_resumed_activity: [0,com.miui.gallery/.activity.HomePageActivity,resumeTopActivity - onActivityStateChanged]
10-11 10:58:57.074  3998 11823 I wm_relaunch_resume_activity: [0,197612339,22,com.miui.gallery/.activity.HomePageActivity,200]