Android 屏幕旋转事件流程分析

本文转自：https://blog.csdn.net/wo_sxn/article/details/52345323

WindowManagerService.java (android-6.0\frameworks\base\services\core\java\com\android\server\wm)

[java] view plain copy print?private void initPolicy() {
UiThread.getHandler().runWithScissors(new Runnable() {
@Override
public void run() {
WindowManagerPolicyThread.set(Thread.currentThread(), Looper.myLooper());

mPolicy.init(mContext, WindowManagerService.this, WindowManagerService.this);
}
}, 0);
}

private void initPolicy() {
UiThread.getHandler().runWithScissors(new Runnable() {
@Override
public void run() {
WindowManagerPolicyThread.set(Thread.currentThread(), Looper.myLooper());

mPolicy.init(mContext, WindowManagerService.this, WindowManagerService.this);
}
}, 0);
}

在WMS构造方法中就调用initPolicy方法。在这个方法中，很明显是在初始化mPolicy：WindowManagerPolicy这个变量。

在WMS中，该变量实质是PhoneWindowManager对象。PhoneWindowManager类实现了WindowManagerPolicy接口类。

PhoneWindowManager.java (android-6.0\frameworks\base\services\core\java\com\android\server\policy)

[java] view plain copy print?/** {@inheritDoc} */
@Override
public void init(Context context, IWindowManager wind
4000
owManager,
WindowManagerFuncs windowManagerFuncs) {
mContext = context;
mWindowManager = windowManager;
mWindowManagerFuncs = windowManagerFuncs;

mOrientationListener = new MyOrientationListener(mContext, mHandler);
try {
mOrientationListener.setCurrentRotation(windowManager.getRotation());
} catch (RemoteException ex) { }

}

/** {@inheritDoc} */
@Override
public void init(Context context, IWindowManager windowManager,
WindowManagerFuncs windowManagerFuncs) {
mContext = context;
mWindowManager = windowManager;
mWindowManagerFuncs = windowManagerFuncs;

mOrientationListener = new MyOrientationListener(mContext, mHandler);
try {
mOrientationListener.setCurrentRotation(windowManager.getRotation());
} catch (RemoteException ex) { }

}

发现在初始化的过程中，实例化一个方位监听对象MyOrientationListener，并且给它设置了初始值。该初始值从WMS中获取，默认为0。

MyOrientationListener类是PhoneWindowManager的一个内部类，它继承了WindowOrientationListener类。

WindowOrientationListener.java (android-6.0\frameworks\base\services\core\java\com\android\server\policy)

[java] view plain copy print?private WindowOrientationListener(Context context, Handler handler, int rate) {
mHandler = handler;
mSensorManager = (SensorManager)context.getSystemService(Context.SENSOR_SERVICE);
mRate = rate;
mSensor = mSensorManager.getDefaultSensor(USE_GRAVITY_SENSOR
? Sensor.TYPE_GRAVITY : Sensor.TYPE_ACCELEROMETER);
if (mSensor != null) {
// Create listener only if sensors do exist
mSensorEventListener = new SensorEventListenerImpl(context);
}
}

private WindowOrientationListener(Context context, Handler handler, int rate) {
mHandler = handler;
mSensorManager = (SensorManager)context.getSystemService(Context.SENSOR_SERVICE);
mRate = rate;
mSensor = mSensorManager.getDefaultSensor(USE_GRAVITY_SENSOR
? Sensor.TYPE_GRAVITY : Sensor.TYPE_ACCELEROMETER);
if (mSensor != null) {
// Create listener only if sensors do exist
mSensorEventListener = new SensorEventListenerImpl(context);
}
}

看到这边，一下子就明白旋屏事件上报的大致流程。首先由传感器计算数据确认是否上报，然后通过Handler或者回调方法来处理。这么想是因为构造器中传递进来一个Handler对象，另外本身就是通过其子类调用才进入WindowOrientationListener。具体是怎么一个流程，还要分析接下来的代码。

在这里，默认采用的传感器是加速度传感器，USE_GRAVITY_SENSOR：false

在Android7.0中，默认采用的是方向传感器。

WindowOrientationListener构造器中，mSensorManager、mSensor、mSensorEventListener对象。在后面的enable方法中，通过mSensorManager调用registerListener为mSensor注册监听事件mSensorEventListener。

[java] view plain copy print? * Enables the WindowOrientationListener so it will monitor the sensor and call
* {@link #onProposedRotationChanged(int)} when the device orientation changes.
*/
public void enable() {

mSensorManager.registerListener(mSensorEventListener, mSensor, mRate, mHandler);
mEnabled = true;
}
}
}

* Enables the WindowOrientationListener so it will monitor the sensor and call
* {@link #onProposedRotationChanged(int)} when the device orientation changes.
*/
public void enable() {

mSensorManager.registerListener(mSensorEventListener, mSensor, mRate, mHandler);
mEnabled = true;
}
}
}

这里不关注这些个点，还是去看传感器监听处理这一块内容。

SensorEventListenerImpl是WindowOrientationListener的内部类，它实现了接口。

@Override

[java] view plain copy print?public void onSensorChanged(SensorEvent event) {
int proposedRotation;
int oldProposedRotation;

synchronized (mLock) {
// The vector given in the SensorEvent points straight up (towards the sky) under
// ideal conditions (the phone is not accelerating). I’ll call this up vector
// elsewhere.
float x = event.values[ACCELEROMETER_DATA_X];
float y = event.values[ACCELEROMETER_DATA_Y];
float z = event.values[ACCELEROMETER_DATA_Z];
}
}

// Tell the listener.
if (proposedRotation != oldProposedRotation && proposedRotation >= 0) {
if (LOG) {
Slog.v(TAG, ”Proposed rotation changed! proposedRotation=” + proposedRotation
+ ”, oldProposedRotation=” + oldProposedRotation);
}
onProposedRotationChanged(proposedRotation);
}
}

public void onSensorChanged(SensorEvent event) {
int proposedRotation;
int oldProposedRotation;

synchronized (mLock) {
// The vector given in the SensorEvent points straight up (towards the sky) under
// ideal conditions (the phone is not accelerating).  I'll call this up vector
// elsewhere.
float x = event.values[ACCELEROMETER_DATA_X];
float y = event.values[ACCELEROMETER_DATA_Y];
float z = event.values[ACCELEROMETER_DATA_Z];
}
}

// Tell the listener.
if (proposedRotation != oldProposedRotation && proposedRotation >= 0) {
if (LOG) {
Slog.v(TAG, "Proposed rotation changed!  proposedRotation=" + proposedRotation
+ ", oldProposedRotation=" + oldProposedRotation);
}
onProposedRotationChanged(proposedRotation);
}
}

传感器数据计算过程这里省略了，在onSensorChanged方法的最后通过函数回调上报旋屏事件。回顾上面的内容，验证的确如此。

[java] view plain copy print?/**
* Called when the rotation view of the device has changed.
*
* This method is called whenever the orientation becomes certain of an orientation.
* It is called each time the orientation determination transitions from being
* uncertain to being certain again, even if it is the same orientation as before.
*
* @param rotation The new orientation of the device, one of the Surface.ROTATION_* constants.
* @see android.view.Surface
*/
public abstract void onProposedRotationChanged(int rotation);

/**
* Called when the rotation view of the device has changed.
*
* This method is called whenever the orientation becomes certain of an orientation.
* It is called each time the orientation determination transitions from being
* uncertain to being certain again, even if it is the same orientation as before.
*
* @param rotation The new orientation of the device, one of the Surface.ROTATION_* constants.
* @see android.view.Surface
*/
public abstract void onProposedRotat
170df
ionChanged(int rotation);

onProposedRotationChanged方法是声明在WindowOrientationListener类的一个抽象方法，它具体实现在PhoneWindowManager的一个内部类，即MyOrientationListener。

PhoneWindowManager.java (android-6.0\frameworks\base\services\core\java\com\android\server\policy)

[java] view plain copy print?@Override
public void onProposedRotationChanged(int rotation) {
if (localLOGV) Slog.v(TAG, “onProposedRotationChanged, rotation=” + rotation);
updateRotation(false);
}

@Override
public void onProposedRotationChanged(int rotation) {
if (localLOGV) Slog.v(TAG, "onProposedRotationChanged, rotation=" + rotation);
updateRotation(false);
}

[java] view plain copy print?void updateRotation(boolean alwaysSendConfiguration) {
try {
//set orientation on WindowManager
mWindowManager.updateRotation(alwaysSendConfiguration, false); //false、false
} catch (RemoteException e) {
// Ignore
}
}

void updateRotation(boolean alwaysSendConfiguration) {
try {
//set orientation on WindowManager
mWindowManager.updateRotation(alwaysSendConfiguration, false); //false、false
} catch (RemoteException e) {
// Ignore
}
}

很明显，是通知WMS更新rotation。

WindowManagerService.java (android-6.0\frameworks\base\services\core\java\com\android\server\wm)

[java] view plain copy print?/**
* Recalculate the current rotation.
*
* Called by the window manager policy whenever the state of the system changes
* such that the current rotation might need to be updated, such as when the
* device is docked or rotated into a new posture.
*/
@Override
public void updateRotation(boolean alwaysSendConfiguration, boolean forceRelayout) {
updateRotationUnchecked(alwaysSendConfiguration, forceRelayout);
}

/**
* Recalculate the current rotation.
*
* Called by the window manager policy whenever the state of the system changes
* such that the current rotation might need to be updated, such as when the
* device is docked or rotated into a new posture.
*/
@Override
public void updateRotation(boolean alwaysSendConfiguration, boolean forceRelayout) {
updateRotationUnchecked(alwaysSendConfiguration, forceRelayout);
}

[java] view plain copy print?public void updateRotationUnchecked(boolean alwaysSendConfiguration, boolean forceRelayout) {

boolean changed;
synchronized(mWindowMap) {
changed = updateRotationUncheckedLocked(false);

if (changed || alwaysSendConfiguration) {
sendNewConfiguration();
}

}

public void updateRotationUnchecked(boolean alwaysSendConfiguration, boolean forceRelayout) {

boolean changed;
synchronized(mWindowMap) {
changed = updateRotationUncheckedLocked(false);

if (changed || alwaysSendConfiguration) {
sendNewConfiguration();
}

}

一般情况，rotation都是发生变化的，也就是说updateRotationUncheckedLocked返回值通常为true，故会调用sendNewConfiguration。

[java] view plain copy print?/*
* Instruct the Activity Manager to fetch the current configuration and broadcast
* that to config-changed listeners if appropriate.
*/
void sendNewConfiguration() {
try {
mActivityManager.updateConfiguration(null);
} catch (RemoteException e) {
}
}

/*
* Instruct the Activity Manager to fetch the current configuration and broadcast
* that to config-changed listeners if appropriate.
*/
void sendNewConfiguration() {
try {
mActivityManager.updateConfiguration(null);
} catch (RemoteException e) {
}
}

mActivityManager本质是AMS Server端，这里从WMS运行至AMS，

ActivityManagerService.java (android-6.0\frameworks\base\services\core\java\com\android\server\am)

[java] view plain copy print?public void updateConfiguration(Configuration values) {
enforceCallingPermission(android.Manifest.permission.CHANGE_CONFIGURATION,
”updateConfiguration()”);

synchronized(this) {
if (values == null && mWindowManager != null) {
// sentinel: fetch the current configuration from the window manager
values = mWindowManager.computeNewConfiguration();
}

updateConfigurationLocked(values, null, false, false);

}
}

public void updateConfiguration(Configuration values) {
enforceCallingPermission(android.Manifest.permission.CHANGE_CONFIGURATION,
"updateConfiguration()");

synchronized(this) {
if (values == null && mWindowManager != null) {
// sentinel: fetch the current configuration from the window manager
values = mWindowManager.computeNewConfiguration();
}

updateConfigurationLocked(values, null, false, false);

}
}

AMS中，第一步：检查权限，没有权限则抛一个异常；第二步：从WMS中获取Configuration值；第三步：去真正更新Configuration值。

[java] view plain copy print?/**
* Do either or both things: (1) change the current configuration, and (2)
* make sure the given activity is running with the (now) current
* configuration. Returns true if the activity has been left running, or
* false if <var>starting</var> is being destroyed to match the new
* configuration.
* @param persistent TODO
*/
boolean updateConfigurationLocked(Configuration values,
ctivityRecord starting, boolean persistent, boolean initLocale) {
int changes = 0;

if (values != null) {
Configuration newConfig = new Configuration(mConfiguration);
changes = newConfig.updateFrom(values);

for (int i=mLruProcesses.size()-1; i>=0; i–) {
ProcessRecord app = mLruProcesses.get(i);
try {
if (app.thread != null) {
if (DEBUG_CONFIGURATION) Slog.v(TAG_CONFIGURATION, “Sending to proc ”
+ app.processName + ” new config ” + mConfiguration);
app.thread.scheduleConfigurationChanged(configCopy);
}
} catch (Exception e) {
}
}

boolean kept = true;
final ActivityStack mainStack = mStackSupervisor.getFocusedStack();
// mainStack is null during startup.
if (mainStack != 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 = mainStack.topRunningActivityLocked(null);
}

if (starting != null) {
kept = mainStack.ensureActivityConfigurationLocked(starting, changes);
// And we need to make sure at this point that all other activities
// are made visible with the correct configuration.
mStackSupervisor.ensureActivitiesVisibleLocked(starting, changes);
}
}

if (values != null && mWindowManager != null) {
mWindowManager.setNewConfiguration(mConfiguration);
}

return kept;
}

/**
* Do either or both things: (1) change the current configuration, and (2)
* make sure the given activity is running with the (now) current
* configuration.  Returns true if the activity has been left running, or
* false if <var>starting</var> is being destroyed to match the new
* configuration.
* @param persistent TODO
*/
boolean updateConfigurationLocked(Configuration values,
ctivityRecord starting, boolean persistent, boolean initLocale) {
int changes = 0;

if (values != null) {
Configuration newConfig = new Configuration(mConfiguration);
changes = newConfig.updateFrom(values);

for (int i=mLruProcesses.size()-1; i>=0; i--) {
ProcessRecord app = mLruProcesses.get(i);
try {
if (app.thread != null) {
if (DEBUG_CONFIGURATION) Slog.v(TAG_CONFIGURATION, "Sending to proc "
+ app.processName + " new config " + mConfiguration);
app.thread.scheduleConfigurationChanged(configCopy);
}
} catch (Exception e) {
}
}

boolean kept = true;
final ActivityStack mainStack = mStackSupervisor.getFocusedStack();
// mainStack is null during startup.
if (mainStack != 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 = mainStack.topRunningActivityLocked(null);
}

if (starting != null) {
kept = mainStack.ensureActivityConfigurationLocked(starting, changes);
// And we need to make sure at this point that all other activities
// are made visible with the correct configuration.
mStackSupervisor.ensureActivitiesVisibleLocked(starting, changes);
}
}

if (values != null && mWindowManager != null) {
mWindowManager.setNewConfiguration(mConfiguration);
}

return kept;
}

通常当发生横竖屏切换的时候，Activity的生命周期通常是：onConfigureationChanged –> onDestroy –> onCreate –> onStart –> onResume。一看这里就分为两步骤，一：通知Configuration已经改变；二：获取栈顶的Activity，重新运行该Activity，以适配新的Configuration。

IApplicationThread是一个aidl文件。这里最终调用的是ApplicationThread对象，而ApplicationThread类是ActivityThread的一个内部类。

ActivityThread.java (android-6.0\frameworks\base\core\java\android\app)

[java] view plain copy print?public void scheduleConfigurationChanged(Configuration config) {
updatePendingConfiguration(config);
sendMessage(H.CONFIGURATION_CHANGED, config);
}

public void scheduleConfigurationChanged(Configuration config) {
updatePendingConfiguration(config);
sendMessage(H.CONFIGURATION_CHANGED, config);
}

直接通过Handler机制与ActivityThread进行通信。

[java] view plain copy print?public void handleMessage(Message msg) {

case CONFIGURATION_CHANGED:
Trace.traceBegin(Trace.TRACE_TAG_ACTIVITY_MANAGER, ”configChanged”);
mCurDefaultDisplayDpi = ((Configuration)msg.obj).densityDpi;
handleConfigurationChanged((Configuration)msg.obj, null);
Trace.traceEnd(Trace.TRACE_TAG_ACTIVITY_MANAGER);
break;
}
if (DEBUG_MESSAGES) Slog.v(TAG, “<<< done: ” + codeToString(msg.what));
}

public void handleMessage(Message msg) {

case CONFIGURATION_CHANGED:
Trace.traceBegin(Trace.TRACE_TAG_ACTIVITY_MANAGER, "configChanged");
mCurDefaultDisplayDpi = ((Configuration)msg.obj).densityDpi;
handleConfigurationChanged((Configuration)msg.obj, null);
Trace.traceEnd(Trace.TRACE_TAG_ACTIVITY_MANAGER);
break;
}
if (DEBUG_MESSAGES) Slog.v(TAG, "<<< done: " + codeToString(msg.what));
}

[java] view plain copy print?final void handleConfigurationChanged(Configuration config, CompatibilityInfo compat) {

ArrayList<ComponentCallbacks2> callbacks = collectComponentCallbacks(false, config);

freeTextLayoutCachesIfNeeded(configDiff);

if (callbacks != null) {
final int N = callbacks.size();
for (int i=0; i<N; i++) {
performConfigurationChanged(callbacks.get(i), config);
}
}
}

final void handleConfigurationChanged(Configuration config, CompatibilityInfo compat) {

ArrayList<ComponentCallbacks2> callbacks = collectComponentCallbacks(false, config);

freeTextLayoutCachesIfNeeded(configDiff);

if (callbacks != null) {
final int N = callbacks.size();
for (int i=0; i<N; i++) {
performConfigurationChanged(callbacks.get(i), config);
}
}
}

[java] view plain copy print?private static void performConfigurationChanged(ComponentCallbacks2 cb, Configuration config) {
// Only for Activity objects, check that they actually call up to their
// superclass implementation. ComponentCallbacks2 is an interface, so
// we check the runtime type and act accordingly.
Activity activity = (cb instanceof Activity) ? (Activity) cb : null;

if (shouldChangeConfig) {
cb.onConfigurationChanged(config);

}

private static void performConfigurationChanged(ComponentCallbacks2 cb, Configuration config) {
// Only for Activity objects, check that they actually call up to their
// superclass implementation.  ComponentCallbacks2 is an interface, so
// we check the runtime type and act accordingly.
Activity activity = (cb instanceof Activity) ? (Activity) cb : null;

if (shouldChangeConfig) {
cb.onConfigurationChanged(config);

}

很明显，在这里调用了onConfigurationChanged方法。也就是常说在横竖屏切换的时候先调用Activity的onConfigurationChanged，通常会重写这个方法，做一些保存参数之类的操作。

在调用完onConfigurationChanged后，Activity会重新创建。所以就回到AMS的updateConfigurationLocked方法中。

kept = mainStack.ensureActivityConfigurationLocked(starting, changes);

mainStack：ActivityStack。

ActivityStack.java (android-6.0\frameworks\base\services\core\java\com\android\server\am)

[java] view plain copy print?/**
* Make sure the given activity matches the current configuration. Returns
* false if the activity had to be destroyed. Returns true if the
* configuration is the same, or the activity will remain running as-is
* for whatever reason. Ensures the HistoryRecord is updated with the
* correct configuration and all other bookkeeping is handled.
*/
final boolean ensureActivityConfigurationLocked(ActivityRecord r,
int globalChanges) {

if ((changes&(~r.info.getRealConfigChanged())) != 0 || r.forceNewConfig) {
// Aha, the activity isn’t handling the change, so DIE DIE DIE.
r.configChangeFlags |= changes;
r.startFreezingScreenLocked(r.app, globalChanges);
r.forceNewConfig = false;
if (r.app == null || r.app.thread == null) {
if (DEBUG_SWITCH || DEBUG_CONFIGURATION) Slog.v(TAG_CONFIGURATION,
”Config is destroying non-running ” + r);
destroyActivityLocked(r, true, “config”);
} else if (r.state == ActivityState.PAUSING) {
// A little annoying: we are waiting for this activity to
// finish pausing. Let’s not do anything now, but just
// flag that it needs to be restarted when done pausing.
if (DEBUG_SWITCH || DEBUG_CONFIGURATION) Slog.v(TAG_CONFIGURATION,
”Config is skipping already pausing ” + r);
r.configDestroy = true;
return true;
} else if (r.state == ActivityState.RESUMED) {
// Try to optimize this case: the configuration is changing
// and we need to restart the top, resumed activity.
// Instead of doing the normal handshaking, just say
// “restart!”.
if (DEBUG_SWITCH || DEBUG_CONFIGURATION) Slog.v(TAG_CONFIGURATION,
”Config is relaunching resumed ” + r);
relaunchActivityLocked(r, r.configChangeFlags, true);
r.configChangeFlags = 0;
} else {
if (DEBUG_SWITCH || DEBUG_CONFIGURATION) Slog.v(TAG_CONFIGURATION,
”Config is relaunching non-resumed ” + r);
relaunchActivityLocked(r, r.configChangeFlags, false);
r.configChangeFlags = 0;
}

// All done… tell the caller we weren’t able to keep this
// activity around.
return false;
}

return true;
}

/**
* Make sure the given activity matches the current configuration.  Returns
* false if the activity had to be destroyed.  Returns true if the
* configuration is the same, or the activity will remain running as-is
* for whatever reason.  Ensures the HistoryRecord is updated with the
* correct configuration and all other bookkeeping is handled.
*/
final boolean ensureActivityConfigurationLocked(ActivityRecord r,
int globalChanges) {

if ((changes&(~r.info.getRealConfigChanged())) != 0 || r.forceNewConfig) {
// Aha, the activity isn't handling the change, so DIE DIE DIE.
r.configChangeFlags |= changes;
r.startFreezingScreenLocked(r.app, globalChanges);
r.forceNewConfig = false;
if (r.app == null || r.app.thread == null) {
if (DEBUG_SWITCH || DEBUG_CONFIGURATION) Slog.v(TAG_CONFIGURATION,
"Config is destroying non-running " + r);
destroyActivityLocked(r, true, "config");
} else if (r.state == ActivityState.PAUSING) {
// A little annoying: we are waiting for this activity to
// finish pausing.  Let's not do anything now, but just
// flag that it needs to be restarted when done pausing.
if (DEBUG_SWITCH || DEBUG_CONFIGURATION) Slog.v(TAG_CONFIGURATION,
"Config is skipping already pausing " + r);
r.configDestroy = true;
return true;
} else if (r.state == ActivityState.RESUMED) {
// Try to optimize this case: the configuration is changing
// and we need to restart the top, resumed activity.
// Instead of doing the normal handshaking, just say
// "restart!".
if (DEBUG_SWITCH || DEBUG_CONFIGURATION) Slog.v(TAG_CONFIGURATION,
"Config is relaunching resumed " + r);
relaunchActivityLocked(r, r.configChangeFlags, true);
r.configChangeFlags = 0;
} else {
if (DEBUG_SWITCH || DEBUG_CONFIGURATION) Slog.v(TAG_CONFIGURATION,
"Config is relaunching non-resumed " + r);
relaunchActivityLocked(r, r.configChangeFlags, false);
r.configChangeFlags = 0;
}

// All done...  tell the caller we weren't able to keep this
// activity around.
return false;
}

return true;
}

[java] view plain copy print?private boolean relaunchActivityLocked(ActivityRecord r, int changes, boolean andResume) {

try {
if (DEBUG_SWITCH || DEBUG_STATES) Slog.i(TAG_SWITCH,
”Moving to ” + (andResume ? “RESUMED” : “PAUSED”) + “ Relaunching ” + r);
r.forceNewConfig = false;
r.app.thread.scheduleRelaunchActivity(r.appToken, results, newIntents, changes,
!andResume, new Configuration(mService.mConfiguration),
new Configuration(mOverrideConfig));
// Note: don’t need to call pauseIfSleepingLocked() here, because
// the caller will only pass in ‘andResume’ if this activity is
// currently resumed, which implies we aren’t sleeping.
} catch (RemoteException e) {
if (DEBUG_SWITCH || DEBUG_STATES) Slog.i(TAG_SWITCH, “Relaunch failed”, e);
}

return true;
}

private boolean relaunchActivityLocked(ActivityRecord r, int changes, boolean andResume) {

try {
if (DEBUG_SWITCH || DEBUG_STATES) Slog.i(TAG_SWITCH,
"Moving to " + (andResume ? "RESUMED" : "PAUSED") + " Relaunching " + r);
r.forceNewConfig = false;
r.app.thread.scheduleRelaunchActivity(r.appToken, results, newIntents, changes,
!andResume, new Configuration(mService.mConfiguration),
new Configuration(mOverrideConfig));
// Note: don't need to call pauseIfSleepingLocked() here, because
// the caller will only pass in 'andResume' if this activity is
// currently resumed, which implies we aren't sleeping.
} catch (RemoteException e) {
if (DEBUG_SWITCH || DEBUG_STATES) Slog.i(TAG_SWITCH, "Relaunch failed", e);
}

return true;
}

一眼就看明白，同样是在ApplicationThread内部通过Handler与ActivityThead进行通信，然后真正去执行relaunch操作。

总结：

旋屏事件上报流程：

1、传感器（默认为加速度传感器）计算数据，决定是否上报旋屏事件。

2、上报是通过回调函数实现的，在PhoneWindowManger中实现指定接口。

3、PhoneWindowManger与WMS进行交互，通知其更新rotation。

4、WMS更新rotation后，发现的确发生改变了，去通知AMS处理。

5、AMS获取WMS中rotation数据，然后更新处理。通常流程是通过ApplicationThread与ActivityThread交互。最后调用流程是 onConfigurationChanged –> Activity重新创建。