本次源码基于Android11分析
相关源码：
/frameworks/base/services/java/com/android/server/SystemServer.java
/frameworks/base/services/core/java/com/android/server/wm/WindowManagerService.java
/frameworks/base/services/core/java/com/android/server/policy/PhoneWindowManager.java
1. WMS的启动过程
WindowManagerService服务在system_server进程中被启动，在其startOtherServices()方法中调用WMS.main()方法开始实例化WMS,如下是WMS的整体启动流程：
wms的启动过程
public final class SystemServer {
private void run() {
try {
// 启动服务
startBootstrapServices(t);
startCoreServices(t);
startOtherServices(t);
} catch (Throwable ex) {
throw ex;
}
}
private void startOtherServices(@NonNull TimingsTraceAndSlog t) {
try {
//...
// 1. WindowManagerService启动
wm = WindowManagerService.main(context, inputManager, !mFirstBoot, mOnlyCore,
new PhoneWindowManager(), mActivityManagerService.mActivityTaskManager);
// 2. 调用WindowManagerService的onInitReady()方法
wm.onInitReady();
//...
// 3.调用WindowManagerService的displayReady()方法
wm.displayReady();
// 4.调用WindowManagerService的systemReady()方法
wm.systemReady(
}
}
}
首先调用WMS.main()实例化WindowManagerService对象，之后分别调用WMS.onInitReady()、WMS.displayReady()、WMS.systemReady()方法做后续的初始化操作。
1.2 WMS.main()
public class WindowManagerService extends IWindowManager.Stub
implements Watchdog.Monitor, WindowManagerPolicy.WindowManagerFuncs {
@VisibleForTesting
public static WindowManagerService main(final Context context, final InputManagerService im,
final boolean showBootMsgs, final boolean onlyCore, WindowManagerPolicy policy,
ActivityTaskManagerService atm, Supplier<SurfaceControl.Transaction> transactionFactory,
Supplier<Surface> surfaceFactory,
Function<SurfaceSession, SurfaceControl.Builder> surfaceControlFactory) {
// DisplayThread线程的创建WindowManagerService
DisplayThread.getHandler().runWithScissors(() ->
// 创建WindowManagerService()实例，
sInstance = new WindowManagerService(context, im, showBootMsgs, onlyCore, policy,
atm, transactionFactory, surfaceFactory, surfaceControlFactory), 0);
return sInstance;
}
private WindowManagerService(Context context, InputManagerService inputManager,
boolean showBootMsgs, boolean onlyCore, WindowManagerPolicy policy,
ActivityTaskManagerService atm, Supplier<SurfaceControl.Transaction> transactionFactory,
Supplier<Surface> surfaceFactory,
Function<SurfaceSession, SurfaceControl.Builder> surfaceControlFactory) {
installLock(this, INDEX_WINDOW);
mGlobalLock = atm.getGlobalLock();
mAtmService = atm;
mContext = context;
mIsPc = mContext.getPackageManager().hasSystemFeature(FEATURE_PC);
mAllowBootMessages = showBootMsgs;
mOnlyCore = onlyCore;
mLimitedAlphaCompositing = context.getResources().getBoolean(
com.android.internal.R.bool.config_sf_limitedAlpha);
mHasPermanentDpad = context.getResources().getBoolean(
com.android.internal.R.bool.config_hasPermanentDpad);
mInTouchMode = context.getResources().getBoolean(
com.android.internal.R.bool.config_defaultInTouchMode);
inputManager.setInTouchMode(mInTouchMode);
mDrawLockTimeoutMillis = context.getResources().getInteger(
com.android.internal.R.integer.config_drawLockTimeoutMillis);
mAllowAnimationsInLowPowerMode = context.getResources().getBoolean(
com.android.internal.R.bool.config_allowAnimationsInLowPowerMode);
mMaxUiWidth = context.getResources().getInteger(
com.android.internal.R.integer.config_maxUiWidth);
mDisableTransitionAnimation = context.getResources().getBoolean(
com.android.internal.R.bool.config_disableTransitionAnimation);
mPerDisplayFocusEnabled = context.getResources().getBoolean(
com.android.internal.R.bool.config_perDisplayFocusEnabled);
mAssistantOnTopOfDream = context.getResources().getBoolean(
com.android.internal.R.bool.config_assistantOnTopOfDream);
mInputManager = inputManager; // Must be before createDisplayContentLocked.
mDisplayManagerInternal = LocalServices.getService(DisplayManagerInternal.class);
mSurfaceControlFactory = surfaceControlFactory;
mTransactionFactory = transactionFactory;
mSurfaceFactory = surfaceFactory;
mTransaction = mTransactionFactory.get();
mDisplayWindowSettings = new DisplayWindowSettings(this);
mPolicy = policy;
mAnimator = new WindowAnimator(this);
mRoot = new RootWindowContainer(this);
mUseBLAST = DeviceConfig.getBoolean(
DeviceConfig.NAMESPACE_WINDOW_MANAGER_NATIVE_BOOT,
WM_USE_BLAST_ADAPTER_FLAG, false);
mWindowPlacerLocked = new WindowSurfacePlacer(this);
mTaskSnapshotController = new TaskSnapshotController(this);
mWindowTracing = WindowTracing.createDefaultAndStartLooper(this,
Choreographer.getInstance());
LocalServices.addService(WindowManagerPolicy.class, mPolicy);
mDisplayManager = (DisplayManager) context.getSystemService(Context.DISPLAY_SERVICE);
mKeyguardDisableHandler = KeyguardDisableHandler.create(mContext, mPolicy, mH);
mPowerManager = (PowerManager) context.getSystemService(Context.POWER_SERVICE);
mPowerManagerInternal = LocalServices.getService(PowerManagerInternal.class);
if (mPowerManagerInternal != null) {
mPowerManagerInternal.registerLowPowerModeObserver(
new PowerManagerInternal.LowPowerModeListener() {
@Override
public int getServiceType() {
return ServiceType.ANIMATION;
}
@Override
public void onLowPowerModeChanged(PowerSaveState result) {
synchronized (mGlobalLock) {
final boolean enabled = result.batterySaverEnabled;
if (mAnimationsDisabled != enabled && !mAllowAnimationsInLowPowerMode) {
mAnimationsDisabled = enabled;
dispatchNewAnimatorScaleLocked(null);
}
}
}
});
mAnimationsDisabled = mPowerManagerInternal
.getLowPowerState(ServiceType.ANIMATION).batterySaverEnabled;
}
mScreenFrozenLock = mPowerManager.newWakeLock(
PowerManager.PARTIAL_WAKE_LOCK, "SCREEN_FROZEN");
mScreenFrozenLock.setReferenceCounted(false);
mDisplayNotificationController = new DisplayWindowListenerController(this);
mActivityManager = ActivityManager.getService();
mActivityTaskManager = ActivityTaskManager.getService();
mAmInternal = LocalServices.getService(ActivityManagerInternal.class);
mAtmInternal = LocalServices.getService(ActivityTaskManagerInternal.class);
mAppOps = (AppOpsManager) context.getSystemService(Context.APP_OPS_SERVICE);
AppOpsManager.OnOpChangedInternalListener opListener =
new AppOpsManager.OnOpChangedInternalListener() {
@Override
public void onOpChanged(int op, String packageName) {
updateAppOpsState();
}
};
mAppOps.startWatchingMode(OP_SYSTEM_ALERT_WINDOW, null, opListener);
mAppOps.startWatchingMode(AppOpsManager.OP_TOAST_WINDOW, null, opListener);
mPmInternal = LocalServices.getService(PackageManagerInternal.class);
final IntentFilter suspendPackagesFilter = new IntentFilter();
suspendPackagesFilter.addAction(Intent.ACTION_PACKAGES_SUSPENDED);
suspendPackagesFilter.addAction(Intent.ACTION_PACKAGES_UNSUSPENDED);
context.registerReceiverAsUser(new BroadcastReceiver() {
@Override
public void onReceive(Context context, Intent intent) {
final String[] affectedPackages =
intent.getStringArrayExtra(Intent.EXTRA_CHANGED_PACKAGE_LIST);
final boolean suspended =
Intent.ACTION_PACKAGES_SUSPENDED.equals(intent.getAction());
updateHiddenWhileSuspendedState(new ArraySet<>(Arrays.asList(affectedPackages)),
suspended);
}
}, UserHandle.ALL, suspendPackagesFilter, null, null);
final ContentResolver resolver = context.getContentResolver();
// Get persisted window scale setting
mWindowAnimationScaleSetting = Settings.Global.getFloat(resolver,
Settings.Global.WINDOW_ANIMATION_SCALE, mWindowAnimationScaleSetting);
mTransitionAnimationScaleSetting = Settings.Global.getFloat(resolver,
Settings.Global.TRANSITION_ANIMATION_SCALE,
context.getResources().getFloat(
R.dimen.config_appTransitionAnimationDurationScaleDefault));
setAnimatorDurationScale(Settings.Global.getFloat(resolver,
Settings.Global.ANIMATOR_DURATION_SCALE, mAnimatorDurationScaleSetting));
mForceDesktopModeOnExternalDisplays = Settings.Global.getInt(resolver,
DEVELOPMENT_FORCE_DESKTOP_MODE_ON_EXTERNAL_DISPLAYS, 0) != 0;
IntentFilter filter = new IntentFilter();
// Track changes to DevicePolicyManager state so we can enable/disable keyguard.
filter.addAction(ACTION_DEVICE_POLICY_MANAGER_STATE_CHANGED);
mContext.registerReceiverAsUser(mBroadcastReceiver, UserHandle.ALL, filter, null, null);
mLatencyTracker = LatencyTracker.getInstance(context);
mSettingsObserver = new SettingsObserver();
mHoldingScreenWakeLock = mPowerManager.newWakeLock(
PowerManager.SCREEN_BRIGHT_WAKE_LOCK | PowerManager.ON_AFTER_RELEASE, TAG_WM);
mHoldingScreenWakeLock.setReferenceCounted(false);
mSurfaceAnimationRunner = new SurfaceAnimationRunner(mTransactionFactory,
mPowerManagerInternal);
mAllowTheaterModeWakeFromLayout = context.getResources().getBoolean(
com.android.internal.R.bool.config_allowTheaterModeWakeFromWindowLayout);
mTaskPositioningController = new TaskPositioningController(
this, mInputManager, mActivityTaskManager, mH.getLooper());
mDragDropController = new DragDropController(this, mH.getLooper());
mHighRefreshRateBlacklist = HighRefreshRateBlacklist.create(context.getResources());
mConstants = new WindowManagerConstants(this, DeviceConfigInterface.REAL);
mConstants.start(new HandlerExecutor(mH));
LocalServices.addService(WindowManagerInternal.class, new LocalService());
mEmbeddedWindowController = new EmbeddedWindowController(mAtmService);
mDisplayAreaPolicyProvider = DisplayAreaPolicy.Provider.fromResources(
mContext.getResources());
setGlobalShadowSettings();
}
}
通过DisplayThread线程的Handler,并调用其runWithScissors()方法，该方法会将当前的执行线程阻塞，并直到要执行的任务完成后，在重新唤醒被阻塞的线程：
public class Handler {
public final boolean runWithScissors(@NonNull Runnable r, long timeout) {
// 对runnable和time进行检查
if (r == null) {
throw new IllegalArgumentException("runnable must not be null");
}
if (timeout < 0) {
throw new IllegalArgumentException("timeout must be non-negative");
}
// 检查当前线程的Looper是否等于此mLooper
if (Looper.myLooper() == mLooper) {
r.run(); // 直接运行Runnable.run
return true;
}
BlockingRunnable br = new BlockingRunnable(r);
return br.postAndWait(this, timeout);
}
private static final class BlockingRunnable implements Runnable {
private final Runnable mTask;
private boolean mDone;
public BlockingRunnable(Runnable task) {
mTask = task;
}
@Override
public void run() {
try {
// 执行Runnable创建WMS
mTask.run();
} finally {
synchronized (this) {
mDone = true;
notifyAll();
}
}
}
public boolean postAndWait(Handler handler, long timeout) {
// 将BlockingRunnable加入到handler中
if (!handler.post(this)) {
return false;
}
// 没执行完run()方法则调用wait()让调用的线程等待
synchronized (this) {
if (timeout > 0) {
final long expirationTime = SystemClock.uptimeMillis() + timeout;
while (!mDone) {
long delay = expirationTime - SystemClock.uptimeMillis();
if (delay <= 0) {
return false; // timeout
}
try {
wait(delay);
} catch (InterruptedException ex) {
}
}
} else {
// 没执行完run()方法则调用
while (!mDone) {
try {
wait();
} catch (InterruptedException ex) {
}
}
}
}
return true;
}
}
}
会判断当前执行的线程跟调用的Handler线程是否相等，相等则执行Runnable。如果不想等，则在封装一个Runnable，并在这个Runnable类中判断是否执行了run()方法，如果没有则阻塞当前的执行线程，直到执行完Run方法后才重新唤醒。
所以在DisplayThread线程中创建了WindowManagerService实例对象。
1.3 WMS.onInitReady()
public class WindowManagerService extends IWindowManager.Stub
implements Watchdog.Monitor, WindowManagerPolicy.WindowManagerFuncs {
public void onInitReady() {
// 调用initPolicy()方法
initPolicy();
//...
}
private void initPolicy() {
UiThread.getHandler().runWithScissors(new Runnable() {
@Override
public void run() {
WindowManagerPolicyThread.set(Thread.currentThread(), Looper.myLooper());
// 此mPolicy在构造函数中赋值，由SystemServer类中传入，为PhoneWindowManager()
mPolicy.init(mContext, WindowManagerService.this, WindowManagerService.this);
}
}, 0);
}
}
public class PhoneWindowManager implements WindowManagerPolicy {
// 在UiThread线程中执行
public void init(Context context, IWindowManager windowManager,
WindowManagerFuncs windowManagerFuncs) {
mContext = context;
mWindowManager = windowManager;
mWindowManagerFuncs = windowManagerFuncs;
mWindowManagerInternal = LocalServices.getService(WindowManagerInternal.class);
mActivityManagerInternal = LocalServices.getService(ActivityManagerInternal.class);
mActivityTaskManagerInternal = LocalServices.getService(ActivityTaskManagerInternal.class);
mInputManagerInternal = LocalServices.getService(InputManagerInternal.class);
mDreamManagerInternal = LocalServices.getService(DreamManagerInternal.class);
mPowerManagerInternal = LocalServices.getService(PowerManagerInternal.class);
mAppOpsManager = mContext.getSystemService(AppOpsManager.class);
...
mHandler = new PolicyHandler();
mWakeGestureListener = new MyWakeGestureListener(mContext, mHandler);
...
mPowerManager = (PowerManager) context.getSystemService(Context.POWER_SERVICE);
mBroadcastWakeLock = mPowerManager.newWakeLock(PowerManager.PARTIAL_WAKE_LOCK,
"PhoneWindowManager.mBroadcastWakeLock");
mPowerKeyWakeLock = mPowerManager.newWakeLock(PowerManager.PARTIAL_WAKE_LOCK,
"PhoneWindowManager.mPowerKeyWakeLock");
...
mGlobalKeyManager = new GlobalKeyManager(mContext);
if (!mPowerManager.isInteractive()) {
startedGoingToSleep(WindowManagerPolicy.OFF_BECAUSE_OF_USER);
finishedGoingToSleep(WindowManagerPolicy.OFF_BECAUSE_OF_USER);
}
mWindowManagerInternal.registerAppTransitionListener(new AppTransitionListener() {
@Override
public int onAppTransitionStartingLocked(int transit, long duration,
long statusBarAnimationStartTime, long statusBarAnimationDuration) {
return handleStartTransitionForKeyguardLw(transit, duration);
}
@Override
public void onAppTransitionCancelledLocked(int transit) {
handleStartTransitionForKeyguardLw(transit, 0 /* duration */);
}
});
}
}
在UiThread线程的Handler中执行PhoneWindowManager.init()方法，进行一些变量的的初始化操作。
1.4 WMS.displayReady()、systemReady()
public class WindowManagerService extends IWindowManager.Stub
implements Watchdog.Monitor, WindowManagerPolicy.WindowManagerFuncs {
// 继续在system_server进程中执行WMS.displayReady()方法
public void displayReady() {
synchronized (mGlobalLock) {
if (mMaxUiWidth > 0) {
mRoot.forAllDisplays(displayContent -> displayContent.setMaxUiWidth(mMaxUiWidth));
}
applyForcedPropertiesForDefaultDisplay();
mAnimator.ready();
mDisplayReady = true;
// Reconfigure all displays to make sure that forced properties and
// DisplayWindowSettings are applied.
mRoot.forAllDisplays(DisplayContent::reconfigureDisplayLocked);
mIsTouchDevice = mContext.getPackageManager().hasSystemFeature(
PackageManager.FEATURE_TOUCHSCREEN);
}
try {
mActivityTaskManager.updateConfiguration(null);
} catch (RemoteException e) {
}
}
// 继续在system_server进程中执行WMS.systemReady()方法
public void systemReady() {
mSystemReady = true;
// 执行PhoneWindowManager.systemReady()方法
mPolicy.systemReady();
mRoot.forAllDisplayPolicies(DisplayPolicy::systemReady);
mTaskSnapshotController.systemReady();
mHasWideColorGamutSupport = queryWideColorGamutSupport();
mHasHdrSupport = queryHdrSupport();
UiThread.getHandler().post(mSettingsObserver::loadSettings);
IVrManager vrManager = IVrManager.Stub.asInterface(
ServiceManager.getService(Context.VR_SERVICE));
if (vrManager != null) {
try {
final boolean vrModeEnabled = vrManager.getVrModeState();
synchronized (mGlobalLock) {
vrManager.registerListener(mVrStateCallbacks);
if (vrModeEnabled) {
mVrModeEnabled = vrModeEnabled;
mVrStateCallbacks.onVrStateChanged(vrModeEnabled);
}
}
} catch (RemoteException e) {
// Ignore, we cannot do anything if we failed to register VR mode listener
}
}
}
}
WMS.systemReady()方法会调用PhoneWindowManager.systemReady()方法：
public class PhoneWindowManager implements WindowManagerPolicy {
public void systemReady() {
// In normal flow, systemReady is called before other system services are ready.
// So it is better not to bind keyguard here.
mKeyguardDelegate.onSystemReady();
mVrManagerInternal = LocalServices.getService(VrManagerInternal.class);
if (mVrManagerInternal != null) {
mVrManagerInternal.addPersistentVrModeStateListener(mPersistentVrModeListener);
}
readCameraLensCoverState();
updateUiMode();
mDefaultDisplayRotation.updateOrientationListener();
synchronized (mLock) {
mSystemReady = true;
mHandler.post(new Runnable() {
@Override
public void run() {
updateSettings();
}
});
// If this happens, for whatever reason, systemReady came later than systemBooted.
// And keyguard should be already bound from systemBooted
if (mSystemBooted) {
mKeyguardDelegate.onBootCompleted();
}
}
mAutofillManagerInternal = LocalServices.getService(AutofillManagerInternal.class);
}
}
至此WindowManagerService在system_server进程的启动就完成了，WMS主要有四大功能：
- Window窗口的管理
- Surface的管理
- Input系统的管理
- 窗口动画
如下是WindowManagerService的关联图：
