在Android AMS(二) App启动过程之onCreate中我们讲了onCreate的调用流程，这篇我们接着分析onResume的流程
ActivityThread.java–>handleLaunchActivity()中调用performLaunchActivity()走到activity的onCreate，onStart状态后，会调用handleResumeActivity()方法
final void handleResumeActivity(IBinder token,
boolean clearHide, boolean isForward, boolean reallyResume, int seq, String reason) {
ActivityClientRecord r = mActivities.get(token);
if (!checkAndUpdateLifecycleSeq(seq, r, "resumeActivity")) {
return;
}
// If we are getting ready to gc after going to the background, well
// we are back active so skip it.
unscheduleGcIdler();
mSomeActivitiesChanged = true;
// TODO Push resumeArgs into the activity for consideration
r = performResumeActivity(token, clearHide, reason);
if (r != null) {
final Activity a = r.activity;
if (localLOGV) Slog.v(
TAG, "Resume " + r + " started activity: " +
a.mStartedActivity + ", hideForNow: " + r.hideForNow
+ ", finished: " + a.mFinished);
final int forwardBit = isForward ?
WindowManager.LayoutParams.SOFT_INPUT_IS_FORWARD_NAVIGATION : 0;
// If the window hasn't yet been added to the window manager,
// and this guy didn't finish itself or start another activity,
// then go ahead and add the window.
boolean willBeVisible = !a.mStartedActivity;
if (!willBeVisible) {
try {
willBeVisible = ActivityManager.getService().willActivityBeVisible(
a.getActivityToken());
} catch (RemoteException e) {
throw e.rethrowFromSystemServer();
}
}
if (r.window == null && !a.mFinished && willBeVisible) {
//getWindow就是Activity attach（）中new的PhoneWindow()
r.window = r.activity.getWindow();
View decor = r.window.getDecorView();
decor.setVisibility(View.INVISIBLE);
ViewManager wm = a.getWindowManager();
WindowManager.LayoutParams l = r.window.getAttributes();
a.mDecor = decor;
l.type = WindowManager.LayoutParams.TYPE_BASE_APPLICATION;
l.softInputMode |= forwardBit;
if (r.mPreserveWindow) {
// SPRD: Bug711794, ensure that the decor view is attached to window.
// if the remain decor view is not attached to window, we should make sure
// that it will been attached in the following workflow.
if(DecorView.isAddedToWindow(decor)) a.mWindowAdded = true;
r.mPreserveWindow = false;
// Normally the ViewRoot sets up callbacks with the Activity
// in addView->ViewRootImpl#setView. If we are instead reusing
// the decor view we have to notify the view root that the
// callbacks may have changed.
ViewRootImpl impl = decor.getViewRootImpl();
if (impl != null) {
// add systrace tag for bug 661753
Trace.traceBegin(Trace.TRACE_TAG_ACTIVITY_MANAGER, "notifyChildRebuilt");
impl.notifyChildRebuilt();
// add systrace tag for bug 661753
Trace.traceEnd(Trace.TRACE_TAG_ACTIVITY_MANAGER);
}
}
if (a.mVisibleFromClient) {
if (!a.mWindowAdded) {
a.mWindowAdded = true;
// add systrace tag for bug 661753
Trace.traceBegin(Trace.TRACE_TAG_ACTIVITY_MANAGER, "addView");
wm.addView(decor, l);
// add systrace tag for bug 661753
Trace.traceEnd(Trace.TRACE_TAG_ACTIVITY_MANAGER);
DecorView.setAddedToWindow(a.mDecor);
} else {
// The activity will get a callback for this {@link LayoutParams} change
// earlier. However, at that time the decor will not be set (this is set
// in this method), so no action will be taken. This call ensures the
// callback occurs with the decor set.
a.onWindowAttributesChanged(l);
}
}
// If the window has already been added, but during resume
// we started another activity, then don't yet make the
// window visible.
} else if (!willBeVisible) {
if (localLOGV) Slog.v(
TAG, "Launch " + r + " mStartedActivity set");
r.hideForNow = true;
}
// add systrace tag for bug 661753
Trace.traceBegin(Trace.TRACE_TAG_ACTIVITY_MANAGER, "cleanUpPendingRemoveWindows");
// Get rid of anything left hanging around.
cleanUpPendingRemoveWindows(r, false /* force */);
// add systrace tag for bug 661753
Trace.traceEnd(Trace.TRACE_TAG_ACTIVITY_MANAGER);
// The window is now visible if it has been added, we are not
// simply finishing, and we are not starting another activity.
if (!r.activity.mFinished && willBeVisible
&& r.activity.mDecor != null && !r.hideForNow) {
if (r.newConfig != null) {
performConfigurationChangedForActivity(r, r.newConfig);
if (DEBUG_CONFIGURATION) Slog.v(TAG, "Resuming activity "
+ r.activityInfo.name + " with newConfig " + r.activity.mCurrentConfig);
r.newConfig = null;
}
if (localLOGV) Slog.v(TAG, "Resuming " + r + " with isForward="
+ isForward);
WindowManager.LayoutParams l = r.window.getAttributes();
if ((l.softInputMode
& WindowManager.LayoutParams.SOFT_INPUT_IS_FORWARD_NAVIGATION)
!= forwardBit) {
l.softInputMode = (l.softInputMode
& (~WindowManager.LayoutParams.SOFT_INPUT_IS_FORWARD_NAVIGATION))
| forwardBit;
if (r.activity.mVisibleFromClient) {
ViewManager wm = a.getWindowManager();
View decor = r.window.getDecorView();
// add systrace tag for bug 661753
Trace.traceBegin(Trace.TRACE_TAG_ACTIVITY_MANAGER, "updateViewLayout");
wm.updateViewLayout(decor, l);
// add systrace tag for bug 661753
Trace.traceEnd(Trace.TRACE_TAG_ACTIVITY_MANAGER);
}
}
r.activity.mVisibleFromServer = true;
mNumVisibleActivities++;
if (r.activity.mVisibleFromClient) {
r.activity.makeVisible();
}
}
if (!r.onlyLocalRequest) {
r.nextIdle = mNewActivities;
mNewActivities = r;
if (localLOGV) Slog.v(
TAG, "Scheduling idle handler for " + r);
Looper.myQueue().addIdleHandler(new Idler());
}
r.onlyLocalRequest = false;
if (UsimNotifier.isNotifyEnabled(getApplication())) {
UsimNotifier.getInstance().startNotify(r.activity);
}
// Tell the activity manager we have resumed.
if (reallyResume) {
try {
// add systrace tag for bug 661753
Trace.traceBegin(Trace.TRACE_TAG_ACTIVITY_MANAGER, "activityResumed");
ActivityManager.getService().activityResumed(token);
} catch (RemoteException ex) {
throw ex.rethrowFromSystemServer();
} finally {
// add systrace tag for bug 661753
Trace.traceEnd(Trace.TRACE_TAG_ACTIVITY_MANAGER);
}
}
} else {
// If an exception was thrown when trying to resume, then
// just end this activity.
try {
// add systrace tag for bug 661753
Trace.traceBegin(Trace.TRACE_TAG_ACTIVITY_MANAGER, "finishActivity");
ActivityManager.getService()
.finishActivity(token, Activity.RESULT_CANCELED, null,
Activity.DONT_FINISH_TASK_WITH_ACTIVITY);
} catch (RemoteException ex) {
throw ex.rethrowFromSystemServer();
} finally {
// add systrace tag for bug 661753
Trace.traceEnd(Trace.TRACE_TAG_ACTIVITY_MANAGER);
}
}
}主要作用是调用performResumeActivity()到activity的onResume状态，然后获取DecorView，创建一个关联的ViewRootImpl对象,用来配合WindowManagerService服务来管理该Activity组件的窗口状态，最后addView
1.首先看下performResumeActivity()
public final ActivityClientRecord performResumeActivity(IBinder token,
boolean clearHide, String reason) {
ActivityClientRecord r = mActivities.get(token);
if (localLOGV) Slog.v(TAG, "Performing resume of " + r
+ " finished=" + r.activity.mFinished);
if (r != null && !r.activity.mFinished) {
if (clearHide) {
r.hideForNow = false;
r.activity.mStartedActivity = false;
}
try {
r.activity.onStateNotSaved();
r.activity.mFragments.noteStateNotSaved();
checkAndBlockForNetworkAccess();
if (r.pendingIntents != null) {
deliverNewIntents(r, r.pendingIntents);
r.pendingIntents = null;
}
if (r.pendingResults != null) {
deliverResults(r, r.pendingResults);
r.pendingResults = null;
}
// add systrace tag for bug 661753
Trace.traceBegin(Trace.TRACE_TAG_ACTIVITY_MANAGER, "performResume");
r.activity.performResume();
synchronized (mResourcesManager) {
// If there is a pending local relaunch that was requested when the activity was
// paused, it will put the activity into paused state when it finally happens.
// Since the activity resumed before being relaunched, we don't want that to
// happen, so we need to clear the request to relaunch paused.
for (int i = mRelaunchingActivities.size() - 1; i >= 0; i--) {
final ActivityClientRecord relaunching = mRelaunchingActivities.get(i);
if (relaunching.token == r.token
&& relaunching.onlyLocalRequest && relaunching.startsNotResumed) {
relaunching.startsNotResumed = false;
}
}
}
EventLog.writeEvent(LOG_AM_ON_RESUME_CALLED, UserHandle.myUserId(),
r.activity.getComponentName().getClassName(), reason);
r.paused = false;
r.stopped = false;
r.state = null;
r.persistentState = null;
} catch (Exception e) {
if (!mInstrumentation.onException(r.activity, e)) {
throw new RuntimeException(
"Unable to resume activity "
+ r.intent.getComponent().toShortString()
+ ": " + e.toString(), e);
}
} finally {
// add systrace tag for bug 661753
Trace.traceEnd(Trace.TRACE_TAG_ACTIVITY_MANAGER);
}
}
return r;
}Activity.java–>performResume()
final void performResume() {
performRestart();
mFragments.execPendingActions();
mLastNonConfigurationInstances = null;
mCalled = false;
// mResumed is set by the instrumentation
mInstrumentation.callActivityOnResume(this);
if (!mCalled) {
throw new SuperNotCalledException(
"Activity " + mComponent.toShortString() +
" did not call through to super.onResume()");
}
// invisible activities must be finished before onResume() completes
if (!mVisibleFromClient && !mFinished) {
Log.w(TAG, "An activity without a UI must call finish() before onResume() completes");
if (getApplicationInfo().targetSdkVersion
> android.os.Build.VERSION_CODES.LOLLIPOP_MR1) {
throw new IllegalStateException(
"Activity " + mComponent.toShortString() +
" did not call finish() prior to onResume() completing");
}
}
// Now really resume, and install the current status bar and menu.
mCalled = false;
mFragments.dispatchResume();
mFragments.execPendingActions();
onPostResume();
if (!mCalled) {
throw new SuperNotCalledException(
"Activity " + mComponent.toShortString() +
" did not call through to super.onPostResume()");
Instrumentation.java–>callActivityOnResume()
public void callActivityOnResume(Activity activity) {
activity.mResumed = true;
// add systrace tag for bug 661753
Trace.traceBegin(Trace.TRACE_TAG_ACTIVITY_MANAGER, "activity.onResume");
activity.onResume();
// add systrace tag for bug 661753
Trace.traceEnd(Trace.TRACE_TAG_ACTIVITY_MANAGER);
if (mActivityMonitors != null) {
synchronized (mSync) {
final int N = mActivityMonitors.size();
for (int i=0; i<N; i++) {
final ActivityMonitor am = mActivityMonitors.get(i);
am.match(activity, activity, activity.getIntent());
}
}
}
}Activity.java–>onResume()
protected void onResume() {
if (DEBUG_LIFECYCLE) Slog.v(TAG, "onResume " + this);
getApplication().dispatchActivityResumed(this);
mActivityTransitionState.onResume(this, isTopOfTask());
mCalled = true;
}到这里activity已经到了onResume的状态，下面我们继续ViewRootImpl创建的过程
2.ViewRootImpl创建流程
在 Android AMS(二) App启动过程之onCreate我们知道在activity onCreate后，会调用Activity的attach（）方法new PhoneWindow
所以r.window = r.activity.getWindow();得到的就是PhoneWindow的实例
getDecorView()是Window.java的一个抽象方法，PhoneWindow继承了这个Window
@Override
public final View getDecorView() {
if (mDecor == null || mForceDecorInstall) {
installDecor();
}
return mDecor;
}PhoneWindow.java–>installDecor()
private void installDecor() {
mForceDecorInstall = false;
if (mDecor == null) {
mDecor = generateDecor(-1);
......
}PhoneWindow.java–>generateDecor()
protected DecorView generateDecor(int featureId) {
// System process doesn't have application context and in that case we need to directly use
// the context we have. Otherwise we want the application context, so we don't cling to the
// activity.
Context context;
if (mUseDecorContext) {
Context applicationContext = getContext().getApplicationContext();
if (applicationContext == null) {
context = getContext();
} else {
context = new DecorContext(applicationContext, getContext().getResources());
if (mTheme != -1) {
context.setTheme(mTheme);
}
}
} else {
context = getContext();
}
return new DecorView(context, featureId, this, getAttributes());
}创建出DecorView之后，从DecorView中获取ViewRootImpl
ViewRootImpl impl = decor.getViewRootImpl();
我们看下ViewRootImpl的构造方法
public ViewRootImpl(Context context, Display display) {
mContext = context;
mWindowSession = WindowManagerGlobal.getWindowSession();
mDisplay = display;
mBasePackageName = context.getBasePackageName();
mThread = Thread.currentThread();
mLocation = new WindowLeaked(null);
mLocation.fillInStackTrace();
mWidth = -1;
mHeight = -1;
mDirty = new Rect();
mTempRect = new Rect();
mVisRect = new Rect();
mWinFrame = new Rect();
mWindow = new W(this);
mTargetSdkVersion = context.getApplicationInfo().targetSdkVersion;
mViewVisibility = View.GONE;
mTransparentRegion = new Region();
mPreviousTransparentRegion = new Region();
mFirst = true; // true for the first time the view is added
mAdded = false;
mAttachInfo = new View.AttachInfo(mWindowSession, mWindow, display, this, mHandler, this,
context);
mAccessibilityManager = AccessibilityManager.getInstance(context);
mAccessibilityManager.addAccessibilityStateChangeListener(
mAccessibilityInteractionConnectionManager, mHandler);
mHighContrastTextManager = new HighContrastTextManager();
mAccessibilityManager.addHighTextContrastStateChangeListener(
mHighContrastTextManager, mHandler);
mViewConfiguration = ViewConfiguration.get(context);
mDensity = context.getResources().getDisplayMetrics().densityDpi;
mNoncompatDensity = context.getResources().getDisplayMetrics().noncompatDensityDpi;
mFallbackEventHandler = new PhoneFallbackEventHandler(context);
mChoreographer = Choreographer.getInstance();
mDisplayManager = (DisplayManager)context.getSystemService(Context.DISPLAY_SERVICE);
if (!sCompatibilityDone) {
sAlwaysAssignFocus = true;
sCompatibilityDone = true;
}
loadSystemProperties();
}在这里获取了WindowSession，W对象，这个以后我们在WMS学习中再研究
然后addView –>wm.addView(decor, l);
这个wm是ViewManager，ViewManager是个接口，而WindowManager继承了ViewManager，WindowManagerImpl实现了WindowManager
WindowManagerImpl.java–>addView()
@Override
public void addView(@NonNull View view, @NonNull ViewGroup.LayoutParams params) {
applyDefaultToken(params);
mGlobal.addView(view, params, mContext.getDisplay(), mParentWindow);
}WindowManagerGlobal.java–>addView()
public void addView(View view, ViewGroup.LayoutParams params,
Display display, Window parentWindow) {
if (view == null) {
throw new IllegalArgumentException("view must not be null");
}
if (display == null) {
throw new IllegalArgumentException("display must not be null");
}
if (!(params instanceof WindowManager.LayoutParams)) {
throw new IllegalArgumentException("Params must be WindowManager.LayoutParams");
}
final WindowManager.LayoutParams wparams = (WindowManager.LayoutParams) params;
if (parentWindow != null) {
parentWindow.adjustLayoutParamsForSubWindow(wparams);
} else {
// If there's no parent, then hardware acceleration for this view is
// set from the application's hardware acceleration setting.
final Context context = view.getContext();
if (context != null
&& (context.getApplicationInfo().flags
& ApplicationInfo.FLAG_HARDWARE_ACCELERATED) != 0) {
wparams.flags |= WindowManager.LayoutParams.FLAG_HARDWARE_ACCELERATED;
}
}
ViewRootImpl root;
View panelParentView = null;
synchronized (mLock) {
// Start watching for system property changes.
if (mSystemPropertyUpdater == null) {
mSystemPropertyUpdater = new Runnable() {
@Override public void run() {
synchronized (mLock) {
for (int i = mRoots.size() - 1; i >= 0; --i) {
mRoots.get(i).loadSystemProperties();
}
}
}
};
SystemProperties.addChangeCallback(mSystemPropertyUpdater);
}
int index = findViewLocked(view, false);
if (index >= 0) {
if (mDyingViews.contains(view)) {
// Don't wait for MSG_DIE to make it's way through root's queue.
mRoots.get(index).doDie();
} else {
throw new IllegalStateException("View " + view
+ " has already been added to the window manager.");
}
// The previous removeView() had not completed executing. Now it has.
}
// If this is a panel window, then find the window it is being
// attached to for future reference.
if (wparams.type >= WindowManager.LayoutParams.FIRST_SUB_WINDOW &&
wparams.type <= WindowManager.LayoutParams.LAST_SUB_WINDOW) {
final int count = mViews.size();
for (int i = 0; i < count; i++) {
if (mRoots.get(i).mWindow.asBinder() == wparams.token) {
panelParentView = mViews.get(i);
}
}
}
root = new SprdViewRootImpl(view.getContext(), display);
view.setLayoutParams(wparams);
mViews.add(view);
mRoots.add(root);
mParams.add(wparams);
// do this last because it fires off messages to start doing things
try {
root.setView(view, wparams, panelParentView);
} catch (RuntimeException e) {
// BadTokenException or InvalidDisplayException, clean up.
if (index >= 0) {
removeViewLocked(index, true);
}
throw e;
}
}
}
