Android

Android

setContentView Activity Activity getWindow() Window PhoneWindow setContentView( )

frameworks/base/core/java/android/app/Activity.java

public class Activity extends ContextThemeWrapper
        implements LayoutInflater.Factory2,
        Window.Callback, KeyEvent.Callback,
        OnCreateContextMenuListener, ComponentCallbacks2,
        Window.OnWindowDismissedCallback {
    ......
    public void setContentView(@LayoutRes int layoutResID) {
        getWindow().setContentView(layoutResID);
        //  ActionBar
        initWindowDecorActionBar();
    }
    ......
}
 

getWindow() mWindow Window Activity/Screen Window API

frameworks/base/core/java/android/app/Activity.java

public class Activity extends ContextThemeWrapper
        implements LayoutInflater.Factory2,
        Window.Callback, KeyEvent.Callback,
        OnCreateContextMenuListener, ComponentCallbacks2,
        Window.OnWindowDismissedCallback {
    ......
    private Window mWindow;
    ......
    public Window getWindow() {
        return mWindow;
    }
    ......
}
 

mWindow attach( ) PhoneWindow

frameworks/base/core/java/android/app/Activity.java

public class Activity extends ContextThemeWrapper
        implements LayoutInflater.Factory2,
        Window.Callback, KeyEvent.Callback,
        OnCreateContextMenuListener, ComponentCallbacks2,
        Window.OnWindowDismissedCallback {
    ......
    final void attach(Context context, ActivityThread aThread,
            Instrumentation instr, IBinder token, int ident,
            Application application, Intent intent, ActivityInfo info,
            CharSequence title, Activity parent, String id,
            NonConfigurationInstances lastNonConfigurationInstances,
            Configuration config, String referrer, IVoiceInteractor voiceInteractor) {
        attachBaseContext(context);

        mFragments.attachHost(null /*parent*/);
        //  PhoneWindow  
        mWindow = new PhoneWindow(this);
        mWindow.setCallback(this);
        mWindow.setOnWindowDismissedCallback(this);
        mWindow.getLayoutInflater().setPrivateFactory(this);
        if (info.softInputMode != WindowManager.LayoutParams.SOFT_INPUT_STATE_UNSPECIFIED) {
            mWindow.setSoftInputMode(info.softInputMode);
        }
        if (info.uiOptions != 0) {
            mWindow.setUiOptions(info.uiOptions);
        }
        ......
        //  WindowManager  WMS  
        mWindow.setWindowManager(
                (WindowManager)context.getSystemService(Context.WINDOW_SERVICE),
                mToken, mComponent.flattenToString(),
                (info.flags & ActivityInfo.FLAG_HARDWARE_ACCELERATED) != 0);
        if (mParent != null) {
            mWindow.setContainer(mParent.getWindow());
        }
        //  WindowManager  
        mWindowManager = mWindow.getWindowManager();
        mCurrentConfig = config;
    }
    ......
}
 

tips:

5.0 Activity Fragment Transitions 4.4 transition UI API scenes transitions scenes UI transitions

Transition

View Animator

1. setContentView getWindow().requestFeature(Window.FEATURE_CONTENT_TRANSITIONS);
2. xml true

Window.FEATURE_CONTENT_TRANSITIONS setContentView( )

1. installDecor() Decor
2. mContentParent
3. layoutResID

frameworks/base/core/java/com/android/internal/policy/PhoneWindow.java

public class PhoneWindow extends Window implements MenuBuilder.Callback {
    ......
    @Override
    public void setContentView(int layoutResID) {
        // 
        //  Window Decor   FEATURE_CONTENT_TRANSITIONS  
        // 
        if (mContentParent == null) {
            //1.   Decor
            installDecor();
        } else if (!hasFeature(FEATURE_CONTENT_TRANSITIONS)) {
            //2.   mContentParent
            mContentParent.removeAllViews();
        }

        if (hasFeature(FEATURE_CONTENT_TRANSITIONS)) {
            final Scene newScene = Scene.getSceneForLayout(mContentParent, layoutResID,
                    getContext());
            transitionTo(newScene);
        } else {
            //3.   layoutResID  mContentParent
            mLayoutInflater.inflate(layoutResID, mContentParent);
        }
        mContentParent.requestApplyInsets();
        final Callback cb = getCallback();
        if (cb != null && !isDestroyed()) {
            cb.onContentChanged();
        }
    }
    ......
}
 

1. generateDecor() DecorView
2. generateLayout( ) mContentParent
3. DecorView WindowCallback WindowTitle

frameworks/base/core/java/com/android/internal/policy/PhoneWindow.java

public class PhoneWindow extends Window implements MenuBuilder.Callback {
    ......
    private void installDecor() {
        if (mDecor == null) {
            //  DecorView
            mDecor = generateDecor();
            // 
            mDecor.setDescendantFocusability(ViewGroup.FOCUS_AFTER_DESCENDANTS);
            mDecor.setIsRootNamespace(true);
            ......
        }
        if (mContentParent == null) {
            //  mContentParent
            mContentParent = generateLayout(mDecor);

            //  UI   Decor   fitsSystemWindows 
            mDecor.makeOptionalFitsSystemWindows();
            //  Decor  
            final DecorContentParent decorContentParent = (DecorContentParent) mDecor.findViewById(
                    R.id.decor_content_parent);

            if (decorContentParent != null) {
                mDecorContentParent = decorContentParent;
                mDecorContentParent.setWindowCallback(getCallback());
                if (mDecorContentParent.getTitle() == null) {
                    mDecorContentParent.setWindowTitle(mTitle);
                }
                ......
            } else {
                ......
            }
            ......
        }
    }
    ......
}
 

generateDecor() DecorView DecorView

frameworks/base/core/java/com/android/internal/policy/PhoneWindow.java

public class PhoneWindow extends Window implements MenuBuilder.Callback {
    ......
    protected DecorView generateDecor() {
        return new DecorView(getContext(), -1);
    }    
    ......
}
 

1. mFeatureId -1 DecorView
2. -
3. Bar

frameworks/base/core/java/com/android/internal/policy/PhoneWindow.java

public class PhoneWindow extends Window implements MenuBuilder.Callback {
    ......
    private final class DecorView extends FrameLayout implements RootViewSurfaceTaker {  
        ......
        public DecorView(Context context, int featureId) {
            super(context);
            //  ID  DecorView  -1
            mFeatureId = featureId;
            // - 
            mShowInterpolator = AnimationUtils.loadInterpolator(context,
                    android.R.interpolator.linear_out_slow_in);
            // - 
            mHideInterpolator = AnimationUtils.loadInterpolator(context,
                    android.R.interpolator.fast_out_linear_in);
            //Bar  
            mBarEnterExitDuration = context.getResources().getInteger(
                    R.integer.dock_enter_exit_duration);
        }        
        ......
    }
    ......
}
 

generateLayout( )

frameworks/base/core/java/com/android/internal/policy/PhoneWindow.java

public class PhoneWindow extends Window implements MenuBuilder.Callback {
    ......
    protected ViewGroup generateLayout(DecorView decor) {
        ......
        //Inflate the window decor.

        int layoutResource;
        int features = getLocalFeatures();
        //System.out.println("Features: 0x" + Integer.toHexString(features));
        if ((features & (1 << FEATURE_SWIPE_TO_DISMISS)) != 0) {
            ......
        } else if ((features & ((1 << FEATURE_LEFT_ICON) | (1 << FEATURE_RIGHT_ICON))) != 0) {
            ......
        } else if ((features & ((1 << FEATURE_PROGRESS) | (1 << FEATURE_INDETERMINATE_PROGRESS))) != 0
                && (features & (1 << FEATURE_ACTION_BAR)) == 0) {
            ......
        } else if ((features & (1 << FEATURE_CUSTOM_TITLE)) != 0) {
            ......
        } else if ((features & (1 << FEATURE_NO_TITLE)) == 0) {
            //If no other features and not embedded, only need a title.
            //If the window is floating, we need a dialog layout
            if (mIsFloating) {
                ......
            } else if ((features & (1 << FEATURE_ACTION_BAR)) != 0) {
                //  ActionBar
                layoutResource = a.getResourceId(
                        R.styleable.Window_windowActionBarFullscreenDecorLayout,
                        R.layout.screen_action_bar);
            } else {
                ......
            }
        } else if ((features & (1 << FEATURE_ACTION_MODE_OVERLAY)) != 0) {
            ......
        } else {
            ......
        }

        mDecor.startChanging();
        // 
        View in = mLayoutInflater.inflate(layoutResource, null);
        decor.addView(in, new ViewGroup.LayoutParams(MATCH_PARENT, MATCH_PARENT));
        // 
        mContentRoot = (ViewGroup) in;
        // ID_ANDROID_CONTENT   Window  
        //ID_ANDROID_CONTENT = com.android.internal.R.id.content
        ViewGroup contentParent = (ViewGroup)findViewById(ID_ANDROID_CONTENT);
        if (contentParent == null) {
            throw new RuntimeException("Window couldn't find content container view");
        }
        ......
        mDecor.finishChanging();

        return contentParent;
    }    
    ......
}
 

screen_action_bar layout ActionBarOverlayLayout mContentRoot FrameLayout android:id="@android:id/content" contentParent

frameworks/base/core/res/res/layout/screen_action_bar.xml

<?xml version="1.0" encoding="utf-8"?>
<!--
  Action Bar  
-->
<com.android.internal.widget.ActionBarOverlayLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/decor_content_parent"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:splitMotionEvents="false"
    android:theme="?attr/actionBarTheme">
    <FrameLayout android:id="@android:id/content"
                 android:layout_width="match_parent"
                 android:layout_height="match_parent"/>
    ......
</com.android.internal.widget.ActionBarOverlayLayout>
 

layoutResID mContentParent inflate xml PULL layout mContentParent FrameLayout

frameworks/base/core/java/android/view/LayoutInflater.java

public abstract class LayoutInflater {
    ......
    public View inflate(@LayoutRes int resource, @Nullable ViewGroup root) {
        return inflate(resource, root, root != null);
    }
    ......
    public View inflate(@LayoutRes int resource, @Nullable ViewGroup root, boolean attachToRoot) {
        final Resources res = getContext().getResources();
        if (DEBUG) {
            Log.d(TAG, "INFLATING from resource:/"" + res.getResourceName(resource) + "\" ("
                    + Integer.toHexString(resource) + ")");
        }

        final XmlResourceParser parser = res.getLayout(resource);
        try {
            return inflate(parser, root, attachToRoot);
        } finally {
            parser.close();
        }
    }
    ......
    public View inflate(XmlPullParser parser, @Nullable ViewGroup root, boolean attachToRoot) {
        synchronized (mConstructorArgs) {
            Trace.traceBegin(Trace.TRACE_TAG_VIEW, "inflate");

            final Context inflaterContext = mContext;
            final AttributeSet attrs = Xml.asAttributeSet(parser);
            Context lastContext = (Context) mConstructorArgs[0];
            mConstructorArgs[0] = inflaterContext;
            View result = root;

            try {
                // 
                int type;
                while ((type = parser.next()) != XmlPullParser.START_TAG &&
                        type != XmlPullParser.END_DOCUMENT) {
                    //Empty
                }

                if (type != XmlPullParser.START_TAG) {
                    throw new InflateException(parser.getPositionDescription()
                            + ": No start tag found!");
                }

                final String name = parser.getName();
                ......
                //merge  
                if (TAG_MERGE.equals(name)) {
                    if (root == null || !attachToRoot) {
                        throw new InflateException("<merge/> can be used only with a valid "
                                + "ViewGroup root and attachToRoot=true");
                    }

                    rInflate(parser, root, inflaterContext, attrs, false);
                } else {
                    //Temp   xml   View
                    final View temp = createViewFromTag(root, name, inflaterContext, attrs);

                    ViewGroup.LayoutParams params = null;

                    if (root != null) {
                        if (DEBUG) {
                            System.out.println("Creating params from root: " +
                                    root);
                        }
                        //  root  
                        params = root.generateLayoutParams(attrs);
                        if (!attachToRoot) {
                            temp.setLayoutParams(params);
                        }
                    }
                    ......
                    // 
                    rInflateChildren(parser, temp, attrs, true);
                    ......
                    //  temp View   root  
                    if (root != null && attachToRoot) {
                        root.addView(temp, params);
                    }
                    ......
                }

            } catch (XmlPullParserException e) {
                ......
            } catch (Exception e) {
                ......
            } finally {
                ......
            }

            Trace.traceEnd(Trace.TRACE_TAG_VIEW);

            return result;
        }
    }
    ......
}
 

Activity Activity ActivityThread handleLaunchActivity handleResumeActivity

1. Window DecorView
2. DecorView
3. WindowManager
4. DecorView ViewManager

frameworks/base/core/java/android/app/ActivityThread.java

public final class ActivityThread {
    ......
    final void handleResumeActivity(IBinder token,
            boolean clearHide, boolean isForward, boolean reallyResume) {
        ......
        //  activity   onResume(...)
        ActivityClientRecord r = performResumeActivity(token, clearHide);

        if (r != null) {
            final Activity a = r.activity;
            ......
            if (r.window == null && !a.mFinished && willBeVisible) {
                r.window = r.activity.getWindow();
                View decor = r.window.getDecorView();
                //  DecorView  
                decor.setVisibility(View.INVISIBLE);
                //  WindowManager  
                ViewManager wm = a.getWindowManager();
                WindowManager.LayoutParams l = r.window.getAttributes();
                a.mDecor = decor;
                l.type = WindowManager.LayoutParams.TYPE_BASE_APPLICATION;
                l.softInputMode |= forwardBit;
                if (a.mVisibleFromClient) {
                    a.mWindowAdded = true;
                    //  DecorView   ViewManager
                    wm.addView(decor, l);
                }

            } else if (!willBeVisible) {
                ......
            }

            ......

            // AMS 
            if (reallyResume) {
                try {
                    ActivityManagerNative.getDefault().activityResumed(token);
                } catch (RemoteException ex) {
                }
            }

        } else {
            ......
        }
    }
    ......
}
 

Window DecorView PhoneWindow mDecor DecorView

frameworks/base/core/java/com/android/internal/policy/PhoneWindow.java

public class PhoneWindow extends Window implements MenuBuilder.Callback {
    ......
    @Override
    public final View getDecorView() {
        if (mDecor == null) {
            installDecor();
        }
        return mDecor;
    }
    ......
}
 

wm WindowManagerImpl WindowManagerImpl addView WindowManagerGlobal addView

frameworks/base/core/java/android/view/WindowManagerImpl.java

public final class WindowManagerImpl implements WindowManager {
    private final WindowManagerGlobal mGlobal = WindowManagerGlobal.getInstance();
    ......
    @Override
    public void addView(@NonNull View view, @NonNull ViewGroup.LayoutParams params) {
        applyDefaultToken(params);
        mGlobal.addView(view, params, mDisplay, mParentWindow);
    }
    ......
}
 

2. WindowManager.LayoutParams
3. mViews DecorView IllegalStateException
4. mViews panelParentView
5. ViewRootImpl
6. DecorView LayoutParams
7. mViews mRoots mParams
8. ViewRootImpl DecorView

frameworks/base/core/java/android/view/WindowManagerImpl.java

public final class WindowManagerGlobal {
    ......
    private final ArrayList<View> mViews = new ArrayList<View>();
    private final ArrayList<ViewRootImpl> mRoots = new ArrayList<ViewRootImpl>();
    private final ArrayList<WindowManager.LayoutParams> mParams =
            new ArrayList<WindowManager.LayoutParams>();
    private final ArraySet<View> mDyingViews = new ArraySet<View>();
    ......
    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");
        }
        //  WindowManager.LayoutParams
        final WindowManager.LayoutParams wparams = (WindowManager.LayoutParams) params;
        if (parentWindow != null) {
            parentWindow.adjustLayoutParamsForSubWindow(wparams);
        } else {
            ......
        }

        ViewRootImpl root;
        View panelParentView = null;

        synchronized (mLock) {
            ......
            //mViews   DecorView
            int index = findViewLocked(view, false);
            if (index >= 0) {
                if (mDyingViews.contains(view)) {
                    ......
                } else {
                    //  IllegalStateException  
                    throw new IllegalStateException("View " + view
                            + " has already been added to the window manager.");
                }
                //The previous removeView() had not completed executing. Now it has.
            }

            //  mViews   panelParentView
            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);
                    }
                }
            }
            //  ViewRootImpl  
            root = new ViewRootImpl(view.getContext(), display);
            //DecorView   LayoutParams
            view.setLayoutParams(wparams);
            // 
            mViews.add(view);
            mRoots.add(root);
            mParams.add(wparams);
        }

        try {
            //ViewRootImpl   DecorView
            root.setView(view, wparams, panelParentView);
        } catch (RuntimeException e) {
            ......
        }
    }
    ......
}
 

ViewRootImpl setView( )

1. requestLayout() layout
2. Session addToDisplay W W ViewRootImpl

frameworks/base/core/java/android/view/ViewRootImpl.java

public final class ViewRootImpl implements ViewParent,
        View.AttachInfo.Callbacks, HardwareRenderer.HardwareDrawCallbacks {
    ......
    final W mWindow;
    ......
    //Surface  
    final Surface mSurface = new Surface();
    ......
    public ViewRootImpl(Context context, Display display) {
        mContext = context;
        mWindowSession = WindowManagerGlobal.getWindowSession();
        mDisplay = display;
        mBasePackageName = context.getBasePackageName();

        mDisplayAdjustments = display.getDisplayAdjustments();

        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);
        mAccessibilityManager = AccessibilityManager.getInstance(context);
        mAccessibilityInteractionConnectionManager =
            new AccessibilityInteractionConnectionManager();
        mAccessibilityManager.addAccessibilityStateChangeListener(
                mAccessibilityInteractionConnectionManager);
        mHighContrastTextManager = new HighContrastTextManager();
        mAccessibilityManager.addHighTextContrastStateChangeListener(
                mHighContrastTextManager);
        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);
        loadSystemProperties();
    }
    ......
    public void setView(View view, WindowManager.LayoutParams attrs, View panelParentView) {
        synchronized (this) {
            if (mView == null) {
                mView = view;
                ......
                //  layout  WMS  
                // 
                requestLayout()
                ......
                try {
                    ......
                    res = mWindowSession.addToDisplay(mWindow, mSeq, mWindowAttributes,
                            getHostVisibility(), mDisplay.getDisplayId(),
                            mAttachInfo.mContentInsets, mAttachInfo.mStableInsets,
                            mAttachInfo.mOutsets, mInputChannel);
                } catch (RemoteException e) {
                    ......
                } finally {
                    ......
                }
                ......
            }
        }
    }
    ......
    static class W extends IWindow.Stub {
        private final WeakReference<ViewRootImpl> mViewAncestor;
        private final IWindowSession mWindowSession;

        W(ViewRootImpl viewAncestor) {
            mViewAncestor = new WeakReference<ViewRootImpl>(viewAncestor);
            mWindowSession = viewAncestor.mWindowSession;
        }
        ......
    }
    ......
}
 

requestLayout() scheduleTraversals()

frameworks/base/core/java/android/view/ViewRootImpl.java

public final class ViewRootImpl implements ViewParent,
        View.AttachInfo.Callbacks, HardwareRenderer.HardwareDrawCallbacks {
    ......
    boolean mHandlingLayoutInLayoutRequest = false;
    ......
    @Override
    public void requestLayout() {
        if (!mHandlingLayoutInLayoutRequest) {
            checkThread();
            mLayoutRequested = true;
            scheduleTraversals();
        }
    }
    ......
}
 

Session addToDisplay

Session Session

addToDisplay WindowManagerService addWindow

frameworks/base/services/core/java/com/android/server/wm/Session.java

final class Session extends IWindowSession.Stub
        implements IBinder.DeathRecipient {
    final WindowManagerService mService;
    ......
    @Override
    public int addToDisplay(IWindow window, int seq, WindowManager.LayoutParams attrs,
            int viewVisibility, int displayId, Rect outContentInsets, Rect outStableInsets,
            Rect outOutsets, InputChannel outInputChannel) {
        return mService.addWindow(this, window, seq, attrs, viewVisibility, displayId,
                outContentInsets, outStableInsets, outOutsets, outInputChannel);
    }
    ......
}
 

addWindow WindowState attach() mWindowMap attach()

frameworks/base/services/core/java/com/android/server/wm/WindowManagerService.java

public class WindowManagerService extends IWindowManager.Stub
        implements Watchdog.Monitor, WindowManagerPolicy.WindowManagerFuncs {
    ......
    //  IWindow IBinder   Window  WindowState 
    final HashMap<IBinder, WindowState> mWindowMap = new HashMap<>();
    ......
    public int addWindow(Session session, IWindow client, int seq,
            WindowManager.LayoutParams attrs, int viewVisibility, int displayId,
            Rect outContentInsets, Rect outStableInsets, Rect outOutsets,
            InputChannel outInputChannel) {
        ......
        WindowState attachedWindow = null;
        ......
        synchronized(mWindowMap) {
            ......
            WindowState win = new WindowState(this, session, client, token,
                    attachedWindow, appOp[0], seq, attrs, viewVisibility, displayContent);
            ......
            //From now on, no exceptions or errors allowed!
            res = WindowManagerGlobal.ADD_OKAY;
            ......
            win.attach();
            mWindowMap.put(client.asBinder(), win);
            ......
        }
        ......
    }
    ......
}