android Gui系统之WMS(2)----窗口的添加

Android系统很多，但是最常用的就两类，一类是有系统进场管理的，系统窗口。还有一类就是由应用程序产生的，应用窗口。

1.系统窗口的添加流程

1.1 addStatusBarWindow

PhoneStatus.java中

    private void addStatusBarWindow() {
        makeStatusBarView();
        mStatusBarWindowManager = new StatusBarWindowManager(mContext);
        mStatusBarWindowManager.add(mStatusBarWindow, getStatusBarHeight());
    }

getStatusBarHeight() 获取状态栏的高度

    public int getStatusBarHeight() {
        if (mNaturalBarHeight < 0) {
            final Resources res = mContext.getResources();
            mNaturalBarHeight =
                    res.getDimensionPixelSize(com.android.internal.R.dimen.status_bar_height);
        }
        return mNaturalBarHeight;
    }

可以看到，高度是固定的，在dimen里面配置。

看看add方法

    public void add(View statusBarView, int barHeight) {

        // Now that the status bar window encompasses the sliding panel and its
        // translucent backdrop, the entire thing is made TRANSLUCENT and is
        // hardware-accelerated.
        mLp = new WindowManager.LayoutParams(
                ViewGroup.LayoutParams.MATCH_PARENT,
                barHeight,
                WindowManager.LayoutParams.TYPE_STATUS_BAR,
                WindowManager.LayoutParams.FLAG_NOT_FOCUSABLE
                        | WindowManager.LayoutParams.FLAG_TOUCHABLE_WHEN_WAKING
                        | WindowManager.LayoutParams.FLAG_SPLIT_TOUCH
                        | WindowManager.LayoutParams.FLAG_WATCH_OUTSIDE_TOUCH
                        | WindowManager.LayoutParams.FLAG_DRAWS_SYSTEM_BAR_BACKGROUNDS,
                PixelFormat.TRANSLUCENT);
        mLp.flags |= WindowManager.LayoutParams.FLAG_HARDWARE_ACCELERATED;
        mLp.gravity = Gravity.TOP;
        mLp.softInputMode = WindowManager.LayoutParams.SOFT_INPUT_ADJUST_RESIZE;
        mLp.setTitle("StatusBar");
        mLp.packageName = mContext.getPackageName();
        mStatusBarView = statusBarView;
        mBarHeight = barHeight;
        mWindowManager.addView(mStatusBarView, mLp);
        mLpChanged = new WindowManager.LayoutParams();
        mLpChanged.copyFrom(mLp);
    }

layoutparams属性，还有设置在顶部。

mLp.softInputMode = WindowManager.LayoutParams.SOFT_INPUT_ADJUST_RESIZE;

软键盘被覆盖，绝大多数情况下，statusbar的显示不会影响到软件盘的位置，如果有，软键盘调整，statusbar优先显示。

最后是将statusbar加入到WMS里面。

mWindowManager = (WindowManager) context.getSystemService(Context.WINDOW_SERVICE);

所以mWindowManager就是WMS的一个bind代理。

然后在看makeStatusBarView:

 protected PhoneStatusBarView makeStatusBarView() {
        final Context context = mContext;

        Resources res = context.getResources();

        updateDisplaySize(); // populates mDisplayMetrics
        updateResources();

        mStatusBarWindow = (StatusBarWindowView) View.inflate(context,
                R.layout.super_status_bar, null);
        mStatusBarWindow.setService(this);
        mStatusBarWindow.setOnTouchListener(new View.OnTouchListener() {
            @Override
            public boolean onTouch(View v, MotionEvent event) {
                checkUserAutohide(v, event);
                if (event.getAction() == MotionEvent.ACTION_DOWN) {
                    if (mExpandedVisible) {
                        animateCollapsePanels();
                    }
                }
                return mStatusBarWindow.onTouchEvent(event);
            }
        });

        mStatusBarView = (PhoneStatusBarView) mStatusBarWindow.findViewById(R.id.status_bar);
        mStatusBarView.setBar(this);

        PanelHolder holder = (PanelHolder) mStatusBarWindow.findViewById(R.id.panel_holder);
        mStatusBarView.setPanelHolder(holder);

        mNotificationPanel = (NotificationPanelView) mStatusBarWindow.findViewById(
                R.id.notification_panel);
        mNotificationPanel.setStatusBar(this);

        if (!ActivityManager.isHighEndGfx()) {
            mStatusBarWindow.setBackground(null);
            mNotificationPanel.setBackground(new FastColorDrawable(context.getColor(
                    R.color.notification_panel_solid_background)));
        }

        mHeadsUpManager = new HeadsUpManager(context, mStatusBarWindow);
        mHeadsUpManager.setBar(this);
        mHeadsUpManager.addListener(this);
        mHeadsUpManager.addListener(mNotificationPanel);
        mNotificationPanel.setHeadsUpManager(mHeadsUpManager);
        mNotificationData.setHeadsUpManager(mHeadsUpManager);

        if (MULTIUSER_DEBUG) {
            mNotificationPanelDebugText = (TextView) mNotificationPanel.findViewById(
                    R.id.header_debug_info);
            mNotificationPanelDebugText.setVisibility(View.VISIBLE);
        }

        try {
            boolean showNav = mWindowManagerService.hasNavigationBar();
            if (DEBUG) Log.v(TAG, "hasNavigationBar=" + showNav);
            if (showNav) {
                mNavigationBarView =
                    (NavigationBarView) View.inflate(context, R.layout.navigation_bar, null);

                mNavigationBarView.setDisabledFlags(mDisabled1);
                mNavigationBarView.setBar(this);
                mNavigationBarView.setOnVerticalChangedListener(
                        new NavigationBarView.OnVerticalChangedListener() {
                    @Override
                    public void onVerticalChanged(boolean isVertical) {
                        if (mAssistManager != null) {
                            mAssistManager.onConfigurationChanged();
                        }
                        mNotificationPanel.setQsScrimEnabled(!isVertical);
                    }
                });
                mNavigationBarView.setOnTouchListener(new View.OnTouchListener() {
                    @Override
                    public boolean onTouch(View v, MotionEvent event) {
                        checkUserAutohide(v, event);
                        return false;
                    }});
            }
        } catch (RemoteException ex) {
            // no window manager? good luck with that
        }

        mAssistManager = new AssistManager(this, context);

        // figure out which pixel-format to use for the status bar.
        mPixelFormat = PixelFormat.OPAQUE;

        mStackScroller = (NotificationStackScrollLayout) mStatusBarWindow.findViewById(
                R.id.notification_stack_scroller);
        mStackScroller.setLongPressListener(getNotificationLongClicker());
        mStackScroller.setPhoneStatusBar(this);
        mStackScroller.setGroupManager(mGroupManager);
        mStackScroller.setHeadsUpManager(mHeadsUpManager);
        mGroupManager.setOnGroupChangeListener(mStackScroller);

        mKeyguardIconOverflowContainer =
                (NotificationOverflowContainer) LayoutInflater.from(mContext).inflate(
                        R.layout.status_bar_notification_keyguard_overflow, mStackScroller, false);
        mKeyguardIconOverflowContainer.setOnActivatedListener(this);
        mKeyguardIconOverflowContainer.setOnClickListener(mOverflowClickListener);
        mStackScroller.setOverflowContainer(mKeyguardIconOverflowContainer);

        SpeedBumpView speedBump = (SpeedBumpView) LayoutInflater.from(mContext).inflate(
                        R.layout.status_bar_notification_speed_bump, mStackScroller, false);
        mStackScroller.setSpeedBumpView(speedBump);
        mEmptyShadeView = (EmptyShadeView) LayoutInflater.from(mContext).inflate(
                R.layout.status_bar_no_notifications, mStackScroller, false);
        mStackScroller.setEmptyShadeView(mEmptyShadeView);
        mDismissView = (DismissView) LayoutInflater.from(mContext).inflate(
                R.layout.status_bar_notification_dismiss_all, mStackScroller, false);
        mDismissView.setOnButtonClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                MetricsLogger.action(mContext, MetricsLogger.ACTION_DISMISS_ALL_NOTES);
                clearAllNotifications();
            }
        });
        mStackScroller.setDismissView(mDismissView);
        mExpandedContents = mStackScroller;

        mBackdrop = (BackDropView) mStatusBarWindow.findViewById(R.id.backdrop);
        mBackdropFront = (ImageView) mBackdrop.findViewById(R.id.backdrop_front);
        mBackdropBack = (ImageView) mBackdrop.findViewById(R.id.backdrop_back);

        ScrimView scrimBehind = (ScrimView) mStatusBarWindow.findViewById(R.id.scrim_behind);
        ScrimView scrimInFront = (ScrimView) mStatusBarWindow.findViewById(R.id.scrim_in_front);
        View headsUpScrim = mStatusBarWindow.findViewById(R.id.heads_up_scrim);
        mScrimController = new ScrimController(scrimBehind, scrimInFront, headsUpScrim,
                mScrimSrcModeEnabled);
        mHeadsUpManager.addListener(mScrimController);
        mStackScroller.setScrimController(mScrimController);
        mScrimController.setBackDropView(mBackdrop);
        mStatusBarView.setScrimController(mScrimController);
        mDozeScrimController = new DozeScrimController(mScrimController, context);

        mHeader = (StatusBarHeaderView) mStatusBarWindow.findViewById(R.id.header);
        mHeader.setActivityStarter(this);
        mKeyguardStatusBar = (KeyguardStatusBarView) mStatusBarWindow.findViewById(R.id.keyguard_header);
        mKeyguardStatusView = mStatusBarWindow.findViewById(R.id.keyguard_status_view);
        mKeyguardBottomArea =
                (KeyguardBottomAreaView) mStatusBarWindow.findViewById(R.id.keyguard_bottom_area);
        mKeyguardBottomArea.setActivityStarter(this);
        mKeyguardBottomArea.setAssistManager(mAssistManager);
        mKeyguardIndicationController = new KeyguardIndicationController(mContext,
                (KeyguardIndicationTextView) mStatusBarWindow.findViewById(
                        R.id.keyguard_indication_text),
                mKeyguardBottomArea.getLockIcon());
        mKeyguardBottomArea.setKeyguardIndicationController(mKeyguardIndicationController);

        // set the inital view visibility
        setAreThereNotifications();

        mIconController = new StatusBarIconController(
                mContext, mStatusBarView, mKeyguardStatusBar, this);

        // Background thread for any controllers that need it.
        mHandlerThread = new HandlerThread(TAG, Process.THREAD_PRIORITY_BACKGROUND);
        mHandlerThread.start();

        // Other icons
        mLocationController = new LocationControllerImpl(mContext,
                mHandlerThread.getLooper()); // will post a notification
        mBatteryController = new BatteryController(mContext);
        mBatteryController.addStateChangedCallback(new BatteryStateChangeCallback() {
            @Override
            public void onPowerSaveChanged() {
                mHandler.post(mCheckBarModes);
                if (mDozeServiceHost != null) {
                    mDozeServiceHost.firePowerSaveChanged(mBatteryController.isPowerSave());
                }
            }
            @Override
            public void onBatteryLevelChanged(int level, boolean pluggedIn, boolean charging) {
                // noop
            }
        });
        mNetworkController = new NetworkControllerImpl(mContext, mHandlerThread.getLooper());
        mHotspotController = new HotspotControllerImpl(mContext);
        mBluetoothController = new BluetoothControllerImpl(mContext, mHandlerThread.getLooper());
        mSecurityController = new SecurityControllerImpl(mContext);
        if (mContext.getResources().getBoolean(R.bool.config_showRotationLock)) {
            mRotationLockController = new RotationLockControllerImpl(mContext);
        }
        mUserInfoController = new UserInfoController(mContext);
        mVolumeComponent = getComponent(VolumeComponent.class);
        if (mVolumeComponent != null) {
            mZenModeController = mVolumeComponent.getZenController();
        }
        mCastController = new CastControllerImpl(mContext);
        final SignalClusterView signalCluster =
                (SignalClusterView) mStatusBarView.findViewById(R.id.signal_cluster);
        final SignalClusterView signalClusterKeyguard =
                (SignalClusterView) mKeyguardStatusBar.findViewById(R.id.signal_cluster);
        final SignalClusterView signalClusterQs =
                (SignalClusterView) mHeader.findViewById(R.id.signal_cluster);
        mNetworkController.addSignalCallback(signalCluster);
        mNetworkController.addSignalCallback(signalClusterKeyguard);
        mNetworkController.addSignalCallback(signalClusterQs);
        signalCluster.setSecurityController(mSecurityController);
        signalCluster.setNetworkController(mNetworkController);
        signalClusterKeyguard.setSecurityController(mSecurityController);
        signalClusterKeyguard.setNetworkController(mNetworkController);
        signalClusterQs.setSecurityController(mSecurityController);
        signalClusterQs.setNetworkController(mNetworkController);
        final boolean isAPhone = mNetworkController.hasVoiceCallingFeature();
        if (isAPhone) {
            mNetworkController.addEmergencyListener(mHeader);
        }

        mFlashlightController = new FlashlightController(mContext);
        mKeyguardBottomArea.setFlashlightController(mFlashlightController);
        mKeyguardBottomArea.setPhoneStatusBar(this);
        mKeyguardBottomArea.setUserSetupComplete(mUserSetup);
        mAccessibilityController = new AccessibilityController(mContext);
        mKeyguardBottomArea.setAccessibilityController(mAccessibilityController);
        mNextAlarmController = new NextAlarmController(mContext);
        mKeyguardMonitor = new KeyguardMonitor(mContext);
        if (UserSwitcherController.isUserSwitcherAvailable(UserManager.get(mContext))) {
            mUserSwitcherController = new UserSwitcherController(mContext, mKeyguardMonitor,
                    mHandler);
        }
        mKeyguardUserSwitcher = new KeyguardUserSwitcher(mContext,
                (ViewStub) mStatusBarWindow.findViewById(R.id.keyguard_user_switcher),
                mKeyguardStatusBar, mNotificationPanel, mUserSwitcherController);


        // Set up the quick settings tile panel
        mQSPanel = (QSPanel) mStatusBarWindow.findViewById(R.id.quick_settings_panel);
        if (mQSPanel != null) {
            final QSTileHost qsh = new QSTileHost(mContext, this,
                    mBluetoothController, mLocationController, mRotationLockController,
                    mNetworkController, mZenModeController, mHotspotController,
                    mCastController, mFlashlightController,
                    mUserSwitcherController, mKeyguardMonitor,
                    mSecurityController);
            mQSPanel.setHost(qsh);
            mQSPanel.setTiles(qsh.getTiles());
            mBrightnessMirrorController = new BrightnessMirrorController(mStatusBarWindow);
            mQSPanel.setBrightnessMirror(mBrightnessMirrorController);
            mHeader.setQSPanel(mQSPanel);
            qsh.setCallback(new QSTileHost.Callback() {
                @Override
                public void onTilesChanged() {
                    mQSPanel.setTiles(qsh.getTiles());
                }
            });
        }

        // User info. Trigger first load.
        mHeader.setUserInfoController(mUserInfoController);
        mKeyguardStatusBar.setUserInfoController(mUserInfoController);
        mKeyguardStatusBar.setUserSwitcherController(mUserSwitcherController);
        mUserInfoController.reloadUserInfo();

        mHeader.setBatteryController(mBatteryController);
        ((BatteryMeterView) mStatusBarView.findViewById(R.id.battery)).setBatteryController(
                mBatteryController);
        mKeyguardStatusBar.setBatteryController(mBatteryController);
        mHeader.setNextAlarmController(mNextAlarmController);

        PowerManager pm = (PowerManager) mContext.getSystemService(Context.POWER_SERVICE);
        mBroadcastReceiver.onReceive(mContext,
                new Intent(pm.isScreenOn() ? Intent.ACTION_SCREEN_ON : Intent.ACTION_SCREEN_OFF));
        mGestureWakeLock = pm.newWakeLock(PowerManager.SCREEN_BRIGHT_WAKE_LOCK,
                "GestureWakeLock");
        mVibrator = mContext.getSystemService(Vibrator.class);

        // receive broadcasts
        IntentFilter filter = new IntentFilter();
        filter.addAction(Intent.ACTION_CLOSE_SYSTEM_DIALOGS);
        filter.addAction(Intent.ACTION_SCREEN_OFF);
        filter.addAction(Intent.ACTION_SCREEN_ON);
        context.registerReceiverAsUser(mBroadcastReceiver, UserHandle.ALL, filter, null, null);

        IntentFilter demoFilter = new IntentFilter();
        if (DEBUG_MEDIA_FAKE_ARTWORK) {
            demoFilter.addAction(ACTION_FAKE_ARTWORK);
        }
        demoFilter.addAction(ACTION_DEMO);
        context.registerReceiverAsUser(mDemoReceiver, UserHandle.ALL, demoFilter,
                android.Manifest.permission.DUMP, null);

        // listen for USER_SETUP_COMPLETE setting (per-user)
        resetUserSetupObserver();

        // disable profiling bars, since they overlap and clutter the output on app windows
        ThreadedRenderer.overrideProperty("disableProfileBars", "true");

        // Private API call to make the shadows look better for Recents
        ThreadedRenderer.overrideProperty("ambientRatio", String.valueOf(1.5f));

        return mStatusBarView;
    }

看着代码很多，很复杂。其实总的来说很简单，就是new了一个view，然后设置一些属性。

1.2 WMS addwindow

WMS并不关心View的Tree的具体内容，它只要知道个应用进程的显示界面大小，“层级值”（这些信息包含在windowmanager.layoutparams）

 public int addWindow(Session session, IWindow client, int seq,
            WindowManager.LayoutParams attrs, int viewVisibility, int displayId,
            Rect outContentInsets, Rect outStableInsets, Rect outOutsets,
            InputChannel outInputChannel) {
        int[] appOp = new int[1];
        int res = mPolicy.checkAddPermission(attrs, appOp);
        if (res != WindowManagerGlobal.ADD_OKAY) {
            return res;
        }

        boolean reportNewConfig = false;
        WindowState attachedWindow = null;
        long origId;
        final int type = attrs.type;

        synchronized(mWindowMap) {
            if (!mDisplayReady) {
                throw new IllegalStateException("Display has not been initialialized");
            }

            final DisplayContent displayContent = getDisplayContentLocked(displayId);
            if (displayContent == null) {
                Slog.w(TAG, "Attempted to add window to a display that does not exist: "
                        + displayId + ".  Aborting.");
                return WindowManagerGlobal.ADD_INVALID_DISPLAY;
            }
            if (!displayContent.hasAccess(session.mUid)) {
                Slog.w(TAG, "Attempted to add window to a display for which the application "
                        + "does not have access: " + displayId + ".  Aborting.");
                return WindowManagerGlobal.ADD_INVALID_DISPLAY;
            }

            if (mWindowMap.containsKey(client.asBinder())) {
                Slog.w(TAG, "Window " + client + " is already added");
                return WindowManagerGlobal.ADD_DUPLICATE_ADD;
            }

            if (type >= FIRST_SUB_WINDOW && type <= LAST_SUB_WINDOW) {
                attachedWindow = windowForClientLocked(null, attrs.token, false);
                if (attachedWindow == null) {
                    Slog.w(TAG, "Attempted to add window with token that is not a window: "
                          + attrs.token + ".  Aborting.");
                    return WindowManagerGlobal.ADD_BAD_SUBWINDOW_TOKEN;
                }
                if (attachedWindow.mAttrs.type >= FIRST_SUB_WINDOW
                        && attachedWindow.mAttrs.type <= LAST_SUB_WINDOW) {
                    Slog.w(TAG, "Attempted to add window with token that is a sub-window: "
                            + attrs.token + ".  Aborting.");
                    return WindowManagerGlobal.ADD_BAD_SUBWINDOW_TOKEN;
                }
            }

            if (type == TYPE_PRIVATE_PRESENTATION && !displayContent.isPrivate()) {
                Slog.w(TAG, "Attempted to add private presentation window to a non-private display.  Aborting.");
                return WindowManagerGlobal.ADD_PERMISSION_DENIED;
            }

            boolean addToken = false;
            WindowToken token = mTokenMap.get(attrs.token);
            if (token == null) {
                if (type >= FIRST_APPLICATION_WINDOW && type <= LAST_APPLICATION_WINDOW) {
                    Slog.w(TAG, "Attempted to add application window with unknown token "
                          + attrs.token + ".  Aborting.");
                    return WindowManagerGlobal.ADD_BAD_APP_TOKEN;
                }
                if (type == TYPE_INPUT_METHOD) {
                    Slog.w(TAG, "Attempted to add input method window with unknown token "
                          + attrs.token + ".  Aborting.");
                    return WindowManagerGlobal.ADD_BAD_APP_TOKEN;
                }
                if (type == TYPE_VOICE_INTERACTION) {
                    Slog.w(TAG, "Attempted to add voice interaction window with unknown token "
                          + attrs.token + ".  Aborting.");
                    return WindowManagerGlobal.ADD_BAD_APP_TOKEN;
                }
                if (type == TYPE_WALLPAPER) {
                    Slog.w(TAG, "Attempted to add wallpaper window with unknown token "
                          + attrs.token + ".  Aborting.");
                    return WindowManagerGlobal.ADD_BAD_APP_TOKEN;
                }
                if (type == TYPE_DREAM) {
                    Slog.w(TAG, "Attempted to add Dream window with unknown token "
                          + attrs.token + ".  Aborting.");
                    return WindowManagerGlobal.ADD_BAD_APP_TOKEN;
                }
                if (type == TYPE_ACCESSIBILITY_OVERLAY) {
                    Slog.w(TAG, "Attempted to add Accessibility overlay window with unknown token "
                            + attrs.token + ".  Aborting.");
                    return WindowManagerGlobal.ADD_BAD_APP_TOKEN;
                }
                token = new WindowToken(this, attrs.token, -1, false);
                addToken = true;
            } else if (type >= FIRST_APPLICATION_WINDOW && type <= LAST_APPLICATION_WINDOW) {
                AppWindowToken atoken = token.appWindowToken;
                if (atoken == null) {
                    Slog.w(TAG, "Attempted to add window with non-application token "
                          + token + ".  Aborting.");
                    return WindowManagerGlobal.ADD_NOT_APP_TOKEN;
                } else if (atoken.removed) {
                    Slog.w(TAG, "Attempted to add window with exiting application token "
                          + token + ".  Aborting.");
                    return WindowManagerGlobal.ADD_APP_EXITING;
                }
                if (type == TYPE_APPLICATION_STARTING && atoken.firstWindowDrawn) {
                    // No need for this guy!
                    if (localLOGV) Slog.v(
                            TAG, "**** NO NEED TO START: " + attrs.getTitle());
                    return WindowManagerGlobal.ADD_STARTING_NOT_NEEDED;
                }
            } else if (type == TYPE_INPUT_METHOD) {
                if (token.windowType != TYPE_INPUT_METHOD) {
                    Slog.w(TAG, "Attempted to add input method window with bad token "
                            + attrs.token + ".  Aborting.");
                      return WindowManagerGlobal.ADD_BAD_APP_TOKEN;
                }
            } else if (type == TYPE_VOICE_INTERACTION) {
                if (token.windowType != TYPE_VOICE_INTERACTION) {
                    Slog.w(TAG, "Attempted to add voice interaction window with bad token "
                            + attrs.token + ".  Aborting.");
                      return WindowManagerGlobal.ADD_BAD_APP_TOKEN;
                }
            } else if (type == TYPE_WALLPAPER) {
                if (token.windowType != TYPE_WALLPAPER) {
                    Slog.w(TAG, "Attempted to add wallpaper window with bad token "
                            + attrs.token + ".  Aborting.");
                      return WindowManagerGlobal.ADD_BAD_APP_TOKEN;
                }
            } else if (type == TYPE_DREAM) {
                if (token.windowType != TYPE_DREAM) {
                    Slog.w(TAG, "Attempted to add Dream window with bad token "
                            + attrs.token + ".  Aborting.");
                      return WindowManagerGlobal.ADD_BAD_APP_TOKEN;
                }
            } else if (type == TYPE_ACCESSIBILITY_OVERLAY) {
                if (token.windowType != TYPE_ACCESSIBILITY_OVERLAY) {
                    Slog.w(TAG, "Attempted to add Accessibility overlay window with bad token "
                            + attrs.token + ".  Aborting.");
                    return WindowManagerGlobal.ADD_BAD_APP_TOKEN;
                }
            } else if (token.appWindowToken != null) {
                Slog.w(TAG, "Non-null appWindowToken for system window of type=" + type);
                // It is not valid to use an app token with other system types; we will
                // instead make a new token for it (as if null had been passed in for the token).
                attrs.token = null;
                token = new WindowToken(this, null, -1, false);
                addToken = true;
            }

            WindowState win = new WindowState(this, session, client, token,
                    attachedWindow, appOp[0], seq, attrs, viewVisibility, displayContent);
            if (win.mDeathRecipient == null) {
                // Client has apparently died, so there is no reason to
                // continue.
                Slog.w(TAG, "Adding window client " + client.asBinder()
                        + " that is dead, aborting.");
                return WindowManagerGlobal.ADD_APP_EXITING;
            }

            if (win.getDisplayContent() == null) {
                Slog.w(TAG, "Adding window to Display that has been removed.");
                return WindowManagerGlobal.ADD_INVALID_DISPLAY;
            }

            mPolicy.adjustWindowParamsLw(win.mAttrs);
            win.setShowToOwnerOnlyLocked(mPolicy.checkShowToOwnerOnly(attrs));

            res = mPolicy.prepareAddWindowLw(win, attrs);
            if (res != WindowManagerGlobal.ADD_OKAY) {
                return res;
            }

            if (outInputChannel != null && (attrs.inputFeatures
                    & WindowManager.LayoutParams.INPUT_FEATURE_NO_INPUT_CHANNEL) == 0) {
                String name = win.makeInputChannelName();
                InputChannel[] inputChannels = InputChannel.openInputChannelPair(name);
                win.setInputChannel(inputChannels[0]);
                inputChannels[1].transferTo(outInputChannel);

                mInputManager.registerInputChannel(win.mInputChannel, win.mInputWindowHandle);
            }

            // From now on, no exceptions or errors allowed!

            res = WindowManagerGlobal.ADD_OKAY;

            origId = Binder.clearCallingIdentity();

            if (addToken) {
                mTokenMap.put(attrs.token, token);
            }
            win.attach();
            mWindowMap.put(client.asBinder(), win);
            if (win.mAppOp != AppOpsManager.OP_NONE) {
                int startOpResult = mAppOps.startOpNoThrow(win.mAppOp, win.getOwningUid(),
                        win.getOwningPackage());
                if ((startOpResult != AppOpsManager.MODE_ALLOWED) &&
                        (startOpResult != AppOpsManager.MODE_DEFAULT)) {
                    win.setAppOpVisibilityLw(false);
                }
            }

            if (type == TYPE_APPLICATION_STARTING && token.appWindowToken != null) {
                token.appWindowToken.startingWindow = win;
                if (DEBUG_STARTING_WINDOW) Slog.v (TAG, "addWindow: " + token.appWindowToken
                        + " startingWindow=" + win);
            }

            boolean imMayMove = true;

            if (type == TYPE_INPUT_METHOD) {
                win.mGivenInsetsPending = true;
                mInputMethodWindow = win;
                addInputMethodWindowToListLocked(win);
                imMayMove = false;
            } else if (type == TYPE_INPUT_METHOD_DIALOG) {
                mInputMethodDialogs.add(win);
                addWindowToListInOrderLocked(win, true);
                moveInputMethodDialogsLocked(findDesiredInputMethodWindowIndexLocked(true));
                imMayMove = false;
            } else {
                addWindowToListInOrderLocked(win, true);
                if (type == TYPE_WALLPAPER) {
                    mLastWallpaperTimeoutTime = 0;
                    displayContent.pendingLayoutChanges |= FINISH_LAYOUT_REDO_WALLPAPER;
                } else if ((attrs.flags&FLAG_SHOW_WALLPAPER) != 0) {
                    displayContent.pendingLayoutChanges |= FINISH_LAYOUT_REDO_WALLPAPER;
                } else if (mWallpaperTarget != null
                        && mWallpaperTarget.mLayer >= win.mBaseLayer) {
                    // If there is currently a wallpaper being shown, and
                    // the base layer of the new window is below the current
                    // layer of the target window, then adjust the wallpaper.
                    // This is to avoid a new window being placed between the
                    // wallpaper and its target.
                    displayContent.pendingLayoutChanges |= FINISH_LAYOUT_REDO_WALLPAPER;
                }
            }

            final WindowStateAnimator winAnimator = win.mWinAnimator;
            winAnimator.mEnterAnimationPending = true;
            winAnimator.mEnteringAnimation = true;

            if (displayContent.isDefaultDisplay) {
                mPolicy.getInsetHintLw(win.mAttrs, mRotation, outContentInsets, outStableInsets,
                        outOutsets);
            } else {
                outContentInsets.setEmpty();
                outStableInsets.setEmpty();
            }

            if (mInTouchMode) {
                res |= WindowManagerGlobal.ADD_FLAG_IN_TOUCH_MODE;
            }
            if (win.mAppToken == null || !win.mAppToken.clientHidden) {
                res |= WindowManagerGlobal.ADD_FLAG_APP_VISIBLE;
            }

            mInputMonitor.setUpdateInputWindowsNeededLw();

            boolean focusChanged = false;
            if (win.canReceiveKeys()) {
                focusChanged = updateFocusedWindowLocked(UPDATE_FOCUS_WILL_ASSIGN_LAYERS,
                        false /*updateInputWindows*/);
                if (focusChanged) {
                    imMayMove = false;
                }
            }

            if (imMayMove) {
                moveInputMethodWindowsIfNeededLocked(false);
            }

            assignLayersLocked(displayContent.getWindowList());
            // Don't do layout here, the window must call
            // relayout to be displayed, so we'll do it there.

            if (focusChanged) {
                mInputMonitor.setInputFocusLw(mCurrentFocus, false /*updateInputWindows*/);
            }
            mInputMonitor.updateInputWindowsLw(false /*force*/);

            if (localLOGV || DEBUG_ADD_REMOVE) Slog.v(TAG, "addWindow: New client "
                    + client.asBinder() + ": window=" + win + " Callers=" + Debug.getCallers(5));

            if (win.isVisibleOrAdding() && updateOrientationFromAppTokensLocked(false)) {
                reportNewConfig = true;
            }
        }

        if (reportNewConfig) {
            sendNewConfiguration();
        }

        Binder.restoreCallingIdentity(origId);

        return res;
    }

step1. 检查权限

如果窗口类型是

        if (type < FIRST_SYSTEM_WINDOW || type > LAST_SYSTEM_WINDOW) {
            // Window manager will make sure these are okay.
            return WindowManagerGlobal.ADD_OKAY;
        }

非系统窗口，任何app 都可以添加，就没有什么问题。

step2.避免重复添加

            if (mWindowMap.containsKey(client.asBinder())) {
                Slog.w(TAG, "Window " + client + " is already added");
                return WindowManagerGlobal.ADD_DUPLICATE_ADD;
            }

step3.子窗口

            if (type >= FIRST_SUB_WINDOW && type <= LAST_SUB_WINDOW) {
                attachedWindow = windowForClientLocked(null, attrs.token, false);
                if (attachedWindow == null) {
                    Slog.w(TAG, "Attempted to add window with token that is not a window: "
                          + attrs.token + ".  Aborting.");
                    return WindowManagerGlobal.ADD_BAD_SUBWINDOW_TOKEN;
                }
                if (attachedWindow.mAttrs.type >= FIRST_SUB_WINDOW
                        && attachedWindow.mAttrs.type <= LAST_SUB_WINDOW) {
                    Slog.w(TAG, "Attempted to add window with token that is a sub-window: "
                            + attrs.token + ".  Aborting.");
                    return WindowManagerGlobal.ADD_BAD_SUBWINDOW_TOKEN;
                }
            }

通过token，寻找client   windowForClientLocked

Step4. token 检查

根据type的类型，检查token的有效性。

这里有好几个token相关的变量

WindowToken token = mTokenMap.get(attrs.token);

attrs.token

attrs.token 类型为IBinder。它代表这个窗口的“主人”.AMS 为每一个activity对象都创建一个ActivityRecord对象，本质就是IBinder。

boolean addToken = false;

用以表述新的token有没有被添加

这是几个token之间的关系图。

1）如果attrs.token在mTokenMap中找不到的话，说明AMS没有对应的记录

     if (type >= FIRST_APPLICATION_WINDOW && type <= LAST_APPLICATION_WINDOW)
TYPE_INPUT_METHOD
TYPE_VOICE_INTERACTION
TYPE_WALLPAPER
TYPE_DREAM
TYPE_ACCESSIBILITY_OVERLAY

这些是由AMS记录的，不会找不到，如果没有，说明出现不可预知的错误。返回

2）除了上述type之外，WMS允许AMS没有记录的情况，则为这个窗口创建一个token

attrs.token在mTokenMap可以找到的话，此时只有上面检查的那些

 if (type >= FIRST_APPLICATION_WINDOW && type <= LAST_APPLICATION_WINDOW)
TYPE_INPUT_METHOD
TYPE_VOICE_INTERACTION
TYPE_WALLPAPER
TYPE_DREAM
TYPE_ACCESSIBILITY_OVERLAY

才有可能被找到。所以，需要做一些判断和比较。

Step5. WindowState

如果一切顺利，new 一个WindowState

            WindowState win = new WindowState(this, session, client, token,
                    attachedWindow, appOp[0], seq, attrs, viewVisibility, displayContent);

this代表WMS自身

session 是WMS给窗口使用者的IWindowSession

client是IWindow，即窗口给WMS的一个访问通道

step6

if (win.mDeathRecipient == null)

如果窗口已经dead，就不需要进行下去。

step6

mPolicy.adjustWindowParamsLw(win.mAttrs);

step7

通过Policy进行调整。

            if (addToken) {
                mTokenMap.put(attrs.token, token);
            }

step8  添加新创建的token

            if (addToken) {
                mTokenMap.put(attrs.token, token);
            }

step9 重新排列layer值。

因为我们新增加了一个窗口，很可能需要插入，所以需要进行排序。

step10. getInsetHintLw

            if (displayContent.isDefaultDisplay) {
                mPolicy.getInsetHintLw(win.mAttrs, mRotation, outContentInsets, outStableInsets,
                        outOutsets);

计算窗口的tContentInset

step11.给排好序列的窗口，最终赋一个layer值

1.3 addAppWindowToListLocked

private void addWindowToListInOrderLocked(final WindowState win, boolean addToToken) {
        if (DEBUG_FOCUS_LIGHT) Slog.d(TAG, "addWindowToListInOrderLocked: win=" + win +
                " Callers=" + Debug.getCallers(4));
        if (win.mAttachedWindow == null) {
            final WindowToken token = win.mToken;
            int tokenWindowsPos = 0;
            if (token.appWindowToken != null) {
                tokenWindowsPos = addAppWindowToListLocked(win);
            } else {
                addFreeWindowToListLocked(win);
            }
            if (addToToken) {
                if (DEBUG_ADD_REMOVE) Slog.v(TAG, "Adding " + win + " to " + token);
                token.windows.add(tokenWindowsPos, win);
            }
        } else {
            addAttachedWindowToListLocked(win, addToToken);
        }

        if (win.mAppToken != null && addToToken) {
            win.mAppToken.allAppWindows.add(win);
        }
    }

1)win.mAttachedWindow == null

最外围的if，判断的是，是不是子类窗口，我们这里分析的是statusbar是系统窗口，所以考虑==null的情况

2）token.appWindowToken != null 

当前窗口是不是activity相关的，因为appWindowToken 是activity相关的。

2 Activity窗口的添加

WMS添加窗口是不区分系统还是应用的窗口，只是他们的权限还有层级不一样。

AMS在启动Activity的时候，会把必要的信息传递给WMS

servicescorejavacomandroidserveramActivityStack.java

 final void startActivityLocked(ActivityRecord r, boolean newTask,
            boolean doResume, boolean keepCurTransition, Bundle options) {
            mWindowManager.addAppToken(task.mActivities.indexOf(r),
                    r.appToken, r.task.taskId, mStackId, r.info.screenOrientation, r.fullscreen,
                    (r.info.flags & ActivityInfo.FLAG_SHOW_FOR_ALL_USERS) != 0, r.userId,
                    r.info.configChanges, task.voiceSession != null, r.mLaunchTaskBehind);

}

WMS 会把token记录到我们之前看到的mTokenMap中

Activity什么时候会经历Add view 进而通过WMS addwindow 把窗口添加到系统中呢？

我们看下ActivityThread中的handleResumeActivity

ActivityClientRecord r = performResumeActivity(token, clearHide);

首先Resume的启动，就是在这里执行的

DecorView是每个Activity的最外面的一层布局。

if (r.window == null && !a.mFinished && willBeVisible) {
                r.window = r.activity.getWindow();
                View decor = r.window.getDecorView();//DecorView
                decor.setVisibility(View.INVISIBLE);//可见性
                ViewManager wm = a.getWindowManager();//WindowManagerImpl
                WindowManager.LayoutParams l = r.window.getAttributes();//窗口参数
                a.mDecor = decor;
                l.type = WindowManager.LayoutParams.TYPE_BASE_APPLICATION;//窗口类型

　　　　　　　　　l.softInputMode |= forwardBit; if (a.mVisibleFromClient) { a.mWindowAdded = true; wm.addView(decor, l);
 }

将窗口添加wm.addView(decor, l)

在WMS添加窗口的过程基本与上面statusbar类似。

在WMS中：

private int addAppWindowToListLocked(final WindowState win) 

这里分2中情况

1）application已经含有窗口的情况下

if (!tokenWindowList.isEmpty()) {
            // If this application has existing windows, we
            // simply place the new window on top of them... but
            // keep the starting window on top.

2）如果没有窗口，情况就复杂一点

WMS将部分token的数据放到了　　

AppTokenList tokens = tasks.get(taskNdx).mAppTokens;

在所有apptoken中，寻找当前token适合的位子。

// We now know the index into the apps.  If we found
        // an app window above, that gives us the position; else
        // we need to look some more.
        if (pos != null) {

如果找到了合适的位置，pos就有值。

check WindowToken的位置，如果有对应的，就直接返回对应的pos

                    WindowState bottom = tokenWindowList.get(0);
                    if (bottom.mSubLayer < 0) {
                        pos = bottom;
                    }
                }

如果参考窗口没有，就直接选中最后一个。

如果pos == null，也就是没有找到对应的参考值。

这时候就寻找下一个token对应的值。如果找到就用pos

如果还没有找到，那只能对应BaseLayer的值，找到一个合适的位置。

参考：

《深入理解Android 内核设计思想》 林学森