Android4.1 关于Rotation相关的Configuration整体分析

关于Rotation方面在Android中有点会涉及到。

1. 在Settings->Display中有“Auto-rotate screen” 选项,当enable或者disable的时候都会影响到系统的Rotation

2. 当旋转手机的时候,系统会做怎么的操作去通知Activity要旋转界面了。

3. 当新启一个应用需要强制横屏或者竖屏的时候,系统是怎么去判断的。

1. 当我们enable或者disable “Auto-rotate screen”的时候,系统会做什么

1.  RotationPolicy.setRotationLockForAccessibility()

     1. 当用户enable或者disable “Auto-rotate screen”的时候,会调用RotationPolicy.setRotationLockForAccessibility(), 而在这个函数里面如果是enable就调用wm.freezeRotation(Suface.ROTATION_0);   // goto 1.1

      2. 否则就调用wm.thawRotation().

    public static void setRotationLockForAccessibility(Context context, final boolean enabled) {
        Settings.System.putIntForUser(context.getContentResolver(),
                Settings.System.HIDE_ROTATION_LOCK_TOGGLE_FOR_ACCESSIBILITY, enabled ? 1 : 0,
                        UserHandle.USER_CURRENT);

        AsyncTask.execute(new Runnable() {
            @Override
            public void run() {
                try {
                    IWindowManager wm = WindowManagerGlobal.getWindowManagerService();
                    if (enabled) {
                        wm.freezeRotation(Surface.ROTATION_0);
                    } else {
                        wm.thawRotation();
                    }
                } catch (RemoteException exc) {
                    Log.w(TAG, "Unable to save auto-rotate setting");
                }
            }
        });
    }

1.1 WindowManagerService.freezeRotation()

      1. mPolicy.setUserRotationMode 通过PhoneWindowManager.setUserRotationMode()去设置Settings.System相关的数据库值,在PhoneWindowManager中会有一个Observe去监听Settings.System的数值变化,如果有变动就去调用SettingsObserver.onChange()   //goto 1.1.1

       2. updateRotationUnchecked(false, false);   // goto  1.1.2

    public void freezeRotation(int rotation) {
        ... ...
        if (DEBUG_ORIENTATION) Slog.v(TAG, "freezeRotation: mRotation=" + mRotation);

        mPolicy.setUserRotationMode(WindowManagerPolicy.USER_ROTATION_LOCKED,
                rotation == -1 ? mRotation : rotation);
        updateRotationUnchecked(false, false);
    }

1.1.1 SettingsObserver.onChange()

    1. updateSettings();  跟新系统相关的设置  //goto 1.1.1.1

    2. updateRotation(false);  

        @Override public void onChange(boolean selfChange) {
            updateSettings();
            updateRotation(false);
        }

1.1.2  WindowManagerService.updateRotationUnchecked()

      这是freezeRotation里面做的第二个动作,为什么要把它写在前面,因为在debug的时候,发现这个函数中会调用policy中函数请求mLock的锁,然后block住1.1.1.1 PhoneWindowManager.updateSettings()。

     1. updateRotationUncheckedLocked(false);   如果返回的是false,就去直接执行performLayoutAndPlaceSurfacesLocked 去进行后续的刷新工作 // goto 1.1.2.1

     2. 如果满足相应的条件, performLayoutAndPlaceSurfacesLocked()  //

     3. 如果Configuration有变化或者明确要求sendConfiguration,就调用sendNewConfiguration(); 让AMS去updateConfiguration。 //这时候还不会执行

    public void updateRotationUnchecked(boolean alwaysSendConfiguration, boolean forceRelayout) {

        long origId = Binder.clearCallingIdentity();
        boolean changed;
        synchronized(mWindowMap) {
            changed = updateRotationUncheckedLocked(false);  // goto 1.1.2.1
            if (!changed || forceRelayout) {
                getDefaultDisplayContentLocked().layoutNeeded = true;
                performLayoutAndPlaceSurfacesLocked();  //后续分析
            }
        }

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

1.1.2.1 WindowManagerService.updateRotationUncheckedLocked()

      1. mPolicy.rotationForOrientationLw(mForcedAppOrientation, mRotation);   // 返回0  goto 1.1.2.1.1

      2.  mPolicy.rotationHasCompatibleMetricsLw 

      3. 如果roataion 和altOrientataion都没有发生变化就直接返回 false.  (这种情况是在portrait模式下enable rotation),如果是landscape模式下就应该往下走了。

      4. computeScreenConfigurationLocked(null); // Update application display metrics. 跟新屏幕相关的信息。

    public boolean updateRotationUncheckedLocked(boolean inTransaction) {
        ... ...
        int rotation = mPolicy.rotationForOrientationLw(mForcedAppOrientation, mRotation);
        boolean altOrientation = !mPolicy.rotationHasCompatibleMetricsLw(
                mForcedAppOrientation, rotation);

        if (mRotation == rotation && mAltOrientation == altOrientation) {
            // No change.
            return false;
        }

        mRotation = rotation;
        mAltOrientation = altOrientation;
        mPolicy.setRotationLw(mRotation);

        mWindowsFreezingScreen = true;
        mH.removeMessages(H.WINDOW_FREEZE_TIMEOUT);
        mH.sendMessageDelayed(mH.obtainMessage(H.WINDOW_FREEZE_TIMEOUT),
                WINDOW_FREEZE_TIMEOUT_DURATION);
        mWaitingForConfig = true;
        getDefaultDisplayContentLocked().layoutNeeded = true;
        startFreezingDisplayLocked(inTransaction, 0, 0);
        // startFreezingDisplayLocked can reset the ScreenRotationAnimation.
        screenRotationAnimation =
                mAnimator.getScreenRotationAnimationLocked(Display.DEFAULT_DISPLAY);

        // We need to update our screen size information to match the new
        // rotation.  Note that this is redundant with the later call to
        // sendNewConfiguration() that must be called after this function
        // returns...  however we need to do the screen size part of that
        // before then so we have the correct size to use when initializing
        // the rotation animation for the new rotation.
        computeScreenConfigurationLocked(null);

        final DisplayContent displayContent = getDefaultDisplayContentLocked();
        final DisplayInfo displayInfo = displayContent.getDisplayInfo();
        if (!inTransaction) {
            if (SHOW_TRANSACTIONS) {
                Slog.i(TAG, ">>> OPEN TRANSACTION setRotationUnchecked");
            }
            Surface.openTransaction();
        }
        try {
            // NOTE: We disable the rotation in the emulator because
            //       it doesn't support hardware OpenGL emulation yet.
            if (CUSTOM_SCREEN_ROTATION && screenRotationAnimation != null
                    && screenRotationAnimation.hasScreenshot()) {
                if (screenRotationAnimation.setRotationInTransaction(
                        rotation, mFxSession,
                        MAX_ANIMATION_DURATION, mTransitionAnimationScale,
                        displayInfo.logicalWidth, displayInfo.logicalHeight)) {
                    updateLayoutToAnimationLocked();
                }
            }

            mDisplayManagerService.performTraversalInTransactionFromWindowManager();
        } finally {
            if (!inTransaction) {
                Surface.closeTransaction();
                if (SHOW_LIGHT_TRANSACTIONS) {
                    Slog.i(TAG, "<<< CLOSE TRANSACTION setRotationUnchecked");
                }
            }
        }

        final WindowList windows = displayContent.getWindowList();
        for (int i = windows.size() - 1; i >= 0; i--) {
            WindowState w = windows.get(i);
            if (w.mHasSurface) {
                if (DEBUG_ORIENTATION) Slog.v(TAG, "Set mOrientationChanging of " + w);
                w.mOrientationChanging = true;
                mInnerFields.mOrientationChangeComplete = false;
            }
        }

        for (int i=mRotationWatchers.size()-1; i>=0; i--) {
            try {
                mRotationWatchers.get(i).onRotationChanged(rotation);
            } catch (RemoteException e) {
            }
        }

        scheduleNotifyRotationChangedIfNeededLocked(displayContent, rotation);

        return true;
    }

1.1.2.1.1 PhoneWindowManager.rotationForOrientationLw()

       这个函数的主要作用是返回跟Orientation相关的rotation,如果没有固定的设置,系统会返回一个默认的Rotation值。

       1.  先去调用mOrientationListener.getProposeRotation()去获取Sensor认为的合适的rotation值,通常是-1,我debug的时候返回的就是。mOrientationListener 为MyOrientationListener对象

       2. 由于此时mUserRotationMode == WindowManagerPolicy.USER_ROTATION_LOCKED 所以把preferredRotation = mUserRotation; 然后跟据对应的orientation选择对应的Rotation返回,我们这个case是走到default里面把preferredRotation返回回去。

    public int rotationForOrientationLw(int orientation, int lastRotation) {

        synchronized (mLock) {
            int sensorRotation = mOrientationListener.getProposedRotation(); // may be -1
            if (sensorRotation < 0) {
                sensorRotation = lastRotation;
            }

            final int preferredRotation;
            if (mLidState == LID_OPEN && mLidOpenRotation >= 0) {
               .... ...
            } else if (mUserRotationMode == WindowManagerPolicy.USER_ROTATION_LOCKED
                    && orientation != ActivityInfo.SCREEN_ORIENTATION_NOSENSOR) {
                // Apply rotation lock.  Does not apply to NOSENSOR.
                // The idea is that the user rotation expresses a weak preference for the direction
                // of gravity and as NOSENSOR is never affected by gravity, then neither should
                // NOSENSOR be affected by rotation lock (although it will be affected by docks).
                preferredRotation = mUserRotation;
            } else {
                // No overriding preference.
                // We will do exactly what the application asked us to do.
                preferredRotation = -1;
            }

            switch (orientation) {
                case ActivityInfo.SCREEN_ORIENTATION_PORTRAIT:
                    // Return portrait unless overridden.
                    if (isAnyPortrait(preferredRotation)) {
                        return preferredRotation;
                    }
                    return mPortraitRotation;

                case ActivityInfo.SCREEN_ORIENTATION_LANDSCAPE:
                    // Return landscape unless overridden.
                    if (isLandscapeOrSeascape(preferredRotation)) {
                        return preferredRotation;
                    }
                    return mLandscapeRotation;

                case ActivityInfo.SCREEN_ORIENTATION_REVERSE_PORTRAIT:
                    // Return reverse portrait unless overridden.
                    if (isAnyPortrait(preferredRotation)) {
                        return preferredRotation;
                    }
                    return mUpsideDownRotation;

                case ActivityInfo.SCREEN_ORIENTATION_REVERSE_LANDSCAPE:
                    // Return seascape unless overridden.
                    if (isLandscapeOrSeascape(preferredRotation)) {
                        return preferredRotation;
                    }
                    return mSeascapeRotation;

                case ActivityInfo.SCREEN_ORIENTATION_SENSOR_LANDSCAPE:
                    // Return either landscape rotation.
                    if (isLandscapeOrSeascape(preferredRotation)) {
                        return preferredRotation;
                    }
                    if (isLandscapeOrSeascape(lastRotation)) {
                        return lastRotation;
                    }
                    return mLandscapeRotation;

                case ActivityInfo.SCREEN_ORIENTATION_SENSOR_PORTRAIT:
                    // Return either portrait rotation.
                    if (isAnyPortrait(preferredRotation)) {
                        return preferredRotation;
                    }
                    if (isAnyPortrait(lastRotation)) {
                        return lastRotation;
                    }
                    return mPortraitRotation;

                default:
                    // For USER, UNSPECIFIED, NOSENSOR, SENSOR and FULL_SENSOR,
                    // just return the preferred orientation we already calculated.
                    if (preferredRotation >= 0) {
                        return preferredRotation;
                    }
                    return Surface.ROTATION_0;
            }
        }
    }

1.1.1.1 PhoneWindowManager.updateSettings()

   当 1.1.2的lock释放之后,也就是 PhoneWindowManager.rotationForOrientationLw()执行完,updateSettings会等到mLock锁.

   由于userRotation和userRotationMode都发生了变化,所以会先后执行

     1. updateOrientationListenerLp();  // goto 1.1.1.1.1

      2. updateRotation(true);  //这个操作跟1.1.1.2是一样的,只不过这次需要去sendConfiguration了。

    public void updateSettings() {
        ContentResolver resolver = mContext.getContentResolver();
        boolean updateRotation = false;
        synchronized (mLock) {
            ... ...

            // Configure rotation lock.
            int userRotation = Settings.System.getIntForUser(resolver,
                    Settings.System.USER_ROTATION, Surface.ROTATION_0,
                    UserHandle.USER_CURRENT);
            if (mUserRotation != userRotation) {
                mUserRotation = userRotation;
                updateRotation = true;
            }
            int userRotationMode = Settings.System.getIntForUser(resolver,
                    Settings.System.ACCELEROMETER_ROTATION, 0, UserHandle.USER_CURRENT) != 0 ?
                            WindowManagerPolicy.USER_ROTATION_FREE :
                                    WindowManagerPolicy.USER_ROTATION_LOCKED;
            if (mUserRotationMode != userRotationMode) {
                mUserRotationMode = userRotationMode;
                updateRotation = true;
                updateOrientationListenerLp();
            }

        }
        if (updateRotation) {
            updateRotation(true);
        }
    }

1.1.1.1.1 PhoneWindowManager.updateOrientationListenerLp();

  这是函数很简单,由于我们把Rotation打开了,所以就去enable mOrientationListener (MyOrientationListener),作为Sensor变化的一个listener的回调函数。

    void updateOrientationListenerLp() {
        if (!mOrientationListener.canDetectOrientation()) {
            // If sensor is turned off or nonexistent for some reason
            return;
        }
        //Could have been invoked due to screen turning on or off or
        //change of the currently visible window's orientation
        if (localLOGV) Log.v(TAG, "Screen status="+mScreenOnEarly+
                ", current orientation="+mCurrentAppOrientation+
                ", SensorEnabled="+mOrientationSensorEnabled);
        boolean disable = true;
        if (mScreenOnEarly) {
            if (needSensorRunningLp()) {
                disable = false;
                //enable listener if not already enabled
                if (!mOrientationSensorEnabled) {
                    mOrientationListener.enable();
                    if(localLOGV) Log.v(TAG, "Enabling listeners");
                    mOrientationSensorEnabled = true;
                }
            } 
        } 
        //check if sensors need to be disabled
        if (disable && mOrientationSensorEnabled) {
            mOrientationListener.disable();
            if(localLOGV) Log.v(TAG, "Disabling listeners");
            mOrientationSensorEnabled = false;
        }
    

1.1.1.1 PhoneWindowManager.sendNewConfiguration()

 调用AMS去updateconfigurattion,后续分析

    void sendNewConfiguration() {
        try {
            mActivityManager.updateConfiguration(null);
        } catch (RemoteException e) {
        }
    }

    原文作者:Shen_JC
    原文地址: https://blog.csdn.net/Siobhan/article/details/8526006
    本文转自网络文章,转载此文章仅为分享知识,如有侵权,请联系博主进行删除。
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