Android 14 双击power键唤起安全相机流程解析
2024-02-13 / 龙之叶   

前言

事件处理主要都是在 PhoneWindowManager.java 中，电源键处理在 PhoneWindowManager#interceptKeyBeforeQueueing() 中：
frameworks/base/services/core/java/com/android/server/policy/PhoneWindowManager.java

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public int interceptKeyBeforeQueueing(KeyEvent event, int policyFlags) {
 
        // 省略部分代码......
        if ((event.getFlags() & KeyEvent.FLAG_FALLBACK) == 0) {
            Log.d(TAG,"handleKeyGesture +000");
            handleKeyGesture(event, interactiveAndOn);
        }
        // 省略部分代码......
}
 
private void handleKeyGesture(KeyEvent event, boolean interactive) {
    // 省略部分代码......
    if (event.getKeyCode() == KEYCODE_POWER && event.getAction() == KeyEvent.ACTION_DOWN) {
        mPowerKeyHandled = handleCameraGesture(event, interactive);
        if (mPowerKeyHandled) {
            // handled by camera gesture.
            mSingleKeyGestureDetector.reset();
            return;
        }
    }

    mSingleKeyGestureDetector.interceptKey(event, interactive);
}

// The camera gesture will be detected by GestureLauncherService.
private boolean handleCameraGesture(KeyEvent event, boolean interactive) {
    // camera gesture.
    // 省略部分代码......
    final boolean intercept =
            mGestureLauncherService.interceptPowerKeyDown(event, interactive, outLaunched);
    // 省略部分代码......
}

接着看 GestureLauncherService.java
frameworks/base/services/core/java/com/android/server/GestureLauncherService.java

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public boolean interceptPowerKeyDown(KeyEvent event, boolean interactive,
        MutableBoolean outLaunched) {
    // 省略部分代码......

    if (launchCamera) {
        Slog.i(TAG, "Power button double tap gesture detected, launching camera. Interval="
                + powerTapInterval + "ms");
        launchCamera = handleCameraGesture(false /* useWakelock */,
                StatusBarManager.CAMERA_LAUNCH_SOURCE_POWER_DOUBLE_TAP);
        if (launchCamera) {
            mMetricsLogger.action(MetricsEvent.ACTION_DOUBLE_TAP_POWER_CAMERA_GESTURE,
                    (int) powerTapInterval);
            mUiEventLogger.log(GestureLauncherEvent.GESTURE_CAMERA_DOUBLE_TAP_POWER);
        }
    } else if (launchEmergencyGesture) {
        Slog.i(TAG, "Emergency gesture detected, launching.");
        launchEmergencyGesture = handleEmergencyGesture();
        mUiEventLogger.log(GestureLauncherEvent.GESTURE_EMERGENCY_TAP_POWER);
    }
    // 省略部分代码......
}

@VisibleForTesting
boolean handleCameraGesture(boolean useWakelock, int source) {
    // 省略部分代码......
        if (useWakelock) {
            // Make sure we don't sleep too early
            mWakeLock.acquire(500L);
        }
        StatusBarManagerInternal service = LocalServices.getService(
                StatusBarManagerInternal.class);
        service.onCameraLaunchGestureDetected(source);
        return true;
    // 省略部分代码......
}

StatusBarManagerInternal.java 是一个 interface 接口，实现在 StatusBarManagerService.java 。
StatusBarManagerService#onCameraLaunchGestureDetected()
frameworks/base/services/core/java/com/android/server/statusbar/StatusBarManagerService.java

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@Override
public void onCameraLaunchGestureDetected(int source) {
    if (mBar != null) {
        try {
            mBar.onCameraLaunchGestureDetected(source);
        } catch (RemoteException e) {
        }
    }
}

mBar 是 IStatusBar 对象，被 CommandQueue.java 继承；CentralSurfacesCommandQueueCallbacks 又继承了实现了 CommandQueue.Callbacks ，最终下一步会调用到 CentralSurfacesCommandQueueCallbacks#onCameraLaunchGestureDetected()

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public void onCameraLaunchGestureDetected(int source) {
    mCentralSurfaces.setLastCameraLaunchSource(source);
    if (mCentralSurfaces.isGoingToSleep()) {
        if (CentralSurfaces.DEBUG_CAMERA_LIFT) {
            Slog.d(CentralSurfaces.TAG, "Finish going to sleep before launching camera");
        }
        mCentralSurfaces.setLaunchCameraOnFinishedGoingToSleep(true);
        return;
    }
    if (!mNotificationPanelViewController.canCameraGestureBeLaunched()) {
        if (CentralSurfaces.DEBUG_CAMERA_LIFT) {
            Slog.d(CentralSurfaces.TAG, "Can't launch camera right now");
        }
        return;
    }
    if (!mCentralSurfaces.isDeviceInteractive()) {
        mPowerManager.wakeUp(SystemClock.uptimeMillis(), PowerManager.WAKE_REASON_CAMERA_LAUNCH,
                "com.android.systemui:CAMERA_GESTURE");
    }
    vibrateForCameraGesture();
    if (source == StatusBarManager.CAMERA_LAUNCH_SOURCE_POWER_DOUBLE_TAP) {
        Log.v(CentralSurfaces.TAG, "Camera launch");
        // 屏蔽人脸或者指纹解锁
        mKeyguardUpdateMonitor.onCameraLaunched();
    }
    if (!mStatusBarKeyguardViewManager.isShowing()) {
        final Intent cameraIntent = CameraIntents.getInsecureCameraIntent(mContext);
        mCentralSurfaces.startActivityDismissingKeyguard(cameraIntent,
                false /* onlyProvisioned */, true /* dismissShade */,
                true /* disallowEnterPictureInPictureWhileLaunching */, null /* callback */, 0,
                null /* animationController */, UserHandle.CURRENT);
    } else {
        if (!mCentralSurfaces.isDeviceInteractive()) {
            // 当我们立即启动相机并且弹跳器启动时，避免稀松布闪烁                
            mCentralSurfaces.acquireGestureWakeLock(
                    CentralSurfaces.LAUNCH_TRANSITION_TIMEOUT_MS + 1000L);
        }
        if (isWakingUpOrAwake()) {
            if (CentralSurfaces.DEBUG_CAMERA_LIFT) {
                Slog.d(CentralSurfaces.TAG, "Launching camera");
            }
            if (mStatusBarKeyguardViewManager.isBouncerShowing()) {
                mStatusBarKeyguardViewManager.reset(true /* hide */);
            }
            // 启动相机
            mNotificationPanelViewController.launchCamera(mCentralSurfaces.isDeviceInteractive() /* animate */, source);
            mCentralSurfaces.updateScrimController();
        } else {
            if (CentralSurfaces.DEBUG_CAMERA_LIFT) {
                Slog.d(CentralSurfaces.TAG, "Deferring until screen turns on");
            }
            mCentralSurfaces.setLaunchCameraOnFinishedWaking(true);
        }
    }
}

再看 NotificationPanelViewController#launchCamera() :
frameworks/base/packages/SystemUI/src/com/android/systemui/shade/NotificationPanelViewController.java

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public void launchCamera(boolean animate, int source) {
    if (source == StatusBarManager.CAMERA_LAUNCH_SOURCE_POWER_DOUBLE_TAP) {
        mLastCameraLaunchSource = KeyguardBottomAreaView.CAMERA_LAUNCH_SOURCE_POWER_DOUBLE_TAP;
    } else if (source == StatusBarManager.CAMERA_LAUNCH_SOURCE_WIGGLE) {
        mLastCameraLaunchSource = KeyguardBottomAreaView.CAMERA_LAUNCH_SOURCE_WIGGLE;
    } else if (source == StatusBarManager.CAMERA_LAUNCH_SOURCE_LIFT_TRIGGER) {
        mLastCameraLaunchSource = KeyguardBottomAreaView.CAMERA_LAUNCH_SOURCE_LIFT_TRIGGER;
    } else {
        // Default.
        mLastCameraLaunchSource = KeyguardBottomAreaView.CAMERA_LAUNCH_SOURCE_AFFORDANCE;
    }
    if (!isFullyCollapsed()) {
        setLaunchingAffordance(true);
    } else {
        animate = false;
    }
    mAffordanceHasPreview = mKeyguardBottomArea.getRightPreview() != null;
    // 启动相机
    mAffordanceHelper.launchAffordance(
            animate, mView.getLayoutDirection() == View.LAYOUT_DIRECTION_RTL);
}

接着看 KeyguardAffordanceHelper#launchAffordance() :

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public void launchAffordance(boolean animate, boolean left) {
    if (mSwipingInProgress) {
        // We don't want to mess with the state if the user is actually swiping already.
        return;
    }
    KeyguardAffordanceView targetView = left ? mLeftIcon : mRightIcon;
    KeyguardAffordanceView otherView = left ? mRightIcon : mLeftIcon;
    startSwiping(targetView);
    // Do not animate the circle expanding if the affordance isn't visible,
    // otherwise the circle will be meaningless.
    if (targetView.getVisibility() != View.VISIBLE) {
        animate = false;
    }
    if (animate) {
        fling(0, false, !left);  // 这里面会回调 KeyguardAffordanceHelperCallback#onAnimationToSideStarted() 方法，去启动相机，并且里面有个动画。
        updateIcon(otherView, 0.0f, 0, true, false, true, false);
    } else {
        mCallback.onAnimationToSideStarted(!left, mTranslation, 0);
        mTranslation = left ? mCallback.getMaxTranslationDistance()
                : mCallback.getMaxTranslationDistance();
        updateIcon(otherView, 0.0f, 0.0f, false, false, true, false);
        targetView.instantFinishAnimation();
        mFlingEndListener.onAnimationEnd(null);
        mAnimationEndRunnable.run();
    }
}

当动画执行完成，则会执行 mAnimationEndRunnable.run()，进而回调到： KeyguardAffordanceHelperCallback#onAnimationToSideEnded() ： 方法里

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public void onAnimationToSideEnded() {
    mIsLaunchTransitionRunning = false;
    mIsLaunchTransitionFinished = true;
    if (mLaunchAnimationEndRunnable != null) {
        // 这里会去销毁密码锁界面、图案锁界面；
        mLaunchAnimationEndRunnable.run();
        mLaunchAnimationEndRunnable = null;
    }
    mCentralSurfaces.readyForKeyguardDone();
}

这里补充个流程： 在未解锁的情况下，打开临时占用的app，比如 相机，紧急拨号等会调用如下函数：

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public void setOccluded(boolean occluded, boolean animate) {
    final boolean isOccluding = !mOccluded && occluded;
    final boolean isUnOccluding = mOccluded && !occluded;
    setOccludedAndUpdateStates(occluded);
    if (mShowing && isOccluding) {
        SysUiStatsLog.write(SysUiStatsLog.KEYGUARD_STATE_CHANGED,
                SysUiStatsLog.KEYGUARD_STATE_CHANGED__STATE__OCCLUDED);
        if (mCentralSurfaces.isInLaunchTransition()) {
            final Runnable endRunnable = new Runnable() {
                @Override
                public void run() {
                    ///M: [ALPS01807921]
                    ///   mOccluded may be changed before the runnable is executed.
                    if (mOccluded) {
                        mNotificationShadeWindowController.setKeyguardOccluded(mOccluded);
                        reset(true /* hideBouncerWhenShowing */);
                    } else {
                        Log.d(TAG, "setOccluded.run() - mOccluded was set to false") ;
                    }
                }
            };
            
            mCentralSurfaces.fadeKeyguardAfterLaunchTransition(
                    null /* beforeFading */,
                    endRunnable,
                    endRunnable);
            return;
        }
        // 省略部分代码......
}
本文链接：
http://longzhiye.top/2024/02/13/2024-02-13/