Android关机流程简析

关机有几种方式:按键、重启或者其他模式

在关机过程中,主要做了三件事:
1.发送关机广播
2.关闭一些主要服务进程
3.通过PowerManagerService调用底层进行关机
有的模块可能需要监听手机关机事件,所以在关机时发送关机广播,通知相关模块处理。


接下来主要讲解按键响应关机整个流程:

PhoneWindowManager.java | framework\base\services\core\java\com\android\server\policy

    private void interceptPowerKeyDown(KeyEvent event, boolean interactive) {
        // Hold a wake lock until the power key is released.
        if (!mPowerKeyWakeLock.isHeld()) {
            mPowerKeyWakeLock.acquire();
        }
        ......
         if (hasLongPressOnPowerBehavior()) {//是否存在长按事件
                    Message msg = mHandler.obtainMessage(MSG_POWER_LONG_PRESS);
                    msg.setAsynchronous(true);//如果是长按power键就发送MSG_POWER_LONG_PRESS
                    mHandler.sendMessageDelayed(msg,//发送delay消息, delay 500ms给用户一些时间长按power键显示关机dialog, 同时delay时间也可以通过config.xml中配置

                    ViewConfiguration.get(mContext).getDeviceGlobalActionKeyTimeout());
                }
        ......
    }

延迟消息最终会在PolicyHandler的handleMessage中处理长按事件。

private class PolicyHandler extends Handler {
        @Override
        public void handleMessage(Message msg) {
              //......
                case MSG_POWER_LONG_PRESS:
                    powerLongPress();//处理长按事件
                    break;
           //........
            }
        }
    }

当按下电源按键的时候会有不同的响应,可能什么都不做,也可能直接关机,没有给用户任何提醒. 或者弹出dialog让用户自己选择. 下面将主要讲解弹出dialog关机的情况。

GlobalActions.java | framework\base\services\core\java\com\android\server\policy

static final int LONG_PRESS_POWER_NOTHING = 0;       //长按power键什么都不做
    static final int LONG_PRESS_POWER_GLOBAL_ACTIONS = 1;     //为全局动作, 显示关机dialog
    static final int LONG_PRESS_POWER_SHUT_OFF = 2;    //只有关机一个选项
    static final int LONG_PRESS_POWER_SHUT_OFF_NO_CONFIRM = 3;   //直接关机不用确认

    private void powerLongPress() {
        final int behavior = getResolvedLongPressOnPowerBehavior();
        switch (behavior) {
        case LONG_PRESS_POWER_NOTHING://什么都不做,返回
            break;
        case LONG_PRESS_POWER_GLOBAL_ACTIONS:
            mPowerKeyHandled = true;
            if (!performHapticFeedbackLw(null, HapticFeedbackConstants.LONG_PRESS, false)) {
                performAuditoryFeedbackForAccessibilityIfNeed();
            }
            showGlobalActionsInternal();//shutDownRing();//显示全局Dailog
            break;
        case LONG_PRESS_POWER_SHUT_OFF:
        case LONG_PRESS_POWER_SHUT_OFF_NO_CONFIRM://直接关机
            mPowerKeyHandled = true;
            performHapticFeedbackLw(null, HapticFeedbackConstants.LONG_PRESS, false);
            sendCloseSystemWindows(SYSTEM_DIALOG_REASON_GLOBAL_ACTIONS);
            mWindowManagerFuncs.shutdown(behavior == LONG_PRESS_POWER_SHUT_OFF);
            break;
        }
    }

延伸:

可以在调用showGlobalActionsInternal()方法显示全局Dailog之前做一些定制化处理,比如随机播放关机铃声,如shutDownRing()方法:

private void shutDownRing(){
        //Merged by lefty.lan @20180803 for shutdown_ring, start
        Random random = new Random();
        int num = random.nextInt(4)%(4-1+1) + 1;
        MediaPlayer mPlayer = new MediaPlayer();
        try {
            if(mPlayer != null){
                switch (num) {
                case 1:
                    mPlayer.setDataSource("/system/media/01.wav");
                    break;
                case 2:
                    mPlayer.setDataSource("/system/media/02.wav");
                    break;
                case 3:
                    mPlayer.setDataSource("/system/media/03.wav");
                    break;
                case 4:
                    mPlayer.setDataSource("/system/media/04.wav");
                    break;
                }
            mPlayer.prepare();
            mPlayer.start();
            try{
                Thread.sleep(2000);
                } catch (Exception e) {
                //e.printStackTrace();
            }
            }
        } catch (Exception e) {
        e.printStackTrace();
        }

        showGlobalActionsInternal();

        if(mPlayer != null){
        mPlayer.stop();
        }
        //end
    }

言归正传

    void showGlobalActionsInternal() {
        sendCloseSystemWindows(SYSTEM_DIALOG_REASON_GLOBAL_ACTIONS);//关闭系统Dailog
        if (mGlobalActions == null) {
            mGlobalActions = new GlobalActions(mContext, mWindowManagerFuncs);//创建Dailog
        }
        final boolean keyguardShowing = isKeyguardShowingAndNotOccluded();//keyguard是否在显示
        mGlobalActions.showDialog(keyguardShowing, isDeviceProvisioned());//显示Dailog
        if (keyguardShowing) {
            // since it took two seconds of long press to bring this up,
            // poke the wake lock so they have some time to see the dialog.
            mPowerManager.userActivity(SystemClock.uptimeMillis(), false);//通知power发生了一次用户时间, 让用户可以看到dialog
        }
    }

在GlobalActions中如果已经存在mDialog就将原来的dismiss掉,之后发送消息重新show出来,否则就新创建出来一个显示。

    /**
     * Show the global actions dialog (creating if necessary)
     * @param keyguardShowing True if keyguard is showing
     */
    public void showDialog(boolean keyguardShowing, boolean isDeviceProvisioned) {
        mKeyguardShowing = keyguardShowing;
        mDeviceProvisioned = isDeviceProvisioned;
        if (mDialog != null) {
            mDialog.dismiss();
            mDialog = null;
            // Show delayed, so that the dismiss of the previous dialog completes
            mHandler.sendEmptyMessage(MESSAGE_SHOW);
        } else {
            handleShow();//如果不存在mDialog, 就调用handleShow处理
        }
    }

    private void handleShow() {
        awakenIfNecessary();
        mDialog = createDialog();//创建Dailog
        prepareDialog();//准备Dailog

        // If we only have 1 item and it's a simple press action, just do this action.
        if (mAdapter.getCount() == 1
                && mAdapter.getItem(0) instanceof SinglePressAction
                && !(mAdapter.getItem(0) instanceof LongPressAction)) {
            ((SinglePressAction) mAdapter.getItem(0)).onPress(); //调用onPress函数
        } else {
            WindowManager.LayoutParams attrs = mDialog.getWindow().getAttributes();
            attrs.setTitle("GlobalActions");
            mDialog.getWindow().setAttributes(attrs);
            mDialog.show();//显示Dailog
            mDialog.getWindow().getDecorView().setSystemUiVisibility(View.STATUS_BAR_DISABLE_EXPAND);

            //add by lefty_lan,2018-7-3 13:48:55
            //mWindowManagerFuncs.shutdown(true);
            // try
            // {
            // Thread.sleep(2000);
            // } catch (Exception e) {
            //  //e.printStackTrace();
            //  }
            //mWindowManagerFuncs.shutdown(false);
        }
    }

通过在(frameworks\base\core\res\res\values)config.xml中的actionslist记录的长按power键可以选择执行的动作,遍历actions列表进行匹配动作为其创建对应的Action对象.之后就创建dialog并返回。


    
        power
        bugreport
        users
    

    /**
     * Create the global actions dialog.
     * @return A new dialog.
     */
    private GlobalActionsDialog createDialog() {
        ......

        mItems = new ArrayList();
        String[] defaultActions = mContext.getResources().getStringArray(
                com.android.internal.R.array.config_globalActionsList);//获取config.xml中的action list记录在defaultActions数组中

        ArraySet addedKeys = new ArraySet();
        for (int i = 0; i < defaultActions.length; i++) {//遍历defaultActions列表
            String actionKey = defaultActions[i];
            if (addedKeys.contains(actionKey)) {
                //如果action已经在addedKeys列表中就不再添加了
                // If we already have added this, don't add it again.
                continue;
            }
            if (GLOBAL_ACTION_KEY_POWER.equals(actionKey)) {//对action list中actio进行匹配,如果能匹配上就创建对应对象放入mItems列表中
                mItems.add(new PowerAction());//长按power键动作
            } else if (GLOBAL_ACTION_KEY_AIRPLANE.equals(actionKey)) {
                mItems.add(mAirplaneModeOn);
            } else if (GLOBAL_ACTION_KEY_BUGREPORT.equals(actionKey)) {
                if (Settings.Global.getInt(mContext.getContentResolver(),
                        Settings.Global.BUGREPORT_IN_POWER_MENU, 0) != 0 && isCurrentUserOwner()) {
                    mItems.add(new BugReportAction());
                }
            } else if (GLOBAL_ACTION_KEY_SILENT.equals(actionKey)) {
                if (mShowSilentToggle) {
                    mItems.add(mSilentModeAction);
                }
            } else if (GLOBAL_ACTION_KEY_USERS.equals(actionKey)) {
                if (SystemProperties.getBoolean("fw.power_user_switcher", false)) {
                    addUsersToMenu(mItems);
                }
            } else if (GLOBAL_ACTION_KEY_SETTINGS.equals(actionKey)) {
                mItems.add(getSettingsAction());
            } else if (GLOBAL_ACTION_KEY_LOCKDOWN.equals(actionKey)) {
                mItems.add(getLockdownAction());
            } else if (GLOBAL_ACTION_KEY_VOICEASSIST.equals(actionKey)) {
                mItems.add(getVoiceAssistAction());
            } else if (GLOBAL_ACTION_KEY_ASSIST.equals(actionKey)) {
                mItems.add(getAssistAction());
            }
            // Add by Avar.wu @20161021 to add reboot action, start
            else if(GLOBAL_ACTION_KEY_REBOOT.equals(actionKey)) {
                mItems.add(new RebootAction());
            // end
            // Add by Avar.wu @20170303 to add region-screenshot action
            } else if (GLOBAL_ACTION_KEY_REGION_SCREENSHOT.equals(actionKey)) {
                mItems.add(new ScreenShotAction());
            // end
            } else {
                Log.e(TAG, "Invalid global action key " + actionKey);
            }
            // Add here so we don't add more than one.
            addedKeys.add(actionKey);//最后将actionKey放入列表, 不重复处理
        }

        mAdapter = new MyAdapter();

        AlertParams params = new AlertParams(mContext);
        params.mAdapter = mAdapter;
        params.mOnClickListener = this;
        params.mForceInverseBackground = true;

        GlobalActionsDialog dialog = new GlobalActionsDialog(mContext, params);//创建dialog
        dialog.setCanceledOnTouchOutside(false); // Handled by the custom class.当点击dialog外面,就会将dialog取消掉

        dialog.getListView().setItemsCanFocus(true);
        dialog.getListView().setLongClickable(true);
        dialog.getListView().setOnItemLongClickListener(
                new AdapterView.OnItemLongClickListener() {
                    @Override
                    public boolean onItemLongClick(AdapterView parent, View view, int position,
                            long id) {
                        final Action action = mAdapter.getItem(position);
                        if (action instanceof LongPressAction) {
                            return ((LongPressAction) action).onLongPress();
                        }
                        return false;
                    }
        });
        dialog.getWindow().setType(WindowManager.LayoutParams.TYPE_KEYGUARD_DIALOG);

        dialog.setOnDismissListener(this);

        return dialog;//返回Dailog
    }

当进行关机操作时就会调用PowerAction的onPress函数,进行调用WindowManagerFuncs接口中的shutdown函数, shutdown函数的具体实现在WindowManagerService中。

private final class PowerAction extends SinglePressAction implements LongPressAction {
        private PowerAction() {
            super(com.android.internal.R.drawable.ic_lock_power_off,
                R.string.global_action_power_off);
        }

        @Override
        public boolean onLongPress() {
            UserManager um = (UserManager) mContext.getSystemService(Context.USER_SERVICE);
            if (!um.hasUserRestriction(UserManager.DISALLOW_SAFE_BOOT)) {
                mWindowManagerFuncs.rebootSafeMode(true);
                return true;
            }
            return false;
        }

       //.............

        @Override
        public void onPress() {
            // shutdown by making sure radio and power are handled accordingly.
            mWindowManagerFuncs.shutdown(false /* confirm */);    //关机
        }
    }

由于WindowManagerService实现了接口WindowManagerFuncs, 所以就会调用到WMS中的shutdown函数. 进而调用ShutdownThread中去实现关机功能。

    // Called by window manager policy.  Not exposed externally.
    @Override
    public void shutdown(boolean confirm) {
        ShutdownThread.shutdown(mContext, PowerManager.SHUTDOWN_USER_REQUESTED, confirm);
    }

ShutdownThread.java | framework\base\services\core\java\com\android\server\power

    /**
     * Request a clean shutdown, waiting for subsystems to clean up their
     * state etc.  Must be called from a Looper thread in which its UI
     * is shown.
     *
     * @param context Context used to display the shutdown progress dialog.
     * @param reason code to pass to android_reboot() (e.g. "userrequested"), or null.
     * @param confirm true if user confirmation is needed before shutting down.
     */
    public static void shutdown(final Context context, String reason, boolean confirm) {
        mReboot = false;
        mRebootSafeMode = false;
        mReason = reason;

        Log.d(TAG, "!!! Request to shutdown !!!");

        if (mSpew) {
            StackTraceElement[] stack = new Throwable().getStackTrace();
            for (StackTraceElement element : stack)
            {
                Log.d(TAG, "    |----" + element.toString());
            }
        }

        if (SystemProperties.getBoolean("ro.monkey", false)) {
            Log.d(TAG, "Cannot request to shutdown when Monkey is running, returning.");
            return;
        }

        shutdownInner(context, confirm);
    }

        static void shutdownInner(final Context context, boolean confirm) {
        // ensure that only one thread is trying to power down.
        // any additional calls are just returned
        synchronized (sIsStartedGuard) {
            if (sIsStarted) {
                Log.d(TAG, "Request to shutdown already running, returning.");
                return;
            }
        }

        final int longPressBehavior = context.getResources().getInteger(
                        com.android.internal.R.integer.config_longPressOnPowerBehavior);
        final int resourceId = mRebootSafeMode
                ? com.android.internal.R.string.reboot_safemode_confirm
                : (longPressBehavior == 2
                        ? com.android.internal.R.string.shutdown_confirm_question
                        : com.android.internal.R.string.shutdown_confirm);//关机确认信息
        Log.d(TAG, "Notifying thread to start shutdown longPressBehavior=" + longPressBehavior);

        if (confirm) {
            final CloseDialogReceiver closer = new CloseDialogReceiver(context);
            if (sConfirmDialog != null) {
                sConfirmDialog.dismiss();
            }
            bConfirmForAnimation = confirm;
            Log.d(TAG, "PowerOff dialog doesn't exist. Create it first");
            sConfirmDialog = new AlertDialog.Builder(context)//需要再次确认关机,创建dialog
                .setTitle(mRebootSafeMode
                        ? com.android.internal.R.string.reboot_safemode_title
                        : com.android.internal.R.string.power_off)
                .setMessage(resourceId)
                .setPositiveButton(com.android.internal.R.string.yes,
                        new DialogInterface.OnClickListener() {
                    public void onClick(DialogInterface dialog, int which) {
                        beginShutdownSequence(context);//确认关机
                    }
                })
                .setNegativeButton(com.android.internal.R.string.no, null)//不关机了
                .create();
            closer.dialog = sConfirmDialog;
            sConfirmDialog.setOnDismissListener(closer);
            sConfirmDialog.getWindow().setType(WindowManager.LayoutParams.TYPE_KEYGUARD_DIALOG);
            sConfirmDialog.show();

            //add by lefty_lan,2018-7-3 13:49:22
            //beginShutdownSequence(context);
        } else {
            beginShutdownSequence(context);//如果不需要确认就直接关机
        }
    }


摘录自:https://blog.csdn.net/fu_kevin0606/article/details/54586009

在关机的时候如果sdcard处于MOUNTED状态下,就需要发送消息H_UNMOUNT_PM_UPDATE将sdcard 进行unmount操作。
如果sdcard为emulated模拟内卡,就不需要进行unmount操作,所以模拟内卡比物理内卡的手 机关机速度要快很多。
在进行unmount操作时,需要先调用PackageManagerService进行更新一下包状态,删除安装在 sd卡上的软件。完成之后回调到MountService中。
之后需要向底层发送命令查询占用sd卡的进程(如数据库,slog所在进程),然后调用AMS将占 用sd卡的进程杀死。由于占用sd卡的进程比较顽强,可能杀死后还会起来,所以杀完后再进行 查询占用sd卡的进程。如果所查进程数仍然不为NULL,就会再次杀,最多尝试杀四次,如果还 杀不死就调用底层vold进行强制杀死。故,如果占用sd卡的进程较多,这部分就会较耗时。 上层的准备工作处理完毕后,就需要向底层发送命令来进行卸载sd卡。
底层在卸载sd卡的过程中,要将sd卡的状态改变发广播到上层,通知MountSevice。
sd卡状态由Mounted变为Unmounting时,为了给上层framework一定的反应时间,底层在发送广播后睡了1s。
之后开始umount操作,如果在上层没有将占用sd卡的进程杀死,就会在底层强制杀进程。系统 原生给了10次机会,每次umount失败一次系统都会睡1s之后在尝试umount,如果在最后一次仍 然没有成功就强制杀进程。所以重新umount的次数越多耗时就会越长。

系统关机
当Shutdown MountService完成之后,回调至ShutdownThread中,将线程唤醒,继续往下执。 在关机之前获得振动器震动手机,由于震动手机与调用power关机异步进行,所以为了避免关机太快来不及震动,上层会在调用用振动器后睡500ms。最后调到power中,然后经过内核进行关机。

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