Android 系统关机流程分析

正文

关机动作从按键触发中断，linux kernel层给android framework层返回按键事件进入 framework层，再从 framework层到kernel层执行kernel层关机任务。

长按键对应的handler代码：

frameworks/policies/base/phone/com/android/internal/policy/impl/PhoneWindowManager.java
Runnable mPowerLongPress;

[java]
private final Runnable mPowerLongPress = new Runnable() {
        public void run() {
            if (!mPowerKeyHandled) {
                mPowerKeyHandled = true;
                performHapticFeedbackLw(null, HapticFeedbackConstants.LONG_PRESS, false);
                sendCloseSystemWindows(SYSTEM_DIALOG_REASON_GLOBAL_ACTIONS);
                showGlobalActionsDialog();
            }
        }
    };

private final Runnable mPowerLongPress = new Runnable() {
        public void run() {
            if (!mPowerKeyHandled) {
                mPowerKeyHandled = true;
                performHapticFeedbackLw(null, HapticFeedbackConstants.LONG_PRESS, false);
                sendCloseSystemWindows(SYSTEM_DIALOG_REASON_GLOBAL_ACTIONS);
                showGlobalActionsDialog();
            }
        }
    };mPowerLongPress 启动关机对话框

(frameworks/policies/base/phone/com/android/internal/policy/impl/GlobalActions.java)

如果我们选择Power OFF’,会调用 ShutdownThread.shutdown. 启动关机线程执行关机动作。

frameworks/base/core/java/com/android/internal/app/ShutdownThread.java

真正关机流程：

(1)广播全局事件， ACTION_SHUTDOWN Intent

(2)shutdown ActivityManager 服务

(3) 停止蓝牙服务

(4) 停止电话服务 (radio phone service)

(5)停止mount 服务

(6) 调用 Power.shutdown() 进入native 层

frameworks/base/core/java/android/os/Power.java

power的native实现代码：

frameworks/base/core/jni/android_os_Power.cpp

[java]
static void android_os_Power_shutdown(JNIEnv *env, jobject clazz)
{
sync();
#ifdef HAVE_ANDROID_OS
reboot(RB_POWER_OFF);
#endif
}

static void android_os_Power_shutdown(JNIEnv *env, jobject clazz)
{
sync();
#ifdef HAVE_ANDROID_OS
reboot(RB_POWER_OFF);
#endif
}
sync, reboot 为linux系统调用，进入linux内核关机流程。

补充：移动开发 , Android ,