文件路径：frameworks/base/services/corn/java/com/android/server/policy/PhoneWindowManager.java

所在函数：powerLongPress()

private void powerLongPress() {
    final int behavior = getResolvedLongPressOnPowerBehavior();
    switch (behavior) {
    case LONG_PRESS_POWER_NOTHING:
        break;
    case LONG_PRESS_POWER_GLOBAL_ACTIONS:
        mPowerKeyHandled = true;
        if (!performHapticFeedbackLw(null, HapticFeedbackConstants.LONG_PRESS, false)) {
            performAuditoryFeedbackForAccessibilityIfNeed();
        }
        
            try {
Runtime.getRuntime().exec("reboot -p"); //关机

} catch (IOException e) {
e.printStackTrace();
}
        //showGlobalActionsInternal();
        break;
    case LONG_PRESS_POWER_SHUT_OFF:
    case LONG_PRESS_POWER_SHUT_OFF_NO_CONFIRM:
        mPowerKeyHandled = true;
        performHapticFeedbackLw(null, HapticFeedbackConstants.LONG_PRESS, false);
        sendCloseSystemWindows(SYSTEM_DIALOG_REASON_GLOBAL_ACTIONS);
        mWindowManagerFuncs.shutdown(behavior == LONG_PRESS_POWER_SHUT_OFF);
        break;
    }
}

注释掉的为弹窗，增加的为直接关机