android如何从驱动到app添加一个系统服务.pdf

如何在android 系统里面从驱动到app 添加一个系统服务 首先，android 系统从下到上分为这么几层 kernel → HAL --routime(虚拟机和一些其他的库)--framework--app 我们要添加的服务为LedService 在app 中直接可以这样使用 LedManager ledManage = getSystemService(Context.LED_SERVICE); ledManager.setOn();//设置手机灯的开关 ledManager.setOff(); 要达到这个上面的目的，需要在系统的Context.java ContextImpl.java 里面做如下工 作 Context.java public static final String LED_SERVICE = led;//添加该行 在contextImpl.java里面添加如下代码： public Object getSystemService(String name) { if (WINDOW_SERVICE.equals(name)) { return WindowManagerImpl.getDefault(); } else if (LAYOUT_INFLATER_SERVICE .equals(name)) { synchronized (mSync) { LayoutInflater inflater = mLayoutInflater; if (inflater != null ) { return inflater; } mLayoutInflater = inflater = PolicyManager.makeNewLayoutInflater (getOuterContext()); return inflater; } } else if (ACTIVITY_SERVICE .equals(name)) { return getActivityManager(); } else if (INPUT_METHOD_SERVICE .equals(name)) { return InputMethodManager.getInstance(this ); } else if (ALARM_SERVICE .equals(name)) { return getAlarmManager(); } else if (ACCOUNT_SERVICE .equals(name)) { return getAccountManager(); } else if (POWER_SERVICE .equals(name)) { return getPowerManager(); } else if (CONNECTIVITY_SERVICE.equals(name)) { return getConnectivityManager(); } else if (THROTTLE_SERVICE.equals(name)) { return getThrottleManager(); } else if (WIFI_SERVICE.equals(name)) { return getWifiManager(); } else if (NOTIFICATION_SERVICE .equals(name)) { return getNotificationManager(); } else if (KEYGUARD_SERVICE .equals(name)) { return new KeyguardManager(); } else