在Android系统启动的时候，会在./frameworks/base/services/java/com/android/server/SystemServer.java类中启动许多服务，其中和Wifi相关的服务就在这里初始化。在SystemServer的main方法中，我们可以看到
thr.initAndLoop();
这里调用了它的内部类对象的initAndLoop方法，在这个方法的作用主要就是初始化系统启动需要加载的服务的，我们在这个方法中可以找到
try {
Slog.i(TAG, "Wi-Fi Service");
wifi = new WifiService(context);
ServiceManager.addService(Context.WIFI_SERVICE, wifi);
} catch (Throwable e) {
reportWtf("starting Wi-Fi Service", e);
}
try {
Slog.i(TAG, "Connectivity Service");
connectivity = new ConnectivityService(
context, networkManagement, networkStats, networkPolicy);
ServiceManager.addService(Context.CONNECTIVITY_SERVICE, connectivity);
networkStats.bindConnectivityManager(connectivity);
networkPolicy.bindConnectivityManager(connectivity);
wifiP2p.connectivityServiceReady();
wifi.checkAndStartWifi();
} catch (Throwable e) {
reportWtf("starting Connectivity Service", e);
}
这里我们可以看到初始化了一个WifiService和ConnectivityService对象，并把这2个对象注册到ServiceManager中，然后通过创建的对象wifi 来调用checkAndStartWifi方法，具体的WifiService的分析我们下一章再做详细介绍，现在我们简单分析下ConnectivityService。
ConnectivityService是管理系统中所有的数据连接服务，其中就包括Wifi，我们来看看它的构造函数，路径：./frameworks/base/services/java/com/android/server/ConnectivityService.java
public ConnectivityService(Context context, INetworkManagementService netd,
INetworkStatsService statsService, INetworkPolicyManager policyManager) {
// Currently, omitting a NetworkFactory will create one internally
// TODO: create here when we have cleaner WiMAX support
this(context, netd, statsService, policyManager, null);
}
这里就是调用了同名的构造方法
public ConnectivityService(Context context, INetworkManagementService netManager,
INetworkStatsService statsService, INetworkPolicyManager policyManager,
NetworkFactory netFactory) {
if (DBG) log("ConnectivityService starting up");
HandlerThread handlerThread = new HandlerThread("ConnectivityServiceThread");
handlerThread.start();
mHandler = new InternalHandler(handlerThread.getLooper());
mTrackerHandler = new NetworkStateTrackerHandler(handlerThread.getLooper());
// Create and start trackers for hard-coded networks
for (int targetNetworkType : mPriorityList) {
final NetworkConfig config = mNetConfigs[targetNetworkType];
final NetworkStateTracker tracker;
try {
/** M: Hotspot Manager @{*/
if(config.radio == TYPE_USB){
log("new UsbDataStateTracker");
mNetTrackers[targetNetworkType] = new UsbDataStateTracker(targetNetworkType, config.name, mNetd);
mNetTrackers[targetNetworkType].startMonitoring(context, mTrackerHandler);
continue;
}
if(true == FeatureOption.MTK_ALPS_BOX_SUPPORT && config.radio == TYPE_ETHERNET){
if (DBG) log("Starting Ethernet Service.");
mNetTrackers[TYPE_ETHERNET] = makeEthStateTracker(context);
if(mNetTrackers[TYPE_ETHERNET] != null){
if (DBG) log("mNetTrackers[TYPE_ETHERNET] != null");
mNetTrackers[TYPE_ETHERNET].startMonitoring(context, mTrackerHandler);
if (config.isDefault()) {
mNetTrackers[TYPE_ETHERNET].reconnect();
}
}
continue;
}
/*@} */
/*@} */
///M:new a Teledongle Data Tracker @by mtk94127 @{
if(FeatureOption.MTK_EXTERNAL_DONGLE_SUPPORT && (config.radio == TYPE_TEDONGLE)) {
log("new TedongleDataStateTracker");
mNetTrackers[targetNetworkType] = makeTedongleDataTracker();
log("new TedongleDataStateTracker medium!");
mNetTrackers[targetNetworkType].startMonitoring(context, mTrackerHandler);
log("new TedongleDataStateTracker end!");
continue;
}
///M:@}
tracker = netFactory.createTracker(targetNetworkType, config);
mNetTrackers[targetNetworkType] = tracker;
} catch (IllegalArgumentException e) {
Slog.e(TAG, "Problem creating " + getNetworkTypeName(targetNetworkType)
+ " tracker: " + e);
continue;
}
tracker.startMonitoring(context, mTrackerHandler);
if (config.isDefault()) {
tracker.reconnect();
}
}
}
这里根据com.android.internal.R.array.networkAttributes配置的属性去创建一个个tracker，并监听其状态，tracker.startMonitoring(context, mTrackerHandler);可以看出tracker可以通过mTrackerHandler向ConnectivityService发送消息，这些消息有
/**
* The network state has changed and the NetworkInfo object
* contains the new state.
*
* msg.what = EVENT_STATE_CHANGED
* msg.obj = NetworkInfo object
*/
public static final int EVENT_STATE_CHANGED = BASE_NETWORK_STATE_TRACKER;
/**
* msg.what = EVENT_CONFIGURATION_CHANGED
* msg.obj = NetworkInfo object
*/
public static final int EVENT_CONFIGURATION_CHANGED = BASE_NETWORK_STATE_TRACKER + 1;
/**
* msg.what = EVENT_RESTORE_DEFAULT_NETWORK
* msg.obj = FeatureUser object
*/
public static final int EVENT_RESTORE_DEFAULT_NETWORK = BASE_NETWORK_STATE_TRACKER + 2;
/**
* msg.what = EVENT_NETWORK_SUBTYPE_CHANGED
* msg.obj = NetworkInfo object
*/
public static final int EVENT_NETWORK_SUBTYPE_CHANGED = BASE_NETWORK_STATE_TRACKER + 3;
/**
* msg.what = EVENT_NETWORK_CONNECTED
* msg.obj = LinkProperties object
*/
public static final int EVENT_NETWORK_CONNECTED = BASE_NETWORK_STATE_TRACKER + 4;
/**
* msg.what = EVENT_NETWORK_CONNECTION_DISCONNECTED
* msg.obj = LinkProperties object, same iface name
*/
public static final int EVENT_NETWORK_DISCONNECTED = BASE_NETWORK_STATE_TRACKER + 5;
当WiFi的连接AP成功后，就会想 ConnectivityService发送一个EVENT_STATE_CHANGED消息。
接着我们来看创建了哪些tracker，找到createTracker方法
@Override
public NetworkStateTracker createTracker(int targetNetworkType, NetworkConfig config) {
switch (config.radio) {
case TYPE_WIFI:
return new WifiStateTracker(targetNetworkType, config.name);
case TYPE_MOBILE:
return new MobileDataStateTracker(targetNetworkType, config.name);
case TYPE_DUMMY:
return new DummyDataStateTracker(targetNetworkType, config.name);
case TYPE_BLUETOOTH:
return BluetoothTetheringDataTracker.getInstance();
case TYPE_WIMAX:
return makeWimaxStateTracker(mContext, mTrackerHandler);
case TYPE_CSD:
return new CsdStateTracker(targetNetworkType, config.name);
default:
throw new IllegalArgumentException(
"Trying to create a NetworkStateTracker for an unknown radio type: "
+ config.radio);
}
}
这里我们主要关注TYPE_WIFI，创建了一个WifiStateTracker对象，进入到WifiStateTracker的构造方法
public WifiStateTracker(int netType, String networkName) {
///M:@{
mNetType = netType;
///@}
mNetworkInfo = new NetworkInfo(netType, 0, networkName, "");
mLinkProperties = new LinkProperties();
mLinkCapabilities = new LinkCapabilities();
mNetworkInfo.setIsAvailable(false);
setTeardownRequested(false);
}
接着调用startMonitoring
/**
* Begin monitoring wifi connectivity
*/
public void startMonitoring(Context context, Handler target) {
mCsHandler = target;
mContext = context;
mWifiManager = (WifiManager) mContext.getSystemService(Context.WIFI_SERVICE);
IntentFilter filter = new IntentFilter();
///M:seperate p2p and wifi @{
if (mNetType == ConnectivityManager.TYPE_WIFI) {
filter.addAction(WifiManager.NETWORK_STATE_CHANGED_ACTION);
filter.addAction(WifiManager.LINK_CONFIGURATION_CHANGED_ACTION);
}
///@}
mWifiStateReceiver = new WifiStateReceiver();
mContext.registerReceiver(mWifiStateReceiver, filter);
}
这里就是注册了一个广播用于接收NETWORK_STATE_CHANGED_ACTION和LINK_CONFIGURATION_CHANGED_ACTION广播，ConnectivityService我们就分析到这里，下一章我们将详细分析WifiService。
时间： 2024-09-13 08:04:23