Android WIFI 详解
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if (mSelected != null) {
mWifiManager.updateNetwork(config);
saveNetworks();
}
} else {
int networkId =mWifiManager.addNetwork(config);
if (networkId != -1) {
mWifiManager.enableNetwork(networkId, false);
config.networkId =networkId;
if (mDialog.edit || requireKeyStore(config)){
saveNetworks();
} else {
connect(networkId);
}
}
}
}
}
FrameworksbasewifijavaandroidnetwifiWifiManager.java
public intupdateNetwork(WifiConfiguration config) {
if(config == null || config.networkId 0) {
return -1;
}
return addOrUpdateNetwork(config);
}
private intaddOrUpdateNetwork(WifiConfiguration config) {
try {
return mService.addOrUpdateNetwork(config);
} catch (RemoteException e) {
return -1;
}
}
WifiService.addOrUpdateNetwork()通过调用mWifiStateTracker.setNetworkVariable()将连接命令发送到Wpa_supplicant。
(4)获取IP地址
当连接到supplicant后，WifiMonitor就会通知WifiStateTracker。
Frameworks/base/wifi/java/android/net/wifi/WifiMonitor.java
Public void Run(){
if (connectToSupplicant()) {
// Send a message indicatingthat it is now possible to send commands
// to the supplicant
mWifiStateTracker.notifySupplicantConnection();
} else {
mWifiStateTracker.notifySupplicantLost();
return;
}
……
}
WifiStateTracker发送EVENT_SUPPLICANT_CONNECTION消息到消息队列，这个消息有自己的handlermessage()函数处理，它会启动一个DHCP线程，而这个线程会一直等待一个消息事件，来启动DHCP协议分配IP地址。
frameworks/base/wifi/java/android/net/wifi/WifiStateTracker.java
void notifySupplicantConnection() {
sendEmptyMessage(EVENT_SUPPLICANT_CONNECTION);
}
public void handleMessage(Message msg) {
Intent intent;
switch (msg.what) {
case EVENT_SUPPLICANT_CONNECTION:
……
HandlerThread dhcpThread = newHandlerThread(DHCP Handler Thread);
dhcpThread.start();
mDhcpTarget = newDhcpHandler(dhcpThread.getLooper(), this);
……
……
}
当Wpa_supplicant连接到AP后，它会发送一个消息给上层来通知连接成功，WifiMonitor会接受到这个消息并上报给WifiStateTracker。
Frameworks/base/wifi/java/android/net/wifi/WifiMonitor.java
void handleEvent(int event, String remainder) {
switch (event) {
case DISCONNECTED:
handleNetworkStateChange(NetworkInfo.DetailedState.DISCONNECTED,remainder);
break;
case CONNECTED:
handleNetworkStateChange(NetworkInfo.DetailedState.CONNECTED,remainder);
break;
……
}
private voidhandleNetworkStateChange(NetworkInfo.DetailedState newState, String data) {
StringBSSID = null;
intnetworkId = -1;
if(newState == NetworkInfo.DetailedState.CONNECTED) {
Matcher match = mConnectedEventPattern.matcher(data);
if(!match.find()) {
if (Config.LOGD) Log.d(TAG, Could not find BSSID in CONNECTEDevent string);
}else {
BSSID = match.group(1);
try {
networkId = Integer.parseInt(match.group(2));
} catch (NumberFormatException e) {
networkId = -1;
}
}
}
mWifiStateTracker.notifyStateChange(newState,BSSID, networkId);
}
void notifyStateChange(DetailedState newState, StringBSSID, int networkId) {
Messagemsg = Message.obtain(
this, EVENT_NETWORK_STATE_CHANGED,
newNetworkStateChangeResult(newState, BSSID, networkId));
msg.sendToTarget();
}
caseEVENT_NETWORK_STATE_CHANGED:
……
configureInterface();
……
private void configureInterface() {
checkPollTimer();
mLastSignalLevel = -1;
if(!mUseStaticIp) { //使用DHCP线程动态IP
if(!mHaveIpAddress !mObtainingIpAddress) {
mObtainingIpAddress = true;
//发送启动DHCP线程获取IP
mDhcpTarget.sendEmptyMessage(EVENT_DHCP_START);
}
} else { //使用静态IP，IP信息从mDhcpInfo中获取
intevent;
if(NetworkUtils.configureInterface(mInterfaceName, mDhcpInfo)) {
mHaveIpAddress = true;
event = EVENT_INTERFACE_CONFIGURATION_SUCCEEDED;
if (LOCAL_LOGD) Log.v(TAG, Static IP configurationsucceeded);
}else {
mHaveIpAddress = false;
event = EVENT_INTERFACE_CONFIGURATION_FAILED;
if (LOCAL_LOGD) Log.v(TAG, Static IP configuration failed);
}
sendEmptyMessage(event); //发送IP获得成功消息事件
}
}
DhcpThread获取EVENT_DHCP_START消息事件后，调用handleMessage()函数，启动DHCP获取IP地址的服务。
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