Android Wifi的forget()操作实例详解
我们在处理某个Wifi连接时，有时会需要忘掉当前连接的密码信息。执行这项操作，我们需要调用WifiManager::forget()函数：
/**
* Delete the network in the supplicant config.
*
* This function is used instead of a sequence of removeNetwork()
* and saveConfiguration().
*
* @param config the set of variables that describe the configuration,
* contained in a {@link WifiConfiguration} object.
* @param listener for callbacks on success or failure. Can be null.
* @throws IllegalStateException if the WifiManager instance needs to be
* initialized again
* @hide
*/
public void forget(int netId, ActionListener listener) {
if (netId < 0) throw new IllegalArgumentException("Network id cannot be negative");
validateChannel();
sAsyncChannel.sendMessage(FORGET_NETWORK, netId, putListener(listener));
}
从函数介绍可知，调用forget()函数，当前网络连接的配置信息就会从wpa_supplicant.conf中删掉；之后这个网络就不会有自动重连的动作，因为conf文件中已经没有该网络的配置信息。
跟踪FORGET_NETWORK消息，WifiServiceImpl::ClientHandler处理：
case WifiManager.FORGET_NETWORK:
if (isOwner(msg.sendingUid)) {
mWifiStateMachine.sendMessage(Message.obtain(msg));
} else {
Slog.e(TAG, "Forget is not authorized for user");
replyFailed(msg, WifiManager.FORGET_NETWORK_FAILED,
WifiManager.NOT_AUTHORIZED);
}
break;
简单地将该消息转发给WifiStateMachine。此时Wifi是连接状态，WifiStateMachine中当前状态是ConnectedState，它的父状态ConnectModeState处理：
case WifiManager.FORGET_NETWORK:
// Debug only, remember last configuration that was forgotten
WifiConfiguration toRemove
= mWifiConfigStore.getWifiConfiguration(message.arg1);
if (toRemove == null) {
lastForgetConfigurationAttempt = null;
} else {
lastForgetConfigurationAttempt = new WifiConfiguration(toRemove);
}
// check that the caller owns this network
netId = message.arg1;
if (!mWifiConfigStore.canModifyNetwork(message.sendingUid, netId,
/* onlyAnnotate */ false)) {
logw("Not authorized to forget network "
+ " cnid=" + netId
+ " uid=" + message.sendingUid);
replyToMessage(message, WifiManager.FORGET_NETWORK_FAILED,
WifiManager.NOT_AUTHORIZED);
break;
}
if (mWifiConfigStore.forgetNetwork(message.arg1)) {
replyToMessage(message, WifiManager.FORGET_NETWORK_SUCCEEDED);
broadcastWifiCredentialChanged(WifiManager.WIFI_CREDENTIAL_FORGOT,
(WifiConfiguration) message.obj);
} else {
loge("Failed to forget network");
replyToMessage(message, WifiManager.FORGET_NETWORK_FAILED,
WifiManager.ERROR);
}
break;
mWifiConfigStore.forgetNetwork()：
/**
* Forget the specified network and save config
*
* @param netId network to forget
* @return {@code true} if it succeeds, {@code false} otherwise
*/
boolean forgetNetwork(int netId) {
if (showNetworks) localLog("forgetNetwork", netId);
WifiConfiguration config = mConfiguredNetworks.get(netId);
boolean remove = removeConfigAndSendBroadcastIfNeeded(netId);
if (!remove) {
//success but we dont want to remove the network from supplicant conf file
return true;
}
if (mWifiNative.removeNetwork(netId)) {
if (config != null && config.isPasspoint()) {
writePasspointConfigs(config.FQDN, null);
}
mWifiNative.saveConfig();
writeKnownNetworkHistory(true);
return true;
} else {
loge("Failed to remove network " + netId);
return false;
}
}
根据传入的当前网络的netId，分别调用WifiNative的removeNetwork()、saveConfig()方法删除conf文件的配置信息并进行保存；执行完成后，forget()函数结束了。通过代码我们发现，执行forget()函数并不会引起WifiStateMachine中状态的切换。
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