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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