安卓WiFi管理器enableNetwork返回true，但NetworkInfo状态始终为DISCONNECTED/SCANNING

Question

我已经编写了一些代码来启用具有给定networkId的网络，并通过BroadcastReceiver处理异步响应。但是，即使enableNetwork返回true (表示操作系统成功发出命令)，我的BroadcastReceiver也从未收到状态为CONNECTED的NetworkInfo，它收到两个事件：DISCONNECTED，然后是DISCONNECTED/SCANNING。

从我读过的所有官方文档和各种SO问题来看，如果enableNetwork返回true，那么注册用于处理NETWORK_STATE_CHANGED_ACTION意图的BroadcastReceiver应该始终接收一个状态为CONNECTED的NetworkInfo对象。

代码如下：

/**
 * Connects to the wifi access point at specified [ssid] with specified [networkId]
 * And returns the [WifiInfo] of the network that has been connected to
 */
private fun connect(context: Context,
                    wifiManager: WifiManager,
                    ssid: String,
                    networkId: Int) = Single.create<WifiInfo> { emitter ->

    val wifiConnectionReceiver = object : BroadcastReceiver() {
        var oldSupplicantState: SupplicantState? = null

        override fun onReceive(context: Context, intent: Intent) {
            if (intent.action == WifiManager.NETWORK_STATE_CHANGED_ACTION) {
                val networkInfo = intent.getParcelableExtra<NetworkInfo>(WifiManager.EXTRA_NETWORK_INFO) ?: return

                if (networkInfo.detailedState == NetworkInfo.DetailedState.DISCONNECTED) {
                    context.applicationContext.unregisterReceiver(this)
                    emitter.onError(WiFiException("Failed to connect to wifi network"))
                }
                else if (networkInfo.detailedState == NetworkInfo.DetailedState.CONNECTED) {
                    val wifiInfo = intent.getParcelableExtra<WifiInfo>(WifiManager.EXTRA_WIFI_INFO) ?: return
                    if (ssid == wifiInfo.ssid.unescape()) {
                        context.applicationContext.unregisterReceiver(this)
                        emitter.onSuccess(wifiInfo)
                    }
                }
            } else if (intent.action == WifiManager.SUPPLICANT_STATE_CHANGED_ACTION) {
                val supplicantState = intent.getParcelableExtra<SupplicantState>(WifiManager.EXTRA_NEW_STATE)
                val oldSupplicantState = this.oldSupplicantState
                this.oldSupplicantState = supplicantState

                if (supplicantState == SupplicantState.DISCONNECTED) {
                    if (oldSupplicantState == null || oldSupplicantState == SupplicantState.COMPLETED) {
                        return
                    }
                    val possibleError = intent.getIntExtra(WifiManager.EXTRA_SUPPLICANT_ERROR, -1)
                    if (possibleError == WifiManager.ERROR_AUTHENTICATING) {
                        context.applicationContext.unregisterReceiver(this)
                        emitter.onError(WiFiException("Wifi authentication failed"))
                    }
                } else if (supplicantState == SupplicantState.SCANNING && oldSupplicantState == SupplicantState.DISCONNECTED) {
                    context.applicationContext.unregisterReceiver(this)
                    emitter.onError(WiFiException("Failed to connect to wifi network"))
                }
            }
        }
    }

    val networkStateChangedFilter = IntentFilter(WifiManager.NETWORK_STATE_CHANGED_ACTION)
    networkStateChangedFilter.addAction(WifiManager.SUPPLICANT_STATE_CHANGED_ACTION)

    context.applicationContext.registerReceiver(wifiConnectionReceiver, networkStateChangedFilter)

    emitter.setCancellable {
        if (!emitter.isDisposed)
            context.applicationContext.unregisterReceiver(wifiConnectionReceiver)
    }

    wifiManager.enableNetwork(networkId, true)
}

有人能帮上忙吗？我真的被难住了。我传递的networkId是有效的，因为它是从addNetwork创建的，由于它没有返回-1，所以它成功了。

Answer 1

好了，我终于弄明白了这一点，我希望我的答案能为将来遇到类似问题的任何人提供一些启发，因为这很糟糕，让我很头疼。

我问题中的代码并不完全正确，但它也不是我问题的根本原因。问题的根本原因是我错误地配置了通过WiFiConfigManager.addNetwork()在WiFiConfig表中注册的WiFiConfig对象。

我对WifiConfigManager.addNetwork()的合同做了一个巨大的假设。我假设如果该操作成功(即未返回-1)，则传递的WiFiConfig配置正确。这个假设是错误的，我正在创建的WiFiConfig上的allowedAuthAlgorithms、allowedProtocols、allowedKeyManagers和allowedPairwiseCipher BitSet是不正确的，但是对addNetwork()的调用成功了。我相信这是因为对addNetwork()的调用实际上并不做任何事情，只是验证配置是否有效，可以放在WiFiConfig表中，这与验证它是否是给定WiFi访问点的正确配置有很大的不同。这一点得到了addNetwork()源代码中的注释的支持，这些注释没有像许多其他WiFiManager函数那样声明异步状态的传递，这表明(至少对我而言)，由于调用addNetwork()，操作系统没有尝试与接入点进行通信。

由于一位同事提出了一个非常有用的建议:通过操作系统连接到有问题的接入点，然后将操作系统为该接入点创建的WiFiConfig对象与我自己的代码生成的对象进行比较，以找出差异，我注意到我的WiFiConfig配置不正确。在这之后不久，我解决了最初的问题。

现在，为什么我的WiFiConfig对象创建得不正确？这是因为我对如何配置WiFi (即各种术语以及所有协议、算法和密钥管理器背后的含义)知之甚少。因此，在阅读了官方文档但没有收集到太多有用的信息后，我转向StackOverflow问题和答案，找到了正确设置WiFiConfig的循环模式，它们似乎都使用BitWise运算符来创建Int值，该值最终被传递给WiFiConfig.allowedProtocols.set()、WiFiConfig.allowedPairwiseCiphers.set()、WiFiConfig.allowedKeyManagement.set()和WiFiConfig.allowedAuthAlgorithm.set()函数。

事实证明，这些配置选项中的每一个的底层BitSet是一种数据结构，该数据结构维护位的动态大小调整向量，其中WiFiConfig对象中给定BitSet实例中的位的索引对应于String数组中的元素的索引，该元素与WiFiConfig对象内的上述BitSet隐式关联。因此，如果您希望提供多个protocols、keyManagements、pairwiseCiphers或authAlgorithms，则需要在底层BitSet上调用set，传入与所选协议匹配的字符串数组元素所对应的正确索引。

在重写了我的WiFiConfig创建代码之后，这个问题自行解决了。虽然我在原始帖子中的代码中有一个bug，但它也已经被修复了。

下面是新的WiFiConfig创建代码：

/**
 * Emits a single of the [WifiConfiguration] created from the passed [scanResult] and [preSharedKey]
 */
private fun createWifiConfiguration(scanResult: WiFiScanResult, preSharedKey: String) = Single.fromCallable<WifiConfiguration> {
    val auth = scanResult.auth
    val keyManagement = scanResult.keyManagement
    val pairwiseCipher = scanResult.pairwiseCipher

    val config = WifiConfiguration()
    config.SSID = "\"" +  scanResult.ssid + "\""
    config.BSSID = scanResult.bssid

    if (auth.contains("WPA") || auth.contains("WPA2")) {
        config.allowedProtocols.set(WifiConfiguration.Protocol.WPA)
        config.allowedProtocols.set(WifiConfiguration.Protocol.RSN)
    }

    if (auth.contains("EAP"))
        config.allowedAuthAlgorithms.set(WifiConfiguration.AuthAlgorithm.LEAP)
    else if (auth.contains("WPA") || auth.contains("WPA2"))
        config.allowedAuthAlgorithms.set(WifiConfiguration.AuthAlgorithm.OPEN)
    else if (auth.contains("WEP"))
        config.allowedAuthAlgorithms.set(WifiConfiguration.AuthAlgorithm.SHARED)

    if (keyManagement.contains("IEEE802.1X"))
        config.allowedKeyManagement.set(WifiConfiguration.KeyMgmt.IEEE8021X)
    else if (auth.contains("WPA") && keyManagement.contains("EAP"))
        config.allowedKeyManagement.set(WifiConfiguration.KeyMgmt.WPA_EAP)
    else if (auth.contains("WPA") && keyManagement.contains("PSK"))
        config.allowedKeyManagement.set(WifiConfiguration.KeyMgmt.WPA_PSK)
    else if (auth.contains("WPA2") && keyManagement.contains("PSK"))
        config.allowedKeyManagement.set(WifiConfiguration.KeyMgmt.WPA_PSK)

    if (pairwiseCipher.contains("CCMP") || pairwiseCipher.contains("TKIP")) {
        config.allowedPairwiseCiphers.set(WifiConfiguration.PairwiseCipher.CCMP)
        config.allowedPairwiseCiphers.set(WifiConfiguration.PairwiseCipher.TKIP)
    }

    if (preSharedKey.isNotEmpty()) {
        if (auth.contains("WEP")) {
            if (preSharedKey.matches("\\p{XDigit}+".toRegex())) {
                config.wepKeys[0] = preSharedKey
            } else {
                config.wepKeys[0] = "\"" + preSharedKey + "\""
            }
            config.wepTxKeyIndex = 0
        } else {
            config.preSharedKey = "\"" + preSharedKey + "\""
        }
    }

    config
}

下面是新的连接代码：

/**
 * Connects to the wifi access point at specified [ssid] with specified [networkId]
 * And returns the [WifiInfo] of the network that has been connected to
 */
private fun connect(context: Context,
                    wifiManager: WifiManager,
                    ssid: String,
                    networkId: Int) = Single.create<WifiInfo> { emitter ->

    val wifiConnectionReceiver = object : BroadcastReceiver() {
        override fun onReceive(context: Context, intent: Intent) {
            if (intent.action == WifiManager.NETWORK_STATE_CHANGED_ACTION) {
                val networkInfo = intent.getParcelableExtra<NetworkInfo>(WifiManager.EXTRA_NETWORK_INFO) ?: return

                if (networkInfo.detailedState == NetworkInfo.DetailedState.CONNECTED) {
                    val wifiInfo = intent.getParcelableExtra<WifiInfo>(WifiManager.EXTRA_WIFI_INFO) ?: return
                    if (ssid.unescape() == wifiInfo.ssid.unescape()) {
                        context.applicationContext.unregisterReceiver(this)
                        emitter.onSuccess(wifiInfo)
                    }
                }
            }
        }
    }

    val networkStateChangedFilter = IntentFilter(WifiManager.NETWORK_STATE_CHANGED_ACTION)
    networkStateChangedFilter.addAction(WifiManager.SUPPLICANT_STATE_CHANGED_ACTION)

    context.applicationContext.registerReceiver(wifiConnectionReceiver, networkStateChangedFilter)

    emitter.setCancellable {
        if (!emitter.isDisposed)
            context.applicationContext.unregisterReceiver(wifiConnectionReceiver)
    }

    wifiManager.enableNetwork(networkId, true)
}