Android 9中ConnectivityManager获取WiFi连接状态异常问题

原代码问题分析 #

你的代码存在两个核心问题：

1. 判断逻辑偏差：hasTransport(NetworkCapabilities.TRANSPORT_WIFI)仅能判断设备的WiFi模块是否激活（即WiFi开关是否打开），而非是否已连接到有效WiFi热点。因此WiFi开启但未连接热点时会错误返回true。
2. activeNetwork的局限性：connectivityManager.activeNetwork获取的是当前系统正在使用的活跃网络，若此时活跃网络是移动数据，即便WiFi已连接，也会错误返回false。

正确实现方案 #

方案1：直接从广播Intent获取WiFi状态（推荐） #

WifiManager.NETWORK_STATE_CHANGED_ACTION广播会直接携带当前WiFi的连接状态，无需额外查询ConnectivityManager，结果更准确：

class WifiStateReceiver : BroadcastReceiver() {
    override fun onReceive(ctx: Context, intent: Intent) {
        if (intent.action == WifiManager.NETWORK_STATE_CHANGED_ACTION) {
            // 从广播Intent中提取WiFi网络状态
            val networkInfo = intent.getParcelableExtra<NetworkInfo>(WifiManager.EXTRA_NETWORK_INFO)
            val isWifiConnected = networkInfo?.isConnected == true
            Log.i("TEST", "Wifi Connection: $isWifiConnected")
        }
    }
}

方案2：修正ConnectivityManager判断逻辑 #

如果需要通过ConnectivityManager判断，需遍历所有网络，检查是否存在已连接且可用的WiFi网络：

class WifiStateReceiver : BroadcastReceiver() {
    override fun onReceive(ctx: Context, intent: Intent) {
        if (intent.action == WifiManager.NETWORK_STATE_CHANGED_ACTION) {
            Log.i("TEST", "Wifi Connection: ${isWifiConnected(ctx)}")
        }
    }

    private fun isWifiConnected(context: Context): Boolean {
        val connectivityManager = context.getSystemService(Context.CONNECTIVITY_SERVICE) as ConnectivityManager
        return if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
            // 遍历所有网络，查找已验证的WiFi连接
            connectivityManager.allNetworks.any { network ->
                val capabilities = connectivityManager.getNetworkCapabilities(network)
                capabilities != null &&
                        capabilities.hasTransport(NetworkCapabilities.TRANSPORT_WIFI) &&
                        capabilities.hasCapability(NetworkCapabilities.NET_CAPABILITY_VALIDATED)
            }
        } else {
            // 低版本直接获取WiFi类型的网络状态
            val wifiNetworkInfo = connectivityManager.getNetworkInfo(ConnectivityManager.TYPE_WIFI)
            wifiNetworkInfo?.isConnected == true
        }
    }
}

关键注意事项 #

1. 权限配置：在AndroidManifest.xml中添加必要权限：

   <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
   

2. 广播注册方式：Android 8.0（API 26）及以上版本，静态注册WifiManager.NETWORK_STATE_CHANGED_ACTION会失效，需动态注册：

   // 在Activity/Service中动态注册
   private lateinit var wifiReceiver: WifiStateReceiver
   
   override fun onCreate(savedInstanceState: Bundle?) {
       super.onCreate(savedInstanceState)
       wifiReceiver = WifiStateReceiver()
       val intentFilter = IntentFilter(WifiManager.NETWORK_STATE_CHANGED_ACTION)
       registerReceiver(wifiReceiver, intentFilter)
   }
   
   override fun onDestroy() {
       super.onDestroy()
       unregisterReceiver(wifiReceiver)
   }
   

内容的提问来源于stack exchange，提问作者timeislikewind