Android API 28及以上连接WiFi时如何获取SSID、频段等AP详细信息

原有代码核心问题 #

• 用到的NetworkInfo、ConnectivityManager.TYPE_WIFI、WifiManager.NETWORK_STATE_CHANGED_ACTION均已在安卓高版本中废弃，官方推荐使用ConnectivityManager.NetworkCallback替代实现网络状态监听
• SSID为空主要是权限适配不到位、缺少动态权限申请、高版本安卓权限规则变更导致

最优实现方案 #

步骤1：适配全版本Manifest权限配置 #

<!-- 基础WiFi、网络状态权限 -->
<uses-permission android:name="android.permission.ACCESS_WIFI_STATE" />
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />

<!-- 安卓12及以下，获取SSID需要位置权限 -->
<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" android:maxSdkVersion="32" />

<!-- 安卓13及以上，获取WiFi相关信息用Nearby Devices权限，无需位置权限 -->
<uses-permission android:name="android.permission.NEARBY_WIFI_DEVICES" 
    android:usesPermissionFlags="neverForLocation" 
    tools:targetApi="33" />

步骤2：动态申请危险权限 #

安卓系统中位置权限、Nearby WiFi设备权限属于危险权限，仅在Manifest中声明无效，必须动态申请用户同意后才能正常获取WiFi信息。

步骤3：使用NetworkCallback实现WiFi状态监听 #

private val TAG = "[MainActivity]"
private lateinit var connectivityManager: ConnectivityManager

// WiFi网络状态回调
private val wifiNetworkCallback = object : ConnectivityManager.NetworkCallback() {
    // WiFi连接成功时回调
    override fun onAvailable(network: Network) {
        super.onAvailable(network)
        val wifiManager = applicationContext.getSystemService(Context.WIFI_SERVICE) as WifiManager
        val wifiInfo = wifiManager.connectionInfo
        // trim去掉SSID前后自带的双引号
        Log.d(TAG, "WiFi详情：SSID=${wifiInfo.ssid.trim('"')}, BSSID=${wifiInfo.bssid}, 信号强度=${wifiInfo.rssi}dBm")
    }

    // WiFi断开时回调
    override fun onLost(network: Network) {
        super.onLost(network)
        Log.d(TAG, "WiFi已断开连接")
    }
}

override fun onCreate(savedInstanceState: Bundle?) {
    super.onCreate(savedInstanceState)
    setContentView(R.layout.activity_main)
    connectivityManager = getSystemService(Context.CONNECTIVITY_SERVICE) as ConnectivityManager

    if (hasRequiredPermissions()) {
        registerWifiCallback()
    } else {
        requestRequiredPermissions()
    }
}

// 检查所需权限是否已授权
private fun hasRequiredPermissions(): Boolean {
    return if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.TIRAMISU) {
        ContextCompat.checkSelfPermission(this, Manifest.permission.NEARBY_WIFI_DEVICES) == PackageManager.PERMISSION_GRANTED
    } else {
        ContextCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION) == PackageManager.PERMISSION_GRANTED
    }
}

// 申请所需权限
private fun requestRequiredPermissions() {
    val permissions = if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.TIRAMISU) {
        arrayOf(Manifest.permission.NEARBY_WIFI_DEVICES)
    } else {
        arrayOf(Manifest.permission.ACCESS_FINE_LOCATION)
    }
    ActivityCompat.requestPermissions(this, permissions, 1001)
}

// 注册WiFi状态监听
private fun registerWifiCallback() {
    val request = NetworkRequest.Builder()
        .addTransportType(NetworkCapabilities.TRANSPORT_WIFI)
        .build()
    connectivityManager.registerNetworkCallback(request, wifiNetworkCallback)
}

// 权限申请结果回调
override fun onRequestPermissionsResult(requestCode: Int, permissions: Array<out String>, grantResults: IntArray) {
    super.onRequestPermissionsResult(requestCode, permissions, grantResults)
    if (requestCode == 1001 && grantResults.isNotEmpty() && grantResults[0] == PackageManager.PERMISSION_GRANTED) {
        registerWifiCallback()
    } else {
        Toast.makeText(this, "权限被拒绝，无法获取WiFi信息", Toast.LENGTH_SHORT).show()
    }
}

override fun onDestroy() {
    super.onDestroy()
    // 注销回调避免内存泄漏
    if (::connectivityManager.isInitialized) {
        connectivityManager.unregisterNetworkCallback(wifiNetworkCallback)
    }
}

补充注意事项 #

• 安卓12及以下设备，除位置权限外还需要开启设备定位服务，否则即使授权也无法获取到真实SSID
• 如果需要获取扫描到的所有周边WiFi AP信息而非仅当前连接的WiFi，还需要添加CHANGE_WIFI_STATE权限，调用wifiManager.startScan()方法获取扫描列表
• 部分定制ROM可能存在额外权限限制，若仍无法获取SSID可检查应用的位置、WiFi相关权限是否被系统限制

内容的提问来源于stack exchange，提问作者chelsea