这是我对 SDK 29 的解决方案：一个名为 NetworkWatcher 的类，它观察网络的变化。它提供了诸如isWifiOn 之类的原始变量，以及通过Flow 和LiveData 观察网络随时间变化的选项。
@ExperimentalCoroutinesApi
class NetworkWatcher
@RequiresPermission(android.Manifest.permission.ACCESS_NETWORK_STATE)
private constructor(
application: Application
) {
private val connectivityManager =
application.applicationContext.getSystemService(Context.CONNECTIVITY_SERVICE)
as ConnectivityManager
// general availability of Internet over any type
var isOnline = false
get() {
updateFields()
return field
}
var isOverWifi = false
get() {
updateFields()
return field
}
var isOverCellular = false
get() {
updateFields()
return field
}
var isOverEthernet = false
get() {
updateFields()
return field
}
companion object {
@Volatile
private var INSTANCE: NetworkWatcher? = null
fun getInstance(application: Application): NetworkWatcher {
synchronized(this) {
if (INSTANCE == null) {
INSTANCE = NetworkWatcher(application)
}
return INSTANCE!!
}
}
}
@Suppress("DEPRECATION")
private fun updateFields() {
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
val networkAvailability =
connectivityManager.getNetworkCapabilities(connectivityManager.activeNetwork)
if (networkAvailability != null &&
networkAvailability.hasCapability(NetworkCapabilities.NET_CAPABILITY_INTERNET) &&
networkAvailability.hasCapability(NetworkCapabilities.NET_CAPABILITY_VALIDATED)
) {
//has network
isOnline = true
// wifi
isOverWifi =
networkAvailability.hasTransport(NetworkCapabilities.TRANSPORT_WIFI)
// cellular
isOverCellular =
networkAvailability.hasTransport(NetworkCapabilities.TRANSPORT_CELLULAR)
// ethernet
isOverEthernet =
networkAvailability.hasTransport(NetworkCapabilities.TRANSPORT_ETHERNET)
} else {
isOnline = false
isOverWifi = false
isOverCellular = false
isOverEthernet = false
}
} else {
val info = connectivityManager.activeNetworkInfo
if (info != null && info.isConnected) {
isOnline = true
val wifi = connectivityManager.getNetworkInfo(ConnectivityManager.TYPE_WIFI)
isOverWifi = wifi != null && wifi.isConnected
val cellular = connectivityManager.getNetworkInfo(ConnectivityManager.TYPE_MOBILE)
isOverCellular = cellular != null && cellular.isConnected
val ethernet = connectivityManager.getNetworkInfo(ConnectivityManager.TYPE_ETHERNET)
isOverEthernet = ethernet != null && ethernet.isConnected
} else {
isOnline = false
isOverWifi = false
isOverCellular = false
isOverEthernet = false
}
}
}
fun watchNetwork(): Flow<Boolean> = watchWifi()
.combine(watchCellular()) { wifi, cellular -> wifi || cellular }
.combine(watchEthernet()) { wifiAndCellular, ethernet -> wifiAndCellular || ethernet }
fun watchNetworkAsLiveData(): LiveData<Boolean> = watchNetwork().asLiveData()
fun watchWifi(): Flow<Boolean> = callbackFlowForType(NetworkCapabilities.TRANSPORT_WIFI)
fun watchWifiAsLiveData() = watchWifi().asLiveData()
fun watchCellular(): Flow<Boolean> = callbackFlowForType(NetworkCapabilities.TRANSPORT_CELLULAR)
fun watchCellularAsLiveData() = watchCellular().asLiveData()
fun watchEthernet(): Flow<Boolean> = callbackFlowForType(NetworkCapabilities.TRANSPORT_ETHERNET)
fun watchEthernetAsLiveData() = watchEthernet().asLiveData()
private fun callbackFlowForType(@IntRange(from = 0, to = 7) type: Int) = callbackFlow {
offer(false)
val networkRequest = NetworkRequest.Builder()
.addTransportType(type)
.build()
val callback = object : ConnectivityManager.NetworkCallback() {
override fun onLost(network: Network?) {
offer(false)
}
override fun onUnavailable() {
offer(false)
}
override fun onLosing(network: Network?, maxMsToLive: Int) {
// do nothing
}
override fun onAvailable(network: Network?) {
offer(true)
}
}
connectivityManager.registerNetworkCallback(networkRequest, callback)
awaitClose { connectivityManager.unregisterNetworkCallback(callback) }
}
}
例如，您可以在应用程序中订阅有关手机网络状态的更新，例如：
GlobalScope.launch {
NetworkWatcher.getInstance(this@MyApplication).watchNetwork().collect { connected ->
Log.d("TAG", "Network In App: $connected")
}
}
或者要回答您的问题，只需阅读 Wifi 值，例如：
if (NetworkWatcher.getInstance(this@BaseApp).isOverWifi) {
// do stuff
}
旁注：我没有一直使用getInstance()，而是使用Koin 等DI 框架将NetworkWatcher 注入到我需要的地方。