当我们使用registerNetworkCallback方法注册网络回调时,有时它不会触发,有时它会触发假阳性:
- 如果我们通过互联网连接启动应用,
onAvailable方法将触发。
- 但是,如果启动应用程序时设备上没有互联网连接,则不会
NetworkCallback调用任何内容(由于第1页,这很奇怪)
- 如果我们有wifi连接但没有互联网连接,则
onAvailable方法触发。我认为这是假阳性行为,因为我们希望观察到互联网连接。
如您在下面的代码中看到的,默认情况下,Internet连接可用,并且只有在更改时才会触发。没有假阳性触发器。
只需总结一下,这个答案即可(但仅适用于API> = 21):
class ConnectionManager @Inject constructor(
private val connectivityManager: ConnectivityManager,
private val disposable: CompositeDisposable,
private val singleTransformer: SingleTransformer<*, *>
) : LiveData<Boolean>() {
private var isNetworkAvailable = true
private val builder = NetworkRequest.Builder()
.addCapability(NetworkCapabilities.NET_CAPABILITY_INTERNET)
.addTransportType(NetworkCapabilities.TRANSPORT_CELLULAR)
.addTransportType(NetworkCapabilities.TRANSPORT_WIFI)
private val callback = object : ConnectivityManager.NetworkCallback() {
override fun onAvailable(network: Network) {
ping()
}
override fun onLost(network: Network) {
ping()
}
}
private fun ping() {
disposable.add(
Single.fromCallable {
try {
val timeoutMs = 1500
val socket = Socket()
val socketAddress = InetSocketAddress("8.8.8.8", 53)
socket.connect(socketAddress, timeoutMs)
socket.close()
true
} catch (e: IOException) {
false
}
}
.compose(singleTransformer as SingleTransformer<Boolean, Boolean>)
.subscribeBy {
if (isNetworkAvailable != it){
value = it
isNetworkAvailable = it
}
}
)
}
override fun onActive() {
ping()
connectivityManager.registerNetworkCallback(builder.build(), callback)
}
override fun onInactive() {
disposable.clear()
connectivityManager.unregisterNetworkCallback(callback)
}
}
如何提供依赖
@Provides
fun provideTransformer(): SingleTransformer<Boolean, Boolean> {
return SingleTransformer<Boolean, Boolean> { upstream: Single<Boolean> ->
upstream.subscribeOn(Schedulers.io())
.observeOn(AndroidSchedulers.mainThread())
}
}
@Singleton
@Provides
fun provideConnectivityManager(context: Context): ConnectivityManager =
context.getSystemService(Context.CONNECTIVITY_SERVICE) as ConnectivityManager
@Singleton
@Provides
fun provideConnectionManager(connectivityManager: ConnectivityManager, singleTransformer: SingleTransformer<Boolean, Boolean>): ConnectionManager =
ConnectionManager(connectivityManager, singleTransformer)
以及如何使用:
@Inject
lateinit var connectionManager: ConnectionManager
//....
viewLifecycleOwner.observe(connectionManager) { isInternetAvailable ->
// TODO
}
targetSdkVersion将N 提升到N或更高,该怎么办?