Android 监听网络状态变化（无切换中间态版）

import android.content.BroadcastReceiver
import android.content.Context
import android.content.Intent
import android.content.IntentFilter
import android.net.ConnectivityManager
import android.net.Network
import android.net.NetworkCapabilities
import android.net.NetworkRequest
 
class NetworkStateReceiver(private val networkStateChangeListener: NetworkStateChangeListener) : BroadcastReceiver() {
 
    private val networkCallback = object : ConnectivityManager.NetworkCallback() {
        override fun onAvailable(network: Network) {
            super.onAvailable(network)
            networkStateChangeListener.onNetworkAvailable()
        }
 
        override fun onLosing(network: Network, maxMsToComplete: Int) {
            super.onLosing(network, maxMsToComplete)
            networkStateChangeListener.onNetworkLosing()
        }
 
        override fun onLost(network: Network) {
            super.onLost(network)
            networkStateChangeListener.onNetworkLost()
        }
 
        override fun onCapabilitiesChanged(network: Network, networkCapabilities: NetworkCapabilities) {
            super.onCapabilitiesChanged(network, networkCapabilities)
            networkStateChangeListener.onNetworkCapabilitiesChanged()
        }
    }
 
    fun register(context: Context) {
        val connectivityManager = context.getSystemService(Context.CONNECTIVITY_SERVICE) as ConnectivityManager
        val networkRequest = NetworkRequest.Builder()
            .addCapability(NetworkCapabilities.NET_CAPABILITY_INTERNET)
            .build()
        connectivityManager.registerNetworkCallback(networkRequest, networkCallback)
    }
 
    fun unregister(context: Context) {
        val connectivityManager = context.getSystemService(Context.CONNECTIVITY_SERVICE) as ConnectivityManager
        connectivityManager.unregisterNetworkCallback(networkCallback)
    }
 
    override fun onReceive(context: Context, intent: Intent) {
        if (intent.action == ConnectivityManager.CONNECTIVITY_ACTION) {
            networkStateChangeListener.onNetworkStateChange()
        }
    }
 
    interface NetworkStateChangeListener {
        fun onNetworkAvailable()
        fun onNetworkLosing()
        fun onNetworkLost()
        fun onNetworkCapabilitiesChanged()
        fun onNetworkStateChange()
    }
}

使用方法：

1. 创建\`Network