在Android中监听网络连接的简单方法

要使用 Kotlin 监控 Android 中的互联网连接，您可以使用该类ConnectivityManager，这是一个允许您查询网络状态的系统服务。以下是如何使用它的示例：

1. 将以下权限添加到您的 AndroidManifest.xml 文件：

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

2. 创建一个监控网络状态的类：

class NetworkMonitor(context: Context) {private val connectivityManager =context.getSystemService(Context.CONNECTIVITY_SERVICE) as ConnectivityManagerfun isNetworkAvailable(): Boolean {val networkInfo = connectivityManager.activeNetworkInforeturn networkInfo != null && networkInfo.isConnected}fun registerNetworkCallback(networkCallback: ConnectivityManager.NetworkCallback) {if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.N) {connectivityManager.registerDefaultNetworkCallback(networkCallback)} else {val builder = NetworkRequest.Builder()connectivityManager.registerNetworkCallback(builder.build(), networkCallback)}}fun unregisterNetworkCallback(networkCallback: ConnectivityManager.NetworkCallback) {connectivityManager.unregisterNetworkCallback(networkCallback)}
}

在上面的类中，我们创建了三个函数：

• isNetworkAvailable()：此功能检查设备是否连接到互联网。它返回一个布尔值。
• registerNetworkCallback()：此函数注册一个NetworkCallback对象来监听网络状态变化。它以一个NetworkCallback对象作为参数。
• unregisterNetworkCallback()：此函数取消注册以前注册的NetworkCallback对象。它以一个NetworkCallback对象作为参数。

3. 创建NetworkCallback监听网络状态变化的对象：

val networkCallback = object : ConnectivityManager.NetworkCallback() {override fun onAvailable(network: Network) {// Called when a network is available}override fun onLost(network: Network) {// Called when a network is lost}
}

4. NetworkCallback向NetworkMonitor类注册对象：

val networkMonitor = NetworkMonitor(context)
networkMonitor.registerNetworkCallback(networkCallback)

5. 最后，不要忘记NetworkCallback在不再需要时注销该对象：

networkMonitor.unregisterNetworkCallback(networkCallback)

• 使用BroadcastReceiver检查网络连接事件：

class ConnectivityReceiver : BroadcastReceiver() {override fun onReceive(context: Context, intent: Intent) {val connectivityManager =context.getSystemService(Context.CONNECTIVITY_SERVICE) as ConnectivityManagerval networkInfo = connectivityManager.activeNetworkInfoif (networkInfo != null && networkInfo.isConnected) {// internet connection is available} else {// internet connection is not available}}
}

使用回调接口在网络连接发生变化时发出通知：

interface ConnectivityListener {fun onConnectivityChanged(isConnected: Boolean)
}class ConnectivityMonitor(private val context: Context) {private val connectivityManager =context.getSystemService(Context.CONNECTIVITY_SERVICE) as ConnectivityManagerprivate val callbackList = mutableListOf<ConnectivityListener>()private val connectivityCallback = object : ConnectivityManager.NetworkCallback() {override fun onAvailable(network: Network) {notifyListeners(true)}override fun onLost(network: Network) {notifyListeners(false)}}fun registerListener(listener: ConnectivityListener) {callbackList.add(listener)}fun unregisterListener(listener: ConnectivityListener) {callbackList.remove(listener)}fun startMonitoring() {val builder = NetworkRequest.Builder()connectivityManager.registerNetworkCallback(builder.build(), connectivityCallback)}fun stopMonitoring() {connectivityManager.unregisterNetworkCallback(connectivityCallback)}private fun notifyListeners(isConnected: Boolean) {for (listener in callbackList) {listener.onConnectivityChanged(isConnected)}}
}

• 使用像RxAndroid这样的库来监控网络连接：

class MainActivity : AppCompatActivity() {private val connectivityObservable = ConnectivityObservable()override fun onCreate(savedInstanceState: Bundle?) {super.onCreate(savedInstanceState)setContentView(R.layout.activity_main)connectivityObservable.observe(this).subscribeOn(Schedulers.io()).observeOn(AndroidSchedulers.mainThread()).subscribe { isConnected ->if (isConnected) {// internet connection is available} else {// internet connection is not available}}}override fun onDestroy() {super.onDestroy()connectivityObservable.stopObserving(this)}
}

参考链接

https://medium.com/@manuchekhrdev/simple-ways-to-monitor-internet-connectivity-in-android-a3bef75bd3d9