如何检查Android上的互联网接入?InetAddress从不超时

我得到了一个AsyncTask，应该检查对主机名的网络访问。但是doInBackground()永远不会超时。有人知道吗?

public class HostAvailabilityTask extends AsyncTask<String, Void, Boolean> {

    private Main main;

    public HostAvailabilityTask(Main main) {
        this.main = main;
    }

    protected Boolean doInBackground(String... params) {
        Main.Log("doInBackground() isHostAvailable():"+params[0]);

        try {
            return InetAddress.getByName(params[0]).isReachable(30); 
        } catch (UnknownHostException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
        return false;       
    }

    protected void onPostExecute(Boolean... result) {
        Main.Log("onPostExecute()");

        if(result[0] == false) {
            main.setContentView(R.layout.splash);
            return;
        }

        main.continueAfterHostCheck();
    }   
}

当前回答

使用这个Kotlin扩展:

/**
 * Check whether network is available
 *
 * @param context
 * @return Whether device is connected to Network.
 */
fun Context.isNetworkAvailable(): Boolean {
    with(getSystemService(Context.CONNECTIVITY_SERVICE) as ConnectivityManager) {
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
            //Device is running on Marshmallow or later Android OS.
            with(getNetworkCapabilities(activeNetwork)) {
                return hasTransport(NetworkCapabilities.TRANSPORT_WIFI) || hasTransport(
                    NetworkCapabilities.TRANSPORT_CELLULAR
                )
            }
        } else {
            activeNetworkInfo?.let {
                // connected to the internet
                @Suppress("DEPRECATION")
                return listOf(ConnectivityManager.TYPE_WIFI, ConnectivityManager.TYPE_MOBILE).contains(it.type)
            }
        }
    }
    return false
}

2019-12-25 14:14:42

其他回答

看一下ConnectivityManager类。您可以使用这个类来获取主机上活动连接的信息。http://developer.android.com/reference/android/net/ConnectivityManager.html

编辑:你可以使用

Context.getSystemService(Context.CONNECTIVITY_SERVICE)
    .getNetworkInfo(ConnectivityManager.TYPE_MOBILE)

Context.getSystemService(Context.CONNECTIVITY_SERVICE)
    .getNetworkInfo(ConnectivityManager.TYPE_WIFI)

并解析返回NetworkInfo对象的DetailedState枚举

EDIT EDIT:查看是否可以访问主机

Context.getSystemService(Context.CONNECTIVITY_SERVICE)
    .requestRouteToHost(TYPE_WIFI, int hostAddress)

显然，我使用Context.getSystemService(Context.CONNECTIVITY_SERVICE)作为代理来表示

ConnectivityManager cm = Context.getSystemService(Context.CONNECTIVITY_SERVICE);
cm.yourMethodCallHere();

2009-10-13 15:38:47

使用这个Kotlin扩展:

/**
 * Check whether network is available
 *
 * @param context
 * @return Whether device is connected to Network.
 */
fun Context.isNetworkAvailable(): Boolean {
    with(getSystemService(Context.CONNECTIVITY_SERVICE) as ConnectivityManager) {
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
            //Device is running on Marshmallow or later Android OS.
            with(getNetworkCapabilities(activeNetwork)) {
                return hasTransport(NetworkCapabilities.TRANSPORT_WIFI) || hasTransport(
                    NetworkCapabilities.TRANSPORT_CELLULAR
                )
            }
        } else {
            activeNetworkInfo?.let {
                // connected to the internet
                @Suppress("DEPRECATION")
                return listOf(ConnectivityManager.TYPE_WIFI, ConnectivityManager.TYPE_MOBILE).contains(it.type)
            }
        }
    }
    return false
}

2019-12-25 14:14:42

这里有一个简单的解决方案，以确保你的应用程序可以访问互联网:

static final String CHECK_INTERNET_ACCESS_URL = "https://www.google.com";

public static void isInternetAccessWorking(Context context) {

    StringRequest stringRequest = new StringRequest(Request.Method.GET, CHECK_INTERNET_ACCESS_URL,
            new Response.Listener<String>() {
                @Override
                public void onResponse(String response) {
                    // Internet access is OK
                }
            }, new Response.ErrorListener() {
        @Override
        public void onErrorResponse(VolleyError error) {
            // NO internet access
        }
    });

    Volley.newRequestQueue(context).add(stringRequest);
}

这个解决方案使用Android的Volley库，必须在build.gradle中声明:

implementation 'com.android.volley:volley:1.1.1'

2022-09-29 09:18:22

正如Android文档建议的那样，之后

getActiveNetworkInfo()在Android 10中已弃用。使用而不是针对Android 10 (API级别)的应用程序的NetworkCallbacks 29)更高。

下面是我们目前检查网络连接的方法:

val cm = context.getSystemService(Context.CONNECTIVITY_SERVICE) as ConnectivityManager
val activeNetwork: NetworkInfo? = cm.activeNetworkInfo
val isConnected: Boolean = activeNetwork?.isConnectedOrConnecting == true

使用NetworkCallbacks检查网络连接的新方法

步骤1:

    private lateinit var connectivityManager:ConnectivityManager

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        ...
        connectivityManager = getSystemService(Context.CONNECTIVITY_SERVICE) as ConnectivityManager
    }

步骤2:创建回调:

private val callback = object : ConnectivityManager.NetworkCallback() {
    override fun onAvailable(network: Network) {
        super.onAvailable(network)
        Timber.e("Network:onAvailable")
    }

    override fun onLost(network: Network) {
        super.onLost(network)
        Timber.e("Network:onLost")
    }

}

步骤3:注册和取消注册回调:

private fun registerNetworkCallback() {
    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.N) {
        connectivityManager.registerDefaultNetworkCallback(callback)
    } else {
        // Old way to check network connection
    }
}

override fun onStop() {
    unRegisterNetworkCallback()
    super.onStop()
}

private fun unRegisterNetworkCallback() {
    connectivityManager.unregisterNetworkCallback(callback)
}

结帐更新详情如下链接:

https://developer.android.com/training/monitoring-device-state/connectivity-status-type

2019-12-17 05:19:18

在我目前所见过的所有方法中，最短、最干净的方法应该是:

public final static boolean isConnected( Context context )
{   
   final ConnectivityManager connectivityManager = 
         (ConnectivityManager) context.getSystemService( Context.CONNECTIVITY_SERVICE );  
   final NetworkInfo networkInfo = connectivityManager.getActiveNetworkInfo();    
   return networkInfo != null && networkInfo.isConnected();
}

PS:这不会ping任何主机，它只是检查连接状态，所以如果你的路由器没有互联网连接，而你的设备连接到它，这个方法将返回true，尽管你没有互联网。对于实际的测试，我建议执行一个HttpHead请求(例如到www.google.com)并检查状态，如果它是200 OK，一切正常，并且您的设备有互联网连接。

2012-09-19 08:10:53

如何检查Android上的互联网接入?InetAddress从不超时

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