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

下面是我使用的方法:

public boolean isNetworkAvailable(final Context context) {
    return ((ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE)).getActiveNetworkInfo() != null;
}

更好的是，检查确保它是“连接”的:

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

下面是如何使用该方法:

if (isNetworkAvailable(context)) {
    // code here
} else {
    // code
}

需要许可:

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

https://stackoverflow.com/a/16124915/950427

2013-07-11 00:50:50

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

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

以下是您需要的许可:

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

2016-08-17 13:56:42

public static boolean isNetworkAvailable(Context ctx) {
ConnectivityManager connMgr = (ConnectivityManager)ctx.getSystemService(Context.CONNECTIVITY_SERVICE);
if(connMgr.getNetworkInfo(ConnectivityManager.TYPE_WIFI).isConnected() ||
    connMgr.getNetworkInfo(ConnectivityManager.TYPE_MOBILE).isConnected()){
        return true;
}

return false;
 }

用户这

2013-10-03 10:22:57

下面是我使用的方法:

public boolean isNetworkAvailable(final Context context) {
    return ((ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE)).getActiveNetworkInfo() != null;
}

更好的是，检查确保它是“连接”的:

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

下面是如何使用该方法:

if (isNetworkAvailable(context)) {
    // code here
} else {
    // code
}

需要许可:

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

https://stackoverflow.com/a/16124915/950427

2013-07-11 00:50:50

使用以下方法检查互联网连接，同时ConnectivityManager.getActiveNetworkInfo()在API 28中已弃用

@Suppress("DEPRECATION")
fun isNetworkConnected(context: Context): Boolean {
    val cm = context.getSystemService(Context.CONNECTIVITY_SERVICE) as ConnectivityManager?
    return cm?.run {
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
            cm.getNetworkCapabilities(cm.activeNetwork)?.run {
                when {
                    hasTransport(NetworkCapabilities.TRANSPORT_WIFI) -> true
                    hasTransport(NetworkCapabilities.TRANSPORT_CELLULAR) -> true
                    hasTransport(NetworkCapabilities.TRANSPORT_ETHERNET) -> true
                    else -> false
                }
            }
        } else {
            cm.activeNetworkInfo?.run {
                when (type) {
                    ConnectivityManager.TYPE_WIFI -> true
                    ConnectivityManager.TYPE_MOBILE -> true
                    else -> false
                }
            }
        }
    } ?: false

}

还要向清单添加以下权限

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

hatransport_ethernet (NetworkCapabilities.TRANSPORT_ETHERNET)用于为Android TV开发的应用程序，其中TV可以直接连接到以太网

2019-12-06 12:02:46

如何检查Android上的互联网接入?InetAddress从不超时

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