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

可以通过该方法检测网络可用性-

public static boolean isDeviceOnline(Context context) {
        boolean isConnectionAvail = false;
        try {
            ConnectivityManager cm = (ConnectivityManager) context
                    .getSystemService(Context.CONNECTIVITY_SERVICE);
            NetworkInfo netInfo = cm.getActiveNetworkInfo();
            return netInfo.isConnected();
        } catch (Exception e) {
            e.printStackTrace();
        }
        return isConnectionAvail;
    }

2015-02-04 08:21:31

其他回答

我已经应用了@Levit提供的解决方案，并创建了不会调用额外Http请求的函数。

它将解决无法解析主机的错误

public static boolean isInternetAvailable(Context context) {
    ConnectivityManager cm = (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE);
    NetworkInfo activeNetwork = cm.getActiveNetworkInfo();
    if (activeNetwork == null) return false;

    switch (activeNetwork.getType()) {
        case ConnectivityManager.TYPE_WIFI:
            if ((activeNetwork.getState() == NetworkInfo.State.CONNECTED ||
                    activeNetwork.getState() == NetworkInfo.State.CONNECTING) &&
                    isInternet())
                return true;
            break;
        case ConnectivityManager.TYPE_MOBILE:
            if ((activeNetwork.getState() == NetworkInfo.State.CONNECTED ||
                    activeNetwork.getState() == NetworkInfo.State.CONNECTING) &&
                    isInternet())
                return true;
            break;
        default:
            return false;
    }
    return false;
}

private static boolean isInternet() {

    Runtime runtime = Runtime.getRuntime();
    try {
        Process ipProcess = runtime.exec("/system/bin/ping -c 1 8.8.8.8");
        int exitValue = ipProcess.waitFor();
        Debug.i(exitValue + "");
        return (exitValue == 0);
    } catch (IOException | InterruptedException e) {
        e.printStackTrace();
    }

    return false;
}

现在叫它，

if (!isInternetAvailable(getActivity())) {
     //Show message
} else {
     //Perfoem the api request
}

2017-01-09 06:57:11

不需要太复杂。最简单的框架方式是使用ACCESS_NETWORK_STATE权限并创建一个连接的方法

public boolean isOnline() {
    ConnectivityManager cm =
        (ConnectivityManager) getSystemService(Context.CONNECTIVITY_SERVICE);

    return cm.getActiveNetworkInfo() != null && 
       cm.getActiveNetworkInfo().isConnectedOrConnecting();
}

如果您有特定的主机和连接类型(wifi/移动)，也可以使用requestRouteToHost。

你还需要:

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

在你的android清单中。

2010-01-04 20:01:47

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

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

如果您正在使用API 23或更高版本，您现在可以使用NetworkCapabilities检查internet是否处于活动状态。net_capacity_validated，由谷歌自己的ping服务支持。

ConnectivityManager.NetworkCallback networkCallback = new ConnectivityManager.NetworkCallback() {
    @Override
    public void onLost(Network network) {
        // handle network lost
    }

    @Override
    public void onAvailable(Network network) {
        ConnectivityManager cm = (ConnectivityManager) getApplicationContext().getSystemService(Context.CONNECTIVITY_SERVICE);
        NetworkInfo info = cm.getNetworkInfo(network);
        boolean isConnected = (info != null && info.isConnectedOrConnecting());

        if (isConnected) {
            NetworkCapabilities nc = cm.getNetworkCapabilities(network);
            if (nc != null) {
                boolean isInternetValid = nc.hasCapability(NetworkCapabilities.NET_CAPABILITY_VALIDATED);
                if (isInternetValid) {
                    // internet is valid
                }
            }
        }
    }
};

NetworkRequest request = new NetworkRequest.Builder().addCapability(NetworkCapabilities.NET_CAPABILITY_INTERNET).build();
ConnectivityManager connectivityManager = (ConnectivityManager) getApplicationContext().getSystemService(Context.CONNECTIVITY_SERVICE);
connectivityManager.registerNetworkCallback(request, networkCallback);

2017-04-15 00:09:30

如何检查Android上的互联网接入?InetAddress从不超时

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