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

if(isConnected()){
                Toast.makeText(getApplication(),"Thank you",Toast.LENGTH_SHORT).show();
        }
        else{

            AlertDialog.Builder builder =
                    new AlertDialog.Builder(this, R.style.AppCompatAlertDialogStyle);
            builder.setTitle("Amar Bhat");
            builder.setMessage("Oops...You are not connected to Internet!!!");
            builder.setPositiveButton("OK", null);
            builder.setNegativeButton("Cancel", null);
            builder.show();
            //Toast.makeText(getApplication(),"You are not connected",Toast.LENGTH_SHORT).show();
        }




//And outside the class define isConnected()

 public boolean isConnected(){
        ConnectivityManager connMgr = (ConnectivityManager) getSystemService(Activity.CONNECTIVITY_SERVICE);
        NetworkInfo networkInfo = connMgr.getActiveNetworkInfo();
        if (networkInfo != null && networkInfo.isConnected())
            return true;
        else
            return false;
    }

// In minifest add these permission
<uses-permission android:name="android.permission.INTERNET" />

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

2015-11-17 05:25:36

其他回答

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

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

我使用这段代码而不是InetAddress:

    try {

        URL url = new URL("http://"+params[0]);

        HttpURLConnection urlc = (HttpURLConnection) url.openConnection();
        urlc.setRequestProperty("User-Agent", "Android Application:"+Z.APP_VERSION);
        urlc.setRequestProperty("Connection", "close");
        urlc.setConnectTimeout(1000 * 30); // mTimeout is in seconds
        urlc.connect();
        if (urlc.getResponseCode() == 200) {
            Main.Log("getResponseCode == 200");
            return new Boolean(true);
        }
    } catch (MalformedURLException e1) {
        // TODO Auto-generated catch block
        e1.printStackTrace();
    } catch (IOException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }

2009-10-13 16:08:46

非常重要的是检查我们是否与isAvailable()有连接，以及是否可能与isConnected()建立连接

private static ConnectivityManager manager;

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

你可以取消网络活动WiFi的类型:

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

或手机Móvil:

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

不要忘记权限:

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

2017-01-02 18:23:18

这段代码将帮助您找到互联网是否打开。

public final boolean isInternetOn() {
        ConnectivityManager conMgr = (ConnectivityManager) this.con
                .getSystemService(Context.CONNECTIVITY_SERVICE);
        NetworkInfo info = conMgr.getActiveNetworkInfo();
        return (info != null && info.isConnected());
}

此外，您应该提供以下权限

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

2016-03-08 05:02:28

如何检查Android上的互联网接入?InetAddress从不超时

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