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

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

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 static boolean isNetworkAvailable(Context context) {
    boolean flag = checkNetworkAvailable(context);

    if (!flag) {
        Log.d("", "No network available!");
    } 
    return flag;
}


private static boolean checkNetworkAvailable(Context context) {
    ConnectivityManager connectivityManager
            = (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE);
    NetworkInfo activeNetworkInfo = connectivityManager.getActiveNetworkInfo();
    return activeNetworkInfo != null;
}

2018-06-21 06:49:59

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

如果您想在连接丢失时显示警报。你可以使用下面的方法。

此方法用于一次检查连接。首先，你必须在你的类中创建这个。

private boolean isNetworkConnected() {
        ConnectivityManager cm = (ConnectivityManager) getSystemService(Context.CONNECTIVITY_SERVICE);
        if(!(cm.getActiveNetworkInfo() != null && cm.getActiveNetworkInfo().isConnected())){
            showNetworkDialog();
            return false;
        }
        return true;
    }

在类中创建此方法作为连接侦听器。

private void ConnectionCheck(){
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
            ConnectivityManager connectivityManager = (ConnectivityManager) getSystemService(Context.CONNECTIVITY_SERVICE);
            NetworkRequest networkRequest = new NetworkRequest.Builder().build();
            connectivityManager.registerNetworkCallback(networkRequest, new ConnectivityManager.NetworkCallback() {
                @Override
                public void onAvailable(Network network) {
                    super.onAvailable(network);
                    Log.i("Tag", "active connection");
                }

                @Override
                public void onLost(Network network) {
                    super.onLost(network);
                    Log.i("Tag", "losing active connection");
                    isNetworkConnected();
                }
            });
        }
    }

为了显示对话框，你可以创建showDialog()方法。

private void showNetworkDialog(){
    new AlertDialog.Builder(MainActivity.this)
            .setIcon(android.R.drawable.ic_dialog_alert)
            .setTitle("Connection lost?")
            .setMessage("Please check your internet connection!")
            .setCancelable(false)
            .setPositiveButton("Exit", new DialogInterface.OnClickListener() {
                @Override
                public void onClick(DialogInterface dialog, int which) {
                    finish();
                }
            })
            .setNegativeButton("Retry", new DialogInterface.OnClickListener() {
                @Override
                public void onClick(DialogInterface dialog, int which) {
                    isNetworkConnected();
                }
            })
            .show();
}

最后你可以在onCreate()方法中调用这个方法。

if(isNetworkConnected()){
            ConnectionCheck();
        }

在清单文件中，你必须提到许可。

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

2021-03-07 13:45:17

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

如何检查Android上的互联网接入?InetAddress从不超时

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