Android：检查网络和真实的互联网连接-Java 学习之路

下面是一段Android代码，它可以很好地检查网络是否连接 .

public static boolean isNetworkAvailable(Context context) 
{
    ConnectivityManager mConnectivityManager = (ConnectivityManager)context.getSystemService(Context.CONNECTIVITY_SERVICE);
    return (mConnectivityManager != null && mConnectivityManager.getActiveNetworkInfo().isConnectedOrConnecting()) ? true : false;
}

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

但是，拥有有效的网络接口并不能保证特定的网络服务可用 .

很多时候我们连接到网络但仍然无法访问常见的互联网网络服务，例如，谷歌

常见场景：

Android设备连接到Wi-Fi，后来证明是专用网络 . 因此isNetworkAvailable将返回该网络已连接，但无法连接到任何其他服务
有时电话信号显示它已连接到服务提供商数据计划 . 所以网络连接是真的，但仍然无法访问谷歌/雅虎 .

One way is to check if "isNetworkAvailable" function returns TRUE, then run following code

HttpGet request = new HttpGet(url));
   HttpParams httpParameters = new BasicHttpParams();
   int timeoutConnection = 60000;
   HttpConnectionParams.setConnectionTimeout(httpParameters, timeoutConnection);
   int timeoutSocket = 60000;
   HttpConnectionParams.setSoTimeout(httpParameters, timeoutSocket);

   DefaultHttpClient httpClient = new DefaultHttpClient(httpParameters);
   request.addHeader("Content-Type", "application/json");
   HttpResponse response = httpClient.execute(request);

   HttpEntity entity = response.getEntity();


     if (entity != null)
      {
         result = EntityUtils.toString(entity);
      }

   }
 catch (SocketException e)
  {
     return "Socket Exceptiopn:" + e.toString();
  }
 catch (Exception e)
  {
     return "General Execption:" + e.toString();
  }

但我认为这不是一个好方法，因为它可能会耗费大量时间

So is there any alternative efficient (in terms of time taken,speed) way ensure that we are connected to network as well as reachable to most common internet services ?

3 回答

检查这段代码......它对我有用:)

public static void isNetworkAvailable(final Handler handler, final int timeout) {

        // ask fo message '0' (not connected) or '1' (connected) on 'handler'
        // the answer must be send before before within the 'timeout' (in milliseconds)

        new Thread() {

            private boolean responded = false;

            @Override
            public void run() {

                // set 'responded' to TRUE if is able to connect with google mobile (responds fast)

                new Thread() {

                    @Override
                    public void run() {
                        HttpGet requestForTest = new HttpGet("http://m.google.com");
                        try {
                            new DefaultHttpClient().execute(requestForTest); // can last...
                            responded = true;
                        } catch (Exception e) {}
                    }

                }.start();

                try {
                    int waited = 0;
                    while(!responded && (waited < timeout)) {
                        sleep(100);
                        if(!responded ) { 
                            waited += 100;
                        }
                    }
                } 
                catch(InterruptedException e) {} // do nothing 
                finally { 
                    if (!responded) { handler.sendEmptyMessage(0); } 
                    else { handler.sendEmptyMessage(1); }
                }

            }

        }.start();

}

然后，我定义处理程序：

Handler h = new Handler() {

    @Override
    public void handleMessage(Message msg) {

        if (msg.what != 1) { // code if not connected

        } else { // code if connected

        }

    }
};

并启动测试：

isNetworkAvailable(h,2000); // get the answser within 2000 ms

代码来自Gilbou https://stackoverflow.com/a/5803489/2603719

我希望我能帮助你

回复于 2024-04-19T15:27:12+08:00

0
Issue #1:
Android设备连接到Wi-Fi，后来证明是专用网络 .
因此 isNetworkAvailable 将返回该网络已连接，但无法连接到任何其他服务 .

Issue #2:
有时电话信号显示它已连接到服务提供商数据计划 . 所以网络连接是真的，但仍然无法访问谷歌/雅虎 .
```
I'm not sure about Issue #1 but I'm sure that following approach will solve Issue #2.
```
最终，您需要 Monitor 网络连接的变化，

Step 1:

只需注册 BroadcastReceiver 即可执行以下操作

<action android:name="android.net.conn.CONNECTIVITY_CHANGE"/>

Step 2:

当您在 onReceive(Context context,Intent intent) 方法上获得回调时，请检查连接状态 .

即： boolean isConnected = getIntent().getExtras().getBoolean(ConnectivityManager.EXTRA_NO_CONNECTIVITY);

//除了 EXTRA_NO_CONNECTIVITY 之外，还有其他参数也可用于监控

Reference:

Examples:

Working Example of Step1,Step2: how-to-monitor-network-connectivity-in-android

Android-getting-notified-of-connectivity-changes

Github: Example for network-detect-notify

Android Docs:

Connectivity Monitoring

Connectivity Manager

我希望它会有所帮助!!
回复于 2024-04-19T15:27:12+08:00

使用此代码检查互联网连接，它检查设备上的所有互联网连接 . 并且确保你已经在menifest中添加了Internet权限 .

boolean flag=false;
        ConnectivityManager connectivity = (ConnectivityManager) getApplicationContext().getSystemService(Context.CONNECTIVITY_SERVICE);
        if (connectivity != null)
        {
            NetworkInfo[] info = connectivity.getAllNetworkInfo();
            if (info != null)
                for (int i = 0; i < info.length; i++)
                    if (info[i].getState() == NetworkInfo.State.CONNECTED)
                    {
                        flag=true;

                    }

        }
        if(flag==true)
        {
             Log.e("TAG","Internet Is Connected");
        }
        else
        {
              Log.e("TAG","Internet Is Not Connected");
        }

回复于 2024-04-19T15:27:12+08:00

Android：检查网络和真实的互联网连接

3 回答

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