Android中判断网络连接是否可用及监控网络状态

获取网络信息需要在AndroidManifest.xml文件中加入相应的权限。 
 
1）判断是否有网络连接

 1 public boolean isNetworkConnected(Context context) { 
 2 if (context != null) { 
 3 ConnectivityManager mConnectivityManager = (ConnectivityManager) context 
 4 .getSystemService(Context.CONNECTIVITY_SERVICE); 
 5 NetworkInfo mNetworkInfo = mConnectivityManager.getActiveNetworkInfo(); 
 6 if (mNetworkInfo != null) { 
 7 return mNetworkInfo.isAvailable(); 
 8 } 
 9 } 
10 return false; 
11 }

2）判断WIFI网络是否可用

 1 public boolean isWifiConnected(Context context) { 
 2 if (context != null) { 
 3 ConnectivityManager mConnectivityManager = (ConnectivityManager) context 
 4 .getSystemService(Context.CONNECTIVITY_SERVICE); 
 5 NetworkInfo mWiFiNetworkInfo = mConnectivityManager 
 6 .getNetworkInfo(ConnectivityManager.TYPE_WIFI); 
 7 if (mWiFiNetworkInfo != null) { 
 8 return mWiFiNetworkInfo.isAvailable(); 
 9 } 
10 } 
11 return false; 
12 }

3）判断MOBILE网络是否可用

 1 public boolean isMobileConnected(Context context) { 
 2 if (context != null) { 
 3 ConnectivityManager mConnectivityManager = (ConnectivityManager) context 
 4 .getSystemService(Context.CONNECTIVITY_SERVICE); 
 5 NetworkInfo mMobileNetworkInfo = mConnectivityManager 
 6 .getNetworkInfo(ConnectivityManager.TYPE_MOBILE); 
 7 if (mMobileNetworkInfo != null) { 
 8 return mMobileNetworkInfo.isAvailable(); 
 9 } 
10 } 
11 return false; 
12 }

4）获取当前网络连接的类型信息

 1 public static int getConnectedType(Context context) { 
 2 if (context != null) { 
 3 ConnectivityManager mConnectivityManager = (ConnectivityManager) context 
 4 .getSystemService(Context.CONNECTIVITY_SERVICE); 
 5 NetworkInfo mNetworkInfo = mConnectivityManager.getActiveNetworkInfo(); 
 6 if (mNetworkInfo != null && mNetworkInfo.isAvailable()) { 
 7 return mNetworkInfo.getType(); 
 8 } 
 9 } 
10 return -1; 
11 }

 

有时候我们连接上一个没有外网连接的WiFi或者有线就会出现这种极端的情况，目前Android SDK还不能识别这种情况，一般的解决办法就是ping一个外网。（ping 3次时间比较长）

/* @author suncat


  * @category 判断是否有外网连接（普通方法不能判断外网的网络是否连接，比如连接上局域网）
  * @return
  */ 
 public static final boolean ping() { 
 
   String result = null; 
   try { 
      String ip = "www.baidu.com";// ping 的地址，可以换成任何一种可靠的外网 
      Process p = Runtime.getRuntime().exec("ping -c 3 -w 100 " + ip);// ping网址3次 




    // 读取ping的内容，可以不加 
      InputStream input = p.getInputStream(); 
      BufferedReader in = new BufferedReader(new InputStreamReader(input)); 
      StringBuffer stringBuffer = new StringBuffer(); 
      String content = ""; 
      while ((content = in.readLine()) != null) { 
          stringBuffer.append(content); 
      } 
      Log.d("WifiReceiver", "result content : " + stringBuffer.toString()); 
      // ping的状态 
      int status = p.waitFor(); 
      if (status == 0) { 
          result = "success"; 
          return true; 
      } else { 
          result = "failed"; 
      } 
  } catch (IOException e) { 
      result = "IOException"; 
  } catch (InterruptedException e) { 
      result = "InterruptedException"; 
  } finally { 
      Log.d("WifiReceiver", "result = " + result); 
 } 
   return false;
}