检测Android设备是否连接到互联网

4 回答

• 8

  创建一个类：

  public class Utility {
      public static boolean isNetworkAvailable(Context context) {
          ConnectivityManager connectivityManager
                  = (ConnectivityManager)  context.getSystemService(Context.CONNECTIVITY_SERVICE);
          NetworkInfo activeNetworkInfo = connectivityManager.getActiveNetworkInfo();
          return activeNetworkInfo != null && activeNetworkInfo.isConnected();
      }
  }
  

  然后从活动中调用methode，它将返回true或false：

  Utility.isNetworkAvailable(AnyActivity.this);
  

  并且不要忘记为android清单添加权限

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

  回复于 2024-05-16T13:11:24+08:00
• 0

  这不是ConnectivityManager为此 Build 的ConnectivityManager类 .

  它使用起来非常简单，您只需执行以下操作即可检查网络连接：

  ConnectivityManager cm =
          (ConnectivityManager)context.getSystemService(Context.CONNECTIVITY_SERVICE);
  
  NetworkInfo activeNetwork = cm.getActiveNetworkInfo();
  boolean isConnected = activeNetwork != null &&
                        activeNetwork.isConnectedOrConnecting();
  

  这还可以让您确定连接类型，监控等等，以便您可以对正在执行的网络任务做出明智的决策 .

  Android开发者网站上的this lesson中有更多信息 .

  回复于 2024-05-16T13:11:24+08:00
• 0

  你必须在asynctask中做到这一点 . 我使用http://clients3.google.com/generate_204来检测连接 .

  import java.net.HttpURLConnection;
      import java.net.URL;
  
  
      ...
  
      private int inter = 0;   
  
  
      ...
  
  
       new checkconne().execute();
  
      ...
  
  
  
      class checkconne extends AsyncTask<String, String, String> {
  
                              @Override
                              protected void onPreExecute() {
                                  super.onPreExecute();
  
  
  
                              }
                              @Override
                              protected String doInBackground(String... args) {
  
                                  int kk=0;
                                  try {
                                      HttpURLConnection urlc = (HttpURLConnection)
                                              (new URL("http://clients3.google.com/generate_204")
                                                      .openConnection());
                                      urlc.setRequestProperty("User-Agent", "Android");
                                      urlc.setRequestProperty("Connection", "close");
                                      urlc.setConnectTimeout(1500);
                                      urlc.connect();
                                      kk= urlc.getResponseCode();
                                  } catch (IOException e) {
  
  
          Log.e("qweqwe", "Error checking internet connection", e);
                              }
  
                              inter=kk;
  
  
  
                              return null;
                          }
                          @Override
                          protected void onPostExecute(String file_url) {
  
  
                              if (inter == 204){       
               Toast.makeText(MainActivity3.this, "is connected", Toast.LENGTH_LONG).show();             
  
                              }else{    
  
  
                                  Toast.makeText(MainActivity3.this, "No connection", Toast.LENGTH_LONG).show();
  
                              }
  
  
                          }
                      }
  

  回复于 2024-05-16T13:11:24+08:00
• 2

  叫这个功能：

  public static boolean isNetworkAvailable()
       {
          StrictMode.ThreadPolicy policy = new StrictMode.ThreadPolicy.Builder().permitAll().build();
          StrictMode.setThreadPolicy(policy);
  
          HttpGet httpGet = new HttpGet("http://www.google.com");
          HttpParams httpParameters = new BasicHttpParams();
          int timeoutConnection = 1000;
          HttpConnectionParams.setConnectionTimeout(httpParameters, timeoutConnection);
          int timeoutSocket = 1500;
          HttpConnectionParams.setSoTimeout(httpParameters, timeoutSocket);
          DefaultHttpClient httpClient = new DefaultHttpClient(httpParameters);
          try
          {
             httpClient.execute(httpGet);
             return true;
          }
          catch(ClientProtocolException e)
          {
             e.printStackTrace();
          }
          catch(IOException e)
          {
             e.printStackTrace();
          }
      return false;
    }
  

  回复于 2024-05-16T13:11:24+08:00