android中判断网络是否连接

在android中，如何监测网络的状态呢，这个有的时候也是十分重要的，方法如下：

public class ConnectionDetector {
  
  private Context _context;
  
  public ConnectionDetector(Context context){
    this._context = context;
  }

  public boolean isConnectingToInternet(){
    ConnectivityManager connectivity = (ConnectivityManager) _context.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)
            {
              return true;
            }

      }
      return false;
  }

调用：

ConnectionDetector cd = new ConnectionDetector(getApplicationContext()); 
  
Boolean isInternetPresent = cd.isConnectingToInternet(); //