android determines whether the network is available and whether the connected network can access the Internet

Network state acquisition

Upload and download need to check the network status of the current mobile phone first, and need to get ConnectionManager

 /**
 *  Determine whether there is a current network connection , However, if the connected network is unable to access the Internet, it will also return true
 * @param mContext
 * @return
 */
 public static boolean isNetConnection(Context mContext) {
 if (mContext!=null){
  ConnectivityManager connectivityManager = (ConnectivityManager) mContext.getSystemService(Context.CONNECTIVITY_SERVICE);
  NetworkInfo networkInfo = connectivityManager.getActiveNetworkInfo();
  boolean connected = networkInfo.isConnected();
  if (networkInfo!=null&&connected){
   if (networkInfo.getState()== NetworkInfo.State.CONNECTED){
    return true;
   }else{
    return false;
   }
  }
 }
 return false;
}

Can the network access the Internet normally

When there is a network connection, if you want to check whether the currently connected network can surf the Internet, you need to open the website address to make a judgment

/**
 *  Open this method in a sub-thread to detect whether the current network can open a web page 
 * true Yes, you can surf the Internet. false You can't surf the Internet 
 * 
 */
public static boolean isOnline(){
 URL url;
 try {
  url = new URL("https://www.baidu.com");
  InputStream stream = url.openStream();
  return true;
 } catch (MalformedURLException e) {
  e.printStackTrace();
 } catch (IOException e) {
  e.printStackTrace();
 }
 return false;
}