android - 安卓连接

Question

嗨，我正在使用来自android的这个片段

public boolean isOnline() {
    ConnectivityManager connMgr = (ConnectivityManager) 
    getSystemService(Context.CONNECTIVITY_SERVICE);
    NetworkInfo networkInfo = connMgr.getActiveNetworkInfo();
    return (networkInfo != null && networkInfo.isConnected());
}  

但是当我从我的桌面中断互联网连接时，它不会发现未连接，并尝试连接。我在安卓模拟器中运行它。我的问题：为什么它不会返回 false 并且仍然认为它是连接的？如果它是通过 3D 连接的，它不应该获取数据吗？

Answer 1

禁用计算机上的 Internet 连接不会反映模拟器上的更改。

您需要像在真手机上一样直接从模拟器中禁用互联网：

Settings -> Wireless and networks -> Mobile Networks -> Use packed data.

（我想路径可能因模拟器而异，具体取决于 SDK 版本）

Answer 2

公共类 HttpManager {

public static String getData(String uri) {

    BufferedReader reader = null;

    try {
        URL url = new URL(uri);
        HttpURLConnection con = (HttpURLConnection) url.openConnection();

        StringBuilder sb = new StringBuilder();
        reader = new BufferedReader(new InputStreamReader(con.getInputStream()));

        String line;
        while ((line = reader.readLine()) != null) {
            sb.append(line + "\n");
        }
        return sb.toString();

    } catch (Exception e) {
        e.printStackTrace();
        return null;
    } finally {
        if (reader != null) {
            try {
                reader.close();
            } catch (IOException e) {
                e.printStackTrace();
                return null;
            }
        }
    }

}

Answer 3

        ConnectivityManager connMgr =
                (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE);
        NetworkInfo networkInfo = connMgr.getActiveNetworkInfo();

        // Checks the user prefs and the network connection. Based on the result, decides
        // whether
        // to refresh the display or keep the current display.
        // If the userpref is Wi-Fi only, checks to see if the device has a Wi-Fi connection.
        if (WIFI.equals(sPref) && networkInfo != null
                && networkInfo.getType() == ConnectivityManager.TYPE_WIFI) {
            // If device has its Wi-Fi connection, sets refreshDisplay
            // to true. This causes the display to be refreshed when the user
            // returns to the app.
            refreshDisplay = true;
            Toast.makeText(context, R.string.wifi_connected, Toast.LENGTH_SHORT).show();

            // If the setting is ANY network and there is a network connection
            // (which by process of elimination would be mobile), sets refreshDisplay to true.
        } else if (ANY.equals(sPref) && networkInfo != null) {
            refreshDisplay = true;

            // Otherwise, the app can't download content--either because there is no network
            // connection (mobile or Wi-Fi), or because the pref setting is WIFI, and there
            // is no Wi-Fi connection.
            // Sets refreshDisplay to false.
        } else {
            refreshDisplay = false;
            Toast.makeText(context, R.string.lost_connection, Toast.LENGTH_SHORT).show();
        }

Answer 4

public class Networking {
 /*
 *@return boolean return true if the application can access the internet
 */
 public static boolean isNetworkAvailable(Context context) {
     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;
  }
}