Question

如何在Android中检查互联网访问权限？

为什么总是返回true？

我确信我没有连接到互联网。为什么返回true？

public static boolean isOnline(Context context) {
    ConnectivityManager cm = (ConnectivityManager)context.getSystemService(Context.CONNECTIVITY_SERVICE);
    // test for connection
    if (cm.getActiveNetworkInfo() != null &&
        cm.getActiveNetworkInfo().isAvailable() &&
        cm.getActiveNetworkInfo().isConnected()) {

        return true;
    } else {
        Log.v("TAG", "Internet Connection Not Present");
        return false;
    }
}

Answer 1

您可以尝试测试以确定哪个连接被视为活动：

public boolean isOnline() {
  ConnectivityManager cm = (ConnectivityManager) getSystemService(Context.CONNECTIVITY_SERVICE);
  NetworkInfo netInfoMob = cm.getNetworkInfo(cm.TYPE_MOBILE);
  NetworkInfo netInfoWifi = cm.getNetworkInfo(cm.TYPE_WIFI);
  if (netInfoMobile != null && netInfoMobile.isConnectedOrConnecting()) {
    Log.v("TAG", "Mobile Internet connected");
    return true;
  } 
  if (netInfoWifi != null && netInfoWifi.isConnectedOrConnecting()) {
    Log.v("TAG", "Wifi Internet connected");
    return true;
  } 
  return false;
}

编辑：在模拟器上，无论计算机的Internet连接如何，它都将始终显示移动连接。根据以下答案，使用F8将其关闭：

https://stackoverflow.com/a/2937915/560092

Answer 2

public boolean isNetworkAvailable() {
        ConnectivityManager connectivityManager 
              = (ConnectivityManager) getSystemService(Context.CONNECTIVITY_SERVICE);
        NetworkInfo activeNetworkInfo = connectivityManager.getActiveNetworkInfo();
        boolean isAvailable = activeNetworkInfo != null && activeNetworkInfo.isConnected();
        if(!isAvailable) {
            Toast.makeText(this,"Unable to connect", Toast.LENGTH_SHORT).show();
        }
        return activeNetworkInfo != null && activeNetworkInfo.isConnected();
    }

Answer 3

您使用的方法始终无法正常工作。有时候，即使你连接到wifi网络（但网络实际上并没有连接到互联网），它也会返回真实状态。另一种选择是

public boolean isOnline() {
  ConnectivityManager cm = (ConnectivityManager) getSystemService(Context.CONNECTIVITY_SERVICE);
  NetworkInfo netInfoMob = cm.getNetworkInfo(cm.TYPE_MOBILE);
  NetworkInfo netInfoWifi = cm.getNetworkInfo(cm.TYPE_WIFI);
  if ((netInfoMobile != null && netInfoMobile.isConnectedOrConnecting()) || (netInfoWifi != null && netInfoWifi.isConnectedOrConnecting())) {
    return true;
}
  return false;
}

在Android中检查互联网访问时，为什么总是返回＆＃34; true＆＃34;？

3 个答案: