AlertDialog without context in Flutter : <p>I want to show an AlertDialog when a http get fails. The function showDialog (<a href="https://api.flutter.dev/flutter/material/showDialog.html" rel="noreferrer">https://api.flutter.dev/flutter/material/showDialog.html</a>) has the parameter "@required BuildContext context", but I want to call the AlertDialog from my async function getNews(), which hasn't a context value. </p>

<p>By analogy with Java, where I use null for dialog without an owner, I tried to put context value to null, but it is not accepted.</p>

<p>This is my code:</p>

<pre><code>  Future&lt;dynamic&gt; getNews() async {
    dynamic retVal;
    try {
      var response = await http.get(url));
      if (response.statusCode == HttpStatus.ok) {
        retVal = jsonDecode(response.body);
      }
    } catch (e) {
      alertDlg(?????????, 'Error', e.toString());
  }
    return
    retVal;
  }

  static Future&lt;void&gt; alertDlg(context, String titolo, String messaggio) async {
    return showDialog&lt;void&gt;(
        context: context,
        barrierDismissible: false, // user must tap button!
        builder: (BuildContext context) {
        return AlertDialog(
              title: Text(titolo),
        ...
    );
  }
</code></pre>
