How to get AlertDialog Callback from method in Flutter? - function

Question

I have AlertDialog in static method, in that I wants to get callback when user clicks on OK button.
I tried using typedef but can't understand.
Below is My Code:
class DialogUtils{
static void displayDialogOKCallBack(BuildContext context, String title,
String message)
{
showDialog(
context: context,
builder: (BuildContext context) {
return AlertDialog(
title: new Text(title, style: normalPrimaryStyle,),
content: new Text(message),
actions: <Widget>[
new FlatButton(
child: new Text(LocaleUtils.getString(context, "ok"), style: normalPrimaryStyle,),
onPressed: () {
Navigator.of(context).pop();
// HERE I WANTS TO ADD CALLBACK
},
),
],
);
},
);
}
}

Answer 1

You can simply wait for the dialog to be dismissed {returns null} or closed by clicking OK which, in this case, will return true
class DialogUtils {
static Future<bool> displayDialogOKCallBack(
BuildContext context, String title, String message) async {
return await showDialog<bool>(
context: context,
builder: (BuildContext context) {
return AlertDialog(
title: new Text(title, style: normalPrimaryStyle,),
content: Text(message),
actions: <Widget>[
FlatButton(
child: Text(LocaleUtils.getString(context, "ok"), style: normalPrimaryStyle,),
onPressed: () {
Navigator.of(context).pop(true);
// true here means you clicked ok
},
),
],
);
},
);
}
}
And then when you call displayDialogOKCallBack you should await for the result
Example:
onTap: () async {
var result =
await DialogUtils.displayDialogOKCallBack();
if (result) {
// Ok button is clicked
}
}

Answer 2

Then Callback function for Future work:
DialogUtils.displayDialogOKCallBack().then((value) {
if (value) {
// Do stuff here when ok button is pressed and dialog is dismissed.
}
});

Answer 3

This thread is a bit old, but I found a solution that wasn't touched upon, so I thought I'd add it here.
I had a form in my AlertDialog, and I needed to keep the dialog open if there were any errors. This solution worked for me.
final GlobalKey<FormState> formKey = GlobalKey<FormState>();
Future _showEditDialog(BuildContext context) {
return showDialog(
context: context,
builder: (context) {
return WillPopScope(
onWillPop: () async {
return formKey.currentState!.validate();
},
child: AlertDialog(
title: const Text("Awesome AlertDialog"),
content: SingleChildScrollView(
physics: const BouncingScrollPhysics(),
child: Form(
key: formKey,
child: Column(
children: [
TextFormField(
validator: (value) {
if (value!.isEmpty) return "Please Fill Out This Field";
return null;
},
),
],
),
),
),
actions: <Widget>[
MaterialButton(
child: const Text("Cancel"),
onPressed: () {
Navigator.pop(context);
},
),
],
),
);
},
);
}
The important part is the WillPopScope that I wrapped the AlertDialog. I think this absorbs all the Navigator.pop() calls and passes them through the onWillPop parameter. This parameter is passed an async function which returns a Future. I just returned the validation check boolean, but in the real world there would also be a http request here too.
Remember to add a way for the user to cancel the form without triggering the form validation. I just added a cancel button that runs Navigator.pop().
Hope this helps, let me know if anyone has any questions.