Flutter AlertDialog examples – how to show dialog and get returned result

An alert dialog which consists of an optional title and an optional list of actions informs the user about situations that require acknowledgement.

Open an dialog

showDialog(
      context: context,
      barrierDismissible: false,
      builder: (_) => AlertDialog(
        title: Text('Result'),
        content: Text('Dialog content'),
        actions: <Widget>[
          new OutlineButton(
            child: new Text('Share'),
            onPressed: () {
            },
          ),
          new FlatButton(
            child: new Text('OK', style: TextStyle(color: Colors.white),),
            color: Colors.blue,
            onPressed: () {
              Navigator.of(context).pop();
            },
          ),
        ],
      )
  );

showDialog() then can be called in any events such as onPressed, onTap.

RaisedButton(onPressed: _calculate)

Prevent dialog from closing from touching outside

barrierDismissible property determines whether you can dismiss this route by tapping the modal barrier.

showDialog(
      context: context,
      barrierDismissible: false,
...
)

To close the dialog, call Navigator.of(context).pop() within onPressed event:

onPressed: () {
    Navigator.of(context).pop();
},

Get result from dialog

Dialog

class MyDialog extends StatelessWidget {
  final TextEditingController _controller = TextEditingController();

  @override
  Widget build(BuildContext context) {
    return AlertDialog(
      title: Text('Add emoji'),
      shape: RoundedRectangleBorder(borderRadius: BorderRadius.circular(8.0)),
      content: Column(
        mainAxisSize: MainAxisSize.min,
        children: <Widget>[
          TextField(
            controller: _controller,
            decoration: InputDecoration(labelText: 'Emoji'),
          ),
          Row(
            mainAxisAlignment: MainAxisAlignment.end,
            children: <Widget>[
              FlatButton(
                  onPressed: () {
                    Navigator.of(context).pop();
                  },
                  child: Text("Cancel")),
              FlatButton(
                  onPressed: () {
                    Navigator.pop(context, _controller.text);
                  },
                  color: Colors.blue,
                  child: Text("Save", style: TextStyle(color: Colors.white),)),
            ],
          )
        ],
      ),
    );
  }
}

Call dialog and get dialog’s input data in Flutter TextField:

showDialog(    
    builder: (_) => MyDialog()).then((value)
{
  if (value != null){
    print(value);
  }
});