Scala, Java, Unix, MacOS tutorials (page 92)

Here’s a little example of a Flutter time preferences widget, something I’ll be using in the new version of my Just Be app. Probably most important thing about this source code is that it shows an example of how to use the Flutter RadioListTile:

import 'package:flutter/material.dart';

class TimeValue {
    final int _key;
    final String _value;
    TimeValue(this._key, this._value);
}

class TimePreferencesWidget extends StatefulWidget {
    @override
    TimePreferencesWidgetState createState() => TimePreferencesWidgetState();
}

class TimePreferencesWidgetState extends State<TimePreferencesWidget> {
    int _currentTimeValue = 1;

    final _buttonOptions = [
        TimeValue(30,  "30 minutes"),
        TimeValue(60,  "1 hour"),
        TimeValue(120, "2 hours"),
        TimeValue(240, "4 hours"),
        TimeValue(480, "8 hours"),
        TimeValue(720, "12 hours"),
    ];

    @override
    Widget build(BuildContext context) {
        return Scaffold(
            appBar: AppBar(
                title: Text("Time Preferences"),
            ),
            body: ListView(
                padding: EdgeInsets.all(8.0),
                children: _buttonOptions.map((timeValue) => RadioListTile<int>(
                    groupValue: _currentTimeValue,
                    title: Text(timeValue._value),
                    value: timeValue._key,
                    onChanged: (val) {
                        setState(() {
                            debugPrint('VAL = $val');
                            _currentTimeValue = val;
                        });
                    },
                )).toList(),
            ),
        );
    }
}

I initially wanted to create _buttonOptions as a Map, but I ended up creating the TimeValue class to get what I wanted. (I’m still new to Dart, and I couldn’t find a good way to convert _buttonOptions.map from a Map to a List, which is required for the children parameter, so I went with the approach shown.)

Here’s an image of what this code creates:

In summary, if you wanted to see an example of a Flutter RadioListTile inside a ListView, I hope this example is helpful.

Working with yoga is often interesting. You stretch and twist and focus, trying to be very conscious and aware of your movements, and then one day in the middle of a twisting pose you see your left foot coming out from behind your right ear. At first that’s a real surprise, a shock. You think, “Well, that can’t be my foot over there”, and then you realize it is your foot, and with that comes a strong sense of accomplishment, and maybe a little smile.

Then you do the same pose in the opposition direction, but twist and stretch as you might, your right foot doesn’t come out from behind your left ear. You know you can’t push it any more, at least not while doing the pose properly, so you realize you have a little imbalance. You accept that you have some work to do, but it’s a good thing, so you push on.

I think life is like that too, or can be like that. If you enjoy the struggle, if it’s a worthy struggle — Castaneda’s “a path with heart” — the effort comes willingly, and with its own rewards.

If you need to supply an initial value to a Flutter TextFormField (and possibly a TextField), the initialValue parameter may not do what you expect it to do. (More on this in the Discussion.) Instead, I just used this technique to populate the initial value for a TextFormField when using it with a TextEditingController: