How to convert flutter TimeOfDay to DateTime?

I have a time picker that returns the TimeOfDay object. But I have to save that value in a database as an integer of milliseconds which obtained from DateTime.millisecondsSinceEpoch. How can I achieve that?

You can use entension like this and also can add some more extension methods in separate file like dateTime_extensions.dart to make your work easy for future projects as well


file: **dateTime_extensions.dart;**

```

extension DateTimeExtension on DateTime {
DateTime setTimeOfDay(TimeOfDay time) {
return DateTime(this.year, this.month, this.day, time.hour, time.minute);
}

DateTime setTime(
{int hours = 0,
int minutes = 0,
int seconds = 0,
int milliSeconds = 0,
int microSeconds = 0}) {
return DateTime(this.year, this.month, this.day, hours, minutes, seconds,
milliSeconds, microSeconds);
}

DateTime clearTime() {
return DateTime(this.year, this.month, this.day, 0, 0, 0, 0, 0);
}

///..... add more methods/properties for your convenience
}

```

use it like this
```

import 'package:your_app/dateTime_extensions.dart';

date.clearTime(); //to clear timeSpan
date.setTime(); //also be used to clear time if you don't provide any parameters
date.setTime(hours: 16,minutes: 23,seconds: 24); // will set time to existing date eg. existing_date 16:23:24
date.setTimeOfDay(TimeOfDay(hour: 16, minute: 59));

```

You can use DateTime extension

extension DateTimeExtension on DateTime {
DateTime applied(TimeOfDay time) {
return DateTime(year, month, day, time.hour, time.minute);
}
}

then you can use it like this:

`final dateTime = yourDate.applied(yourTimeOfDayValue);`

and change your sdk version in pubspec.yaml to

environment:
sdk: ">=2.7.0 <3.0.0"

Here's just a tiny method to join a `DateTime` and a `HourOfDay`:

```dart
DateTime join(DateTime date, TimeOfDay time) {
return new DateTime(date.year, date.month, date.day, time.hour, time.minute);
}
```

This is not possible.
`TimeOfDay` holds _only_ the hour and minute. While a `DateTime` also has day/month/year


If you want to convert it, you will need more information. Such as the current DateTime. And then merge the two into one final datetime.

```flutter
TimeOfDay t;
final now = new DateTime.now();
return new DateTime(now.year, now.month, now.day, t.hour, t.minute);
```

You can set an extension on the `TimeOfDay` class:

```dart
extension TOD on TimeOfDay {
DateTime toDateTime() {
return DateTime(1, 1, 1, hour, minute);
}
}
```

then use it like this:

```dart
TimeOfDay timeOfDay = TimeOfDay.now();

DateTime dateTimeOfDay = timeOfDay.toDateTime();
```

if you define the extenson in another file and you have not imported it yet, if you are using `vsc` you can just type `timeOfDay.toDateTime();` then `ctrl + .` and `vsc` will suggest importing that file. if you're not using `vsc`, then I guess you have to import the file of the extension manually.