When Should one use style: TextStyle() and Theme.of() - flutter

Question

I am learning Flutter. Sometimes I see coders use
text: Text("text", style: TextStyle(color: kTextColor)
and sometimes they use
child: Text("text",
style: Theme.of(context).textTheme.bodyText1,
What is the difference between these two code snippets? And what does context mean?

Answer 1

in my opinion: in a big project it's good practice to define your theme first. Then, you implement it in your app. Therefore, I'd go with the second approach to define headlines and body texts and button texts.
Instead, when you want to personalize some text in your app a little you can use:
style: Theme.of(context).textTheme.headline5?.copywith(
// personalize even more, with exact the same properties of TextStyle
...
)
which copies everything in that textTheme besides the stuff you define in that block.
OF COURSE it makes sense to use TextStyle in some contexts, like when you want to quickly format some text that you know that it doesn't need refactoring at the moment you're writing it, i.e. you just want to style some text regardless of theming.

Answer 2

If you take a look at MainApp(), that used by main method. You can find something like this,
#override
Widget build(BuildContext context) {
return MaterialApp(
debugShowCheckedModeBanner: false,
theme: ThemeData(
buttonTheme: ButtonThemeData(
textTheme: ButtonTextTheme.primary,
),
textTheme: Theme.of(context).textTheme.copyWith(
headline1: TextStyle(fontSize: 33, color: Colors.orange),
headline2: TextStyle(
fontSize: 12,
color: Colors.pink,
),
),
),
home: DropDOOO(),
);
}
So you can see there is a parameter call ThemeData. This will be used by default and when you will call Theme.of(). You can find textTheme here too.
Next one TextStyle(), you can override Texttheme using TextStyle() using it.
For more, visit
themes
TextTheme