No Directionality widget found
Solution 1:
flutter doesn't know whether the text is LTR or RTL, so you need to tell him the textDirection explicitly
new Text("Hello", textDirection: TextDirection.ltr)
or you can just wrap the Text with a Directionality Widget
new Directionality(
textDirection: TextDirection.ltr,
child: new Text('Hello')
and the purpuse of that is :
A widget that determines the ambient directionality of text and text-direction-sensitive render objects.
And a Text widget in the scope of a MaterialApp widget does not need to be given an explicit writing direction because The default localization in the widgets and material libraries is LTR
Solution 2:
If you don't use MaterialApp
you need to wrap your app into some widgets yourself
import 'dart:ui' as ui;
...
runApp(
new MediaQuery(
data: new MediaQueryData.fromWindow(ui.window),
child: new Directionality(
textDirection: TextDirection.rtl,
child: new MyHome())))