All language subtitles for 16. Visible (Input Output) & Invisible (Layout Control) Widgetsf

In this first, a little bit more realistic application, I want to build a very simple personality quiz

application where you answer a couple of questions and based on the choices you made, we charge your personality.

For that, we'll use that current application we have here, this very lean application where we right

now only output the default text and we'll build up on that to present a question and some buttons that

allow the user to choose an answer.

Now for that, we certainly need a text widget to output the question and below that, I want to have

a couple of buttons that allow the user to choose different answers

and now here's a problem. We have

body and body is the place where we add the widget that should be shown in all that white area

and body only takes one widget,

I can't add a second widget here, I can't add another text, second text. You already see I get an error

here because now this would actually not be passed as an additional value to body But Dart would try

to pass this as a positional argument passed to scaffold which doesn't take any positional arguments

here.

So that does not work

and we also can't concatenate this by adding a plus here,

all of that doesn't work.

We can really only pass one widget here to body

so what can we do?

I want to pass more than one widget, I want to have a text and a couple of buttons.

For this, it's important to understand

that we have different types of widgets in Flutter.

We have the visible widgets which are related to user input and to outputting data, things like a button

or a text or a card

and we have only seen the text from all these examples here thus far but there are more widgets like

the RaisedButton which renders a button and other widgets and we'll see all of those throughout

the course.

Now these are the widgets which we see,

we see a button,

we see the text right,

that is what we see and that is of course crucial for any application

but equally crucial are invisible widgets that help us with layout and with controlling how our widget

tree behaves and how it looks like and there we got things like row, column, ListView and so on.

These are also widgets that ship with Flutter which we don't have to build ourselves, which we don't

see themselves but which help us with structuring our content. So these widgets give our app structure and

control how visible widgets are drawn onto the screen and therefore of course, they're super important.

There also is a very important widget which also ships with Flutter, the container widget which kind

of belongs into both categories as you will learn once we use it because it by default is invisible

but you can also give it some styling so that you can see it

but before we focus on that, let's actually take row, column and so on to work on our quiz app and add both a

question and a couple of answer buttons.