![]() ![]() The State class holds the variables and tells the StatefulWidget class when and how to build itself.The StatefulWidget class initializes the State class.There is a StatefulWidget class and a State class. ![]() So if we have a variable that we want to change, then we need a State fulWidget. That is, they don't have any mutable variables. You notice in the code above that it's a StatelessWidget. Similarly, when we talk about a widget, the state refers to the values (in other words, the current condition) of the variables associated with that widget. It’s similar in idea to the phrases “the state of affairs” or a “State of the Union Address,” which deal with the current conditions of some people or country. But to recreate the Text widget we need to put the string into a variable. That's because widgets are immutable: they can't be changed. That layout above was fine as far as layouts go, but if you try to change the text when the button is pressed, you’ll run into problems. Review exerciseīefore I give you the boilerplate code that we’ll use in the examples below, let's see if you can create the following layout on your own. The commands and shortcuts are a little different, but they both fully support Flutter. If you are using Visual Studio Code, though, it shouldn't be a problem. This lesson was tested using Flutter 1.0 with Android Studio. I’m assuming that you have a basic knowledge of object oriented programming, but I don't assume that you know Dart. In this tutorial we’ll start to do a little more programming with the Dart language. ![]() However, I’m assuming that you have the Flutter development environment set up and that you know how to create basic layouts using widgets. This tutorial is for beginning Flutter developers. This will greatly increase your overall learning. Make little changes to the code and see how that affects the behavior. I strongly encourage you to work along as we go through each one. The emphasis will be on simple, easy to reproduce examples. Today we’re going to explore how to actually do something when the user interacts with the widgets that we’ve added to our layout. You could touch and tap and swipe them all day and they wouldn't do a thing. The thing about those layouts, though, is that they were static. The majority of these layouts can be built by dividing your design into rows (use the Row widget), columns (use the Column widget), and layers (use the Stack widget). Simple widgets can be combined together to make complex layouts. In the two previous tutorials we saw that widgets are blueprints for everything that you can see (and many things that you can't see) in the user interface.
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