Tour of Dart

 

Getting Started

DartPad

DartPad is setup like a typical IDE. There is:

  • An Editor pane on the left
  • A Run button to run code in the editor
  • A Console on the upper right showing output
  • An Info panel on the bottom right showing information highlighted code
  • A Samples dropdown to show some sample code
  • A Share button you can use to share DartPad files you’ve created

The main function is preceded by a return type, which in Dart is void, meaning nothing is returned. The parentheses after main indicate that this is a function definition, and the curly braces contain the body of the function. Inside main, you add the Dart code for your program.

Variables, Comments, and Data Types

The first thing we’ll add to main is a variable assignment statement. Variables hold the data that your program will work on. You can think of a variable like a box in your computer’s memory that holds a value. Each box has a name, the name for the variable. You use the var keyword in Dart to denote a variable.

Basic Dart Types

Dart Data Types

 

Operators

There are arithmetic operators, equality, increment and decrement, comparison, and logical operators.

print(42 < 43); // true
print(42 >= 43); // false
print(42 == 43); // false
print(42 != 43); // true 

 

Strings

The Dart string type is String. Strings are expressed in Dart using text surrounded by either single or double quotes.

var firstName = 'Albert';
String lastName = "Einstein";

 

 

Comments

Post a Comment

Popular posts from this blog

Flutter: Statefull vs Stateless widget

Image
What is the difference between Stateful and Stateless Widget. In Flutter all the UI components are known as widgets. The widget which contains the code for a single screen of the app can be just of two types — Stateful Stateless Stateless Stateless widgets do not require mutable state, i.e., it is immutable . In simple words, Stateless widgets cannot change their state during the runtime of the app, which means the widgets cannot be redrawn while the app is in action. The structure of a Stateless widget looks like this: So, let’s understand what is there in this small code snippet. The name of this Stateless Widget is “ StartScreen ”, inside which we have to override the “ build” method. This build method takes in a “ BuildContext ” as the parameter and returns a widget. That’s why you can see that the return type of the build method is a widget. And this the place where you can design the UI of this screen, which is Stateless. In Stateless widget, The “ build ” method can be c...
Read more

Flutter: Container, Column and Rows

Image
  Flutter Container The container in Flutter is a parent widget that can contain multiple child widgets and manage them efficiently through width, height, padding, background color, etc. It is a widget that combines common painting, positioning, and sizing of the child widgets. It is also a class to store one or more widgets and position them on the screen according to our needs. Generally, it is similar to a box for storing contents. It allows many attributes to the user for decorating its child widgets, such as using margin , which separates the container with other contents. A container widget is same as <div> tag in html. If this widget does not contain any child widget, it will fill the whole area on the screen automatically. Otherwise, it will wrap the child widget according to the specified height & width. It is to note that this widget cannot render directly without any parent widget. We can use Scaffold widget, Center widget, Padding widget, Row w...
Read more

Dart: Control Flow

Image
  Control Flow Control flow lets you dictate that certain lines of code are executed, skipped over, or repeated. Control flow is handled in Dart with conditionals and loops . Conditionals The most basic form of control flow is deciding whether to execute or skip over certain parts of your code, depending on conditions that occur as your program runs. The language construct for handling conditions is the if / else statement. if / else in Dart looks nearly identical to the use in other C-like languages. Suppose you have an animal variable that's currently a fox. While Loops Loops let you repeat code a certain number of times or based on certain conditions. The latter are handled by while loops . There are two forms of while loop in Dart, while and do-while . The difference is that for while , the loop condition is before the code block, and in do-while the condition is after. So for do-while , the code block is guaranteed to run at least one time. Create a variable i ...
Read more