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https://github.com/hirwa13/flutter-dice-roller-app


https://github.com/hirwa13/flutter-dice-roller-app

dart flutter

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README 

        
# flutter_mind



A deep dive of flutter with it's features



## Key contents: 



**|MaterialApp Widget|**: This is a base widget that most flutter apps includes and it's role is to provide us the ability to use `Google`'s Material design hence providing a set of styles and guide lines that we can build upon and make our applications look quite nice.



[Note] -> In the end, when building applications with flutter it's all about combining widgets



### Flutter applications are build with widgets: 

-> when building applications with flutter you typically combine multiple widgets and at the end we get aa widget tree.



-> Flutter UIs are created by combining and nesting widgets.

-> Flutter provides many built-in widgets e.g., Buttons, forms inputs, layout widgets and so forth.

-> in flutter we can also build our own widgets, i.e custom widgets.



## The Scaffold Widget



->  This is a widget that helps us set up good looking screen layouts in our app when using the `MaterialApp Widget`

-> it contains widgets that we can use to build and customize to get our desired UI.



## Types in Dart and Flutter: 



Why do we need types in Flutter?



-> Dart is a type-safe language

-> The type feature exists in dart so that we won't work with wrong types in the wrong  place



### Most used  types in dart: 



- int -> for integer numbers, numbers without decimal places, eg: 29, -15



- double -> for fractional numbers, numbers with decimal places, eg: 3.91, -12.81



- num -> integer or fractional numbers,  numbers with or without decimal places, 15, 15.01, -2.82



- String -> Text, Text, wrapped with single or double quotes, 'Hello world'



- bool   -> Boolean values, true or  false, [true or false]



- Object -> Any kind of object, the base type of all values. 'Hi', 29, false



## Lists and Generics in Dart



### Lists



-> in dart, Lists are defined as collections of multiple values

 eg: ['blue', 'red', 'green'] -> List contents are always wrapped in square brackets



### Generics: 



-> Generics are `Flexible types` that `work together` with other types.



eg: [List]-> this says that we wan a list of color objects.



## Understanding Classes



-> Dart is an Object Oriented Programming language and in Dart, every value is an `object` either primitive values (texts, numbers, etc) or complex  values such as Widgets, gradient config  objects, etc all are objects



-> So classes are in the end `blue prints of objects`



-> Objects are Data structures when stored in memory: 

    - They contain data (variables or properties)

    - Functions or methods



-> So we can say in the  end  Objects helps with organizing data and separating logic



So we can say that, Objects  are constructed from classes.

-> an Object  is created by calling the  `Constructor function` of a class.



## Variables



-> Variables are actually data containers

-> In dart variables can be declared using var, final and const



### Nullable variables: 



-> Dart will throw an error when it notices a variable that is or will be null so to avoid that we need to add a question mark in front of the variable's type



```dart

String newVariable; // the variable that has been declared and has nothing in it, by default dart will assign it `null` and will thrown an error



// to fix that: 



String? theVariable // this tells dart that this will contains a string or null -> hence allowing dart to accept null value on the variable

```



### final and const declared variables: