Section 7: Dicee - Building Apps with State

Expanded class

• A widget that expands a child of a Row, Column, or Flex so that the child fills the available space.
• Using an Expanded widget makes a child of a Row, Column, or Flex expand to fill the available space along the main axis.
• If multiple children are expanded, the available space is divided among them according to the flex factor.
• An Expanded widget must be a descendant of a Row, Column, or Flex

Constructors

Expanded({Key? key, int flex = 1, required Widget child})

Properties

• child → Widget
  • The widget below this widget in the tree.
• flex → int
  • The flex factor to use for this child.

TextButton class

• A Material Design “Text Button”.
• Use text buttons on toolbars, in dialogs, or inline with other content but offset from that content with padding so that the button’s presence is obvious.
• buttons do not have visible borders and must therefore rely on their position relative to other content for context.
• Avoid using text buttons where they would blend in with other content, for example in the middle of lists.
• A text button is a label child displayed on a (zero elevation) Material widget.
• The static styleFrom method is a convenient way to create a text button ButtonStyle from simple values.
  • example

    TextButton(
            style: TextButton.styleFrom(
              textStyle: const TextStyle(fontSize: 20),
            )
    

• If the onPressed and onLongPress callbacks are null, then this button will be disabled, it will not react to touch.

Constructors

• TextButton({Key? key, required VoidCallback? onPressed, VoidCallback? onLongPress, ButtonStyle? style, FocusNode? focusNode, bool autofocus = false, Clip clipBehavior = Clip.none, required Widget child})

Properties

• autofocus → bool
  • True if this widget will be selected as the initial focus when no other node in its scope is currently focused.
• child → Widget?
  • Typically the button’s label.
• enabled → bool
  • Whether the button is enabled or disabled
• style → ButtonStyle?
  • Customizes this button’s appearance.
• onLongPress → VoidCallback?
  • Called when the button is long-pressed.
• onPressed → VoidCallback?
  • Called when the button is tapped or otherwise activated.

dart:math library

• Mathematical constants and functions, plus a random number generator.
• To use this library in your code:

  import 'dart:math';
  

Classes

• MutableRectangle A class for representing two-dimensional axis-aligned rectangles with mutable properties.
• Point A utility class for representing two-dimensional positions.
• Random A generator of random bool, int, or double values.
• Rectangle A class for representing two-dimensional rectangles whose properties are immutable.

Constants

• pi → const double The PI constant.
• e → const double Base of the natural logarithms
• ln2 → const double Natural logarithm of 2.
• log2e → const double Base-2 logarithm of e.
• log10e → const double Base-10 logarithm of e.

Functions

• log(num x) → double Converts x to a double and returns the natural logarithm of the value.
• max(T a, T b) → T Returns the larger of two numbers.
• min(T a, T b) → T Returns the lesser of two numbers.
• pow(num x, num exponent) → num Returns x to the power of exponent.
• sin(num radians) → double Converts radians to a double and returns the sine of the value.
• sqrt(num x) → double Converts x to a double and returns the positive square root of the value.

Random Class

• A generator of random bool, int, or double values.
• The default implementation supplies a stream of pseudo-random bits that are not suitable for cryptographic purposes.
• Use the Random.secure constructor for cryptographic purposes.

Constructors

• Random([int seed ]) Creates a random number generator.
• Random.secure() Creates a cryptographically secure random number generator.

Methods

• nextBool() → bool Generates a random boolean value.
• nextDouble() → double Generates a non-negative random floating point value uniformly distributed in the range from 0.0, inclusive, to 1.0, exclusive.
• nextInt(int max) → int Generates a non-negative random integer uniformly distributed in the range from 0, inclusive, to max, exclusive.