UNIVERSITY AT BUFFALO, THE STATE UNIVERSITY OF NEW YORK
The Department of Computer Science & Engineering

STUART C. SHAPIRO: CSE 115 C

We will use Containers, Components, and EventHandlers
java.awt.Container is a subclass of java.awt.Component, so every container is also a component.

Every component must go inside a container.
Every container has or inherits the public Component add(Component comp) method.

javax.swing.JFrame

• A javax.swing.JFrame is a Container that must be the outermost Container of any GUI or other graphic display.
  Everything else goes inside the JFrame.

  To create a Frame, use javax.swing.Jframe frame = new javax.swing.JFrame();
  or javax.swing.Jframe frame = new javax.swing.JFrame("Title");

• Arrange for the program to terminate when the frame's close button is clicked, with frame.setDefaultCloseOperation(javax.swing.JFrame.EXIT_ON_CLOSE);

• Add components to the frame with frame.add(component);

• Adjust the size of the frame to the size of its components with frame.pack();

• Finally, make the frame and its components visible by frame.setVisible(true);

java.awt.LayoutManager

is an interface that specifies methods that know how to arrange components in containers.
Using LayoutManagers can be complicated, so we provide two Containers that have simple LayoutManagers predefined:

• containers.Column
  Components added to a Column are added in order, top-down.
  Create a Column with new containers.Column()

• containers.Row
  Components added to a Row are added in order, left-right.
  Create a Row with new containers.Row()

Components

• javax.swing.JLabel
  Constructor: javax.swing.JLabel("Label")

• javax.swing.JButton
  Constructor: javax.swing.JButton("Title")

• javax.swing.JSlider
  Constructor: javax.swing.JSlider(int min, int max, int value)

• Drawing Canvas
  A DrawingCanvas is a Container, and therefore also a Component. It is the only Container we will be using that allows a Component to be drawn into it at a specific x,y location.

  Among the properties of a DrawingCanvas are a color and a dimension.

  The color should be drawn from the static variables of java.awt.Color, for example java.awt.Color.green

  The dimension must be an instance of java.awt.Dimension. You should create an instance of java.awt.Dimension using the constructor java.awt.Dimension(int width, int height), where the width and height are measured in pixels. The default width and height of a new DrawingCanvas are both zero.

  Constructor: graphics.DrawingCanvas()
Some Methods

  void	setColor(java.awt.Color c)
  java.awt.Color	getColor()
  void	setDimension(java.awt.Dimension d)
  java.awt.Dimension	getDimension()

  For example,

  graphics.DrawingCanvas canvas = graphics.DrawingCanvas();
  canvas.setDimension(new java.awt.Dimension(300,500));
  canvas.setColor(java.awt.Color.green);
  

• Rectangles
  A graphics.Rectangle is a graphical object that looks like a rectangle, has a Color and Dimension, and can be added to a DrawingCanvas at a particular Location. The color and dimension of a rectangle are like those for a DrawingCanvas.

  The Location of a rectangle is relative to its containing DrawingCanvas, and must be an instance of java.awt.Point. You should create an instance of java.awt.Point using the constructor java.awt.Point(int x, int y), where x and y are measured in pixels from the origin, (0,0). The origin is at the top left-hand corner of the DrawingCanvas. x is the distance from the orgin toward the right. y is the distance from the origin down the screen. The default location of a new Rectangle is (0,0).

  Constructor: graphics.Rectangle()
Some Methods

  void	setColor(java.awt.Color c)
  java.awt.Color	getColor()
  void	setDimension(java.awt.Dimension d)
  java.awt.Dimension	getDimension()
  void	setLocation(java.awt.point d)
  java.awt.point	getLocation()

  Ellipses
  A graphics.Ellipse is a graphical object that looks like an ellipse, has a Color and Dimension, and can be added to a DrawingCanvas at a particular Location. The color, dimension, and location of a rectangle are like those for a Rectangle.

  Constructor: graphics.Ellipse()
  Some Methods

  void	setColor(java.awt.Color c)
  java.awt.Color	getColor()
  void	setDimension(java.awt.Dimension d)
  java.awt.Dimension	getDimension()
  void	setLocation(java.awt.point d)
  java.awt.point	getLocation()