Java - Trang ď SwingGUI-1

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What is GUI

‰ Graphic User Interface

 Outer Interface of Program

 GUI is Built by GUI Components

 GUI Component : Visual Object to Interact With

Outside such as Mouse, Keyboard, etc.

 Ex) AWT, Swing Components

‰ Interfaces Provided by Java

 Graphic : line, rectangle, polygon, arc, ….

 Interaction Elements : button, textfield, menu, …

 Image : image files

GUI and AWT

‰ Abstract Window Toolkit (AWT)

 Java.awt package

9 Component Class : Button, List, Menu, TextArea,

Window, MenuBar, Dialog

9 Graphics Related Classes : Graphics Context, Font ,

Color

9 Event Class : For Event Handling

9 Layout Management Class : Size and Position of

Component

GUI Component Hierarchy

GUI Operation Outline

‰ Procedure for Making GUI in Java

 Select the Container Component and Arrange the

Basic Components within this container Select the

Layout Manager Also.

 Make the Event Handling Routine and Register it

8 Event Listener

 Insert the Drawing Code to Override the paint()

method in order to draw some figure on component

8 Paint(), repaint(), update()

Make the GUI Component

‰ Procedure to put the GUI components into Frame or

Panel which is container

 Make the container object

 Declare and create the component object

 Put the objects created into container

‰ Layout Manager

 FlowLayout : From Left to Right in Panel, Default Manager

 GridLayout : With Grid, Arrange in Lattice Type

 GridBagLayout : Arrange Different Size Component on Grid

 BorderLayout : Up, Down, Left, Right, Center

 CardLayout : Arrange Several Cards

Graphics User Interface (I)

‰ Component Class

 Abstract Class which provides :

 Methods to control size and position on the screen

 Methods to setup cursor and return the cursor

position

 Methods for drawing such as

paint(),update(),repaint()

 Methods to determine keyboard input, visibility

 Function for providing event handling registration

 Methods related with Font and Color

Graphics User Interface (I)

‰ Label

 Not able to change

 Describes Text information

‰ Button

 When user presses

 Occur events to make some action

‰ Check Box

 Has two states of ON and OFF

 When user selects one of two

 For multiple selection, CheckboxGroup can be used

Graphics User Interface (I)

‰ Choice Button

 Select one of several items to select

 When user clicks arrow button, then the selection list is

 A line of text area to input

 It is possible to disable/enable input

‰ Text Area

 Multi-lines of text area to input

 To create display area for graphic

 Building a customized component by user

Graphics User Interface (II)

‰ Panel

 Inherited from Container class (Super of Applet)

 Components can be added into Panel

‰ Frame

 Window to have Title Bar and Border

 Independent of Window( compare to Dialog)

‰ Dialog Box

 Window to have Title Bar

 Dependent on Parent Window

 Modal Dialog (Can do work only after terminating the Dialog)

 Non-Modal Dialog

Graphics User Interface (II)

‰ Scroll Pane

 To make an area to be scrolled easily

 To display the child component as large as possible

 If child component is larger than Scroll Pane, it adds the

horizontal or vertical scroll bar

‰ Low Level Event :

 Mouse, MouseMotion, Key, Component, Container,

Focus, Window

‰ High Level (Have Semantics) Event:

 Action, Adjustment, Item, Text

Events

JFC & Swing

‰ JFC (Java Foundation Class)

 Give a group of class to help people build GUI

JFC & Swing

‰ Differences between AWT and Swing

 Swing components are implemented with

absolutely no native code => can be present on

JFC & Swing

‰ Capabilities beyond AWT

 Swing buttons and labels can display images instead of, or in

addition to, text

 You can easily add or change borders drawn around most Swing

components

 You can easily change the behavior or appearance of a Swing

component by either invoking methods on it or creating a

subclass of it

 Swing components need not be rectangular

 Assistive technologies such as screen readers can easily get

information from Swing components

‰ Top Level Containers

 The components at the top of any Swing containment hierarchy

– Applet, Dialog, Frame

‰ General Purpose Containers

 Intermediate containers that can be used under many different

circumstances – Panel, Scroll Pane, Split Pane, Tabbed Pane,

Tool bar

Swing Components

‰ Special Purpose Containers

 Intermediate containers that play specific roles in the UI – Internal Frame,

Layered Pane, Root pane

‰ Basic Controls

 Atomic components that exist primarily to get input from the user; they

generally also show simple state – Buttons, Combo Box, List, Menu, Slider,

Spinner, Text Field

‰ Uneditable Information Displays

 Atomic components that exist solely to give the user information – Label,

Progress bar, Tool tip

‰ Editable Displays for Formatted Information

 Atomic components that display highly formatted information that (if you

choose) can be edited by the user – Color chooser, File chooser, Table, Text,

Tree

Import java.awt.*; Import java.awt.event.*;

‰ Choosing the Look and Feel

 Java Look and Feel, Windows Look and Feel, CDE/Motif Look and Feel

public static void main(String[] args) { try { UIManager.setLookAndFeel(

UIManager.getCrossPlatformLookAndFeelClassName()); } catch

(Exception e) { }

//Create and show the GUI }

Swing Application Code

‰ Setting Up a Top-Level Container

 Instances of JFrame, JDialog, JApplet

 JFrame : implements a single main window

 JDialog : implements a secondary window

 JApplet : implements an applet’s display area within

a browser windows

Ex)

JFrame frame = new JFrame(“SwingApplication”);

Swing Application Code

‰ Setting Up Buttons and Labels

 Make component objects and set up attribute

Ex)

JButton button = new JButton("I'm a Swing button!");

button.setMnemonic(KeyEvent.VK_I); //use Alt-i

button.addActionListener( create an action listener );

final JLabel label = new JLabel(labelPrefix + "0 ");

label.setLabelFor(button); //in the event handler for button

clicks: label.setText(labelPrefix + numClicks);

Swing Application Code

‰ Adding Components to Containers

 To group a label and button in a container (a

JPanel) before adding components to the frame

Swing Application Code

‰ Adding Borders Around Components

 Provides some empty space around the panel’s contents

Swing Application Code

‰ Dealing with Thread Issues

 Because the event handler runs in the same thread

that performs all event handling and painting for the

application, there's no possibility that two threads

will try to manipulate the GUI at once

 All manipulation of the GUI such as setText,

getText, etc, is performed in event handlers such as

actionPerformed()

Swing Application Code

‰ Supporting Assistive Technologies

 Support for assistive technologies devices such

as screen readers that provide alternate ways of

accessing information in a GUI is already

included in every Swing component.

 The only code in SwingApplication that exists solely

to support assistive technologies is this:

label.setLabelFor(button);

GUI Design Using IDE TOOL

‰ There are several Integrated Development

Environment (IDE) Tools