advanced java java swing...
TRANSCRIPT
Fachbereich Informatik und Elektrotechnik
Programming in Java, Helmut Dispert
Java Swing
Advanced Java
Java SwingProgramming
Fachbereich Informatik und Elektrotechnik
Programming in Java, Helmut Dispert
Java Swing
Design GoalsThe overall goal for the Swing project was:To build a set of extensible GUI components to enable developers to more
rapidly develop powerful Java front ends for commercial applications.
The design goals mandated that Swing would:1. Be implemented entirely in Java to promote cross-platform consistency and
easier maintenance.2. Provide a single API capable of supporting multiple look-and-feels so that
developers and end-users would not be locked into a single look-and-feel.Enable the power of model-driven programming without requiring it in the highest-level API.
3. Adhere to JavaBeans design principles to ensure that components behave well in IDEs and builder tools.
4. Provide compatibility with AWT APIs where there is overlapping, to leverage the
AWT knowledge base and ease porting.
Ref.:Sun Microsystems
Fachbereich Informatik und Elektrotechnik
Programming in Java, Helmut Dispert
Contents
� Introduction� History
� JFC – Java Foundation Classes
� What makes Swing so special?� Lightweight Components
� PLAF
� MVC
� Delegation Event Model
� How to use Swing� Components
� JComponent
� Layouts
� Example
� Summary
Fachbereich Informatik und Elektrotechnik
Programming in Java, Helmut Dispert
AWT
Widget = Window Gadget
Problems with the AWT
• AWT is not functional enough for full scale applications– small widget library
– widgets have only basic functionality
– extensions commonly needed
• AWT Components rely on native peers– no platform independency:
widgets do not perform exactly the same on different platforms
Fachbereich Informatik und Elektrotechnik
Programming in Java, Helmut Dispert
AWT vs. Swing APIs
Java AWT (Abstract Windowing Toolkit)
� Package: java.awt
� GUI functionality (graphical user interface)� Component libraries:
labels, buttons, textfields, etc. (platform dependent)� Helper classes:
event handling, layout managers (window layouts), etc.
The Swing APIs
� Package: javax.swing
� Greater platform independence- portable "look and feel" (buttons, etc.)
Easy upgrading using "J": Applet →→→→ JApplet
Button →→→→ JButton
AWT and Swing are part of the JFC (Java Foundation Classes)
Fachbereich Informatik und Elektrotechnik
Programming in Java, Helmut Dispert
Classes, Packages
Component
Container
Panel
Applet
java.lang.Object
java.awt.Component
java.awt.Container
java.awt.Panel
java.applet.Applet
Fachbereich Informatik und Elektrotechnik
Programming in Java, Helmut Dispert
Class JApplet
Component
Container
Panel
Applet
java.lang.Object
java.awt.Component
java.awt.Container
java.awt.Panel
java.applet.Applet
javax.swing.JApplet
JApplet
Class JApplet:An extended version of java.applet.Applet
that adds support for the JFC/Swingcomponent architecture.
Fachbereich Informatik und Elektrotechnik
Programming in Java, Helmut Dispert
Classes, Packages
public class Name extends java.applet.Applet
{
...
}
Syntax:
imported package
class
Fachbereich Informatik und Elektrotechnik
Programming in Java, Helmut Dispert
JFC
• AWT:the original GUI toolkit
• Swing:the new GUI toolkit
• Accessibility:tools to develop support for users challenged
by traditional UI’s
• 2D API:classes for more complex use of painting,
shape, colour, and fonts
• Drag and Drop:tools for implementing the transfer of
information between Java applications and
native applications
Java Foundation Classes
AWT
Swing
Accessibility
2D API
Drag and Drop
Fachbereich Informatik und Elektrotechnik
Programming in Java, Helmut Dispert
JFC
Java Foundation Classesconsist of:
• Abstract Windowing Toolkit (AWT)
• Swing
– Ab JDK1.2
– Leichtgewichtige Komponenten (ohne Betriebsystem Support)
Die Swing-Klassenbibliothek baut auf AWT auf und erweitert diese
um Komponenten und dem Model-View-Controller (MVC)
• Java 2D
– Erstellen und bearbeiten von Bildern und 2D Grafiken
• Drag and Drop
– Verschieben mit der Maus
• Accessibility
– Schnittstelle zur Einbindung zusätzlicher Ein- und Ausgabegeräte.
continued
Fachbereich Informatik und Elektrotechnik
Programming in Java, Helmut Dispert
JFC
Java Foundation Classesconsist of:
• Abstract Windowing Toolkit (AWT)
– Schwergewichtige Komponenten (verwenden betriebsystemnahe Funktionen)
– Umfasst drei Elemente
• Komponenten
– Oberflächenelemente
– Beispiel: Buttons, Labels, ...
• Container
– Gruppieren und enthalten Oberflächenelemente
– Beispiel: Fenster
• Layout Manager
– Legen fest, wie die Komponenten im Container angesprochen werden können
– Beispiel: Border Layout (Nord, Süd, Ost, West, Center)
Fachbereich Informatik und Elektrotechnik
Programming in Java, Helmut Dispert
AWT
Architecture of the Swing Class Library
OS-independentpart of API
OS-dependentpart of API
Button
WindowsButtonPeer
MotifButtonPeer
ButtonPeer
The button peer interface specifies the methods that all implementations of Abstract Window Toolkit buttons must define.
Fachbereich Informatik und Elektrotechnik
Programming in Java, Helmut Dispert
Swing Components
Concept of Java peers:When instantiating an AWT component the native environment creates the component. User sees the native look-and-feel, component acts like the native control.Peer: native code that provides this look-and-feel.Each platform has its own set of peers.
Example:A Java button appears (and acts) as a Windows button under Windows, as a Macintosh button under Macintosh, and as a Unix button under Unix.
Problem:Not all native controls respond in the same way to the same events, so that a Java program shows different behavior under different Java AWT environments.
Solution:Lightweight components, written entirely in Java. Swing provides a set of pure Java lightweight components, ensuring better cross-platform compatibility.A lightweight component subclasses java.awt.Component - implementing the look-and-feel of the component in Java rather than delegating the look-and-feel to a native peer.
Fachbereich Informatik und Elektrotechnik
Programming in Java, Helmut Dispert
AWT
• Heavyweight Komponenten (AWT)
– Die Anbindung der Komponenten geschieht mit sogenannten Peer-Objekten, welche für jedes Betriebsystem neu geschrieben werden.
• Lightweight Komponenten (Swing)
– Werden von Java selbst gezeichnet
– Die Containerklassen (Frame, Dialog, Window, Applet) wurden aus AWT übernommen und erweitert:
• JFrame, JDialog, JWindow, JApplet als toplevel Container
• Alle leichtgewichtigen Komponenten können direkt in den Frame gezeichnet werden.
Architecture of the Swing Class Library
Fachbereich Informatik und Elektrotechnik
Programming in Java, Helmut Dispert
AWT
AWT - Heavyweight Components
� Rectangular
� Opaque
� Always drawn over top of lightweight components
� Rely on native peers
� Look and Feel tied to operating system
� functionality determined by operating system
� faster, because the OS handles the work
Fachbereich Informatik und Elektrotechnik
Programming in Java, Helmut Dispert
Swing
Swing - Lightweight Components
� Swing uses lightweight components
� It uses a variant of the
Model View Controller Architecture (MVC)
� It has Pluggable Look And Feel (PLAF)
� It uses the Delegation Event Model
Fachbereich Informatik und Elektrotechnik
Programming in Java, Helmut Dispert
Swing
Swing - Lightweight Components
� Any shape� Transparent portions� Overlap� Mouse events fall through transparent portions� Do not rely on native peers
� Look and Feel drawn at runtime so can vary
� functionality is the same on all platforms
� slower because Java has to do the work
Fachbereich Informatik und Elektrotechnik
Programming in Java, Helmut Dispert
Swing
Lightweight vs. Heavyweight
Fachbereich Informatik und Elektrotechnik
Programming in Java, Helmut Dispert
Model View Controller
Roots in MVC
Swing architecture is rooted in the model-view-controller
(MVC) design that dates back to SmallTalk.
MVC architecture calls for a visual application to be broken up into three separate parts:
� A model that represents the data for the application.
� The view that is the visual representation of that data.
� A controller that takes user input on the view and translates that to changes in the model.
Fachbereich Informatik und Elektrotechnik
Programming in Java, Helmut Dispert
Model View Controller
Independent MVC-elements:
� Model � state data for each component� different data for different models
� View � how the component looks onscreen,
displays the data
� Controller� dictates how the component reacts to I/O events
ControllerModel
View
Fachbereich Informatik und Elektrotechnik
Programming in Java, Helmut Dispert
Model View Controller
Model
• Encapsulates application state
• Responds to state queries
• Exposes application functionality
• Notifies views of changes
Model
• Encapsulates application state
• Responds to state queries
• Exposes application functionality
• Notifies views of changes
Controller
• Defines application behaviour
• Maps user actions to model updates
• Selects view for response
• One for each functionality
Controller
• Defines application behaviour
• Maps user actions to model updates
• Selects view for response
• One for each functionality
View
• Renders the models
• Requests updates from models
• Sends user gestures to controller
• Allows controller to select view
View
• Renders the models
• Requests updates from models
• Sends user gestures to controller
• Allows controller to select view
StateQuery
ChangeNotification
StateChange
View Selection
User Gestures
Method Invocations
Events
Fachbereich Informatik und Elektrotechnik
Programming in Java, Helmut Dispert
Modified MVC – UI Delegate
The Java Swing Architecture uses a modified MVC-model in which the "view" and "controller" are combined in a so-called UI object (User-interface).
Component
UIObject
MUI
Manager
The UI Object is also called the "UI delegate" or the "delegate object".The modified MVC-model is also referred to a "separable model architecture".
Fachbereich Informatik und Elektrotechnik
Programming in Java, Helmut Dispert
Modified MVC – UI Delegate
Example: JButton
ButtonUI
ButtonModel
Controller View
JButton
Fachbereich Informatik und Elektrotechnik
Programming in Java, Helmut Dispert
ButtonUI
Modified MVC – UI Delegate
ButtonModel
Controller View
JButton
Example: JButton - Pluggable Look and Feel(PLAF)
UIFactory
Fachbereich Informatik und Elektrotechnik
Programming in Java, Helmut Dispert
ComponentUI (Delegate)
Modified MVC – UI Delegate
JComponent(MVC Model)
MVCController
MVCView
Swing Look & Feel
Component
PlatformWidget(native)
Peer(native)
AWT Look & Feel
Fachbereich Informatik und Elektrotechnik
Programming in Java, Helmut Dispert
Swing Components and Container
Fachbereich Informatik und Elektrotechnik
Programming in Java, Helmut Dispert
Swing Packages
Important Swing Packages:
• javax.accessibility
Provides accessibility for disabled persons• javax.swing
Provides a set of "lightweight" (all-Java language) components that, to the maximum degree possible, work the same on all platforms.
• javax.swing.border
Provides classes and interface for drawing specialized borders around a Swing component.
• javax.swing.event
Provides for events fired by Swing components. javax.swing.plaf
Provides user interface objects built according to the Basic look-and-feel.
Fachbereich Informatik und Elektrotechnik
Programming in Java, Helmut Dispert
Swing Components: JComponent, JFrame
Swing components are similar to components in the Abstract Windowing Toolkit (AWT) but are subclasses of the JComponent class.� common root of most of the Swing GUI classes� guiding framework for GUI objects� extends java.awt.Container class
Swing applications are subclasses of the class JFrame.
Fachbereich Informatik und Elektrotechnik
Programming in Java, Helmut Dispert
Swing Components
Swing components and containers are added to a content pane which represents the full frame area.The content pane is added to the frame.
Fachbereich Informatik und Elektrotechnik
Programming in Java, Helmut Dispert
RootPane
Structure of a RootPane
GlasPane
Menu
ContentPane
LayeredPane
Fachbereich Informatik und Elektrotechnik
Programming in Java, Helmut Dispert
Swing Components
The Swing version of a Label.JLabel
Encapsulates a combo box (a combination of a
drop-down list and text field).
JComboBox
The Swing check box class.JCheckBox
The Swing push button class.JButton
The Swing frame that is more sophisticated than
the AWT frame. We can add components in layers,
add a menu bar, or paint over the component
through a component called a glass pane.
JFrame
The Swing version of Applet.JApplet
Encapsulates an icon.ImageIcon
Encapsulates a mutually exclusive set of buttons.ButtonGroup
Abstract Superclass for Swing buttons.AbstractButton
continued
Fachbereich Informatik und Elektrotechnik
Programming in Java, Helmut Dispert
Swing Components
The Swing version of a radio button. JRadioButton
Encapsulates a rectangular area in which a
component may be viewed.
JScrollPane
Encapsulates a tabbed window. JTabbedpane
Encapsulates a table-based control. JTable
The Swing version of a text field. JTextField
Encapsulate a tree-based control. JTree
A text field that does not display the text entered
into it, but displays the specified character, e.g. *
as input is given into the field.
JPasswordField
The option panes in Swing. Option panes are
dialog boxes that display some information to the
user or get confirmation from the user so that the
program can be executed further based on the
choice the user makes.
JOptionPane
Fachbereich Informatik und Elektrotechnik
Programming in Java, Helmut Dispert
Look and Feel
PLAF - Pluggable Look and Feel
Swing supplies three choices for look and feel:
- Metal style - Swing's default cross-platform LAF
- Motif X-Windows system style LAF
- Windows style LAF
- Mac style (not part of the JDK)
- New styles can be designed
- Style can be reset/changed at runtime
Method:setLookAndFeel(plaf)
Fachbereich Informatik und Elektrotechnik
Programming in Java, Helmut Dispert
Sample Program - PLAF
WindowsLook-and-Feel
MotifLook-and-Feel
MetalLook-and-Feel
SwingExamp01
Java
Fachbereich Informatik und Elektrotechnik
Programming in Java, Helmut Dispert
Sample Program - PLAF
import java.awt.event.*;
import java.awt.*;
import javax.swing.*;
public class SwingExamp01 extends Jframe implements ActionListener
{
private static final String[] MONTHS = {
"January", "February", "March", "April",
"May", "June", "July", "August",
"September", "October", "November", "December"
};
public static void main(String[] args)
{
SwingExamp01 frame = new SwingExamp01();
frame.setLocation(100, 100);
frame.pack();
frame.setVisible(true);
}
Fachbereich Informatik und Elektrotechnik
Programming in Java, Helmut Dispert
Sample Program - PLAF
public SwingExamp01()
{
super("Our first Swing-Program");
//Panel zur Namenseingabe hinzufügen
JPanel namePanel = new JPanel();
JLabel label = new JLabel(
"Name:",
new ImageIcon("triblue.gif"),
SwingConstants.LEFT
);
namePanel.add(label);
JTextField tf = new JTextField(30);
tf.setToolTipText("Enter your name");
namePanel.add(tf);
namePanel.setBorder(BorderFactory.createEtchedBorder());
getContentPane().add(namePanel, BorderLayout.NORTH);
//Monatsliste hinzufügen
JList list = new JList(MONTHS);
list.setToolTipText("Select the month of your birthday");
getContentPane().add(new JScrollPane(list), BorderLayout.CENTER);
//Panel mit den Buttons hinzufügen
JPanel buttonPanel = new JPanel();
JButton button1 = new JButton("Metal");
Fachbereich Informatik und Elektrotechnik
Programming in Java, Helmut Dispert
Sample Program - PLAF
button1.addActionListener(this);
button1.setToolTipText("Metal-Look-and-Feel");
buttonPanel.add(button1);
JButton button2 = new JButton("Motif");
button2.addActionListener(this);
button2.setToolTipText("Motif-Look-and-Feel");
buttonPanel.add(button2);
JButton button3 = new JButton("Windows");
button3.addActionListener(this);
button3.setToolTipText("Windows-Look-and-Feel");
buttonPanel.add(button3);
buttonPanel.setBorder(BorderFactory.createEtchedBorder());
getContentPane().add(buttonPanel, BorderLayout.SOUTH);
//Windows-Listener
addWindowListener(new WindowClosingAdapter(true));
}
Fachbereich Informatik und Elektrotechnik
Programming in Java, Helmut Dispert
Sample Program - PLAF
public void actionPerformed(ActionEvent event)
{
String cmd = event.getActionCommand();
try {
//PLAF-Klasse auswählen
String plaf = "unknown";
if (cmd.equals("Metal")) {
plaf = "javax.swing.plaf.metal.MetalLookAndFeel";
} else if (cmd.equals("Motif")) {
plaf = "com.sun.java.swing.plaf.motif.MotifLookAndFeel";
} else if (cmd.equals("Windows")) {
plaf = "com.sun.java.swing.plaf.windows.WindowsLookAndFeel";
}
Fachbereich Informatik und Elektrotechnik
Programming in Java, Helmut Dispert
Sample Program - PLAF
//LAF umschalten
UIManager.setLookAndFeel(plaf);
SwingUtilities.updateComponentTreeUI(this);
} catch (UnsupportedLookAndFeelException e) {
System.err.println(e.toString());
} catch (ClassNotFoundException e) {
System.err.println(e.toString());
} catch (InstantiationException e) {
System.err.println(e.toString());
} catch (IllegalAccessException e) {
System.err.println(e.toString());
}
}
}
Fachbereich Informatik und Elektrotechnik
Programming in Java, Helmut Dispert
Layout Managers
Layout Managers
are used to arrange components according to predefined patterns and to allow more complex UIs.
Fachbereich Informatik und Elektrotechnik
Programming in Java, Helmut Dispert
Layout Managers
Mit einem Layout-Manager werden die Komponenten nach bestimmten Vorgaben auf einer Bedienoberfläche bzw. in einem Container angeordnet.
– Jeder Container hat eine standardmässige Referenz auf ein Objekt, das ein Interface LayoutManagerimplementiert.
– Mit setLayout(LayoutManager) kann dieser überschrieben werden.
– Komponenten werden mit add(Component) dem Container hinzugefügt und in dieser Reihenfolge angeordnet.
– Bei Top-Level Containern muss der Aufruf der beiden Methoden auf der ContentPane erfolgen.
Fachbereich Informatik und Elektrotechnik
Programming in Java, Helmut Dispert
Layout Managers - Flow Layout
The Flow Layout� arranges components in a left-to-right flow, much like lines of text in
a paragraph. Flow layouts are typically used to arrange buttons in a
panel. It will arrange buttons left to right until no more buttons fit on
the same line. Each line is centered.
Fachbereich Informatik und Elektrotechnik
Programming in Java, Helmut Dispert
import java.awt.*;import java.awt.event.*;
public class Flow extends Frame{public static void main(String[] args){Flow wnd = new Flow();wnd.setVisible(true);
}
public Flow(){super("Test FlowLayout");addWindowListener(new WindowClosingAdapter(true));//Layout setzen und Komponenten hinzufügensetLayout(new FlowLayout(FlowLayout.LEFT,20,20));add(new Button("Button 1"));add(new Button("Button 2"));add(new Button("Button 3"));add(new Button("Button 4"));add(new Button("Button 5"));pack();
}}
Layout Managers - Flow Layout
Fachbereich Informatik und Elektrotechnik
Programming in Java, Helmut Dispert
Layout Managers - Border Layout
The BorderLayout� lays out a container, arranging and resizing its components to fit in
five regions:
north, south, east, west, and center.
Each region may contain no more than one component, and is
identified by a corresponding constant: NORTH, SOUTH, EAST,
WEST, and CENTER.
Fachbereich Informatik und Elektrotechnik
Programming in Java, Helmut Dispert
Layout Managers - Grid Layout
The GridLayout� lays out a container's components in a rectangular grid. The
container is divided into equal-sized rectangles, and one component
is placed in each rectangle.
Fachbereich Informatik und Elektrotechnik
Programming in Java, Helmut Dispert
Layout Managers - Grid Layoutimport java.awt.*;import java.awt.event.*;
public class Gridextends Frame{public static void main(String[] args){Grid wnd = new Grid();wnd.setVisible(true);
}
public Grid(){super("Test GridLayout");addWindowListener(new WindowClosingAdapter(true));//Layout setzen und Komponenten hinzufügensetLayout(new GridLayout(4,2));add(new Button("Button 1"));add(new Button("Button 2"));add(new Button("Button 3"));add(new Button("Button 4"));add(new Button("Button 5"));add(new Button("Button 6"));add(new Button("Button 7"));pack();
}}
Fachbereich Informatik und Elektrotechnik
Programming in Java, Helmut Dispert
Layout Managers - Grid Bag Layout
Example:GridLayout
Java
Fachbereich Informatik und Elektrotechnik
Programming in Java, Helmut Dispert
Layout Managers - Grid Bag Layout
The GridBagLayout� The GridBagLayout class is a flexible layout manager that aligns
components vertically and horizontally, without requiring that the
components be of the same size. Each GridBagLayout object
maintains a dynamic, rectangular grid of cells, with each component
occupying one or more cells, called its display area.
Fachbereich Informatik und Elektrotechnik
Programming in Java, Helmut Dispert
Layout Managers - Grid Bag Layout
Fachbereich Informatik und Elektrotechnik
Programming in Java, Helmut Dispert
Layout Managers
Further Layout Manager• CardLayout
• Kann mehrere Container in einem übergeordneten Container anordnen, erzeugt einen Stapel von Containern, die hintereinander liegen.
• BoxLayout• Ähnlich wie FlowLayout. Die zu einem Container hinzugefügten
Komponenten werden von oben nach unten oder von links nach rechts angeordnet.
• OverlayLayout• Ermöglicht das Stapeln von Komponenten bzw. das
Übereinanderlegen.• ViewportLayout
• Ein Viewport ist ein sichtbarer Bereich eines scrollbaren Fensters.
• NullLayout• Komponenten können durch Vorgabe fester Koordinaten
platziert werden (absolute Positionierung).
Fachbereich Informatik und Elektrotechnik
Programming in Java, Helmut Dispert
NullLayoutimport java.awt.*;
import java.awt.event.*;
public class NullLayout
extends Frame
{
public static void main(String[] args)
{
NullLayout wnd = new NullLayout();
wnd.setVisible(true);
}
public NullLayout()
{
super("Dialogelemente ohne Layoutmanager");
addWindowListener(new WindowClosingAdapter(true));
//Layout setzen und Komponenten hinzufügen
setSize(300,250);
setLayout(null);
for (int i = 0; i < 5; ++i) {
Button button = new Button("Button"+(i+1));
button.setBounds(10+i*35,40+i*35,100,30);
add(button);
}
}
}
Java
Fachbereich Informatik und Elektrotechnik
Programming in Java, Helmut Dispert
Swing MVC
Advanced Java
MVC Example
Fachbereich Informatik und Elektrotechnik
Programming in Java, Helmut Dispert
Swing MVC
Example: Simple Calculator
Main program:The main program initializes everything and ties everything together.
View:creates the display, calls the model as necessary to get information.
Controller:Responds to user requests. It is implemented as an Observer pattern -- the Controller registers listeners that are called when the View detects a user interaction. Based on the user request, the Controller calls methods in the View and Model to accomplish the requested action.
Model:independent of the user interface, performs the basic calculator function.
Fachbereich Informatik und Elektrotechnik
Programming in Java, Helmut Dispert
Swing MVC
Main program:
import javax.swing.*;
public class CalcMVC {
public static void main(String[] args) {
CalcModel model = new CalcModel();
CalcView view = new CalcView(model);
CalcController controller = new CalcController(model, view);
view.setVisible(true);
}
}
Createmodel, view, and controllerJava