Intro to Swing GUI development. Swing is A big API Built on AWT (another big API) Used for...

Intro to Swing

GUI development

Swing is

• A big API

• Built on AWT (another big API)

• Used for GUI's

Component

Container

Panel Window JComponent

JApplet

Frame JWindowDialog

JFrame JDialog

JLabel JPanel JTable JTree

Swing class hierarchy fragmentAWT

Swing

Other basic classes

• AWT classes defined in the package java.awt– Color, ( an immutable class)– Point, – Dimension, – Font

JOptionPane Examples

JComboBox A JComboBox looks like a text field with an

arrow next to it. If you click on the arrow, the list of possible values is displayed.

If the Jcombobox is set to be editable, then you can edit the current selection as if it was a text field.

Only one item can be selected at a time. You can retrieve it by calling: getSelectedItem method.

Add the choice items to the end of the list with the addItem method.

Progress Bar

• Displays progress of operation– Can be used like a gauge

• Usage:– Initialize

JProgressBar progressBar = new JProgressBar();progressBar.setMinimum(0);progressBar.setMaximum(numberSubOperations);

– GoprogressBar.setValue(progressBar.getMinimum());for (int i = 0; i < numberSubOperations; i++) { progressBar.setValue(i); performSubOperation(i);}

Intro to The Progress Dialog

Dynamic Feedback

Why Dynamic Feedback?

• Users interact more smoothly with your application if you keep them informed about the application's state.

– Progress animation--an indicator such as a progress bar that shows what percentage of an operation is complete

When?

• Use a progress bar whenever users are blocked from interacting with the application for more than 6 seconds.

Use

• Users cannot interact with a progress bar.•  Update the progress bar to show the proportion

completed at least every 4 seconds.• If you overestimate how much is already done,

the progress bar can remain at 99 percent until the task is complete.

• If you underestimate how much is already done, fill the remaining portion of the progress bar when the operation completes.

• The percentage done should never decrease.

Component

Container

Panel Window JComponent

JApplet

Frame JWindowDialog

JFrame JDialog

JLabel JPanel JTable JTree

Swing class hierarchy fragmentAWT

Swing

Progress Bar

• Displays progress of operation– Can be used like a gauge

• Usage:– Initialize

JProgressBar progressBar = new JProgressBar();progressBar.setMinimum(0);progressBar.setMaximum(numberSubOperations);

– GoprogressBar.setValue(progressBar.getMinimum());for (int i = 0; i < numberSubOperations; i++) { progressBar.setValue(i); performSubOperation(i);}

JProgressBar Methods

javax.swing.JProgressBar

+JProgressBar()

+JProgressBar(min: int, max: int)

+JProgressBar(orient: int)

+JProgressBar(orient: int, min: int, max: int)

+getMaximum(): int

+setMaximum(n: int): void

+getMinimum(): int

+setMinimum(n: int): void

+getOrientation(): int

+setOrientation(orient: int): void

+getPercentComplete():double

+getValus(): int

+setValus(n: int): void

+getString(): String

+setString(s: String): void

+isStringPainted(): Boolean

+setStringPainted(b: boolean): void

Creates a horizontal progress bar with min 0 and max 100.

Creates a horizontal progress bar with specified min and max.

Creates a progress bar with min 0 and max 100 and a specified orientation.

Creates a progress bar with a specified orientation, min, and max.

Gets the maximum value. (default: 100)

Sets a new maximum value.

Gets the minimum value. (default: 0)

Sets a new minimum value.

Gets the orientation value. (default: HORIZONTAL)

Sets a new minimum value.

Returns the percent complete for the progress bar. 0 <= a value <= 1.0.

Returns the progress bar's current value

Sets the progress bar's current value.

Returns the current value of the progress string.

Sets the value of the progress string.

Returns the value of the stringPainted property.

Sets the value of the stringPainted property, which determines whether the progress bar should render a progress percentage string. (default: false)

javax.swing.JComponent

Example: JProgressBar DemoObjective: Write a GUI application that lets you copy files. A progress bar is used to show the progress of the copying operation.

CopyFileCopyFile RunRun

• Menu related classes

Basic Controls

The Components

• A subclass of the java.awt.Component class is called a Component

• A Component has a size, color, etc.

• A Component can normally be painted.

• When a component is painted it is visible on the screen.

Component Subclasses

• Container extends Component

• Button extends Component

• Window extends Container

• Frame extends a Window

• Dialog extends a Window

• Panel extends a Container

• Applet extends a Panel, etc.

Swing and AWT

• Swing is built on JComponent.

• JComponent extends Component

• JLabel, JButton, JCheckbox, etc all extend JComponent

• Why?

Why does JComponent extend Component?

• Swing uses LightWeight Components!

• AWT uses HeavyWeight components!

• What is the difference?

• What is so good about a LightWeight Component?

• What are the drawbacks?

Do I still need AWT when using Swing?

• Yes!

• AWT has many useful tools.

• Taken together they form a Framework.

Basic components to gather input

• JButton• JCheckBox a toggled on/off button displaying state

to user.

• JRadioButton a toggled on/off button displaying its state to user.

basic components

• JComboBox a drop-down list with optional editable text field. The user can key in a value or select a value from drop-down list.

• Jlist allows a user to select one or more items from a list.

• Jmenu popup list of items from which the user can select.

• Jslider lets user select a value by sliding a knob.

• JTextField area for entering a single line of input.

Basic components to present information

• JLabel contains text string, an image, or both.

• JProgressBar communicates progress of some work.

• JToolTip describes purpose of another component.

• JTree a component that displays hierarchical data in outline form.

• JTable a component user to edit and display data in a two-dimensional grid.

• JTextArea, JTextPane, JEditorPane

– define multi-line areas for displaying, entering, and editing text.

Swing components

Container

• Component that can contain other components and containers.

has

JComponent

Component

Container

Intermediate components

• Used to organize and position other components. – JPanel container of components.

– JScrollPane panel with scrollbars.

– JSplitPane divides two components graphically.

– JTabbedPane lets the user switch between a group of components by clicking on a labeled tab;

– JToolBar used for displaying a set of commonly used controls.

Example of component organization

• Wherever this panel is used, it will present the two buttons.

The following creates a JPanel and adds two buttons, labeled “on” and “off.”

JPanel p = new JPanel();p.add(new JButton("on"));p.add(new JButton("off"));

Getting the screen size

public static Dimension getSize() {

Toolkit t = Toolkit.getDefaultToolkit();

return t.getScreenSize();

}

An example of AWT usagepublic class Screen {

public static int getDpi() {

Toolkit t =

Toolkit.getDefaultToolkit();

return t.getScreenResolution();

}

Top-level container

• It’s not contained in any other container.

• provide screen area where other components can display themselves. – JApplet, JDialog, JFrame, and JWindow are

commonly used as top-level containers.

JFrame

• It’s a window with title, border, (optional) menu bar and user-specified components.

• It can be moved, resized, iconified.

• It is not a subclass of JComponent.

• Delegates responsibility of managing user-specified components to a content pane, an instance of JPanel.

Jframe

Jframe internal structure

Jframe

JFrame

• To add a component to a JFrame, add it to the content pane:

JFrame f = new JFrame("A Frame");

JButton b = new JButton("Press");

Container cp = f.getContentPane();

cp.add(b)

JFrame components are in its content pane.

JFramecontent pane

Container

Component

Swing vs AWT

• Swing has lightweight components

• Light weight components have no peers

• Look and feel variations available

• Swing is SLOW

• AWT is heavyweight • heavyweight comps

require peers.• Always looks like the

platform it runs on.• AWT is FAST

Simple Output, a message dialog

public static void messageDialog(Object o) {

JOptionPane.showMessageDialog(null, o);

}

Simple Input

public class In {

public static String getString(Object o) {

return JOptionPane.showInputDialog(o);

}

How do we get an int?

Getting an Int

public static int getInt(Object o) {

return Integer.parseInt(

getString(o));

}

JList

– a component that allows a user to select one or more elements from a listString[] data = {"one", "two", ...};

JList list = new JList(data);

JList

– requires a ListSelectionListener that implementspublic void valueChanged(ListSelectionEvent e) { if (e.getValueIsAdjusting() == false) { //selected: list.getSelectedValue() }}

– selection mode can be set to single, single interval, or multiple interval

• list.setSelectionMode(ListSelectionModel.SINGLE_SELECTION);

Lists can be dynamic

– suppose you want the list to change during execution of the program

– use a ListModel (normally DefaultListModel) to contain the data

dynamic jlist

– create the list and pass in the ListModel as input

– add or remove elements in the ListModel

– the GUI will update the list dynamically

DefaultListModel listModel = new DefaultListModel();

JList list = new JList(listModel);

listModel.addElement(object);

listModel.removeElement(i);

Scroll Panes

– sometimes the list will be too long to display in the GUI

– Solution: display the list inside a JScrollPane• create a scroll pane containing the list

• state how many rows you want to display

• display the scroll pane, not the list

• everything else is as before

jsp

JScrollPane sp = new JScrollPane(list);

list.setVisibleRowCount(5);

add(sp);

Atomic IO

• Atomic actions happen all at once.

• Event driven call-backs can complicate code.

• EmployeeRecord = getEmployeeRecord();

• How is getEmployeeRecord implemented?

JDialog

• Used to create custom dialog windows.

A Jdialog

– a top-level window. – has an owner, generally a frame. – It delegates component management to a

content pane, to which components are added.– It’s displayed by invoking its setVisible

method with an argument of true, and is hidden by invoking its setVisible method with an argument of false

JDialog

• A typical constructor is specified as follows:

public JDialog (Frame owner, String title,boolean modal)

Provides an object to create custom views to get or present data.

Implementing getXXX

• get data – – from a file– from the web– from the user– from …

• Hiding how the data is obtain encapuslates complexity.

JColorChooser dialogs• JColorChooser presents a pane of controls that allow a user to

select and manipulate a color.

Error Control

• int I = getInt(“enter an int [1..10]”,1,10);

• The getInt function protects the range on the int. If the value is not correct, we prompt the user again.

• The RHS waits for the assignment to complete

JFileChooser• Swing provides a file chooser implemented in 100% pure

Java

• JFileChooser contains a method for displaying the chooser within a dialogJFileChooser f = new JFileChooser();

if ( f.showOpenDialog(frame) == JFileChooser.APPROVE_OPTION )

{File file = f.getSelectedFile();

}

• The JFileChooser can display open, save and custom dialogs– showOpenDialog (JComponent)– showSaveDialog (JComponent)– showDialog (JComponent,

String)

• JFileChooser allows multiple files to be selected by setting the MuliSelectionEnabled property to true– setMultiSelectionEnabled(tr

ue);

FileChooser

JFileChooser directory = new JFileChooser();directory.setCurrentDirectory(new File(“.”));directory.showOpenDialog(this); //open dialogFile file = directory.getSelectedFile();

JFileChooser.getSelectedFiles

• JFileChooser.getSelectedFiles can be called to get an array of the selected files– File[] files = f.getSelectedFiles();

• The JFileChooser abstracts the file view from the chooser using the javax.swing.filechooser.JFileView abstract class

• You can write your own file view by subclassing JFileView and passing it to the JFileChooser– f.setFileView (new ImageFileView());

• One method of the JFileView returns an icon

• This can be overridden to display different icons for different types of files in the chooser

But how do you select a directory?

• Can JFileChooser select a directory?

• What about JTree?

Get a Directory

A Directory Chooser

public static File getReadDirFile(String prompt) {

String dir = DirectoryChooser.getDirectory(prompt);

if (dir==null) return null; File f = new File(dir); return f; }

Layouts

• What is a layout manager?

• What does a layout manager do?

• What does a layout manager need?

• Why do I need layouts?

• Can I do GUI's without layouts?

• Can you name a few layouts?

Some simple layouts

• FlowLayout

• GridLayout

• BorderLayout

• BoxLayout

• GridBagLayout….

• What are these layouts for?

Adding Components via Layouts

Gui.layouts

• DialogLayout

ParagraphLayout

Simple ParagraphLayout

ParagraphLayout

• public static void main(String[] args) {• ClosableJFrame cf = new ClosableJFrame();• Container c = cf.getContentPane();• c.setLayout(new ParagraphLayout());• c.add(new JLabel("Name:"));• c.add(new JTextField(20));• c.add(new

JLabel("Name:"),ParagraphLayout.NEW_PARAGRAPH);• c.add(new JTextField(20));• cf.pack();• cf.setVisible(true);• }

PreferredSizeGridLayout

GridLayout ignores preferred size

How do I use PreferredSizeGridLayout?

• public static void PreferredSizeGridLayoutExample() {• JFrame jf = new JFrame();• Container c = jf.getContentPane();• PreferredSizeGridLayout psgl =• new PreferredSizeGridLayout(0, 2, 0, 0);• psgl.setBoundableInterface(new BoundableComponentPlacement());• c.setLayout(psgl);• for (int i = 0; i < 5; i++) {• //rb.setAlignment((int)(Math.random()*8+1));• c.add(new RunButton("ok" + i) {• public void run() {• }• });• c.add(new RunButton("Cancel" + i) {• public void run() {• }• });• }• jf.setSize(200, 200);• jf.setVisible(true);• }

The following line switches automatically to GridLayout

• psgl.setBoundableInterface(new BoundableComponentPlacement());

PreferredSize

• Call:

• Dimension getPreferredSize(){…}

• To get the preferred size of any component.

VerticalFlowLayout

What is a layout manager?

• Responsible for positioning and resizing components.

• LayoutManager is an interface that resides in the java.awt.

Why do I need a Layout Manager?

• You don't need a LayoutManager.

• You can set the Layout to null.

• You can reposition and resize all components your self.

Why is a LayoutManager useful?

• Saves labor?

• Keeps the layout resolution versatile.

• keeps the interface flexible.

How does a LayoutManger work?

• Every layout manager works differently.– Typically, they get components dimensions– components dimensions are used to properly

size and place the components.

Components implement:

Dimension getMinimumSize();

Dimension getMaximumSize();

Dimension getPreferredSize();

What if you don't like your LayoutManager?

• Write your own!

• GridLayout ignores the min and max and preferred sizes! It takes the available space and evenly divides it among all the components.

• All components are grown to the available space.

GridLayout

FlowLayout

BoxLayout

keeps min and max size correct. Also centers alignment

Options passed to the constructor

• X_AXIS - Components are laid out horizontally from left to right.

• Y_AXIS - Components are laid out vertically from top to bottom.

Custom layout managers (1)

• Ensure no existing manager does the job– GridBagLayout / BoxLayout– Layout manager downloads

Custom layout managers (2)

• Create class which implements Layout Manager interface– e.g. public class myManager implements LayoutManager

• Must have 5 methods required by interface– void addLayoutComponent(String, Component)

– void removeLayoutComponent(Component)

– Dimension preferredLayoutSize(Container)

– Dimension minimumLayoutSize(Container)

– Void layoutContainer(Container)• See below URL for more documentation

– http://java.sun.com/docs/books/tutorial/uiswing/layout/custom.html

How do I combine GridLayout with Preferred Size?

• I want a fixed number of rows or columns.

• I want to use the preferred size of each component.

• I want to resize the components only if I don't have enough room.

• I don't want components to fill all available space.

Make your own LayoutManager!

• PreferredSizeGridLayout!

Using a custom layout manager• public static void main(String[] args) {• ClosableJFrame cj = new ClosableJFrame();• Container c = cj.getContentPane();• c.setLayout(new VerticalFlowLayout(0,5));• for (int j = 0; j < 30; j++)• for (int i = 0; i < 10; i++) {• c.add(new RunLabel("Test#" + j + "," + i) {

• public void run() {• System.out.println(getText());• }• });• }• cj.setSize(200, 200);• cj.show();• }

Vertical Flow

Building An AddressBook Index

JTree

JTree Example

JTree

• A tree is a set of hierarchical nodes.• The top of this hierarchy is called “root”.• An element that does not have children is

called “leaf”.• JTree nodes are managed by a

“TreeModel”.• “TreeCellRenderer” converts an object to its

visual representation in the tree.

TreeModel

• Hierarchical data• Parents

• Children

• Siblings

• Ancestors

• Descendents

TreeModel

• Object getRoot()• Object getChild(Object parent, int index)• int getChildCount(Object parent)• boolean isLeaf(Object node)• void valueForPathChanged(TreePath path, Object newVal)• int getIndexOfChild(Object parent, Object child) • void addTreeModelListener(TreeModelListener l)• void removeTreeModelListener(TreeModelListener l)

JTree constructors

• JTree()• JTree(Object[] value)• JTree(Vector value)• JTree(Hashtable value)• JTree(TreeNode root)• JTree(TreeNode root, boolean

asksAllowsChildren)• JTree(TreeModel newModel)

TreeNodes

• Default tree model uses objects of TreeNode to represent the nodes in the tree.

• A default implementation of it is DefaultMutableTreeNode.• TreeNode methods

– TreeNode getChildAt(int childIndex)– int getChildCount()– TreeNode getParent()– int getIndex(TreeNode node)– boolean getAllowsChildren()– boolean isLeaf()– Enumeration children()

• DefaultMutableTreeNode constructors– DefaultMutableTreeNode()– DefaultMutableTreeNode(Object userObject)– DefaultMutableTreeNode(Object userObject, boolean allowsChildren)

JTree exampleimport javax.swing.* ;import javax.swing.tree.* ;import java.awt.event.* ;import java.awt.* ;import java.util.* ;public class TreeNodeExample extends JPanel {

public TreeNodeExample() {DefaultMutableTreeNode rootNode = new DefaultMutableTreeNode("Categories") ;DefaultMutableTreeNode parentNode = new DefaultMutableTreeNode("Metals") ;parentNode.add(new DefaultMutableTreeNode("Gold",false)) ;parentNode.add(new DefaultMutableTreeNode("Silver",false)) ;parentNode.add(new DefaultMutableTreeNode("Bronze",false)) ;parentNode.add(new DefaultMutableTreeNode("Copper",false)) ;parentNode.add(new DefaultMutableTreeNode("Iron",false)) ;parentNode.add(new DefaultMutableTreeNode("Platinium",false)) ;parentNode.add(new DefaultMutableTreeNode("Titanium",false)) ;rootNode.add(parentNode) ;parentNode = new DefaultMutableTreeNode("Companies") ;parentNode.add(new DefaultMutableTreeNode("Paradigm Research",false)) ;parentNode.add(new DefaultMutableTreeNode("JavaSoft",false)) ;parentNode.add(new DefaultMutableTreeNode("Wiley Press",false)) ;rootNode.add(parentNode) ;setLayout(new BorderLayout());add(new JScrollPane(new JTree(rootNode)),"Center") ;

}public Dimension getPreferredSize()

{ return new Dimension(200,120) ; }public static void main(String[]args) {

JFrame frame = new JFrame("Tree Node Example") ;TreeNodeExample panel = new TreeNodeExample() ;frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE) ;frame.getContentPane().add(panel,"Center") ;frame.setSize(panel.getPreferredSize()) ;frame.setVisible(true) ;

}}

TreeModel Listener

• TreeModelListener methods– void treeNodesChanged(TreeModelEvent e)– void treeNodesInserted(TreeModelEvent e)– void treeNodesRemoved(TreeModelEvent e)– void treeStructureChanged(TreeModelEvent e)

• TreeModelEvent methods– TreePath getTreePath()– Object[] getPath()– Object[] getChildren()– int[] getChildIndices()

Custom TreeModel Implementation

• Implement interface TreeModel

Custom Tree Model Exampleimport java.io.* ;import java.util.* ;class FileHolder { File myFile ; Vector children ; public FileHolder(File f) { myFile = f ; } public File getFile() { return myFile ; } public Vector getChildren() { if (myFile.isDirectory() && (children==null)) { int max=0; String list[] ; File curFile ; FileHolder curHolder ; children = new Vector() ; list = myFile.list() ; if (list!=null) max = list.length ; for (int i=0;i<max;++i) { curFile = new File(myFile,list[i]) ; curHolder = new FileHolder(curFile) ; children.addElement(curHolder) ; } } return children ; } public String toString() { return myFile.getName() ; }}

Custom Tree Model Exampleimport javax.swing.* ;import javax.swing.tree.* ;import javax.swing.event.* ;import java.io.* ;import java.util.* ;class FileSystemTreeModel implements TreeModel { protected FileHolder root ; protected Vector listeners ; public FileSystemTreeModel(File r) { root = new FileHolder(r) ; listeners = new Vector() ; } public Object getRoot() { return root ; } public Object getChild(Object parent, int index) { Object retVal=null ; Vector children ; if (parent instanceof FileHolder) { children = ((FileHolder)parent).getChildren() ; if (children!=null) if (index<children.size()) retVal=children.elementAt(index) ; } return retVal ; } public int getChildCount(Object parent) { int retVal = 0 ; Vector children ; if (parent instanceof FileHolder) { children = ((FileHolder)parent).getChildren() ; if (children!=null) retVal = children.size() ; } return retVal ; }

public boolean isLeaf(Object node)

{ boolean retVal = true ;

File file ;

if (node instanceof FileHolder) {

file = ((FileHolder)node).getFile() ;

retVal = file.isFile() ;

}

return retVal ; }

public void valueForPathChanged(TreePath path, Object newVal)

{ }

public int getIndexOfChild(Object parent, Object child)

{ int retVal = -1 ;

Vector children ;

if (parent instanceof FileHolder) {

children = ((FileHolder)parent).getChildren() ;

if (children!=null)

retVal = children.indexOf(child) ;

}

return retVal ; }

public void addTreeModelListener(TreeModelListener l)

{ if ((l!=null)&&!listeners.contains(l))

listeners.addElement(l) ; }

public void removeTreeModelListener(TreeModelListener l)

{ listeners.removeElement(l) ; }

}

Custom Tree Model Exampleimport javax.swing.* ;import java.awt.event.* ;import java.awt.* ;import java.io.* ;import java.util.* ;public class FileTree extends JPanel { public FileTree(String startPath) { JTree tree = new JTree() ; tree.setModel(new FileSystemTreeModel(new File(startPath))) ; setLayout(new BorderLayout()) ; add(new JScrollPane(tree),"Center") ; } public Dimension getPreferredSize() { return new Dimension(250,200) ; } public static void main(String[]s) { JFrame frame = new JFrame("File Tree Example") ; FileTree panel = new FileTree(s.length>0?s[0]:"/") ; frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE) ; frame.getContentPane().add(panel,"Center") ; frame.setSize(panel.getPreferredSize()) ; frame.setVisible(true) ; }}

Jtree

DefaultTreeModel

• Interface TreeModel– Declares methods for representing tree structure

• Class DefaultTreeModel– Default TreeModel implementation

•TreeNode•MutableTreeNode•DefaultMutableTreeNode

DefaultTreeModel

«interface»MutableTreeNode

«interface»TreeNode

getRoot() : ObjectgetChildCount(in parent : Object) : intgetChild(in parent : Object, in index : int) : ObjectgetIndexOfChild(in parent : Object, in child : Object) : intisLeaf(in node : Object) : booleanvalueForPathChanged(in Parameter1)

«interface»TreeModel

root

1

DefaultMutableTreeNode

0..*

children

1

parent

«interface»RowMapper

JTreemodel

*

TreeUI

BasicTreeUI

uiDelegate

*

AbstractLayoutCachetreePathMapping

*

FixedHeightLayoutCache VariableHeightLayoutCache

JTree Architecture

TreePaths (1)lastPathComponent parentPath

TreePaths (2)

• A child TreePath prevents all of its ancestors from being gc’d

• Used throughout JTree as a unique address for a tree node

• Allows equal() node objects to be used in the same tree

• Some duplicate functionality with the data model– trace node parentage– indent level– higher speed, more memory

JTree expandedState Cache

• Treepath used as key, value is Boolean

• Cache entry is not removed when node is collapsed

• Child entry is not removed if parent is collapsed– JTree "remembers" expansion state of child nodesBoolean.TRUE

Boolean.TRUE

Boolean.TRUE

Boolean.TRUE

JTree Layout Cache• BasicTreeUI treePathMapping table

• Position and bounding box info for visible nodes

• VariableHeightLayoutCache– Is JTree default

– Caches all visible nodes

• FixedHeightLayoutCache– Caches only expanded visible nodes

– Only enabled if JTree largeModel = true and rows are explicitly set to a fixed height

JTree Caching Summaryexpandedstate

previously expanded

variableheight

fixedheight

Custom Tree Model Exampleimport java.io.* ;import java.util.* ;class FileHolder { File myFile ; Vector children ; public FileHolder(File f) { myFile = f ; } public File getFile() { return myFile ; } public Vector getChildren() { if (myFile.isDirectory() && (children==null)) { int max=0; String list[] ; File curFile ; FileHolder curHolder ; children = new Vector() ; list = myFile.list() ; if (list!=null) max = list.length ; for (int i=0;i<max;++i) { curFile = new File(myFile,list[i]) ; curHolder = new FileHolder(curFile) ; children.addElement(curHolder) ; } } return children ; } public String toString() { return myFile.getName() ; }}

Custom Tree Model Exampleimport javax.swing.* ;import javax.swing.tree.* ;import javax.swing.event.* ;import java.io.* ;import java.util.* ;class FileSystemTreeModel implements TreeModel { protected FileHolder root ; protected Vector listeners ; public FileSystemTreeModel(File r) { root = new FileHolder(r) ; listeners = new Vector() ; } public Object getRoot() { return root ; } public Object getChild(Object parent, int index) { Object retVal=null ; Vector children ; if (parent instanceof FileHolder) { children = ((FileHolder)parent).getChildren() ; if (children!=null) if (index<children.size()) retVal=children.elementAt(index) ; } return retVal ; } public int getChildCount(Object parent) { int retVal = 0 ; Vector children ; if (parent instanceof FileHolder) { children = ((FileHolder)parent).getChildren() ; if (children!=null) retVal = children.size() ; } return retVal ; }

public boolean isLeaf(Object node)

{ boolean retVal = true ;

File file ;

if (node instanceof FileHolder) {

file = ((FileHolder)node).getFile() ;

retVal = file.isFile() ;

}

return retVal ; }

public void valueForPathChanged(TreePath path, Object newVal)

{ }

public int getIndexOfChild(Object parent, Object child)

{ int retVal = -1 ;

Vector children ;

if (parent instanceof FileHolder) {

children = ((FileHolder)parent).getChildren() ;

if (children!=null)

retVal = children.indexOf(child) ;

}

return retVal ; }

public void addTreeModelListener(TreeModelListener l)

{ if ((l!=null)&&!listeners.contains(l))

listeners.addElement(l) ; }

public void removeTreeModelListener(TreeModelListener l)

{ listeners.removeElement(l) ; }

}

Custom Tree Model Exampleimport javax.swing.* ;import java.awt.event.* ;import java.awt.* ;import java.io.* ;import java.util.* ;public class FileTree extends JPanel { public FileTree(String startPath) { JTree tree = new JTree() ; tree.setModel(new FileSystemTreeModel(new File(startPath))) ; setLayout(new BorderLayout()) ; add(new JScrollPane(tree),"Center") ; } public Dimension getPreferredSize() { return new Dimension(250,200) ; } public static void main(String[]s) { JFrame frame = new JFrame("File Tree Example") ; FileTree panel = new FileTree(s.length>0?s[0]:"/") ; frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE) ; frame.getContentPane().add(panel,"Center") ; frame.setSize(panel.getPreferredSize()) ; frame.setVisible(true) ; }}

Class: javax.swing.JTableSwing Component

• displays data in table• edit the data

Why do we need a table?

• The JTable component is useful for presenting information of a tabular nature

JTable properties

– Column is the basic unit of the Table. – Row collection of columns – Cell the location of data.

Architecture• MVC (Model-View-Controller)

• Model:data of the components.

• View:visual representation.

• Controller:describe how the component interacts with user.

MVC

Model Class

Data AccessorMethods

View Class

Display Methods

Controller Class

Event HandlingMethods

MVC

• MVC paradigm– Model

• Data storage, no presentation elements

– View• No data storage, presentation elements

– Controller like a mediator• Glue to tie the Model and the view together

Why use MVC?

• Modular design

• Consistency

• Complexity hiding

Constructors:

• JTable( ) - JTable( int rows, int columns )

• JTable( Object[ ][ ] rowData, Object[ ] columnNames )• JTable( Vector rowData, Vector columnNames )• JTable( TableModel model )• JTable( TableModel model,

TableColumnModel tcModel )• JTable( TableModel model,

TableColumnModel tcModel, ListSelectionModel lsModel )

Object[][] data = {{“Mary”, “Campione”, “Snowboarding”, new Integer(5), new Boolean(false)},{“Alison”, “Huml”, “Rowing”, new Integer(3), new Boolean(true)},{“Kathy”, “Walrath”, “Chasing Toddlers”, new Integer(2), new Boolean(false)},{“Mark”, “Andrews”, “Speed Reading”, new Integer(20), new Boolean(true)},{“Angela”, “Lih”, “Teaching high school”, new Integer(4), new Boolean(false)}

};

String[] columnNames = {

“First Name”,“Last Name”,“Sport”,“# of Years”,“Vegetarian”

};

JTable table = new JTable(data, columnNames);

Interfaces

• TableColumnModel manages column selection and spacing

• TableModel provides data.

Events

• TableColumnEvent caused by column model changed.

• TableModelEvent caused by TableModel changed

Change Width

TableColumn column;for (int i = 0; i < 5; i++){

column = table.getColumnModel().getColumn(i);

if (i == 2)column.setPreferredWidth(100);

elsecolumn.setPreferredWidth(50);

}

To change column widths

TableColumn column = null; for (int i = 0; i < 5; i++) {

column = table.getColumnModel().getColumn(i); if (i == 2) {

column.setPreferredWidth(100); //second column is bigger} else { column.setPreferredWidth(50);}

}

Build ModelTableModel tm = new AbstractTableModel(){

public void getColumnCount(){

return columnNames.length;

}public void getRowCount(){

return data.length;

}public Object getValueAt(int row, int col){

return data[row][col];

}public Class getColumnClass(int col){

return getValueAt(0, col).getClass();

}

Put the JTable in a JScrollPane

• This automatically deals space for the header and does the right things!

Split pane

• Allows user-controlled resizing of two components

• Can move divider programmatically with setDividierLocation– int parameter

• absolute position

– float parameter • percentage

Tabbed Pane

• Tabbed panel control

• Similar to using CardLayout with buttons for selecting cards

• Use addTab to add components/panels

The JDesktopPane

• Parent JLayeredPane.

• Can hold multiple overlapping internal frames.

• Internal frames may be dragged, resized, iconified.

• events handled by DesktopManager.

JDesktopPane Pro

• more window behavior control over than JFrames.

• Can control minimization,

• Can control window look and feel.

• Appearance same on all platforms, easily configurable.

Cons

• Requires more management.

• Can’t just add components without saying where.

• Minimization prefs.

JDesktopPane and JInternalFrame

• Multiple-document interface– A main window (called the parent window)

contains other windows (called child windows)– Manages several open documents that are being

processed in parallel– Implemented by Swing’s JDesktopPane and JInternalFrame

Using JInternalFrame

• Main constructor– public JInternalFrame(String title,

boolean resizable,

boolean closeable,

boolean maximizable,

boolean iconifiable)

• Other useful methods– moveToFront – moveToBack– setSize (required!)– setLocation (required!)

Internal Frames: Example Code

import java.awt.*;

import java.awt.event.*;

import javax.swing.*;

public class JInternalFrames extends JFrame {

public static void main(String[] args) {

new JInternalFrames();

}

public JInternalFrames() {

super("Multiple Document Interface");

WindowUtilities.setNativeLookAndFeel();

addWindowListener(new ExitListener());

Container content = getContentPane();

content.setBackground(Color.white);

Internal Frames: Example Code (Continued)

JDesktopPane desktop = new JDesktopPane();

desktop.setBackground(Color.white);

content.add(desktop, BorderLayout.CENTER);

setSize(450, 400);

for(int i=0; i<5; i++) {

JInternalFrame frame

= new JInternalFrame(("Internal Frame " + i),

true, true, true, true);

frame.setLocation(i*50+10, i*50+10);

frame.setSize(200, 150);

frame.setBackground(Color.white);

frame.setVisible(true);

desktop.add(frame);

frame.moveToFront();

}

setVisible(true);

} }

Internal Frames: Example Output

Outline• DeskTopTest.java

• (2 of 3)

Internal Frames Minimize Maximize Close

Minimized internal frames Position the mouse over any corner of a child window toresize the window (if resizing is allowed).

Outline• DeskTopTest.java

• (3 of 3)

Maximized internal frame

Extra Fields in JInternalFrame

• closable, closed, desktopIcon, desktopPane, frameIcon, icon, iconifiable, layer, layeredPane, maximizable, maximum, resizable, selected