Swings

Aarti Narang
Jaskiran Kaur
Upneet Kaur

A swing is the primary JAVA GUI widget
toolkit , an API for providing a GUI for java
programs.

 Itwas developed to provide a more
sophisticated set of GUI components Other
than in AWT package.

 Supports more powerful and flexible
components that provides advanced and
pluggable look and feel.

 Platform independent
 Model –View-Controller
 Extensible
 Customizable
 Configurable
 Light weight UI

SWINGS AWT

 Light weighted  Heavy weighted
components. components.
 Completely written in  Uses of native
java. libraries.
 Better design than  Design issues are still
AWT. not good.
 Own look and feel.  Has to code properly.

 Java.awt.*
 Javax.swing.*

Javax : hierarchy of packages and set of
“light weight” components for platform-
independent rich GUI components.

 JApplet
 JButton
 JCheckBox Used for making swing applet
 JLabel instance.

 JComboBox
 JRadioButton
 JScrollPane
 JTabbedPane
 JTable
 JTree
 JTextField

 Swing labels are instances of JLabel class. It
can display text and/or an icon.

 Constructors are:
Jlabel(Icon i)
Jlabel(String s,Icon I,int align)

 Methods are:
Icon getIcon()
String getText()
Void setIcon(Icon i)
Void setText(String s)

Import java.awt.*;
Import javax.swing.*;
/* <applet code=“demo” width=200 height=200> </applet> */
public class demo extends JApplet {

public void init()
{
Container contentPane= getContentPane();

JLabel j1=new JLabel (“HELLO”,i1,JLabel.CENTER);

contentPane.add(j1);
}
}

 Swing image icons are instances of “ImageIcon”
class, which paints an icon from an image.

ImageIcon(URL url)
ImageIcon(String filename)

 Methods are:
int getIconHeight()
int getIconWidth()
void paintIcon(Component c, Graphics g, int x,int y)

Import java.awt.*;
/* <applet code=“demo1” width=200 height=200> </applet> */
public class demo1 extends JApplet {

public void init()
{

ImageIcon i1= new ImageIcon(“1.gif”);

JLabel j1=new JLabel (“HELLO”,i1,JLabel.CENTER);

}
}

 Swingtext field are instances of
JTextComponent class. It has one subclass
“JTextField” , for adding one line of text.

JTextField()
JTextField(int cols)
JTextField(String s,int cols)
JTextField(String s)

Import java.awt.*;

JTextField jtf;

public void init()
{

jtf=new JJTextField(20);
contentPane.add(jtf);
}
}

 AbstractButton is a superclass for
checkboxes, push buttons and radio buttons.
 JButton subclass provides the functionality of a
push button.

JButton(Icon i)
JButton(String s,Icon i)
JButton(String s)

Import java.awt.*;

public void init()
{
ImageIcon img=new ImageIcon(“2.gif”);

JButton jb1=new JButton(img);
contentPane.add(jb1);

JButton jb2=new JButton(“Click here”);
contentPane.add(jb2);
}
}

 JCheckBox class provides the functionality of a
checkbox. Its immediate superclass is
JToggleButton, which provides support for two state
buttons.

JCheckBox(Icon i)
JCheckBox(Icon i, Boolean b)
JCheckBox(String s)
JCheckBox(String s, Boolean b)
JCheckBox(String s,Icon i)
JCheckBox(String s,Icon I, Boolean b)

void setSelected(Boolean b)

Import java.awt.*;

public void init()
{
JCheckBox cb=new JCheckBox(“C”,true);
contentPane.add(cb);

JCheckBox cb=new JCheckBox(“C++”,normal);

JCheckBox cb=new JCheckBox(“Java”,normal);
}
}

 Radio buttons are supported by JRadioButton
class, a subclass of AbstractButton.
 Constructors are same as of checkboxes.

 Radio
buttons must be grouped into one set, so
we use “ButtonGroup” class.

void add(AbstractButton b)

Import java.awt.*;
/* <applet code=“demo5” width=200 height=200> </applet> *
public void init()
{
JRadioButton b1=new JRadioButton(“A”);
contentPane.add(b1);

ButtonGroup bg=new ButtonGroup();
bg.add(b1);
bg.add(b2);
bg.add(b3);
} }

 A tabbed pane is a component that appears as a group of
folders in a file cabinet. Each folder has title and is
selected one at a time.
 Tabbed panes are encapsulated by JTabbedPane class.

void addTab(String str, Component comp)

Procedure to use tabbed pane is:

 Create a JTabbedPane object.
 Call addtab() to add a tab to pane(title, and its
component for each tab).
 Repeat step 2 for each tab.
 Add tabbed pane to content pane of applet.
 Define subclasses for tabs.

public void init()
{
JTabbedPane tabs=new JTabbedPane();
Tabs.addTab(“Home”, new homemenu());
Tabs.addTab(“Insert”, new insertmenu());
Tabs.addTab(“View”, new viewmenu());
getContentPane().add(tabs);
}
}
class homemenu extends Jpanel {
public homemenu() {
---// buttons
}}

class insertmenu extends Jpanel {
public insertmenu() {
---// radio /checkboxes
}}

 A scroll pane is a component that presents a rectangular area in
which a component may be viewed horizontally or vertically.
 Scroll panes are encapsulated by JScrollPane class.

JScrollPane(Component comp)
JScrollPane(int v, int h)
JScrollPane(Component comp, int v, int h)

H and v are constants defined by ScrollPaneConstants
interface, as follows,

 HORIZONTAL_SCROLLBAR_ALWAYS
 HORIZONTAL_SCROLLBAR_AS_NEEDED
 VERTICAL_SCROLLBAR_ALWAYS
 VERTICAL_SCROLLBAR_AS_NEEDED

public void init()
{
contentPane.setLayout(new Borderlayout());

Jpanel jp =new Jpanel();
Jp.setLayout(
ButtonGroup bg=new ButtonGroup();
bg.add(b1);
bg.add(b2);
bg.add(b3);
} }

 A check box is a combination of text field and a drop-
down list.

 Check boxes are provided by JCheckBox class, which
extends JComponent.

JComboBox()
JComboBox(Vector v)

Here v is a vector that initializes the combo box.

 Items are added to list of choices via a method:
void addItem(Object obj)

Here obj is the object to be added to the combo box.

public class demo extends JApplet implements ItemListener
{
public void init()
{
JComboBox jc = new JComboBox();
jc.addItem(“Ludhiana”);
jc.addItem(“Chandigarh”);
jc.addItem(“Moga”);
jc.addItemListener (this);
contentPane.add(jc);

JLabel j1 =new JLabel(“ “);
}
public void itemStateChanged(ItemEvent e)
{
String s=(String) i.getItem();
J1.setText(s);
}}

Swings

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