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Wednesday 17 September 2014

Java Awt Quick Guide 2

Methods inherited

This class inherits methods from the following classes:
  • java.awt.Component
  • java.lang.Object

List Example

Create the following java program using any editor of your choice in say D:/ > AWT > com > tutorialspoint > gui >
AwtControlDemo.java 
package com.tutorialspoint.gui;

import java.awt.*;
import java.awt.event.*;

public class AwtControlDemo {

   private Frame mainFrame;
   private Label headerLabel;
   private Label statusLabel;
   private Panel controlPanel;

   public AwtControlDemo(){
      prepareGUI();
   }

   public static void main(String[] args){
      AwtControlDemo  awtControlDemo = new AwtControlDemo();
      awtControlDemo.showListDemo();
   }

   private void prepareGUI(){
      mainFrame = new Frame("Java AWT Examples");
      mainFrame.setSize(400,400);
      mainFrame.setLayout(new GridLayout(3, 1));
      mainFrame.addWindowListener(new WindowAdapter() {
         public void windowClosing(WindowEvent windowEvent){
            System.exit(0);
         }        
      });    
      headerLabel = new Label();
      headerLabel.setAlignment(Label.CENTER);
      statusLabel = new Label();        
      statusLabel.setAlignment(Label.CENTER);
      statusLabel.setSize(350,100);

      controlPanel = new Panel();
      controlPanel.setLayout(new FlowLayout());

      mainFrame.add(headerLabel);
      mainFrame.add(controlPanel);
      mainFrame.add(statusLabel);
      mainFrame.setVisible(true);  
   }

   private void showListDemo(){                                       

      headerLabel.setText("Control in action: List"); 
      final List fruitList = new List(4,false);

      fruitList.add("Apple");
      fruitList.add("Grapes");
      fruitList.add("Mango");
      fruitList.add("Peer");

      final List vegetableList = new List(4,true);
   
      vegetableList.add("Lady Finger");
      vegetableList.add("Onion");
      vegetableList.add("Potato");
      vegetableList.add("Tomato");

      Button showButton = new Button("Show");

      showButton.addActionListener(new ActionListener() {

         public void actionPerformed(ActionEvent e) {     
            String data = "Fruits Selected: " 
               + fruitList.getItem(fruitList.getSelectedIndex());
            data += ", Vegetables selected: ";
            for(String vegetable:vegetableList.getSelectedItems()){
               data += vegetable + " ";
            }
            statusLabel.setText(data);
         }
      }); 

      controlPanel.add(fruitList);
      controlPanel.add(vegetableList);
      controlPanel.add(showButton);

      mainFrame.setVisible(true);  
   }
}
Compile the program using command prompt. Go to D:/ > AWT and type the following command.
D:\AWT>javac com\tutorialspoint\gui\AwtControlDemo.java
If no error comes that means compilation is successful. Run the program using following command.
D:\AWT>java com.tutorialspoint.gui.AwtControlDemo
Verify the following output
AWT List

AWT TextField Class

Introduction

The textField component allows the user to edit single line of text.When the user types a key in the text field the event is sent to the TextField. The key event may be key pressed, Key released or key typed. The key event is passed to the registered KeyListener. It is also possible to for an ActionEvent if the ActionEvent is enabled on the textfield then ActionEvent may be fired by pressing the return key.

Class declaration

Following is the declaration for java.awt.TextField class:
public class TextField
   extends TextComponent

Class constructors

S.N.Constructor & Description
1TextField()
Constructs a new text field.
2TextField(int columns)
Constructs a new empty text field with the specified number of columns.
3TextField(String text)
Constructs a new text field initialized with the specified text.
4TextField(String text, int columns)
Constructs a new text field initialized with the specified text to be displayed, and wide enough to hold the specified number of columns.

Class methods

S.N.Method & Description
1void addActionListener(ActionListener l)
Adds the specified action listener to receive action events from this text field.
2void addNotify()
Creates the TextField's peer.
3boolean echoCharIsSet()
Indicates whether or not this text field has a character set for echoing.
4AccessibleContext getAccessibleContext()
Gets the AccessibleContext associated with this TextField.
5ActionListener[] getActionListeners()
Returns an array of all the action listeners registered on this textfield.
6int getColumns()
Gets the number of columns in this text field.
7char getEchoChar()
Gets the character that is to be used for echoing.
8<T extends EventListener> T[] getListeners(Class<T> listenerType)
Returns an array of all the objects currently registered as FooListeners upon this TextField.
9Dimension getMinimumSize()
Gets the minumum dimensions for this text field.
10Dimension getMinimumSize(int columns) Gets the minumum dimensions for a text field with the specified number of columns.
11Dimension getPreferredSize()
Gets the preferred size of this text field.
12Dimension getPreferredSize(int columns)
Gets the preferred size of this text field with the specified number of columns.
13Dimension minimumSize()
Deprecated. As of JDK version 1.1, replaced by getMinimumSize().
14Dimension minimumSize(int columns)
Deprecated. As of JDK version 1.1, replaced by getMinimumSize(int).
15protected String paramString()
Returns a string representing the state of this TextField.
16Dimension preferredSize()
Deprecated. As of JDK version 1.1, replaced by getPreferredSize().
17Dimension preferredSize(int columns)
Deprecated. As of JDK version 1.1, replaced by getPreferredSize(int).
18protected void processActionEvent(ActionEvent e)
Processes action events occurring on this text field by dispatching them to any registered ActionListener objects.
19protected void processEvent(AWTEvent e)
Processes events on this text field.
20void removeActionListener(ActionListener l)
Removes the specified action listener so that it no longer receives action events from this text field.
21void setColumns(int columns)
Sets the number of columns in this text field.
22void setEchoChar(char c)
Sets the echo character for this text field.
23void setEchoCharacter(char c)
Deprecated. As of JDK version 1.1, replaced by setEchoChar(char).
24void setText(String t)
Sets the text that is presented by this text component to be the specified text.

Methods inherited

This class inherits methods from the following classes:
  • java.awt.TextComponent
  • java.awt.Component
  • java.lang.Object

TextField Example

Create the following java program using any editor of your choice in say D:/ > AWT > com > tutorialspoint > gui >
AwtControlDemo.java 
package com.tutorialspoint.gui;

import java.awt.*;
import java.awt.event.*;

public class AwtControlDemo {

   private Frame mainFrame;
   private Label headerLabel;
   private Label statusLabel;
   private Panel controlPanel;

   public AwtControlDemo(){
      prepareGUI();
   }

   public static void main(String[] args){
      AwtControlDemo  awtControlDemo = new AwtControlDemo();
      awtControlDemo.showTextFieldDemo();
   }

   private void prepareGUI(){
      mainFrame = new Frame("Java AWT Examples");
      mainFrame.setSize(400,400);
      mainFrame.setLayout(new GridLayout(3, 1));
      mainFrame.addWindowListener(new WindowAdapter() {
         public void windowClosing(WindowEvent windowEvent){
            System.exit(0);
         }        
      });    
      headerLabel = new Label();
      headerLabel.setAlignment(Label.CENTER);
      statusLabel = new Label();        
      statusLabel.setAlignment(Label.CENTER);
      statusLabel.setSize(350,100);

      controlPanel = new Panel();
      controlPanel.setLayout(new FlowLayout());

      mainFrame.add(headerLabel);
      mainFrame.add(controlPanel);
      mainFrame.add(statusLabel);
      mainFrame.setVisible(true);  
   }

   private void showTextFieldDemo(){
      headerLabel.setText("Control in action: TextField"); 

      Label  namelabel= new Label("User ID: ", Label.RIGHT);
      Label  passwordLabel = new Label("Password: ", Label.CENTER);
      final TextField userText = new TextField(6);
      final TextField passwordText = new TextField(6);
      passwordText.setEchoChar('*');

      Button loginButton = new Button("Login");
   
      loginButton.addActionListener(new ActionListener() {
         public void actionPerformed(ActionEvent e) {     
            String data = "Username: " + userText.getText();
            data += ", Password: " + passwordText.getText();
            statusLabel.setText(data);        
         }
      }); 

      controlPanel.add(namelabel);
      controlPanel.add(userText);
      controlPanel.add(passwordLabel);       
      controlPanel.add(passwordText);
      controlPanel.add(loginButton);
      mainFrame.setVisible(true);  
   }
}
Compile the program using command prompt. Go to D:/ > AWT and type the following command.
D:\AWT>javac com\tutorialspoint\gui\AwtControlDemo.java
If no error comes that means compilation is successful. Run the program using following command.
D:\AWT>java com.tutorialspoint.gui.AwtControlDemo
Verify the following output
AWT TextField

AWT TextArea Class

Introduction

The TextArea control in AWT provide us multiline editor area. The user can type here as much as he wants. When the text in the text area become larger than the viewable area the scroll bar is automatically appears which help us to scroll the text up & down and right & left.

Class declaration

Following is the declaration for java.awt.TextArea class:
public class TextArea
   extends TextComponent

Field

Following are the fields for java.awt.TextArea class:
  • static int SCROLLBARS_BOTH -- Create and display both vertical and horizontal scrollbars.
  • static int SCROLLBARS_HORIZONTAL_ONLY -- Create and display horizontal scrollbar only.
  • static int SCROLLBARS_NONE -- Do not create or display any scrollbars for the text area.
  • static int SCROLLBARS_VERTICAL_ONLY -- Create and display vertical scrollbar only.

Class constructors

S.N.Constructor & Description
1TextArea()
Constructs a new text area with the empty string as text.
2TextArea(int rows, int columns)
Constructs a new text area with the specified number of rows and columns and the empty string as text.
3TextArea(String text)
Constructs a new text area with the specified text.
4TextArea(String text, int rows, int columns)
Constructs a new text area with the specified text, and with the specified number of rows and columns.
5TextArea(String text, int rows, int columns, int scrollbars)
Constructs a new text area with the specified text, and with the rows, columns, and scroll bar visibility as specified.

Class methods

S.N.Method & Description
1void addNotify()
Creates the TextArea's peer.
2void append(String str)
Appends the given text to the text area's current text.
3void appendText(String str)
Deprecated. As of JDK version 1.1, replaced by append(String).
4AccessibleContext getAccessibleContext()
Returns the AccessibleContext associated with this TextArea.
5int getColumns()
Returns the number of columns in this text area.
6Dimension getMinimumSize()
Determines the minimum size of this text area.
7Dimension getMinimumSize(int rows, int columns)
Determines the minimum size of a text area with the specified number of rows and columns.
8Dimension getPreferredSize()
Determines the preferred size of this text area.
9Dimension getPreferredSize(int rows, int columns)
Determines the preferred size of a text area with the specified number of rows and columns.
10int getRows()
Returns the number of rows in the text area.
11int getScrollbarVisibility()
Returns an enumerated value that indicates which scroll bars the text area uses.
12void insert(String str, int pos)
Inserts the specified text at the specified position in this text area.
13void insertText(String str, int pos)
Deprecated. As of JDK version 1.1, replaced by insert(String, int).
14Dimension minimumSize()
Deprecated. As of JDK version 1.1, replaced by getMinimumSize().
15Dimension minimumSize(int rows, int columns)
Deprecated. As of JDK version 1.1, replaced by getMinimumSize(int, int).
16protected String paramString()
Returns a string representing the state of this TextArea.
17Dimension preferredSize()
Deprecated. As of JDK version 1.1, replaced by getPreferredSize().
18Dimension preferredSize(int rows, int columns)
Deprecated. As of JDK version 1.1, replaced by getPreferredSize(int, int).
19void replaceRange(String str, int start, int end)
Replaces text between the indicated start and end positions with the specified replacement text.
20void replaceText(String str, int start, int end)
Deprecated. As of JDK version 1.1, replaced by replaceRange(String, int, int).
21void setColumns(int columns)
Sets the number of columns for this text area.
22void setRows(int rows)
Sets the number of rows for this text area.

Methods inherited

This class inherits methods from the following classes:
  • java.awt.TextComponent
  • java.awt.Component
  • java.lang.Object

TextArea Example

Create the following java program using any editor of your choice in say D:/ > AWT > com > tutorialspoint > gui >
AwtControlDemo.java 
package com.tutorialspoint.gui;

import java.awt.*;
import java.awt.event.*;

public class AwtControlDemo {

   private Frame mainFrame;
   private Label headerLabel;
   private Label statusLabel;
   private Panel controlPanel;

   public AwtControlDemo(){
      prepareGUI();
   }

   public static void main(String[] args){
      AwtControlDemo  awtControlDemo = new AwtControlDemo();
      awtControlDemo.showTextAreaDemo();
   }

   private void prepareGUI(){
      mainFrame = new Frame("Java AWT Examples");
      mainFrame.setSize(400,400);
      mainFrame.setLayout(new GridLayout(3, 1));
      mainFrame.addWindowListener(new WindowAdapter() {
         public void windowClosing(WindowEvent windowEvent){
            System.exit(0);
         }        
      });    
      headerLabel = new Label();
      headerLabel.setAlignment(Label.CENTER);
      statusLabel = new Label();        
      statusLabel.setAlignment(Label.CENTER);
      statusLabel.setSize(350,100);

      controlPanel = new Panel();
      controlPanel.setLayout(new FlowLayout());

      mainFrame.add(headerLabel);
      mainFrame.add(controlPanel);
      mainFrame.add(statusLabel);
      mainFrame.setVisible(true);  
   }

   private void showTextAreaDemo(){
      headerLabel.setText("Control in action: TextArea"); 

      Label  commentlabel= new Label("Comments: ", Label.RIGHT);

      final TextArea commentTextArea = new TextArea("This is a AWT tutorial "
      +"to make GUI application in Java.",5,30);

      Button showButton = new Button("Show");

      showButton.addActionListener(new ActionListener() {
         public void actionPerformed(ActionEvent e) {     
            statusLabel.setText( commentTextArea.getText());        
         }
      }); 

      controlPanel.add(commentlabel);
      controlPanel.add(commentTextArea);        
      controlPanel.add(showButton);
      mainFrame.setVisible(true);  
   }
}
Compile the program using command prompt. Go to D:/ > AWT and type the following command.
D:\AWT>javac com\tutorialspoint\gui\AwtControlDemo.java
If no error comes that means compilation is successful. Run the program using following command.
D:\AWT>java com.tutorialspoint.gui.AwtControlDemo
Verify the following output
AWT TextArea

AWT Choice Class

Introduction

Choice control is used to show pop up menu of choices. Selected choice is shown on the top of the menu.

Class declaration

Following is the declaration for java.awt.Choice class:
public class Choice
   extends Component
      implements ItemSelectable, Accessible

Class constructors

S.N.Constructor & Description
1Choice() ()
Creates a new choice menu.

Class methods

S.N.Method & Description
1void add(String item)
Adds an item to this Choice menu.
2void addItem(String item)
Obsolete as of Java 2 platform v1.1.
3void addItemListener(ItemListener l)
Adds the specified item listener to receive item events from this Choice menu.
4void addNotify()
Creates the Choice's peer.
5int countItems()
Deprecated. As of JDK version 1.1, replaced by getItemCount().
6AccessibleContext getAccessibleContext()
Gets the AccessibleContext associated with this Choice.
7String getItem(int index)
Gets the string at the specified index in this Choice menu.
8int getItemCount()
Returns the number of items in this Choice menu.
9ItemListener[] getItemListeners()
Returns an array of all the item listeners registered on this choice.
10<T extends EventListener> T[] getListeners(Class<T> listenerType)
Returns an array of all the objects currently registered as FooListeners upon this Choice.
11int getSelectedIndex()
Returns the index of the currently selected item.
12String getSelectedItem()
Gets a representation of the current choice as a string.
13Object[] getSelectedObjects()
Returns an array (length 1) containing the currently selected item.
14void insert(String item, int index)
Inserts the item into this choice at the specified position.
15protected String paramString()
Returns a string representing the state of this Choice menu.
16protected void processEvent(AWTEvent e)
Processes events on this choice.
17protected void processItemEvent(ItemEvent e)
Processes item events occurring on this Choice menu by dispatching them to any registered ItemListener objects.
18void remove(int position)
Removes an item from the choice menu at the specified position.
19void remove(String item)
Removes the first occurrence of item from the Choice menu.
20void removeAll()
Removes all items from the choice menu.
21void removeItemListener(ItemListener l)
Removes the specified item listener so that it no longer receives item events from this Choice menu.
22void select(int pos)
Sets the selected item in this Choice menu to be the item at the specified position.
23void select(String str)
Sets the selected item in this Choice menu to be the item whose name is equal to the specified string.
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