Programming Java

Tasks studies - laboratory

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OBJECT-ORIENTED PROGRAMMING

GUI JAVA SWING LABORATORY

JPANEL, LAYOUT MANAGER, JBUTTON, JLABEL, JTEXTFIELD

CREATING A PROJECT

File->New Project->We choose to create a Java (1) project and the SDK (2) version, go next (3) and in the next window enter the project name (4) and create it (5).

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In the next step, you need to create Swing UI Designer GUI From. In the next window, we enter the name and we can define the base layout.

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View after creating GUI:
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JFRAME
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public class Example01 extends JFrame {
  private JPanel JPanel1;
  public static void main(String[] args) {
    Example01 SwingExample = new Example01();
    SwingExample.setVisible(true); //*wyświetlanie ramki *//*
  }
  //konstruktor
  public Example01(){
    //I sposób poprzez dziedzczenie z JFrame
    super("Moje pierwsze okieno :) ");
    this.setContentPane(this.JPanel1); // wyświetlenei na ekranie
    this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);//metoda pozwalająca na
    zamknięcie okna
    //this.pack();
    /*upakowanie okna zgodnie z preferowanymi rozmiarami komponentów,
    które są zawarte w Frame, rozmair będzie się doaposowywał do rozmiaru */
  }
}

LAYOUT MANAGER

In Java, we can place components in the following layout:

a) BorderLayout
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b) CardLayout
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c) FlowLayout
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d) GridBagLayout
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e) GridLayoutManager IntelliJ Allows you to place components in a grid of columns and rows, and their size can be different.
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JBUTTON public class JButton extends AbstractButton implements Accessible Commonly used Constructors:

Constructor	Description	——————-	——————————————————-
`JButton()`	It creates a button with no text and icon.
`JButton(String s)`	It creates a button with the specified text.
`JButton(Icon i)`	It creates a button with the specified icon object.

Commonly used Methods of AbstractButton class:

Methods	Description
`void setText(String s)`	It is used to set specified text on button.
`String getText()`	It is used to return the text of the button.
`void setEnabled(boolean b)`	It is used to enable or disable the button.
`void setIcon(Icon b)`	It is used to set the specified Icon on the button.
`Icon getIcon()`	It is used to get the Icon of the button.
`void setMnemonic(int a)`	It is used to set the mnemonic on the button.
`void addActionListener(ActionListener a)`	It is used to add the action listener to this object.

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Example 1.

You need to create two buttons that will allow you to exit the program and display information.

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After adding the button, use Create Listener Ctlt+O, then select ActionListener, and then automatically create the actionPerformed method

Method codes:

button_msg.addActionListener(new ActionListener() {
@Override
public void actionPerformed(ActionEvent e) {
JOptionPane.showMessageDialog(null,"Hello");
 }
});

buttonClose.addActionListener(new ActionListener() {
 @Override
 public void actionPerformed(ActionEvent e) {
 dispose(); //output method
 }
});

buttonDate.addActionListener(new ActionListener() {
 @Override
 public void actionPerformed(ActionEvent e) {
 //System.out.println(new Date());
 JOptionPane.showMessageDialog(null,new Date());
 }
});

JLABEL public class JLabel extends JComponent implements SwingConstants, Accessible

Commonly used Constructors:

Constructor	Description
`JLabel()`	Creates a JLabel instance with no image and with an empty string for the title.
`JLabel(String s)`	Creates a JLabel instance with the specified text.
`JLabel(Icon i)`	Creates a JLabel instance with the specified image.
`JLabel(String s, Icon i, int horizontalAlignment)`	Creates a JLabel instance with the specified text, image, and horizontal alignment.

Commonly usedMethods:

Methods	Description
`String getText()`	It returns the text string that a label displays.
`void setText(String text)`	It defines the single line of text this component will display.
`void setHorizontalAlignment(int alignment)`	It sets the alignment of the label’s contents along the X axis.
`Icon getIcon()`	It returns the graphic image that the label displays.
`int getHorizontalAlignment()`	It returns the alignment of the label’s contents along the X axis.

Example 2.

You should create a GUI according to the drawing below and implement the following events:

• The Close button closes the window.

• Display the date – displays the current date in the JLabel.

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JTEXTFIELD public class JTextField extends JTextComponent implements SwingConstants Commonly used Constructors:

Constructor	Description
`JTextField()`	Creates a new TextField
`JTextField(String text)`	Creates a new TextField initialized with the specified text.
`JTextField(String text, int columns)`	Creates a new TextField initialized with the specified text and columns.
`JTextField(int columns)`	Creates a new empty TextField with the specified number of columns.

Commonly usedMethods:

Methods	Description
`void addActionListener(ActionListener l)`	It is used to add the specified action listener to receive action events from this textfield.
`Action getAction()`	It returns the currently set Action for this ActionEvent source, or null if no Action is set.
`void setFont(Font f)`	It is used to set the current font.
`void removeActionListener(ActionListener l)`	It is used to remove the specified action listener so that it no longer receives action events from this textfield.

Example 3.

After entering a and b and pressing the sum or difference button, the result of the operation will appear, close Closes the window.
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Task 1.

_A GUI application for converting Celsius to Farenheit should be proposed.

The application should have the following functionalities:_

• Typing temp in Celsius

• The field in which the result will appear after pressing the convert button.

Task 2.

Using the components you have learned, you should design an application/clique that will demonstrate the use of available methods for the components discussed.