JComponents

JComponents are the Swing elements the user interacts with and are central to building a ConfigurablePanel. Here are examples of useful components:

The following section is composed of snippets of codes covering often used cases in Swing. In particular, these snippets are useful when implementing the ConfigurablePanel methods propertyhasChanged() and parameterhasChanged() in which JComponents should be modified.

Note that the action listeners are already implemented as static methods in SwingUIListeners and should be called in the ConfigurablePanel method addComponentListeners().

The list is not exhaustive.

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Table of contents

1. JTextField
2. JToggleButton/JCheckBox
3. JButton
4. JComboBox
5. Jslider
6. JSpinner
7. ButtonGroup
8. JLabel
9. Titledborder

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JTextField

Set font

JTextField txtf = new JTextField();
txtf.setFont(new Font("Tahoma", Font.BOLD, 12));

Set text color

JTextField txtf = new JTextField();
txtf.setForeground(Color.red);

Action listeners

To have a trigger when the “Enter” key is pressed:

JTextField txtf = new JTextField();
txtf.addActionListener(new ActionListener(){
	public void actionPerformed(ActionEvent e){
        String text = txtf.getText();
		
        // Do something
        doSomething(text);
	}
});

Or trigger when the focus is lost:

JTextField txtf = new JTextField();
txtf.addFocusListener(new FocusListener() {
	@Override
	public void focusGained(FocusEvent ex) {}

	@Override
	public void focusLost(FocusEvent ex) {
		String s = txtf.getText();
		
        // Do something
        doSomething(text);
	}
});

Note that those actions listeners are not incompatible.

Modifying a JTextField

JTextField txtf = new JTextField("0");
String s = "1";
txtf.setText(s);

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JToggleButton/JCheckBox

Set font

JToggleButton tglb = new JToggleButton("On/Off");
tglb.setFont(new Font("Tahoma", Font.BOLD, 12));

Set margin

JToggleButton tglb = new JToggleButton("On/Off");
tglb.setMargin(new Insets(2, 2, 2, 2));

Set text color

JToggleButton tglb = new JToggleButton("On/Off");
tglb.setForeground(Color.red);

Action listener

JToggleButton tglb = new JToggleButton("On/Off");
tglb.addActionListener(new ActionListener() {
	public void actionPerformed(ActionEvent actionEvent) {
		AbstractButton abstractButton = (AbstractButton) actionEvent.getSource();
		boolean selected = abstractButton.getModel().isSelected();

		// Do something
		doSomething(selected);
	}
});

Modifying a JToggleButton

JToggleButton tglb = new JToggleButton("On/off");
boolean b = false;
tglb.setSelected(b);

Enable/disable

JToggleButton tglb = new JToggleButton("On/off");
boolean b = false;
tglb.setEnable(b);

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JButton

Action listener

JButton btn = new JButton("Click me");
btn.addActionListener(new ActionListener() {
	public void actionPerformed(ActionEvent e) {
		doSomething();
	}
});

Enable/disable

JButton tglb = new JButton("Click me");
boolean b = false;
tglb.setEnable(b);

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JComboBox

Action listener

String[] strarr = {"Value1","Value2","Value3"};
JComboBox<String> cbx = new JComboBox();
cbx.addActionListener(new ActionListener(){
    public void actionPerformed(ActionEvent e){
		String val = String.valueOf(cbx.getSelectedItem());
        int index = cbx.getSelectedIndex();
        
        // Do something
        doSomething(val);
	}
});

Modifying a JComboBox

String[] strarr = {"Value1","Value2","Value3"};
JComboBox<String> cbx = new JComboBox();
cbx.setSelectedIndex(1);
cbx.setSelectedItem(strarr[2]);

Note that this will trigger the action listener of the previous section.

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JSlider

Action listener

JSlider sld = new JSlider();
sld.addMouseListener(new MouseAdapter() {
	public void mouseReleased(MouseEvent e) {
		int val = sld.getValue();

        // Do something
		doSomething();
	}
});

Modifying a JSlider

JSlider sld = new JSlider();
sld.setValue(10);

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JSpinner

Action listener

// integer step size
SpinnerNumberModel model = new SpinnerNumberModel(0,-5,5,1);
JSpinner spnr = new JSpinner(model);
spnr.addChangeListener(new ChangeListener() {
	@Override
	public void stateChanged(ChangeEvent e) {
		int val = (int) spnr.getValue();
				
		// Do something
		doSomething();
	}
});

Modifying a JSpinner

SpinnerNumberModel model = new SpinnerNumberModel(0,-5,5,1);
JSpinner spnr = new JSpinner(model);
spnr.setValue(2);

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ButtonGroup

Action listener

ButtonGroup bg = new ButtonGroup();
		
// Instantiates the buttons and adds them to the button group
int N = 5;
for(int i=0;i<N;i++){
    JToggleButton btn = new JToggleButton("Button"+i);
    bg.add(btn);		    
}

// Adds the action listeners
Enumeration<AbstractButton> enm = bg.getElements();
int counter = 0;
while(enm.hasMoreElements()) {
	final int pos = counter;
	AbstractButton btn = enm.nextElement();		
	btn.addActionListener(new ActionListener(){
	   	public void actionPerformed(ActionEvent e){
			// Do something
            doSomething(pos);
		}
	});	
	counter++;
}

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JLabel

Modifying a JLabel

JLabel lbl = new JLabel("Label");
lbl.setText("New text");

Set font and font size

JLabel lbl = new JLabel("Label");
lbl.setFont(new Font("Tahoma", Font.BOLD, 12));

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TitledBorder

Modifying a TitledBorder title and color

// Instiates the JPanel and its titledborder
JPanel pane = new JPanel();
Font f = new Font("Tahoma", Font.BOLD, 12);
Color c = Color.blue;
pane.setBorder(new TitledBorder(null, "Title", TitledBorder.LEFT, TitledBorder.TOP, f, c));

// Modifying title
TitledBorder border = (TitledBorder) pane.getBorder();
String title = "New title";
border.setTitle(title);
		
// Modifying color
Color c2 = Color.red;
border.setTitleColor(c2);
		
pane.repaint();

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