Java: Summary - Basic GUI Components (Widgets)

Most components have a few common methods.
	cmp.requestFocus();	Puts focus (eg, blinking cursor) in the field, selection of a button, etc.
	tf.setFont(f);	Sets font.
JLabel - For fixed text.
lbl =	new JLabel(t)	Creates JLabel with text on it. Typically created in call to `add()` and not assigned.
JTextField - Box containing one line of text.
tf =	new JTextField(n);	Creates textfield about n columns wide.
s =	tf.getText();	Returns string in textfield.
	tf.setText(s);	Sets text to s.
	tf.addActionListener(lst);	Action listener lst will be called if enter typed.
	tf.setEditable(bool);	Don't allow user to edit text field used for output.
	tf.setHorizontalAlignment(align);	`JTextField.LEFT` (default), `JTextField.CENTER`, or `JTextField.RIGHT`
JButton - Standard clickable button.
btn =	new JButton(t);	Creates button with text t.
btn =	new JButton(img);	Creates button with icon img.
btn =	new JButton(t, img);	Creates button with both text and icon.
	btn.addActionListener(lst);	Action listener lst called when button clicked.
	btn.setEnabled(bool);	Used to enable/disable button.
JTextArea - Box containing multiple lines of text separated by '\n'.
ta =	new JTextField(rows, cols);	Creates textarea with specifed number of rows and columns.
s =	ta.getText();	Returns string in textfield.
	ta.setText(s);	Sets text to s.
	ta.append(s);	Adds s to end of existing text.
	ta.insert(s, pos);	Inserts s at position pos.
	ta.setEditable(bool);	Don't allow user to edit textarea if used for output.
	ta.setLineWrap(bool);	Allow/disallow long lines to wrap.
	ta.setWrapStyleWord(bool);	Call `setLineWrap(true)` first. true wraps at word boundaries, false (default) at characters.
	ta.setBorder(brdr);	Add space between text and edge. Eg, to add 2 pixels use brdr BorderFactory.createEmptyBorder(2,2,2,2)
JCheckBox - Check box followed by text. Use with listener or to get/set state.
cb =	new JCheckBox(text);	Creates check box initially unchecked.
cb =	new JCheckBox(text, bool);	Creates check box with checked state tf.
b =	cb.isSelected();	Returns bool if box is checked/unchecked.
	cb.setSelected(bool);	Sets checked state to tf.
	ta.addItemListener(itemListen);	Adds an item listener.
JList - List of string values. Put in JScrollPane if scrolling needed.
lst =	new JList();	Creates empty JList.
lst =	new JList(sarray);	Creates JList intialized to String array sarray. Can also use array of Objects.
	lst.setListData(sarray);	Sets list "model" to String array sarray.
s =	(String)lst.getSelectedValue();	Returns value as Object value. Typically cast to String. `null` if no selection.
i =	lst.getSelectedIndex();	Returns index of selection or -1 if no selection.

Copyleft 2005 Fred Swartz