Java: Summary - Basic GUI Components
Components share many common methods, for example: | |||
cmp.requestFocus(); | Puts focus (eg, blinking cursor) in field, select button, etc. | ||
cmp.setFont(f); | Sets font. | ||
JLabel - For fixed text. | |||
lbl = | new JLabel(t) | Creates JLabel with text t on it. | |
lbl = | new JLabel(t, align) | Align text JLabel.LEFT, JLabel.CENTER, or JLabel.RIGHT. | |
lbl = | new JLabel(icon) | Displays icon (eg, ImageIcon). | |
lbl = | new JLabel(icon, align) | Align icon to JLabel.LEFT, JLabel.CENTER, or JLabel.RIGHT. | |
JTextField - Box containing one line of text. | |||
tf = | new JTextField(n); | Creates textfield n characters 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(actlstnr); | Action listener actlstnr called when button clicked. | ||
btn.setEnabled(bool); | Used to enable/disable button. | ||
JTextArea - Box containing multiple lines of text separated by '\n'. | |||
ta = | new JTextArea(rows, cols); | Creates textarea with specifed number of rows and columns. | |
s = | ta.getText(); | Returns string in text area. | |
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 4 pixels use brdr BorderFactory.createEmptyBorder(4,4,4,4) | ||
JCheckBox - Check box followed by text. Use either listener or check with isSelected(). | |||
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. | ||
cb.addActionListener(actlstnr); | Adds ActionListener, which is called whenever user clicks. | ||
cb.setEnabled(bool); | Used to enable/disable check box. |
Copyleft 2007 Fred Swartz