Bài giảng Lập trình Java: Buổi 4 - Industrial university of Ho Chi Minh City

1/3/2016<br /> <br /> 04. Graphic User Interface in Java<br /> <br /> Faculty of Information Technologies<br /> Industrial University of Ho Chi Minh City<br /> 1<br /> <br /> GUI components (p3)<br /> Text component<br /> Choice component<br /> Menu<br /> Mnemonic<br /> Toolbar<br /> <br /> Tooltip<br /> Tabbed pane<br /> Scroll pane<br /> Dialog box<br /> 2<br /> <br /> Text component<br /> <br /> 3<br /> <br /> 1<br /> <br /> 1/3/2016<br /> <br /> Text component<br /> <br /> 4<br /> <br /> Text component<br /> Group<br /> <br /> Description<br /> <br /> Text<br /> Also known simply as text fields,<br /> Controls text controls can display only one<br /> line of editable text. Like buttons,<br /> they generate action events.<br /> <br /> Swing Classes<br /> JTextField and its<br /> subclasses<br /> JPasswordField and<br /> JFormattedTextField<br /> <br /> Plain<br /> Text<br /> Areas<br /> <br /> JTextArea can display multiple lines JTextArea<br /> of editable text. Although a text<br /> area can display text in any font, all<br /> of the text is in the same font.<br /> <br /> Styled<br /> Text<br /> Areas<br /> <br /> A styled text component can display JEditorPane<br /> editable text using more than one and its subclass<br /> font. Some styled text components JTextPane<br /> allow embedded images and even<br /> embedded components.<br /> 5<br /> <br /> JTextField<br /> <br /> •<br /> <br /> If the cursor is in the text field, the user presses the<br /> Enter key, JTextField generates an Action event<br /> o<br /> <br /> Listener?<br /> <br /> o<br /> <br /> Method in the listener?<br /> <br /> o<br /> <br /> Register listener to the text field?<br /> <br /> • … implements ActionListener<br /> <br /> • public void actionPerformed(ActionEvent e)<br /> • void addActionListener(ActionListener listener)<br /> <br /> 6<br /> <br /> 2<br /> <br /> 1/3/2016<br /> <br /> JTextField Demo<br /> public class JTextFieldDemo extends JFrame<br /> implements ActionListener<br /> {<br /> JTextField mmText;<br /> JLabel resultLabel;<br /> public JTextFieldDemo() {<br /> super("Chuyen doi don vi");<br /> setLayout(new GridLayout(2,2));<br /> <br /> public void actionPerformed(ActionEvent e)<br /> {<br /> double cm, mm;<br /> mm =<br /> Double.parseDouble(mmText.getText());<br /> cm = mm/10;<br /> resultLabel.setText<br /> (Double.toString(cm));<br /> }<br /> <br /> add (new JLabel (“Nhap vao so millimet:"));<br /> add (mmText = new JTextField (10));<br /> add (new JLabel (“So centimet tuong ung:"));<br /> add (resultLabel = new JLabel ("---"));<br /> mmText.addActionListener (this);<br /> <br /> setDefaultCloseOperation(EXIT_ON_CLOSE);<br /> <br /> setSize(300,90);<br /> <br /> }<br /> <br /> }<br /> <br /> public static void main(String[] args) {<br /> new JTextFieldDemo().setVisible(true);<br /> }<br /> <br /> 7<br /> <br /> JPasswordField<br /> <br /> •<br /> •<br /> <br /> Purpose: used to enter a password<br /> A JPasswordField is similar to a JTextField except the<br /> characters typed in by the user are not echoed back to<br /> the user<br /> o<br /> <br /> Instead, an alternate character such as asterisks (*) is<br /> displayed<br /> <br /> o<br /> <br /> You can set the echo character using the method:<br /> • public void setEchoChar(char c)<br /> <br /> 8<br /> <br /> JPasswordField Demo<br /> pnlRight = new JPanel(new GridLayout(0,1));<br /> pnlRight.add(btnOk = new JButton("OK"));<br /> pnlRight.add(btnCancel=new JButton("Cancel"));<br /> <br /> public class JPasswordFieldDemo extends JFrame<br /> implements ActionListener<br /> {<br /> JPasswordField txtPassword;<br /> JButton btnOk, btnCancel;<br /> <br /> add(pnlLeft, BorderLayout.WEST);<br /> add(pnlRight, BorderLayout.CENTER);<br /> <br /> public JPasswordFieldDemo()<br /> {<br /> super("JPasswordField Demo");<br /> JPanel pnlLeft, pnlRight;<br /> txtPassword = new JPasswordField(12);<br /> txtPassword.addActionListener(this);<br /> <br /> btnOk.addActionListener(this);<br /> btnCancel.addActionListener(this);<br /> setDefaultCloseOperation(EXIT_ON_CLOSE);<br /> setsize(200, 200);<br /> }<br /> <br /> pnlLeft = new JPanel();<br /> pnlLeft.add(new JLabel("Password: "));<br /> pnlLeft.add(txtPassword);<br /> <br /> 9<br /> <br /> 3<br /> <br /> 1/3/2016<br /> <br /> JPasswordField Demo (contd.)<br /> public void actionPerformed(ActionEvent e)<br /> {<br /> Object o = e.getSource();<br /> if (o == btnOk || o == txtPassword)<br /> {<br /> char chPassword[] = txtPassword.getPassword();<br /> String strPassword = new String(chPassword);<br /> if(strPassword.trim().equals("pass")) {<br /> JOptionPane.showMessageDialog(this,"Correct Password");<br /> System.exit(0);<br /> }<br /> else {<br /> JOptionPane.showMessageDialog(this,"Incorrect Password",<br /> "Error Message", JOptionPane.ERROR_MESSAGE);<br /> txtPassword.selectAll();<br /> txtPassword.requestFocus();<br /> }<br /> }<br /> else {<br /> System.exit(0);<br /> }<br /> }<br /> public static void main(String [] args){ new JPasswordFieldDemo().setVisible(true); }<br /> }<br /> <br /> 10<br /> <br /> JTextArea<br /> <br /> •<br /> <br /> Purpose<br /> o<br /> <br /> •<br /> <br /> For texts with more than one line long<br /> <br /> Constructors<br /> o<br /> <br /> JTextArea(int rows, int cols)<br /> <br /> o<br /> <br /> JTextArea(String text, int rows, int cols)<br /> <br /> • constructs a new text area with number of rows and columns<br /> • constructs a new text area with an initial text<br /> <br /> 11<br /> <br /> JTextArea Demo<br /> JPanel buttonPanel = new JPanel();<br /> buttonPanel.add(insertButton=new JButton("Insert"));<br /> buttonPanel.add(wrapButton = new JButton("Wrap"));<br /> add(buttonPanel, BorderLayout.SOUTH);<br /> textArea = new JTextArea(8, 40);<br /> add(textArea, BorderLayout.CENTER);<br /> <br /> 12<br /> <br /> 4<br /> <br /> 1/3/2016<br /> <br /> Outline<br />  Text component<br />  Choice component<br />  Menu<br />  Mnemonic<br />  Toolbar<br /> <br />  Tooltip<br />  Tabbed pane<br />  Scroll pane<br />  Dialog box<br /> 13<br /> <br /> JCheckBox<br /> <br /> •<br /> <br /> Purpose:<br /> o<br /> <br /> Used for multi-option user input that the user may select or<br /> deselect by clicking on them<br /> <br /> •<br /> <br /> Constructors:<br /> o<br /> <br /> JCheckBox()<br /> <br /> o<br /> <br /> JCheckBox(String text)<br /> <br /> • Creates an initially unchecked checkbox with no label<br /> • Creates a checkbox (initially unchecked) with the specified text;<br /> see setSelected for changing it<br /> o<br /> <br /> JCheckBox(String text, boolean selected)<br /> • Creates a checkbox with the specified text<br /> – The initial state is determined by the boolean value<br /> provided<br /> – A value of true means it is checked<br /> 14<br /> <br /> JCheckBox – Methods<br /> <br /> •<br /> <br /> boolean isSelected()<br /> o<br /> <br /> •<br /> <br /> o<br /> <br /> •<br /> •<br /> <br /> sets the checkbox to a new state<br /> <br /> String getText()<br /> void setText(String text)<br /> o<br /> <br /> •<br /> <br /> returns the state of the checkbox<br /> <br /> void setSelected(boolean state)<br /> <br /> gets or sets the button’s text<br /> <br /> addItemListener<br /> o<br /> <br /> Add an ItemListener to process ItemEvent in itemStateChanged<br /> 15<br /> <br /> 5<br /> <br />