Java Doc for Calculator.java in  » Swing-Library » jide-common » com » jidesoft » swing » Java Source Code / Java DocumentationJava Source Code and Java Documentation

To make it more flexible, the Calculator has no text field to display the result. You can create your own JTextField or JLabel to display the result. Here is a simple example to create a text field and associate it with Calculator.

 final JTextField textField = new JTextField();
 textField.setColumns(20);
 textField.setHorizontalAlignment(JTextField.TRAILING);
 Calculator calculator = new Calculator();
 calculator.registerKeyboardActions(textField, JComponent.WHEN_FOCUSED);
 calculator.addPropertyChangeListener(Calculator.PROPERTY_DISPLAY_TEXT, new PropertyChangeListener() {
 public void propertyChange(PropertyChangeEvent evt) {
 textField.setText("" + evt.getNewValue());
 }
 });
 calculator.clear();
 

All numeric and operator keys work as expected. Here are a few special keys that worth mentioning

• 'C', 'c' or ESC to clear current result
• '!' to make current displayed number from positive to negative (or from negative to positive)
• ENTER is equalivent to '='..

Another interesting way to use Calculator is to use it without using GUI.

 Calculator calculator = new Calculator();
 calculator.input('1');
 calculator.input('0');
 calculator.input('*');
 calculator.input('2');
 calculator.input('4');
 calculator.input('=');
 System.out.println("10 * 24 = " + calculator.getDisplayText());
 

There are seveal methods you can use to get internal state of the Calculator.

• Calculator.getDisplayText() : to get the result that should be displayed. Please note, this method return a string.
• Calculator.getResult() : to get the last calculated result. This method returns a double value.
• Calculator.getOperator() : to get the current operator
• Calculator.isOverflow() : to check if there is an overflow. Usually if you try to divide by zero, you will get an overflow.

 AbstractButton button = new JideButton(text, icon);
 button.setOpaque(true);
 button.setContentAreaFilled(true);
 button.setRequestFocusEnabled(false);
 button.setFocusable(false);
 button.addActionListener(this);
 return button;