import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.event.*;
import java.text.*;
import java.util.*;
/** This class manages a window with up to 7 int fields (numbered 0, ..., 6),
* 7 double fields, and 7 string fields, a choice box for locales, and a
* "ready" button. The user is expected to type values in fields and then
* click the "ready" button. When this button is clicked, method buttonPressed
* is called to process the values in the fields and deliver some output,
* possibly in the fields in the window.
*
* Thus, the window is a general GUI, which can be used in a number of
* situations.
*
* To use this class, one needs to write a class X that
*
* (1) Creates an instance of this class (which we will call "view")
*
* (2) Registers an ActionListener with the button via the command
* view.getButton().addActionListener(this);
*
* (3) Implements actionPerformed(ActionEvent), which is the only
* method in ActionListener.
*
* This method actionPerformed(ActionEvent) is called when the "ready"
* button is pressed. In this method, place any code you like to read the
* values of the fields, calculate, and store values in the fields. To
* read the fields, use methods getIntField, getDoubleField, and
* getStringField. To store values in the fields, use methods setIntField,
* setDoubleField, and setStringField.
*/
public class GenericGUI extends JFrame {
// constants
// TOTAL_MAX_FIELDS: max number of fields of one type that is allowed
private static final int TOTAL_MAX_FIELDS= 7;
private static final int MAX_FIELD_LENGTH= 20;
private static final int ROW_SEPARATION= 10;
private static final int COLUMN_SEPARATION= 15;
// maxFields: actual max number of fields used of one type.
private static int maxFields;
// fields
private JTextField[] intFields; // the fields that can contain ints
private JTextField[] doubleFields; // the fields that can contain doubles
private JTextField[] stringFields; // the fields that can contain text
private int numInts; // number of int fields
private int numDoubles; // number of double fields
private int numStrings; // number of text fields
// the button
private JButton theButton;
// These variables are used to provide the choicebox of locales
private Locale locale= Locale.getDefault();
private Locale[] locales= Calendar.getAvailableLocales(); // array of all locales
private JComboBox choiceBox;
/** Constructor: a GUI window with
* max( min(i,MAX_FIELDS), 0) int fields,
* max( min(d,MAX_FIELDS), 0) double fields,
* max( min(s,MAX_FIELDS), 0) String fields,
* and a "ready" button */
public GenericGUI(int i, int d, int s) {
super("Generic GUI");
numInts = Math.max( Math.min(i,TOTAL_MAX_FIELDS), 0);
numDoubles = Math.max( Math.min(d,TOTAL_MAX_FIELDS), 0);
numStrings = Math.max( Math.min(s,TOTAL_MAX_FIELDS), 0);
maxFields = Math.max( Math.max(numInts,numDoubles), numStrings );
intFields = new JTextField[maxFields];
doubleFields = new JTextField[maxFields];
stringFields = new JTextField[maxFields];
createFields();
theButton = createActionButton();
// Tell the program to exit upon closure of this window
setDefaultCloseOperation(EXIT_ON_CLOSE);
// Add the Panel of fields and the button to this window
getContentPane().setLayout(new BorderLayout());
choiceBox = createChoiceBox();
getContentPane().add(choiceBox,BorderLayout.NORTH);
getContentPane().add(createPanel(),BorderLayout.CENTER);
getContentPane().add(theButton,BorderLayout.SOUTH);
}
/** Create elements of arrays intFields, doubleFields, and stringFields */
private void createFields() {
//inv: elts 0..i-1 have been added to each array
for(int i= 0; i< maxFields; i++) {
intFields[i] = new JTextField(MAX_FIELD_LENGTH);
doubleFields[i] = new JTextField(MAX_FIELD_LENGTH);
stringFields[i] = new JTextField(MAX_FIELD_LENGTH);
}
}
/** Yields: the panel of fields that goes in this window */
private JPanel createPanel() {
JPanel panel= new JPanel();
panel.setLayout(new GridLayout(1, 3, COLUMN_SEPARATION, 0));
if (numInts > 0) {
panel.add(createFieldsPanel(numInts, intFields, "Integer fields"));
}
if (numDoubles > 0) {
panel.add(createFieldsPanel(numDoubles, doubleFields, "Double fields"));
}
if (numStrings > 0) {
panel.add(createFieldsPanel(numStrings, stringFields, "String fields"));
}
return panel;
}
/** Yields: a Panel with visible elements a[0..n-1], invisible elements
* a[n..maxFields-1] (to make the vertical sizes nice), and with
* title t above them.
* Pre: n > 0 */
private JPanel createFieldsPanel(int n, JTextField[] a, String t) {
JPanel panel= new JPanel();
panel.setLayout(new GridLayout(maxFields+1, 1, 0, ROW_SEPARATION));
panel.add(new JLabel(t, JLabel.CENTER));
//inv: elts 0..i-1 have been added
for (int i= 0; i < n; i++) {
panel.add(a[i]);
}
// Add the invisible elements.
// inv: items n..i-1 invisible elts have been added
for (int i=n; i < maxFields; i++) {
panel.add(a[i]);
a[i].setVisible(false);
}
return panel;
}
/** Yields: a button with title "Ready!" */
private JButton createActionButton() {
JButton button= new JButton("Ready!");
return button;
}
/** Yields: the choiceBox to contain locales */
private JComboBox createChoiceBox() {
JComboBox cb = new JComboBox();
// Add the locales to cb
// inv: items 0..i-1 have been added
for (int i= 0; i != locales.length; i++) {
cb.addItem(locales[i].getDisplayName());
}
// Set the selected item to the default
// inv: items 0..i-1 have been set to default
for (int i= 0; i != locales.length; i++) {
if (locale.equals(locales[i])) {
cb.setSelectedIndex(i);
}
}
return cb;
}
/** Pack and show this window */
public void showWindow() {
pack();
setVisible(true);
}
// public methods to access the gui components
/** Yields: the integer in int field number f, or 0 if either f is not
* valid or the field doesn't contain an integer. */
public int getIntField(int f) {
try {
return Integer.parseInt( intFields[f].getText() );
} catch (ArrayIndexOutOfBoundsException e) {
return 0;
} catch (NumberFormatException e) {
intFields[f].setText("" + intFields[f].getText() +": NOT AN INTEGER, 0 used");
return 0;
}
}
/** Set int field number f to m. No effect if f is not valid. */
public void setIntField(int f, int m) {
try {
intFields[f].setText("" + m);
} catch (ArrayIndexOutOfBoundsException e) {
return;
}
}
/** Yields: the double in double field number f, or 0 if either f is not
* valid or the field doesn't contain a double. */
public double getDoubleField(int f) {
try {
return Double.valueOf( doubleFields[f].getText() ).doubleValue();
} catch (ArrayIndexOutOfBoundsException e) {
return 0;
} catch (NumberFormatException e) {
doubleFields[f].setText("" + doubleFields[f].getText() +": NOT A DOUBLE, 0 used");
return 0;
}
}
/** Set double field number f to d. No effect if f is not valid. */
public void setDoubleField(int f, double d) {
try {
doubleFields[f].setText("" + d);
} catch (ArrayIndexOutOfBoundsException e) {
return;
}
}
/** Yields: the string in string field number f, or "" if f is not valid. */
public String getStringField(int f) {
try {
return stringFields[f].getText();
} catch (ArrayIndexOutOfBoundsException e) {
return "";
}
}
/** Set string field number f to s. No effect if f is not valid. */
public void setStringField(int f, String s) {
try {
stringFields[f].setText("" + s);
} catch (ArrayIndexOutOfBoundsException e) {
return;
}
}
/** Yields: the "ready" button. Needed to hook up ActionListener */
public JButton getButton() {
return theButton;
}
/** Yields:the locale that was selected from the choice box (the default, if none) */
public Locale getLocale() {
return locales[choiceBox.getSelectedIndex()];
}
}