[program-java] Fruit Basket
- From: "Corbett, James" <James.Corbett@xxxxxxxxxxxxx>
- To: <program-java@xxxxxxxxxxxxx>
- Date: Thu, 12 Mar 2009 10:33:39 -0500
Source Code...
...entry point...
package main;
/*
* entry point of application
* this application frame work is known as
* MVC model view controller
* this approach ensures encapsulation since there is only
* one public interface
* written by j. corbett
* march 10, 2009
*/
public class Main {
public static void main(String[] args) {
new client.FruitBasketDemo();
}
/*
* the above mentioned line of code creates an instance of the
* FruitBasketDemo class with out creating an object.
* this is possible because there will be no further
* reference to any object if declared.
* an import is not required because class FruitBasketDemo is
implicitly declared by prefixing the class name with the package name
* i.e. client.FruitBasketDemo.
*/
} // end of class
************
package client;
/*
* The specifications for a fruit basket program are as follows:
*1. The program is a GUI interface, or the equivalent with at least an edit
box, list box, and two buttons.
*2. The user can type the name of a fruit, e.g., apple, in the edit box.
*3. When the Add button is activated, the fruit is copied into the list box
and the edit box is cleared to be ready for another entry.
*4. When the Delete button is activated, the currently focused fruit in the
list box, or basket, is removed.
*5. For accessibility, static labels should be associated with the edit box
and list box, since these controls do not have captions like buttons.
*6. Keyboard users will also appreciate a unique hot key for each control.
*7. Making Add the default button allows a fruit to be added by simply
pressing Enter after typing its name.
*8. An error message alerts the user if Add is pressed without a fruit in the
edit box or Delete is pressed without a fruit in the list box.
*written by j. corbett
*march 10, 2009
*/
//required libraries for this example
import org.eclipse.swt.SWT;
import org.eclipse.swt.events.*;
import org.eclipse.swt.widgets.*;
import org.eclipse.swt.graphics.*;
public class FruitBasketDemo {
private Display display;
private Shell shell;
/*
* the following items are private members of this class
* all items are controls also known as widgets.
* they are declared private so as the outside world is not aware of
them
* however declaring them at this point of the application
* will make them accessible to the entire class
* regardless of where the instance is created.
*/
private Combo cFruit;
private Text tFruit;
private Button cmdAdd;
private Button cmdDelete;
private Button cmdExit;
private MessageBox msg;
public FruitBasketDemo() {
display = new Display(); // new instance of display
shell = new Shell(display); // new instance of shell with
display passed as a parameter
msg = new MessageBox(shell); // new instance of the message box
widget
run(); // call to the run method
} // end of constructor method
private void run() {
shell.setSize(450, 300);
// centers shell on screen
Monitor primary = display.getPrimaryMonitor ();
Rectangle bounds = primary.getBounds ();
Rectangle rect = shell.getBounds ();
int x = bounds.x + (bounds.width - rect.width) / 2;
int y = bounds.y + (bounds.height - rect.height) / 2;
shell.setLocation (x, y);
// end of centering
// setting font size and style for screen caption
FontData largFont = new FontData("Times New Roman",24,SWT.BOLD);
shell.setFont(new Font(display, largFont));
shell.setText("Fruit Basket Demo using JAVA and SWT");
// end of setting font
registerShellEscapeListener();
//a group is a container
Group grp = new Group(shell, SWT.NONE); // new instance of the
group widget
grp.setSize(400, 200);
grp.setLocation(15, 25);
grp.setText("");
// end of group in this context, however all widgets are now
part of the group
Label label1 = new Label(grp, SWT.FLAT); // new instance of the
label widget
label1.setSize(75, 20);
label1.setLocation(20, 20);
label1.setText("Select a Fruit");
cFruit = new Combo(grp, SWT.DROP_DOWN|SWT.READ_ONLY); // new
instance of the combo widget
cFruit.setSize(100, 20);
cFruit.setLocation(100, 20);
Label label2 = new Label(grp, SWT.FLAT); // new instance of the
label widget
label2.setSize(50, 20);
label2.setLocation(220, 20);
label2.setText("Enter Fruit");
tFruit = new Text(grp, SWT.BORDER); // new instance of the text
widget
tFruit.setSize(100, 20);
tFruit.setLocation(280, 20);
registerTextListener();
cmdAdd = new Button(grp, SWT.PUSH); // new instance of the
button widget
cmdAdd.setSize(60, 20);
cmdAdd.setLocation(90, 80);
cmdAdd.setText("&Add");
cmdDelete = new Button(grp, SWT.PUSH);
cmdDelete.setSize(60, 20);
cmdDelete.setLocation(180, 80);
cmdDelete.setText("&Delete");
cmdExit = new Button(grp, SWT.PUSH);
cmdExit.setSize(60, 20);
cmdExit.setLocation(270, 80);
cmdExit.setText("E&xit");
registerCommandButtonListeners();
shell.open();
while (!this.shell.isDisposed()) {
if (!this.display.readAndDispatch()) {
this.display.sleep();
}
}
} // end of run
/*
* the following method listens for the escape button to be pressed
* and then executes the code.... in this case it closes the shell
*/
private void registerShellEscapeListener() {
shell.addListener (SWT.Traverse, new Listener () {
public void handleEvent (Event event) {
switch (event.detail) {
case SWT.TRAVERSE_ESCAPE:
shell.close ();
event.detail = SWT.TRAVERSE_NONE;
event.doit = false;
break;
}
}
});
} // end of register shell escape listener
/*
* widgets require listeners to determine the event being triggered at
a particular time.
* In the following listener method, the listener for the
* text box is waiting for the enter key to be pressed on the text
widget.
* When ever the event is triggered, control is passed to the method
and code specific to the
* event is executed.
*/
private void registerTextListener() {
tFruit.addTraverseListener(new TraverseListener () {
public void keyTraversed(TraverseEvent e) {
switch (e.detail) {
case SWT.TRAVERSE_RETURN:
setFruitAdded();
}
}
});
} // end of register text listener
private void registerCommandButtonListeners() {
cmdAdd.addSelectionListener(new SelectionAdapter() {
public void widgetSelected(SelectionEvent e) {
setFruitAdded();
}
});
cmdDelete.addSelectionListener(new SelectionAdapter() {
public void widgetSelected(SelectionEvent e) {
setFruitDeleted();
}
});
cmdExit.addSelectionListener(new SelectionAdapter() {
public void widgetSelected(SelectionEvent e) {
shell.close();
}
});
} // end of command button listeners
private void setFruitAdded() {
if (tFruit.getText().equals("")) {
msg.setText("Caution");
msg.setMessage("You cannot leave the edit field empty,
please try again!");
msg.open();
tFruit.setFocus();
return;
} else {
cFruit.add(tFruit.getText());
cFruit.setFocus();
cFruit.select(0);
tFruit.setText("");
}
} // end of set fruit added
private void setFruitDeleted() {
if (cFruit.getItemCount() == 0) {
msg.setText("Caution");
msg.setMessage("You cannot delete an item from the
fruit basket, because there is nothing in the basket!");
msg.open();
cFruit.setFocus();
return;
} else {
cFruit.remove(cFruit.getSelectionIndex());
if (cFruit.getItemCount() > 0) {
cFruit.select(0);
}
cFruit.setFocus();
}
} // end of set fruit deleted
} // end of class
James M. Corbett
A / Technical Specialist
GST/HST Micros | Micros de la TPS/TVH
GST/HST Redesign Division | Division de la restructuration de la TPS/TVH
Revenue and Accounting Systems Directorate (RASD) | Direction des Systèmes de
revenu et de comptabilité (DSRC)
Information Technology Branch (ITB) | Direction générale de l'informatique (DGI)
Canada Revenue Agency | Agence du revenue du Canada
(613) 941-1338
"...Is a hippopotamus a hippopotamus, or just a really cool Opotamus?"
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