Transcript cs288_Lecture005

Object-Oriented Software Engineering
CS288
1
GUI building with NetBeans
Contents
• User Interaction
• JButtons
• JTextFields
• JLabels
• JForms in NetBeans
• Practical steps for building GUI in NetBeans
2
GUI, Graphical User Interface
1.
2.
3.
4.
5.
For the course assignment you will be creating a
Java application with GUI.
GUIs are laborious and complex.
NetBeans Provides a useful GUI builder tool with
drag and drop form creation.
This presentation gives a crash course in using the
tool.
The underlying concepts of GUIs and how they
work in Java will be discussed in depth in later
lectures.
3
What's in a GUI
• Any application involving a human
needs to allow them to
– input data,
– ask for methods to be executed
– and get meaningful responses.
4
What's in a GUI
JButton
JTextFields
JComboBox
shows the main elements
that we will include in our
GUI to provide user interaction.
This whole GUI will be provided
by a new class that we will implement:
FormJFrame
JLabel
5
What's in a GUI
Results displayed in separate window
using a table format.
6
The Building class again
• Methods Signatures:
– public void addRoom(Room newRoom)
– public String[ ][ ] roomsToArrayArray()
– public void setRoom(Vector<Room> newRooms)
• Fields
– private Vector<Room> rooms
This lists the methods and fields we want to use for this exercise.
The lab sessions so far have been building up an enhanced version
of this class.
7
Room Class, with Enum Type
For this exercise we will add a
new Enum Type internally to the
Room Class:
public enum Use {
HALL, LOUNGE,
BEDROOM, KITCHEN,
BATHROOM
}
This will hold the use to which a
room will be put.
8
The Room Class again, with Enum Type
• Methods:
– Constructor:
Room(Double newArea,
int
newDoors,
int
newWindows,
String room_type)
– String[ ] toStringArray()
• Fields:
–
–
–
–
private Double area;
private int doors;
private int windows;
private Use room_type;
This lists the methods and fields we want to use for this exercise.
The lab sessions so far have been using a different version
of this class.
9
Add Room Scenario
10
Where is the Room Class
• This scenario requires the FormJFrame class to
construct a Room object.
• In early versions of Building we wrote Room as an
inner class.
• If we want a Room object to be constructed by other
classes we need to convert it into a stand-alone class
in a file Room.java
• Fortunately the structure of the Building class means
we only need remove the Room code and move it to
a new file Room.java in the same folder. No other
changes are needed to the Building class for it to still
work.
11
Creating Java Forms in NetBeans
• NetBeans allows us to construct GUIs via a drag and
drop tool that integrates with existing code.
12
Creating Java Forms in NetBeans
• From the existing
project that contains
the Building class,
and Room class
add a new JFrom:
13
Creating Java Forms in NetBeans
• Choose some
suitable name or
other
• Click Package
14
Creating Java Forms in NetBeans
• Choose the
package where the
other source files
live.
• Click Finish
15
Design-time, graphical view
Netbeans opens a
drag and drop
GUI design tool for
FormJFrame
16
Design-time, graphical view
• Note NetBeans has
created a whole new
class at this point:
First task is to add three text boxes to input data.
17
Design-time, graphical view
• JTextFields are a Java class specifically designed
for GUIs as a place holder for strings typed in by
users.
• These will be covered in depth in later lectures.
• Drag relevant icon onto the blank form.
• Doing so creates a new Java object of the
relevant class.
• It automatically creates code within that class to
cause the object to appear when the code is run.
18
Design-time, graphical view
List of available graphical elements
for draging onto form
19
Design-time, graphical view
Visual representation
of object.
Java properties of jTexField1 object.
Lists fields of that object which we can
modify
20
Design-time, graphical view
• Rename field value
with inspector
• Right click object
• Change name to
something
meaningful.
21
Design-time, graphical view
• Change default value in design view.
• Double click text in field and type in new value,
say 12.
22
Design-time, graphical view
• Repeat till we have three JTextField objects
with suitable names and default values.
23
Design-time, graphical view
• Follow same process to drag three new JLabel
objects onto the form and give them suitable
names and default values:
24
Design-time, graphical view
• Resize one TextField
• Control click on each TextField
• Right click and choose same size:
25
Design-time, graphical view
• Drag over two JButton
object
• Change the fields
names as before
• Change the display text
as before
26
Design-time, graphical view
• Register action listener to JButton objects
• Action listners will be covered in depth in later lectures
27
Source view of FormJFrame object
Large amounts of code have now been included in the FormJFrame
source file FormJFrame.java. The only parts of this that we need worry
about are the two new methods:
private void showRoomsButtonActionPerformed(java.awt.event.ActionEvent evt)
{/* TODO add your handling code here: */ }
private void addRoomButtonActionPerformed(java.awt.event.ActionEvent evt)
{/* TODO add your handling code here: */ }
28
New Code for JButtons
private void addRoomButtonActionPerformed(java.awt.event.ActionEvent evt) {
// TODO add your handling code here:
String areaString = areaTextField.getText();
String doorString = doorsTextField.getText();
String windowString = windowsTextField.getText();
String roomTypeString = (String)roomTypeComboBox.getSelectedItem();
Double rmArea = new Double(areaString);
int numDoors = (int)(new Integer(doorString));
int numWin = (int)(new Integer(windowString));
Room newRoom = new Room(rmArea, numDoors, numWin, roomTypeString);
frame_building.addRoom(newRoom);
frame_building.showRoomsTable();
}
private void showRoomsButtonActionPerformed(java.awt.event.ActionEvent evt) {
// TODO add your handling code here:
frame_building.showRoomsTable();
}
29