HelloWorld. 3
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UI-.. 6
UI-. 6
UI-.. 7
. 9
Java- Java -. Java- - Java (JVM), Sun's AppletViewer, . Java- Java 1995.
-, HTML. - Java -, Java- .
Java- , . -, -, . - HTML applet, object. .
java.applet.Applet , Swing , javax.swing.JApplet. . (Applet Panel, , , Container).
Java-
Java, ; , JRE, ;
;
, -; ;
, , ;
( ) , C++, , JavaScript
, - , / .
Java- :
Java- (plug-in), ;
, Java-plug-in Sun, 64- ;
, Java-, ;
, , HTML;
- , : , ;
|
|
|
, . .
JRE.
HelloWorld
import javax.swing.JApplet;
import java.awt.Graphics;
public class HelloWorld extends JApplet {
public void paint(Graphics g) {
g.drawRect(0, 0,
getSize().width - 1,
getSize().height - 1);
g.drawString("Hello world!", 5, 15);
}
}
Run as Java Applet. appletviewer, : Hello world!.
GUI Swing, javax.swing.JApplet.
, Swing , java.applet.Applet.
, main. , , , main. .
, :
- java.applet.Applet, init, ( , main).
init ( main), . + Panel ( ) init ( main).
!
:
public ( appletviewer ).
Applet/JApplet, Frame/JFrame.
main.
start and init methods.
GUI Applet, content JFrame'a.
import java.applet.Applet;
import java.awt.Graphics;
// JApplet, ..
// c
public class Simple extends Applet {
StringBuffer buffer;
public void init() {
buffer = new StringBuffer();
addItem("initializing... ");
}
public void start() {
addItem("starting... ");
}
public void stop() {
addItem("stopping... ");
}
public void destroy() {
addItem("preparing for unloading...");
}
private void addItem(String newWord) {
System.out.println(newWord);
buffer.append(newWord);
repaint();
}
public void paint(Graphics g) {
//
g.drawRect(0, 0,
getWidth() - 1,
getHeight() - 1);
//
g.drawString(buffer.toString(), 5, 15);
}
}
, :
( init).
( start).
|
|
|
( stop). , . start.
(c stop, destroy). , , ( ).
, .
import java.awt.event.MouseListener;
import java.awt.event.MouseEvent;
import java.applet.Applet;
import java.awt.Graphics;
// JApplet, ..
// c
public class SimpleClick extends Applet
implements MouseListener {
StringBuffer buffer;
public void init() {
addMouseListener(this);
buffer = new StringBuffer();
addItem("initializing... ");
}
public void start() {
addItem("starting... ");
}
public void stop() {
addItem("stopping... ");
}
public void destroy() {
addItem("preparing for unloading...");
}
void addItem(String newWord) {
System.out.println(newWord);
buffer.append(newWord);
repaint();
}
public void paint(Graphics g) {
//
g.drawRect(0, 0,
getWidth() - 1,
getHeight() - 1);
//
g.drawString(buffer.toString(), 5, 15);
}
//
// MouseAdapter
public void mouseEntered(MouseEvent event) {
}
public void mouseExited(MouseEvent event) {
}
public void mousePressed(MouseEvent event) {
}
public void mouseReleased(MouseEvent event) {
}
public void mouseClicked(MouseEvent event) {
addItem("click!... ");
}
}
, . , click!....
UI-
Buttons (javax.swing.JButton)
Checkboxes (javax.swing.JCheckBox)
Single-line text fields (javax.swing.JTextField)
Larger text display and editing areas (javax.swing.JTextArea)
Labels (javax.swing.JLabel)
Lists (javax.swing.JList)
Pop-ups (javax.swing.Popup)
Scrollbars (javax.swing.JScrollBar)
Sliders (javax.swing.JSlider)
Drawing areas (java.awt.Canvas)
Menus (javax.swing.JMenu,javax.swing.JMenuBar javax.swing.JMenuItem, javax.swing.JCheckBoxMenuItem)
Containers (javax.swing.JPanel, javax.swing.JWindow and its subclasses)
