Example: -
import java.awt.*;
import java.awt.event.*;
class AwtControlDemo {
private Frame mainFrame;
private Label headerLabel;
private Label statusLabel;
private Panel controlPanel;
public AwtControlDemo(){
prepareGUI();
}
public static void main(String[] args){
AwtControlDemo awtControlDemo = new AwtControlDemo();
awtControlDemo.showFileDialogDemo();
}
private void prepareGUI(){
mainFrame = new Frame("Java AWT Examples");
mainFrame.setSize(400,400);
mainFrame.setLayout(new GridLayout(3, 1));
mainFrame.addWindowListener(new WindowAdapter() {
public void windowClosing(WindowEvent windowEvent){
System.exit(0);
}
});
headerLabel = new Label();
headerLabel.setAlignment(Label.CENTER);
statusLabel = new Label();
statusLabel.setAlignment(Label.CENTER);
statusLabel.setSize(350,100);
controlPanel = new Panel();
controlPanel.setLayout(new FlowLayout());
mainFrame.add(headerLabel);
mainFrame.add(controlPanel);
mainFrame.add(statusLabel);
mainFrame.setVisible(true);
}
private void showFileDialogDemo(){
headerLabel.setText("Control in action: FileDialog");
final FileDialog fileDialog = new FileDialog(mainFrame,"Select file");
Button showFileDialogButton = new Button("Open File");
showFileDialogButton.addActionListener(new ActionListener() {
@Override
public void actionPerformed(ActionEvent e) { fileDialog.setVisible(true);
statusLabel.setText("File Selected :"
+ fileDialog.getDirectory() + fileDialog.getFile());
}
});
controlPanel.add(showFileDialogButton);
mainFrame.setVisible(true);
}
}
Output: - C:\java\awt>javac AwtControlDemo.java
C:\java\awt>java AwtControlDemo
6. Applet: - An applet is any small application that performs one specific task that runs within the scope of a dedicated widget engine or a larger program, often as a plug-in.. The term is frequently used to refer to a Java applet, a program written in the Java programming language that is designed to be placed on a web page. Applets are typical examples of transient and auxiliary applications that don't monopolize the user's attention. Applets are not full-featured application programs, and are intended to be easily accessible.
Working with Frame, windows, graphics, color, fonts
Working with Frame, windows
Creating a new frame window from within an applet is actually quite easy. First, create a subclass of Frame. Next, override any of the standard applet methods, such as init( ), start( ), and stop( ), to show or hide the frame as needed. Finally, implement the windowClosing( ) method of the WindowListener interface, calling setVisible(false) when the window is closed.
Once you have defined a Frame subclass, you can create an object of that class. This causes a frame window to come into existence, but it will not be initially visible. You make it visible by calling setVisible(). When created, the window is given a default height and width. You can set the size of the window explicitly by calling the setSize( ) method.
The following applet creates a subclass of Frame called SampleFrame. A window of this subclass is instantiated within the init( ) method of AppletFrame. Notice that SampleFrame calls Frame’s constructor. This causes a standard frame window to be created with the title passed in title. This example overrides the applet’s start( ) and stop( ) methods so that they show and hide the child window, respectively. This causes the window to be removed automatically when you terminate the applet, when you close the window, or, if using a browser, when you move to another page. It also causes the child window to be shown when the browser returns to the applet.
Example: -
import java.awt.*;
import java.awt.event.*;
class AwtContainerDemo {
private Frame mainFrame;
private Label headerLabel;
private Label statusLabel;
private Panel controlPanel;
private Label msglabel;
public AwtContainerDemo(){
prepareGUI();
}
public static void main(String[] args){
AwtContainerDemo awtContainerDemo = new AwtContainerDemo();
awtContainerDemo.showFrameDemo();
}
private void prepareGUI(){
mainFrame = new Frame("Java AWT Examples");
mainFrame.setSize(400,400);
mainFrame.setLayout(new GridLayout(3, 1));
mainFrame.addWindowListener(new WindowAdapter() {
public void windowClosing(WindowEvent windowEvent){
System.exit(0);
}
});
headerLabel = new Label();
headerLabel.setAlignment(Label.CENTER);
statusLabel = new Label();
statusLabel.setAlignment(Label.CENTER);
statusLabel.setSize(350,100);
msglabel = new Label();
msglabel.setAlignment(Label.CENTER);
msglabel.setText("Welcome to TutorialsPoint AWT Tutorial.");
controlPanel = new Panel();
controlPanel.setLayout(new FlowLayout());
mainFrame.add(headerLabel);
mainFrame.add(controlPanel);
mainFrame.add(statusLabel);
mainFrame.setVisible(true);
}
private void showFrameDemo(){
headerLabel.setText("Container in action: Frame");
final Frame frame = new Frame();
frame.setSize(300, 300);
frame.setLayout(new FlowLayout());
frame.add(msglabel);
frame.addWindowListener(new WindowAdapter() {
public void windowClosing(WindowEvent windowEvent){
frame.dispose();
}
});
Button okButton = new Button("Open a Frame");
okButton.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
statusLabel.setText("A Frame shown to the user.");
frame.setVisible(true);
}
});
controlPanel.add(okButton);
mainFrame.setVisible(true);
}
}
Output: -
C:\java\awt>javac AwtControlDemo.java
C:\java\awt>java AwtControlDemo
Working with graphics, color, fonts
A graphics context provides the capabilities of drawing on the screen. The graphics context maintains states such as the color and font used in drawing, as well as interacting with the underlying operating system to perform the drawing. In Java, custom painting is done via the java.awt.Graphics class, which manages a graphics context, and provides a set of device-independent methods for drawing texts, figures and images on the screen on different platforms.
The java.awt.Graphics is an abstract class, as the actual act of drawing is system-dependent and device-dependent. Each operating platform will provide a subclass of Graphics to perform the actual drawing under the platform, but conform to the specification defined in Graphics.
Example: -
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Font;
import java.awt.Graphics;
import javax.swing.JFrame;
import javax.swing.JPanel;
class MainClass extends JPanel {
public void paint(Graphics g) {
Dimension d = this.getPreferredSize();
int fontSize = 20;
g.setFont(new Font("TimesRoman", Font.PLAIN, fontSize));
g.setColor(Color.red);
g.drawString("http://anuj32.net46.net/desktop", 10, 20);
}
public static void main(String[] args) {
JFrame frame = new JFrame();
frame.getContentPane().add(new MainClass());
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setSize(200,200);
frame.setVisible(true);
}
}
Output: -
C:\java\awt>javac AwtControlDemo.java
C:\java\awt>java MainClass
