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Passing images to an applet with getParameter.

 
Caitlin Gibson
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Posts: 12
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Hi.
I am writing an applet that will allow the user to display images either via a JTextField or as a parameter in an HTML file. Here is the current code:
<code>
// Package import statements.
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.border.*;
// Main method declaration. Inherits from JApplet and implements
// the ActionListener interface.
public class Assign11 extends JApplet
implements ActionListener
{
// Declare 4 private instance variables.
private ImagePanel imagePanel;
private JTextField filename;
private JButton display;
private JPanel myPanel;
private String firstImage,
secondImage;

// Initialize the applet.
public void init()
{
// Instantiate four graphical components. The JTextField
// has a maximum width of 25 characters and the JButton
// has the enclosed string displayed on it.
imagePanel = new ImagePanel();
filename = new JTextField( 25 );
display = new JButton( "Display Image" );
myPanel = new JPanel();
firstImage = getParameter("image1");
secondImage = getParameter("image2");

// Set the new layout manager. Add a JLabel to the panel
// in the Western side. It is identified by the string 'Image'.
// Add both the JTextField and the file name onto the JPanel.
myPanel.setLayout( new BorderLayout() );
myPanel.add( new JLabel( "Image: " ), BorderLayout.WEST );
myPanel.add( filename, BorderLayout.CENTER );
myPanel.add( display, BorderLayout.EAST );
// Add the imagePanel and the JPanel to the contentPane.
getContentPane().add( imagePanel, BorderLayout.CENTER );
getContentPane().add( myPanel, BorderLayout.SOUTH );
// Create a red lined border around the imagePanel
imagePanel.setBorder( new LineBorder( Color.white, 1 ));
// 'Enable' the action listener for the JButton
// component.
display.addActionListener( this );
}
// Define the actionPerformed method. Call the displayImage
// method if either the JButton or JTextField is utilized in
// the input of the image file.
public void actionPerformed( ActionEvent e )
{
if( ( e.getSource() instanceof JButton ) )
displayImage();

}

// displayImage method. Remove whitespace from the JTextField
// before obtaining the input w/ the getText method. Retrieve
// the image and store it in 'image'.
private void displayImage()
{
Image image = getImage( getCodeBase(), filename.getText().trim() );

// Display the image.
imagePanel.showImage( image );

}
} // End of the main method.
// ImagePanel class. Inherits from JPanel.
class ImagePanel extends JPanel
{
// Define and initialize a private instance variable called
// image that is a reference to an instance of Image.
private Image image = null;
// Default constructor.
public ImagePanel()
{
}
// showImage method. Receives an Image object as a parameter.
public void showImage( Image image )
{
// Assign the parameter to the local instance variable.
this.image = image;
// Call the repaint method.
repaint();
}
// paintComponent method. Receives a Graphics object as a
// parameter and assigns it to the reference variable 'g'.
public void paintComponent( Graphics g )
{
// Call the paintComponent method in the base class and pass
// it the graphics object as a parameter
super.paintComponent( g );
// Ascertain that the image was obtained.
if( image != null )
// Draw the image on the applet after obtaining the necessary
// dimensions and originating class.
g.drawImage( image, 0, 0, getWidth(), getHeight(), this );
}
} // End of ImagePanel class.
</code>
I have never worked with getParameter before so I'm not where to place the code that will display the images(s) if passed as a parameter.
Thanks,
-CaitlinG
 
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