Gayle j yaverbaum phd professor of information systems penn state harrisburg
Download
1 / 29

Advanced AppletsPowerpoint - PowerPoint PPT Presentation


  • 412 Views
  • Updated On :

Gayle J Yaverbaum, PhD Professor of Information Systems Penn State Harrisburg. INFSY 547: WEB-Based Technologies. Adding More Applets objects to XML Content . <?xml version="1.0"?> <!DOCTYPE panelslayoutapplet SYSTEM "PanelLayoutsApplet.dtd"> <jclass>

Related searches for Advanced AppletsPowerpoint

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about 'Advanced AppletsPowerpoint' - libitha


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
Gayle j yaverbaum phd professor of information systems penn state harrisburg

Gayle J Yaverbaum, PhD

Professor of Information Systems

Penn State Harrisburg

INFSY 547: WEB-Based Technologies


Adding more applets objects to xml content
Adding More Applets objects to XML Content

<?xml version="1.0"?>

<!DOCTYPE panelslayoutapplet SYSTEM "PanelLayoutsApplet.dtd">

<jclass>

<app class="panellayoutsapplet.PanelLayoutsApplet“

width="300" height="250">

</app>

<app class="firstapplet.FirstApplet" width="300" height="250">

</app>

<app class="urlapplet.URLApplet" width="300" height="250">

</app>

</jclass>


Xsl code
xsl Code

<TR>

<xsl:for-each select="app">

<TD width=“30%">

<applet>

<xsl:attribute name="code">

<xsl:value-of select="@class"/>

</xsl:attribute>

<xsl:attribute name="width">

<xsl:value-of select="@width"/>

</xsl:attribute>

<xsl:attribute name="height">

<xsl:value-of select="@height"/>

</xsl:attribute>

</applet>

</TD>

</xsl:for-each>

</TR>



Applet considerations
Applet Considerations

Javax.swing supplies best classes

setSize is unnecessary but aids in

debugging

applet size is set in html


package guisampleapplet;

import javax.swing.JApplet;

import java.awt.*;

publicclass GUISampleApplet extends JApplet

{

PanelClass p;

publicvoid init ()

{

p = new PanelClass();

}

}


Graphical User Example

package guisampleapplet;

import javax.swing.JApplet;

import java.awt.*;

public class GUISampleApplet extends JApplet

{

PanelClass p;

public void init()

{

p = new PanelClass();

this.setSize(300, 40);

this.add("North", p);

}

}

  • Extending our code!

BorderLayout


package guisampleapplet;

import java.awt.Color;

import java.awt.FlowLayout;

import javax.swing.JButton;

import javax.swing.JPanel;

public class PanelClass extends JPanel {

JButton _button1, _button2, _button3;

JPanel _p;

public PanelClass() {

super();

_p = this;

designPanel();

}

private void designPanel() {

_p.setBackground(Color.blue);

_p.setLayout(new FlowLayout());

_button1 = new CreateAButton(_p, _button1, "Button 1 ",Color.orange);

_button2 = new CreateAButton(_p, _button2, "Button 2 ", Color.GREEN);

_button3 = new CreateAButton(_p, _button3, "Button 3 ", Color.YELLOW);

}

}


package guisampleapplet;

import java.awt.Color;

import javax.swing.JButton;

import javax.swing.JPanel;

public class CreateAButton extends JButton

{

public CreateAButton (JPanel p, JButton b, String str, Color c)

{

super (str);

this.setBackground(c);

p.add (this);

}

}


Layout managers
Layout Managers

In JAVA

layout is set in setLayout method

Indicate layout of choice or accept default

Add () and remove () methods are common to all layouts.


Popular layout managers
Popular Layout Managers

FlowLayout

GridLayout

BorderLayout


Panels
Panels

A layout manager may apply to a panel or an applet as a whole

An applet may be divided into panels which may themselves be divided into subpanels and so on.


Panels

  • Labels, buttons and more may be added to containers (panels)

  • Subsequently, panels are added to the applet


  • Run the applet in the browser


    • Add a class to create a label

    • Add labels between each button

    • Remove button labels

    • Change all button colors

    • Line up each button and label –

      one/line using GridLayout

      (see next slide and page 285 of text)


    GridLayout

    package gridlayoutexample;

    import javax.swing.JApplet;

    import javax.swing.JPanel;

    import java.awt.*;

    public class GridLayoutClass extends JApplet

    {

    CreateAButton b;

    JPanel j;

    public void init ()

    {

    this.setBackground (Color.white);

    j = new JPanel ();

    j.setLayout(new GridLayout(5, 2));

    for (int i=1; i<=10; i++)

    {

    b= new CreateAButton (j, i, Color.red, Color.white);

    j.add (b);

    }

    this.add(j);

    }

    }


    package gridlayoutexample;

    import java.awt.Color;

    import javax.swing.JButton;

    import javax.swing.JPanel;

    public class CreateAButton extends JButton

    {

    public CreateAButton (JPanel p, int x, Color c, Color f)

    {

    super ("Button " + x);

    this.setBackground(c);

    this.setForeground (f);

    }

    }


    Event Driven Programming

    • Code that is called by the system when an

      event occurs

    • An event signifies an occurrence

    • The event generator notifies event handlers


    OS Interrupt

    Screen

    Button Object

    Press Button

    (Buttons generate events)

    Event Handling

    Object

    Event Notification

    Text field

    Object

    JAVA AWT Environment: Messages are sent between JAVA Objects

    Update Text Field

    Typical event handling


    Event handling and associated objects
    Event Handling and Associated Objects

    Interface Events Flow

    User clicks a button

    User types text

    User uses a mouse

    When an event occurs, applet is notified

    Program may take action


    Add implements action listenerto the class publicclass PanelClass extends JPanel implements ActionListener1. Add to the action code to:_button1.addActionListener(this);for designPanel method2. Do this for all of your buttons


    • public void actionPerformed(ActionEvent e)

    • {

    • if (e.getSource() == _button1)

    • {

    • _button1.setBackground (Color.red);

    • _button2.setBackground (Color.blue);

    • _button2.setBackground (Color.yellow);

    • }

    • }

    • Change all of the colors for each button clicked to a different color pattern


    BorderLayout Manager

    • o Divides the container (either a panel or whole

    • applet)

    • o Five areas

    • - North

    • -South

    • -East

    • -West

    • -Center

    • May also use the horizontal and vertical gaps as

    • in FlowLayout


    North

    East

    West

    Center

    South

    BorderLayout Manager


    public void PlacePanels ()

    {

    setLayout(new BorderLayout(5,10));

    .

    .

    }

    Note: 1. may simply be (new BorderLayout ()

    2. the 5,10 indicates border space in pixels


    • Pressing a mouse button triggers a mouse event

    • Rather than implementing ActionListener, you will

    • implement MouseListener (note that more than one listener

    • may be implemented)

    • When a mouse is pressed, the location is stored in x,y

    • coordinates and location may be retrieved with getx ()

    • and gety ().

    • MouseEvent handlers are invoked


    Example on next slides demonstrate
    Example on next slides demonstrate:

    Mouse enter

    Mouse exit

    Left mouse click

    Right mouse click


    import java.applet.Applet;

    import java.awt.*;

    import java.awt.event.*;

    public class mousedemo extends Applet implements MouseListener

    { //note that this bracket will having matching end bracket next screen

    TextField mousetext;

    public void init(){

    mousetext = new TextField(25);

    add(mousetext);

    addMouseListener(this); }

    public void mousePressed(MouseEvent e){

    if((e.getModifiers()& InputEvent.BUTTON1_MASK)

    == InputEvent.BUTTON1_MASK){

    mousetext.setText("Left mouse button down at "

    + e.getX() + "," + e.getY());

    }

    else{

    mousetext.setText("Right mouse button down at "

    + e.getX() + "," + e.getY());

    }

    }


    public void mouseClicked(MouseEvent e){

    mousetext.setText("You clicked the mouse at " +

    e.getX() + "," + e.getY());

    }

    public void mouseReleased(MouseEvent e){

    mousetext.setText("The mouse button is up");

    }

    public void mouseEntered(MouseEvent e){

    mousetext.setText("The mouse is in the applet");

    }

    public void mouseExited(MouseEvent e){

    mousetext.setText("The mouse is out of the applet");

    }

    } //note that this bracket ends the applet from previous page


    ad