Develop Reference

how to use mouse click event

Hi i have a class where i am using mouseclick event i want to call another class when i click from my mouse
MouseListener mouseListener = new MouseAdapter() {
public void mouseClicked(MouseEvent mouseEvent) {
JList theList = (JList) mouseEvent.getSource();
if (mouseEvent.getClickCount() == 2) {
int index = theList.locationToIndex(mouseEvent.getPoint());
if (index >= 0) {
Object o = theList.getModel().getElementAt(index);
// System.out.println("Double-clicked on: " + o.toString());
String a=o.toString();
LiistSelection.setListIndex(a);
System.out.println(LiistSelection.getListIndex());
new MyGui4();
}
}
}
};
i want to call this class when user click on list then new window should open
here is my class mygui4.java
public class MyGui4 extends JFrame
{
JLabel jLabel1;
Container pane;
private static ResultSet resultSet = null;
public void Gui( )
{
{
getContentPane().setBackground(new java.awt.Color(255,153,51));
}
this.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
Container c = getContentPane();
setUndecorated(true);
Dimension screenSize = Toolkit.getDefaultToolkit().getScreenSize();
setBounds(0,0,screenSize.width, screenSize.height);
ImageIcon image = new ImageIcon("E:\\SOFTWARE\\TrainPIS\\res\\drawable\\a0.png");
Border border = LineBorder.createGrayLineBorder();
jLabel1 = new JLabel(image);
jLabel1.setBorder(border);
jLabel1.setBackground(Color.red);
c.add(jLabel1);
setLayout(null);
}
public static void main( String[] args )
{
final MyGui4 frame = new MyGui4();
frame.Gui();
frame.setVisible(true);
}
}

You want to Create a object of another Class and call a function using a object.
class second
{
//.....
public void function()
{
//........
}
public void function(int index)
{
//..........
}
}
second s=new second();
s.function()//calling function
int i=10;
s.function(i)//calling function with parameter
Try This Example :
import javax.swing.*;
import java.awt.event.*;
import java.awt.*;
class m extends JFrame
{
String s="The Value of List is 10";
m()
{
setVisible(true);
pack();
setLayout(null);
JButton b=new JButton("Click to Open another form");
b.setBounds(10,10,200,40);
add(b);
b.addMouseListener(new MouseAdapter()
{
public void mouseClicked(MouseEvent e)
{
new s(s);//calling another class contructor
}
});
}
public static void main (String[] args)
{
new m();
}
}
class s extends JFrame
{
s(String s)
{
setVisible(true);
setSize(100,100);
setTitle(s);
}
}
Click The button Another Class and Open The Window

It looks to me like you are tying to invoke the class MyGui4 from the command line when you start the JVM or from another application when you click on the JList, If so then the code needs to be the same in both places.
When invoked from the command line the main() method is invoked which in turn invokes 3 lines of code:
final MyGui4 frame = new MyGui4();
frame.Gui();
frame.setVisible(true);
When you invoke the code when clicking on the JList you invoke 1 line of code:
new MyGui4();
Can you tell me what the difference is?
Of course I still don't understand the point of this code because none of the methods in your MyGui4 class accept a parameter. So it doesn't matter which item in the JList you click on you will still display the same GUI with the same information. You need to pass the selected object from your JList to your GUI.

JFrame paint does not overriding

to execute flow chart Symbols.
But JFrame paint method is not working for this method.
package floating;
import designs.*; //mydesings for executing flow chart Symbols
import java.awt.*;
import javax.swing.*;
public class Test extends JFrame
{
boolean START,PASS; //for using
int SPEED=1;
JSlider jSlider1 = new javax.swing.JSlider();
JSeparator js=new JSeparator();
JToggleButton jToggleButton1 = new javax.swing.JToggleButton("START");
JToggleButton jToggleButton2 = new javax.swing.JToggleButton("PASS");
Test(String a)
{
JFrame jf=new JFrame(a);
Dimension dim=Toolkit.getDefaultToolkit().getScreenSize();
jf.setSize(dim.width,dim.height-30);
jf.setDefaultCloseOperation(jf.EXIT_ON_CLOSE);
jToggleButton1.setLocation((dim.width/2)+30,25);
jToggleButton1.setSize(100,30);
jToggleButton1.addItemListener(new java.awt.event.ItemListener() {
public void itemStateChanged(java.awt.event.ItemEvent evt) {
jToggleButton1ItemStateChanged(evt);
}
});
jToggleButton2.setLocation((dim.width/2)+50+100,25);
jToggleButton2.setSize(100,30);
jToggleButton2.addItemListener(new java.awt.event.ItemListener() {
public void itemStateChanged(java.awt.event.ItemEvent evt) {
jToggleButton2ItemStateChanged(evt);
}
});
js.setOrientation(SwingConstants.VERTICAL);
js.setForeground(Color.red);
js.setLocation(dim.width/2,0);
js.setPreferredSize(dim);
js.setSize(10,dim.height);
jf.add(js);
jSlider1.setLocation(dim.width-300,20);
jSlider1.setSize(250,50);
jSlider1.setToolTipText("Set to Seconds");
jSlider1.setMinimum(1);jSlider1.setMaximum(5);jSlider1.setMajorTickSpacing(1);
jSlider1.setMinorTickSpacing(1);jSlider1.setValue(1);
jSlider1.setPaintLabels(true);
jSlider1.setPaintTicks(true);
jSlider1.setPaintTrack(true);
jSlider1.addMouseListener(new java.awt.event.MouseAdapter() {
public void mouseClicked(java.awt.event.MouseEvent evt) {
jSlider1MouseClicked(evt);
}
});
jf.add(jSlider1);
jf.add(jToggleButton1);
jf.add(jToggleButton2);
jf.setLayout(null);
jf.setVisible(true);
}
public void jToggleButton1ItemStateChanged(java.awt.event.ItemEvent evt)
{
if(jToggleButton1.getActionCommand()=="START")
{
System.out.printf(jToggleButton1.getText());
jToggleButton1.setText("STOP");
this.START=true;
System.out.println(this.START);
}
else
{
System.out.printf(jToggleButton1.getText());
jToggleButton1.setText("START");
this.START=false;
System.out.println(this.START);
}
}
public void jToggleButton2ItemStateChanged(java.awt.event.ItemEvent evt)
{
if( jToggleButton2.getActionCommand()=="PASS")
{
System.out.printf(jToggleButton2.getText());
jToggleButton2.setText("RESUME");
this.PASS=true;
System.out.println(" "+this.PASS);
}
else
{
System.out.printf(jToggleButton2.getText());
jToggleButton2.setText("PASS");
this.PASS=false;
System.out.println( " " +this.PASS);
}
}
private void jSlider1MouseClicked(java.awt.event.MouseEvent evt)
{
this.SPEED=jSlider1.getValue();
System.out.println(SPEED);
}
#Override
public void paint(Graphics g) //testing paint method
{
super.paint(g);
g.drawLine(10, 20, 50, 70);
repaint();
}
public static void main(String args[])
{
Test a=new Test("Test");
}
}

Test class extends JFrame. So if you want to have overridden paint method to work, you have to create an object of Test class. And make it setVisible(true)
In stead, you are creating another JFrame object in Test's constructor. Don't create it. The object of Test itself is a JFrame. Add all components to Test object in stead of JFrame object (jF).
Hope this helps.

Don't invoke repaint() from a painting method. This will cause an infinite loop.
Custom painting is done by overriding the paintComponent() method of a JPanel (or JComponent) and then you add the panel to the frame. Read the section from the Swing tutorial on Custom Painting for more information and examples. Start with the example from the tutorial and make changes so your class is better designed.
Don't use "==" for string comparisons. Use the equals(...) method.
Also, in the future, post a proper SSCCE when you ask a question. Your question is about painting so most of the code you posted is unrelated to the question.

Grapghic doesn't move

I'm trying to make a code that will move a red ball with JButtons (and later add keybinders). There are no problems when I compile and when I run I see the ball but the JButtons won't affect him. I think the problem might be that the ball is drawed only once and then is called again and again without being drawed in the new position but I don't know how to fix that.
1) does anybody know how I can fix that?
2) is there a way to change the shape of a JPanel to a ball? (that would probably be a simpler way to move him)
package il.co.atlantis;
import java.awt.event.KeyAdapter;
import java.awt.event.KeyEvent;
import java.awt.event.KeyListener;
import javax.swing.*;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.event.ActionListener;
import java.awt.event.ActionEvent;
public class KeyBinders implements ActionListener {
boolean right=true, left=false, up=false, down=false, inGame=true;
JPanel backgroundPanel, bannerPanel, scorePanel, applePanel;
JLabel currentScoreLabel, highestScoreLabel;
JButton upButton, downButton, rightButton, leftButton;
long millis =System.currentTimeMillis(), millisn =System.currentTimeMillis();
public static final int WID = 10, HEI = 10;
public static int x1 = 100, y1 = 100;
public class MyGraphics extends JComponent {
private static final long serialVersionUID = 1L;
MyGraphics() {
setPreferredSize(new Dimension(700, 500));
}
public void moveRight(){
++x1;
}
public void moveLeft(){
--x1;
}
public void moveUp(){
--y1;
}
public void moveDown(){
++y1;
}
public void paintComponent(Graphics g){
super.paintComponents(g);
g.setColor(Color.red);
g.fillOval(x1, y1, WID, HEI);
}
}
public JPanel CreateContentPane (){
JPanel totalGUI = new JPanel();
totalGUI.setLayout(null);
backgroundPanel = new JPanel();
backgroundPanel.setBackground(Color.black);
backgroundPanel.setLocation(100, 10);
backgroundPanel.setSize(700, 500);
totalGUI.add(backgroundPanel);
upButton = new JButton("up");
upButton.setLocation(0,0);
upButton.setSize(50,50);
totalGUI.add(upButton);
downButton = new JButton ("down");
downButton.setLocation(0,50);
downButton.setSize(50,50);
totalGUI.add(downButton);
rightButton = new JButton("right");
rightButton.setLocation(0,100);
rightButton.setSize(50,50);
totalGUI.add(rightButton);
leftButton = new JButton("left");
leftButton.setLocation(0,150);
leftButton.setSize(50,50);
totalGUI.add(leftButton);
MyGraphics tr = new MyGraphics();
tr.setLocation(100, 100);
backgroundPanel.add(tr);
return totalGUI;
}
public void ActionPerformed(ActionEvent h){
if(h.getSource() == upButton) {
--y1;
}
else if(h.getSource() == downButton){
++y1;
}
else if(h.getSource() == leftButton){
--x1;
}
else if(h.getSource() == rightButton){
++x1;
}
}
private static void createAndShowGUI() {
JFrame.setDefaultLookAndFeelDecorated(true);
JFrame frame = new JFrame("[=] JButton Scores! [=]");
//Create and set up the content pane.
KeyBinders demo = new KeyBinders();
frame.setContentPane(demo.CreateContentPane());
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setSize(280, 190);
frame.setVisible(true);
}
public static void main(String[] args) {
//Schedule a job for the event-dispatching thread:
//creating and showing this application's GUI.
SwingUtilities.invokeLater(new Runnable() {
public void run() {
createAndShowGUI();
}
});
}
public KeyBinders() {
// TODO Auto-generated constructor stub
}
#Override
public void actionPerformed(ActionEvent arg0) {
// TODO Auto-generated method stub
}
}

When you invoke action event, actionPerformed() function gets called, as you did. You have change the drawing position too. you need to call Component.repaint() which tells Swing t hat the entire component, whichever one you specified to be repainted , must be updated . So add this function calling in your code. For example:
public void ActionPerformed(ActionEvent h){
if(h.getSource() == upButton) {
--y1;
}
else if(h.getSource() == downButton){
++y1;
}
else if(h.getSource() == leftButton){
--x1;
}
else if(h.getSource() == rightButton){
++x1;
}
repaint();
}
Check the tutorial: Performing Custom Painting.

There's a method called repaint() you should familiarize yourself with.
When called on a component (such as a JFrame) it'll repaint all the components within. Naturally you need to call it if you want your changes to become visible on the screen.
As for custom painting, you shouldn't use a Component at all, rather use the Graphics.fillRect/fillOval etc. methods to just draw what you want.
See here for the custom painting tutorial.

how to suspend Applet in browser when tab is unselected

I'm making my first Applet. I have a JPanel which creates a Swing GUI and performs CPU intensive tasks (repainting a Component 60Hz). My Applet displays this JPanel on event dispatching thread. here is an abstraction of the problem. Normally I would launch the applet from an html document instead of having a main method. This program puts about a 40% load on my CPU.
import javax.swing.*;
import java.awt.*;
import java.awt.geom.*;
import java.awt.event.*;
public class TestApplet extends JApplet {
TestPanel tp;
public void init() {
try {
SwingUtilities.invokeAndWait(new Runnable() {
public void run() {
createGUI();
}
});
} catch (Exception e) {
System.err.println("createGUI didn't complete successfully");
}
}
private void createGUI() {
//Create and set up the content pane.
tp = new TestPanel();
tp.setOpaque(true);
setContentPane(tp);
}
public static void main(String[] args) {
JFrame f = new JFrame("Fish Tank");
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
JApplet ap = new TestApplet();
ap.init();
f.add("Center", ap);
f.pack();
f.setVisible(true);
}
}
class TestPanel extends JPanel{
public TestTank tt = new TestTank();
public TestPanel() {add(tt);}
public void stop() {tt.stop();}
public void start() {tt.start();}
}
class TestTank extends Component implements ActionListener{
private javax.swing.Timer timer;
TestTank(){
timer = new javax.swing.Timer(17, this);
timer.setCoalesce(true);
timer.start();
}
public Dimension getPreferredSize(){
return new Dimension(900, 700);
}
public void paint(Graphics g) {
Graphics2D g2 = (Graphics2D) g;
Dimension size = getSize();
g2.setPaint(new GradientPaint(0,0,Color.RED,900, 0,Color.WHITE));
g2.fill(new Rectangle2D.Float(0,0,size.width,size.height));
}
public void actionPerformed(ActionEvent e) {
repaint();
}
public void stop(){timer.stop();}
public void start(){timer.start();}
}
My question: How do I suspend and resume execution of the JPanel (FishTankPanel) when the user switches tabs or minimizes the browser? I want the Applet to stop using the CPU when the user can't see what it is doing. I need to capture browser events in order to execute tp.stop() in the applet. I have tried to execute them with window event listeners in the JPanel, and by overriding the start() and stop() methods in the Applet. I have been unsuccessful. Any suggestions or solutions would be appreciated.

I would do as Dave said and use the JApplet override start and stop methods to call your GUI methods. For instance, see changes in code:
public class TestApplet extends JApplet {
TestPanel tp;
public void init() {
// ... no change
}
private void createGUI() {
// ... no change
}
#Override
public void stop() {
if (tp != null) {
tp.stop();
}
}
#Override
public void start() {
if (tp != null) {
tp.start();
}
}
}
class TestTank extends Component implements ActionListener {
private javax.swing.Timer timer;
// ... no change
public void stop() {
timer.stop();
System.out.println("stop");
}
public void start() {
timer.start();
System.out.println("start");
}
}

It seems you might need to leverage some JS for this. E.G. use the JS shown in this answer to explicitly call the applet start() & stop() methods on focus & blur detection respectively.

The solution for my problem was to use javascript to implement the Page Visibility API. I then called the appropriate Java methods from within the javascript script.

Unable to call the repaint in applet from child frame

I have made an applet name ParentApplet.java whose task is to create a child frame
Child frame coding is defined in ChildFrame.java
ParentApplet.java
public class ParentApplet extends Applet {
ChildFrame frame;
private static int time = 0;
#Override
public void start() {
frame.setVisible(true);
}
#Override
public void stop() {
frame.setVisible(false);
}
#Override
public void init() {
frame = new ChildFrame("Child");
this.setSize(400, 400);
}
#Override
public void paint(Graphics g) {
g.drawString("Child's Info : " + (++time), 50, 100);
g.drawString(frame.getMessage(), 400, 100);
System.out.println(frame.getMessage().isEmpty() ? "Empty" : frame.getMessage());
}
}
ChildFrame.java
public class ChildFrame extends Frame {
private String mess = "";
public ChildFrame(String title) {
super(title);
addMouseListener(new MyMouseAdapter(this));
addWindowListener(new MyWindowAdapter(this));
setSize(300, 500);
}
public String getMessage() {
return mess;
}
public void setMessage(String mess) {
this.mess = mess;
(new ParentApplet()).repaint();
System.out.println("Click");
}
}
MyMouseAdapter.java
public class MyMouseAdapter extends MouseAdapter {
ChildFrame frame;
public MyMouseAdapter(ChildFrame frame) {
this.frame = frame;
}
#Override
public void mouseClicked(MouseEvent e) {
frame.setMessage("Mouse Cliked in Child");
}
}
MyWindowAdapter.java
public class MyWindowAdapter extends WindowAdapter {
ChildFrame frame;
public MyWindowAdapter(ChildFrame frame) {
this.frame = frame;
}
#Override
public void windowClosing(WindowEvent we) {
frame.setVisible(false);
}
}
Now i am unable to reach the paint method again even after calling the repaint method from the ChildFrame class. Please suggest me whether i have done something wrong or some thing i need to understand.
Thanks in advance
Gagandeep Singh

The answer to your question is basically "you don't do that".
The Applet's paint() method is responsible for painting the contents of the actual applet component-- i.e. the visible component that appears in the web page. Your ChildFrame should then have a separate paint() method to paint itself (or in fact, would usually have a Canvas added to it, and that Canvas in turn has its own paint() method).
(Remember that in Java a "Frame" is effectively a "window"-- i.e. a standalone window that opens separately to the web page.)
You can call repaint() on whatever component from wherever you like. This will eventually lead to that component's paint() method being called. In your particular example, you shouldn't call "new ParentApplet()" -- you don't want to call repaint() on some randomly created new applet, but rather on the single already existing one. So change this by passing a reference to your applet into the constructor of ChildFrame which ChildFrame can then hold as an instance variable and re-use when needed:
public class ChildFrame extends Frame {
private String mess = "";
private final ParentApplet parentApplet;
public ChildFrame(ParentApplet applet, String title) {
super(title);
this.parentApplet = applet;
addMouseListener(new MyMouseAdapter(this));
addWindowListener(new MyWindowAdapter(this));
setSize(300, 500);
}
...
public void setMessage(String mess) {
this.mess = mess;
parentApplet.repaint();
}
}
I must admit that so far, it's not immediately obvious why you would have a setMessage() on a separate frame whose purpose is to set the message displayed in the applet. Why not put the setMessage() method on the applet in that case? But maybe you have another reason for doing it your way that isn't apparent so far.