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hi
i have a 10 by 10 grid of buttons and 3 single buttons. when i click any one of the three buttons it triggers the same event but i only want one of them to trigger the event.
how do go about doing this?
i need one of the buttons to trigger more than one event.
how do i go about doing this?
please help
thank you
my code:
import java.awt.*;
import javax.swing.*;
import java.awt.event.*;
public class Robot extends JFrame implements ActionListener
{
private JButton[][] b = new JButton[20][20];
private JButton east, east2, east3, east4;
private JLabel square1Label, direction1Label;
private JTextField squareField, directionField;
public Robot()
{
super ("M shape Program");
Container yourContainer;
yourContainer = getContentPane();
yourContainer.setLayout (new BorderLayout());
JButton east = new JButton("Forward");
JButton east2 = new JButton("Roatate");
JButton east3 = new JButton("Clear");
JButton east4 = new JButton("Exit");
east.addActionListener(this);
east2.addActionListener(this);
east3.addActionListener(this);
east4.addActionListener(this);
JPanel eastPanel = new JPanel();
eastPanel.setLayout(new GridLayout(10,18,5,4));
eastPanel.add(east);
eastPanel.add(east2);
eastPanel.add(east3);
eastPanel.add(east4);
yourContainer.add(eastPanel, BorderLayout.EAST);
JPanel centerPanel = new JPanel ();
centerPanel.setLayout(new GridLayout(10,10));
for(int y = 0;y < 10;y++)
{
for(int x = 0;x < 10;x++)
{
b[x][y] = new JButton("");
centerPanel.add(b[x][y]);
b[x][y].setSize(200,400);
b[x][y].setBackground(Color.green);
b[x][y].addActionListener(this);
}
}
yourContainer.add(centerPanel, BorderLayout.CENTER);
JPanel southPanel = new JPanel ();
square1Label = new JLabel("Square: "); southPanel.add(square1Label);
squareField = new JTextField(2);
southPanel.add(squareField);
direction1Label = new JLabel("Direction: "); southPanel.add(direction1Label);
directionField = new JTextField(2); southPanel.add(directionField);
yourContainer.add(southPanel, BorderLayout.SOUTH);
pack();
setSize(500, 400);
setVisible(true); }
public void actionPerformed(ActionEvent event){
String actioncommand = event.getActionCommand();
if (actioncommand.compareTo("Exit") == 0)
System.exit(0);
{
if(event.getSource() == east);
else b[0][9].setBackground(Color.black);
}
}}
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but i only want one of them to trigger the event
how do go about doing this?
// ...inside constructor
// declaring these (again) as local variables
// ie, JButton east = ...
// leaves the instance variable declarations (above) null
east = new JButton("Forward");
east2 = new JButton("Roatate");
east3 = new JButton("Clear");
east4 = new JButton("Exit");
// its a good idea to set these if you want to use them
east.setActionCommand("forward");
east4.setActionCommand("exit");
...
public void actionPerformed(ActionEvent event)
{
JButton button = (JButton)event.getSource();
String actionCommand = button.getActionCommand();
// show which JButton sent the event:
System.out.println("actionCommand = " + actionCommand);
// two ways to identify a button in this method:
// 1 - use its actionCommand property
if (actionCommand.equals("exit")) // east4
System.exit(0);
if(actionCommand.equals("forward")) // east
;
// 2 - use its reference (from your declaration at top)
if(button == east2) // rotate
{
/* doSomething() */
/* callAnotherMethod() */ ;
}
if(button == east3) // clear
{
/* do some things in this block (curley braces) */
;
}
else
b[0][9].setBackground(Color.black);
}
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i need one of the buttons to trigger more than one event.
how do i go about doing this?
see actionPerformed above for one way: call more than one method or do more than one thing (via statements) inside the curley braces for the JButton that you want to do more than one thing. You can also add more than one ActionListener to a JButton; this is rare.
This code below runs okay. I renamed it so you can run it as–is without name clashing.
import java.awt.*;
import javax.swing.*;
import java.awt.event.*;
public class Robot1 extends JFrame implements ActionListener
{
private JButton[][] b = new JButton[10][10];
private JButton east, east2, east3, east4;
private JLabel square1Label, direction1Label;
private JTextField squareField, directionField;
public Robot1()
{
super ("M shape Program");
Container yourContainer;
yourContainer = getContentPane();
yourContainer.setLayout (new BorderLayout());
// declaring these (again) as local variables
// ie, JButton east = ...
// leaves the instance variable declarations (above) null
east = new JButton("Forward");
east2 = new JButton("Roatate");
east3 = new JButton("Clear");
east4 = new JButton("Exit");
// its a good idea to set these if you want to use them
east.setActionCommand("forward");
east4.setActionCommand("exit");
east.addActionListener(this);
east2.addActionListener(this);
east3.addActionListener(this);
east4.addActionListener(this);
JPanel eastPanel = new JPanel();
eastPanel.setLayout(new GridLayout(10,18,5,4));
eastPanel.add(east);
eastPanel.add(east2);
eastPanel.add(east3);
eastPanel.add(east4);
yourContainer.add(eastPanel, BorderLayout.EAST);
JPanel centerPanel = new JPanel ();
centerPanel.setLayout(new GridLayout(10,10));
for(int y = 0;y < 10;y++)
{
for(int x = 0;x < 10;x++)
{
b[x][y] = new JButton("");
centerPanel.add(b[x][y]);
// this has no affect
// setPreferredSize works better
// b[x][y].setSize(200,400);
b[x][y].setBackground(Color.green);
b[x][y].addActionListener(this);
}
}
yourContainer.add(centerPanel, BorderLayout.CENTER);
JPanel southPanel = new JPanel ();
square1Label = new JLabel("Square: ");
southPanel.add(square1Label);
squareField = new JTextField(2);
southPanel.add(squareField);
direction1Label = new JLabel("Direction: "); southPanel.add(direction1Label);
directionField = new JTextField(2); southPanel.add(directionField);
yourContainer.add(southPanel, BorderLayout.SOUTH);
setDefaultCloseOperation(EXIT_ON_CLOSE);
// use one or the other, not both
// pack();
setSize(500, 400);
setVisible(true);
}
public void actionPerformed(ActionEvent event)
{
JButton button = (JButton)event.getSource();
String actionCommand = button.getActionCommand();
// show which JButton sent the event:
System.out.println("actionCommand = " + actionCommand);
// two ways to identify a button in this method:
// 1 - use its actionCommand property
if (actionCommand.equals("exit")) // east4
System.exit(0);
if(actionCommand.equals("forward")) // east
;
// 2 - use its reference (from your declaration at top)
if(button == east2) // rotate
{
/* doSomething() */
/* callAnotherMethod() */ ;
}
if(button == east3) // clear
{
/* do some things in this block (curley braces) */
;
}
else
b[0][9].setBackground(Color.black);
}
public static void main(String[] args)
{
new Robot1();
}
}
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thank you. i'l try it when i get home.
if i get stuck again could you help out?
thanks my friend
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hi again. you mention these statments:
/* doSomething() */
/* callAnotherMethod() */ ;
i don't understand where to put my statments in this section
i need the forward button to make these event's every time i press the button click after click:
b[0][9].setBackground(Color.black);
b[0][8].setBackground(Color.black);
b[0][7].setBackground(Color.black);
b[0][6].setBackground(Color.black);
b[0][5].setBackground(Color.black);
b[0][4].setBackground(Color.black);
b[0][3].setBackground(Color.black);
b[0][2].setBackground(Color.black);
the things is i don't know how to make it do these events per click in the actionPerformed?
thank you
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You can put them under the if statement that tests for the JButton that you want to trigger the color change, say like
public void actionPerformed(...
...
if (actionCommand.equals("exit")) // east4
System.exit(0);
// or for whatever JButton you want to
// trigger this change...
if(actionCommand.equals("forward")) // east
{
for(int j = 2; j < 10; j++)
b[0][j].setBackground(Color.black);
}
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or you can call a method from actionPerformed and put the code in the method, say
public void actionPerformed(...
...
if (actionCommand.equals("exit")) // east4
System.exit(0);
if(actionCommand.equals("forward")) // east
change backGroundColor();
...
/** somewhere in the Robot class... */
private void changeBackgroundColor()
{
for(int j = 2; j < 10; j++)
b[0][j].setBackground(Color.black);
}
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hi mate.
its turning all those buttons black from pressing forward button once with this statment:
for(int j = 9; j < 10; j++)
b[0][j].setBackground(Color.black);
i need it to be set so that it turns a button black in the grid every time you press forward only.
abit like this
press forward once:
b[0][9].setBackground(Color.black);
press forward again:
b[0][8].setBackground(Color.black);
press forward again
b[0][7].setBackground(Color.black);
kind regards
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Keep track of the row number in the class as an instance variable, say count.
public class Robot1 extends JFrame implements ActionListener
{
...
int count; // instance variable
public Robot1()
{
super ("M shape Program");
count = 9;
...
public void actionPerformed(ActionEvent event)
{
if(actionCommand.equals("forward")) // east
{
if(count < 2 /*some_limit*/)
/* do something about it/reset it */;
b[0][count--].setBackground(Color.black);
}
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Or you could use two instance variables, say row and col and change those (values) around in your event code. You'll have to test for them to keep them within limits to avoid ArrayIndexOutOfBoundsExceptions.
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hi mate
i don't know what statment to put after
if(count < 2....... and on the second line.
i'm just getting errors
if(count < 2 /*some_limit*/)
/* do something about it/reset it */;
b[0][count --].setBackground(Color.black);
i don't understand this section to well only parts of it.
sorry mate
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If we keep pressing the "Forward" button the black buttons march up the left hand column until the top one turns black, ie b[0][0]. The next press of the "forward" button tries to call this:
b[0][-1].setBackground(Color.black);
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in the actionPerformed method. Ouch — ArrayIndexOutOfBoundsException. There is no array element for b[0][-1]. So you want to make sure that the count instance variable cannot go below zero or above the highest index in the b[][this part] array, here, for index = 9. So we can add a test or two to keep count within bounds no matter what the user may do.
if(actionCommand.equals("forward")) // east
{
if(count >= 0 && count < b[0].length) // safe zone
b[0][count--].setBackground(Color.black);
}
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It all depands on what you want to do with the "Formward" button and making the grid buttons black. If you want to keep moving from right to left you could change the indices of b[][] like this
public class Robot1 extends JFrame implements ActionListener
{
// instance variables in class scope
...
int row, col;
public Robot1()
{
super ("M shape Program");
row = 9; // start at
col = 0; // southwest corner
....
}
...
public void actionPerformed(ActionEvent event)
{
JButton button = (JButton)event.getSource();
String actionCommand = button.getActionCommand();
...
if(actionCommand.equals("forward")) // east
{
if(row < 0)
{
col++; // next column
row = b.length-1; // reset to bottom row
}
if(col > b[0].length-1) // past the last column
{
// now what?
col = 0; // start over
// or what ever you have in mind...
}
b[row][col].setBackground(Color.black);
// counting up from bottom to top with each press
// of this button -> row decrements for next time
row--;
}
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finansa
