I am creating a hangman game. I made a button A - Z using the GUI Toolbars in Netbeans as follows:.
My problem is, how can I add an actionlistener to all of it. Is it possible to use a loop? If i click the button A, i will get the character 'a' and so on..
Yes it is possible to use a loop, but since your JButtons were created by using NetBeans code-generation, they won't be in an array or collection initially, and so this is something that you'll have to do: create an array of JButton and fill it with the buttons created by NetBeans. Then it's a trivial matter to create a for loop and in that loop add an ActionListener that uses the ActionEvent's actionCommand (as noted above) in its logic.
Having said this, I think that the better solution is to forgo use of the NetBean's GUI builder (Matisse) and instead to create your Swing code by hand. This will give you much greater control over your code and a much better understanding of it as well. For instance, if you do it this way, then in your for loop you can both create your buttons, add the listeners, and add the button to its container (JPanel).
e.g.,
import java.awt.*;
import java.awt.event.*;
import java.util.ArrayList;
import java.util.List;
import javax.swing.*;
public class Foo2 {
public static void main(String[] args) {
JPanel buttonContainer = new JPanel(new GridLayout(3, 9, 10, 10));
List<JButton> letterButtons = new ArrayList<JButton>(); // *** may not even be necessary
for (char buttonChar = 'A'; buttonChar <= 'Z'; buttonChar++) {
String buttonText = String.valueOf(buttonChar);
JButton letterButton = new JButton(buttonText);
letterButton.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
String actionCommand = e.getActionCommand();
System.out.println("actionCommand is: " + actionCommand);
// TODO fill in with your code
}
});
buttonContainer.add(letterButton);
letterButtons.add(letterButton);
}
JOptionPane.showMessageDialog(null, buttonContainer);
}
}
Well, with some pseudo code, wouldn't this make sence for you?
for(button in bord) {
button.addActionListener(my_actionlistener);
}
Then in your actionlistener you can see which button was pressed
public void actionPerformed(ActionEvent e) {
// button pressed
if ("string".equals(e.getActionCommand()) {
// do something
}
// and so forth
}
You'll need to add the buttons to a list of some kind so you can iterate through them, Netbeans doesn't do this for you when you generate the buttons.
After that, just run a for each loop on the list containing all the buttons. To get the values of the characters just cast the relevant ascii value, which starts at 97 for a lower case a or 65 for an upper case A:
int charNum = 97;
for(Button b : board) {
char charVal = (char)charNum;
charNum++;
//add the action listener
}
Related
To start with -- I'm not sure, that I have properly formulated the question (I'm new in Java and in making programs with GUI).
It is the following thing, I'm trying to do. I have a window with several similar parameters (numbers are just for distinction between lines and it ist just very simplified example, of what should my GUI be):
Initial Window
Then, by clicking on the "+"-button I would like to add an new line, like here:
Line 35 is added
It should be also possible to delete lines, like here: Line 30 was deleted, by pressing "-"-Button.
As I wrote at the beginning, it is possible, that there was such a question, but I couldn't find anything (probably, because I do not now the keywords or I was looking with a wrong ones).
How such window can be done? The only idea I have is to draw a new window after every +/-.
Addition: Code (not working in the part of changing the number of rows).
import javax.swing.*;
import java.awt.event.*;
public class Test extends JFrame {
public Test() {
setSize(200, 600);
JButton plusButton[] = new JButton[100];
JButton minusButton[] = new JButton[100];
JTextField fields[] = new JTextField[100];
JPanel panel1 = new JPanel();
for (int i=0; i<plusButton.length; i++) {
plusButton[i]=new JButton("+");
minusButton[i]=new JButton("-");
fields[i] = new JTextField("Text "+ i);
}
for (int i=1; i<4; i++) {
panel1.add(plusButton[i*10]);
plusButton[i*10].setActionCommand("add after " +String.valueOf(i));
panel1.add(minusButton[i*10]);
minusButton[i*10].setActionCommand("remove " +String.valueOf(i));
panel1.add(fields[i*10]);
}
panel1.setBorder(BorderFactory.createEmptyBorder(10, 10, 10, 10));
this.getContentPane().add(panel1);
setVisible(true);
setDefaultCloseOperation(EXIT_ON_CLOSE);
}
public void actionPerformed(ActionEvent e) {
for (int i=0; i<100; i++) {
String stand1 = "add after "+String.valueOf(i);
String stand2 = "remove "+String.valueOf(i);
if (stand1.equals(e.getActionCommand())) {
//add "row" of elements
panel1.add(plusButton[i]);
plusButton[i+1].setActionCommand("add");
panel1.add(minusButton[i+1]);
minusButton[i+1].setActionCommand("remove");
panel1.add(fields[i+1]);
} else if (stand2.equals(e.getActionCommand())) {
//delete "row" of elements
}
}
}
public static void main(String[] args) {
Test a = new Test();
}
}
The Problem, that is obvious -- when I want to add 2 rows (i think it is proper definition) of buttons after button 20, there will be an doubling of numbers. As a solution I see here a creation of a new panel for each new row. But it is sounds wrong for me.
P.S. Unfortunately I do not have time to end this topic or to post a working example. I actually found some kind of solution, beginning from the Question here, on Stack Overflow:
Adding JButton to JTable as cell.
So, in case somebody will be looking for such topic, it should sounds like "jButton in jTable".
There are multiple GUI frameworks for Java. First decide which one you wanna use.
As for your particular query
Add functionality to the + and - such that it will create an instance of a field object (that line with parameters as you call them) or destroy that particular instance of the object.
+ is clicked -> Create new object on consecutive line and increase the pointer-count(?) of the following fields.
- is clicked -> Call destructor for the particular object and decrease the pointer-count of the following fields.
I'm trying to create a Java AWT program with these codes:
import javax.swing.*;
import java.awt.*;
public class Exer1 extends JFrame {
public Exer1(){
super ("Addition");
JLabel add1 = new JLabel("Enter 1st Integer: ");
JTextField jtf1 = new JTextField(10);
JLabel add2 = new JLabel("Enter 2nd Integer: ");
JTextField jtf2 = new JTextField(10);
JButton calculate = new JButton("Calculate");
FlowLayout flo = new FlowLayout();
setLayout(flo);
add(add1);
add(jtf1);
add(add2);
add(jtf2);
add(calculate);
setSize(200,200);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setVisible(true);
}
public static void main(String[] a){
Exer1 ex1 = new Exer1();
}
}
My problem is HOW to add these 2 integers using JTextField. Can someone help me? Thank you so much. :)
You need to use ActionListener on your JButton.
Then you need to get int's from JTextField's and sum them like next:
calculate.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
try {
int i1 = Integer.valueOf(jtf1.getText());
int i2 = Integer.valueOf(jtf2.getText());
System.out.println("sum=" + (i1 + i2));
} catch (Exception e1){
e1.printStackTrace();
}
}
});
Generally, you should create an event listener for click events on your button: Lesson: Writing Event Listeners. In that handler, you would take contents of your two text fields, convert them to integers:
Integer i1 = Integer.valueOf(jtf1.getText());
Then you can add those two integers and display them in another control or do anything else with them.
Start with How to Use Buttons, Check Boxes, and Radio Buttons and
How to Write an Action Listeners
This will provide you with the information you need to be able to tell when the user presses the button.
JTextField#getText then return's String. The problem then becomes a problem of converting a String to a int, which if you take the time, there are thousands of examples demonstrating how to achieve that
Once you've played around with oddities of converting String to a int, you could take a look at How to Use Spinners and How to Use Formatted Text Fields which perform there own validation on the values been entered
I'm a beginner in GUI.
Is there a quick way of setting the same JButton/Image to multiple locations within the GUI? For better clarification, if I want to use this JButton 10 times at different locations in my GUI, would I have to create a new JButton(new ImageIcon...) 10 times?
The buttons don't have to lead to anything, this is just for show.
JButton jb = new JButton(new ImageIcon("myImage.png"));
jb.setLocation(10,10);
jb.setSize(40, 40);
getContentPane().add(jb);
The short answer is, yes, you will need multiple instances of JButton.
You can use an Action which can be applied to multiple instance of a button (the same instance of Action). The Action class carries properties which will be used to configure the buttons, such as text and icon properties.
A component (like JButton) can only reside within in a single container, therefore, you will need multiple instances of JButton.
Take a look at How to Use Actions and How to Use Buttons, Check Boxes, and Radio Buttons for more details...
Generally, you should avoid using setLocation and setSize and rely more on the use of layout managers, but you've not provided enough context to say if this useful to you or not.
Yes, you need to create a Jbutton object for each desired instance.
Since you have so many JButton that are all similar, I suggest that you declare an array JButton[] buttons = new JButton[10]; and use a for loop to create each individual button and set their attributes.
If it is just for a show, I would do the following to show the 10 button in a row:
int buttonHeight = 10;
int buttonWidth = 10;
for (int i = 0; i < 10; i++) {
JButton button = new Button("Button " + i);
button.setSize(buttonWidth, buttonHeight);
button.setLocation(10 + i * buttonWidth, 10);
getContentPane().add(button);
}
import java.util.Scanner;
import javax.swing.*;
import java.awt.*;
class PROB4_CHAL1 extends JFrame
{
JButton b[]=new JButton[10];
public PROB4_CHAL1()
{
setLayout(null);
setVisible(true);
setSize(100,100);
for(int i=0;i<10;i++)
{
b[i]=new JButton(""+i);// or b[i]=new JButton(new ImageIcon("path"));
b[i].setBounds(i*10,i*20,50,20);
add(b[i]);
}
}
public static void main(String[] args)
{
new PROB4_CHAL1();
}
}
You can Create array of 'JButton [10]' .
For this program, the JButton doesn't seem to show up unless you click the area where the JButton should be; the JFrame starts up blank. The moment you click the button, the respective code runs and the button finally shows up.
How do I get the buttons to show up upon starting the program?
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.*;
/*
The Amazing BlackJack Advisory Tool by JoshK,HieuV, and AlvinC.
Prepare to be amazed :O
*/
public class BlckJackUI {
//main class, will contain the JFrame of the program, as well as all the buttons.
public static void main(String args[])
{
//Creating the JFrame
JFrame GUI = new JFrame("Blackjack Advisor");
GUI.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
GUI.setSize(1300, 900);
GUI.setContentPane(new JLabel(new ImageIcon("C:\\Users\\Hieu Vo\\Desktop\\Green Background.png")));
GUI.setVisible(true);
// Because each button needs to run through the Math class.
final Math math = new Math();
// The Ace Button:
ImageIcon Ace = new ImageIcon("/Users/computerscience2/Downloads/Ace.jpg");
JButton ace = new JButton(Ace);
ace.setSize(300, 100);
ace.setLocation(100, 100);
ace.addActionListener(new ActionListener()
{
public void actionPerformed(ActionEvent e)
{
//Automatically default the the Ace to 11, and if Bust, Ace becomes 1.
if (math.array.playerhandtotal <= 21)
{
math.cardvalue = math.cardvalue + 11;
}
else
{
math.cardvalue = math.cardvalue + 1;
}
math.array.clicktracker++;
math.calcResult();
JOptionPane.showMessageDialog(null,math.array.result);
}
});
GUI.add(ace);
ImageIcon Two = new ImageIcon("/Users/computerscience2/Downloads/2.jpg");
JButton two = new JButton(Two);
two.setSize(300, 100);
two.setLocation(100, 200);
two.addActionListener(new ActionListener ()
{
public void actionPerformed(ActionEvent e)
{
/*
This generally repeats throughout the whole class, and the only
thing different is the changing cardvalue. When a button is pressed,
respective cardvalues are added into the playerhand ArrayList, and
totaled up to form playerhandtotal, which is a major factor in
bringing up the advice.
*/
math.cardvalue = math.cardvalue + 2;
math.array.clicktracker++;
math.calcResult();
JOptionPane.showMessageDialog(null,math.array.result);
}
});
GUI.add(two);
Et cetera, Et cetera... Just a bunch of the same stuff, more buttons coded the same exact way as JButton two, but with different value associated to them.
JButton start = new JButton("Start/Reset");
start.setSize(300, 100);
start.setLocation(500,500);
start.addActionListener(new ActionListener ()
{
public void actionPerformed(ActionEvent e)
{
/*
The start button also acts like a reset button, and the concept is fairly
simple. If we reset all the important values to 0 or "null," then the
program acts as if it was just opened.
*/
Arrays array = new Arrays();
array.playerhand.clear();
array.dealer = 0;
math.array.starttracker++;
math.array.clicktracker = 0;
array.playerhandtotal = 0;
math.cardvalue = 0;
array.result = null;
JOptionPane.showMessageDialog(null,"Please select the card \nthat the dealer is showing :)");
}
});
GUI.add(start);
GUI.setLayout(null);
This is all in the same class, and I understand a layout would be nicer, but perhaps there's a way to fix this issue using what I have now?
The program starts blank because you are calling setVisible before you add components. Call setVisible after you add components (in the end of contructor) and it should work fine.
Also, avoid absolute positioning and call of set|Preferred|Minimum|MaximumSize methods for your components. Learn how to use layout managers.
Write GUI.validate(); after you add all the components to your frame. Any time you add something to a frame you have to validate it like this. Otherwise, you will get the behavior that you have described.
No. The problem is caused by the layout. Before adding anything to a JFrame or a JPanel which you want it to have an absolute position, you have to setLayout(null). Otherwise, you'll have unexpected behaviours all the time. I just figured it out by myself after three hours of experimenting; suddenly, I connected your post with other different subject, and it worked, but this isn't well explained on the Internet yet.
I am fairly new to java so bear with me please, basically, below I have a tabbed pane for each of the four rooms in the rooms Arraylist, and I am creating buttons in each tab depending how many lights each room has, How can I associate the buttons in each tab with a specified the rooms?. So like when I click the light button in the Room 1 tab, the event listener knows that the button belongs to the room1?
Any help is appreciated, thanks.
import java.util.ArrayList;
import java.awt.*;
import javax.swing.*;
import java.awt.event.*;
public class MasterGUI extends JFrame implements ActionListener{
public MasterGUI(){
}
public void DisplayFrame(){
ArrayList<Rooms> rooms;
rooms = Building.getRoomList();
JFrame master = new JFrame("Solar Master Control Panel");
master.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
Container content = master.getContentPane();
content.setBackground(Color.lightGray);
JTabbedPane tabbedPane = new JTabbedPane();
JPanel tmpPanel;
for(int x = 0; x < rooms.size(); x++){
tmpPanel = new JPanel();
String roomName = rooms.get(x).getName();
int id = rooms.get(x).getId();
tabbedPane.addTab(roomName + " Room " + id, tmpPanel);
}
for(int x = 0; x < rooms.size(); x++){
for(int i = 0; i < rooms.get(x).roomLights.size(); i++){
int num = i + 1;
((JPanel) tabbedPane.getComponentAt(x)).add(new JButton("Light" + num));
}
}
master.add(tabbedPane, BorderLayout.CENTER);
master.setSize(800, 600);
content.add(tabbedPane);
master.setVisible(true);
}
public void actionPerformed(ActionEvent e){
}
First of, you need to add the ActionListener to the button so it will be called when the button is clicked.
...
JButton button = new JButton("Light" + num);
button.addActionListener(this);
((JPanel) tabbedPane.getComponentAt(x)).add(button);
...
As far as differentiating between which button was clicked, there are two main ways to address this. The first is to use getSource() on the ActionEvent to get a reference to the object that triggered the event. You can use this to decide how you want to proceed further. The other option is to have MasterGUI not implement ActionListener. Instead, make a unique ActionListener for each button that immediately know what action needs to occur when it was called. The first option makes it easier to register listeners, but requires more work in the handler to determine the source. I prefer the second method.
ActionEvent in actionPerformed() will tell you the source of the button pressed. So you can do one of two things, you can name the button (which is not the same as the button text) something indicative of the room, or you can provide a command string that the button invokes, which is also available from the ActionEvent.
Check out the JButton JavaDoc, it has links to dealing with Actions and specifically button Actions supported.
It will focus your question a little better as well, since you'll have a better idea of how you're looking to achieve your goal.