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]' .
Related
i have a multiple jradiobutton that is inside a for loop and i am trying to put listener on it and this is what i found:
Action listener for multiple radio buttons
Create two dimensional JRadioButton array like
JRadioButton[][] jRadioButtons = new JRadioButton[8][];
ButtonGroup bg = new ButtonGroup();
JPanel panel = new JPanel();
panel.setLayout(new GridLayout(8, 8));
for (int i = 0; i < 8; i++) {
for (int j = 0; j < 8; j++) {
JRadioButton btn = new JRadioButton();
btn.addActionListener(listener);
btn.setName("Btn[" + i + "," + j + "]");
bg.add(btn);
panel.add(btn);
// can be used for other operations
jRadioButtons[i][j] = btn;
}
}
Here is single ActionListener for all JRadioButtons
ActionListener listener = new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
JRadioButton btn = (JRadioButton) e.getSource();
System.out.println("Selected Button = " + btn.getName());
}
};
i kinda understand it but i still have few clarifications:
what's the purpose of two dimensional jradiobutton? i mean i kinda see that it is to set a name for the jradiobuttons but as far as my understanding goes, it's only for display. yes to confirm that that is the jradiobutton you've selected but i don't get what's the purpose of it in putting actionlistener
is the two dimensional jradiobutton really that necessary?
can i just use the name of jradiobuttons
to do something like this:
if(NameOfJRadioButton.isSelected())
{
//some procedures
}
^(i can't seem to convert that into code :/)
if so, how can i do it? or do you have any other suggestions on how to put listener for multiple jradiobuttons? thank you for any of your suggestions :)
On your first and second point, the reason for the two dimensional array is unknown as it is not your code, but is not necessary at all for the use of JRadioButtons. However it is useful to have all your buttons in some type of array, whether it be an arraylist, or a buttonGroup (swing list for buttons) for checking things with the buttons when an action is called. e.g. on your 3rd point, this array list would allow you to iterate through and check which buttons have been selected and act accordingly.
The purpose for the action listener is for executing an action when the user clicks on a button. The most general use for this is making it so the user is only allowed to select a certain amount of JRadioButtons or to disable them once they have been selected. e.g. at a character selection menu.
I'm trying to make a simple calculator in Java using Swing, and I've created my buttons the following way:
//Our number keypad
public static JPanel numbers(){
//our panel to return
JPanel panel = new JPanel();
//Create and add 3x4 grid layout to panel
GridLayout gl = new GridLayout(3, 4);
panel.setLayout(gl);
//For creating and adding buttons to panel
for(int i = 0; i < 10; i++){
//Create a new button where the name is the value of i
String name = "" + i + "";
JButton button = new JButton(name);
//add action listener
button.addActionListener(handler);
//Add button to panel
panel.add(button);
}
return panel;
}
My question is how do I reference each specific button in my event handler? I can't think of a way to do this without having to manually create each button rather than using a loop.
Thanks.
In your listener, call event.getSource(), and that will return the button which has been pressed. Get the text of the button, and you have its number.
Or create a different instance of your handler for every button, and pass the value of the button (i) to the constructor of the handler. This last solution is cleaner, IMO, because it doesn't depend on the text of the button. If you replaced the text by an image, for example, the first technique wouldn't work anymore.
You can distinguish created buttons by adding the following inside handler:
String buttonText = ((JButton) e.getSource()).getText();
if (<text1>.equals(buttonText)){
//do the stuff
} else if (<text2>.equals(buttonText)){
//do the stuff
} else {
//do the stuff
}
Method #1: go through the child components of the parent JPanel (quite tedious, has to be rebuilt every time you modify the contents of that JPanel). Make sure they're JButtons by using an if . . instanceof clause.
Method #2: as you create them in that loop, add them to a List (or even better, a Map). I prefer a Map personally as it lets me customise the key for that specific JComponent
i.e.
HashMap<String, JComponent> buttonList = new HashMap<String, JComponent>();
for(. .) {
buttonList.put("nameForEachButton", button);
}
I recommend generating the button name based off of the loop counter. Either use your existing name value, or just set it to "button" + i;
Declare your buttons using an array.
JButton[] button = new JButton[9]; //outside the for loop
for (int i = 0; i < 10; i++) {
//put your code
button[i] = new JButton(name);
//your code
}
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 have an array I fill with buttons and I want an individual button to change its text when clicked.
for (int i = 0; i<4; i++)
{
button[i] = new JButton ("Add");
button[i].addActionListener(this);
box[i] = new JComboBox();
foodOptions.add(box[i]);
foodOptions.add(button[i]);
}
public void actionPerformed (ActionEvent e)
{
button[this].setText("I've been clicked!");
}
The current doesn't work because of incompatible types, what format is appropriate?
Yes, it makes no sense to pass an object, this, into an array index which expects an int, not your GUI object, so I'm not sure what you were trying to achieve with this.
Just get a reference to the JButton that's been clicked from the ActionEvent's getSource() method:
JButton btn = (JButton)e.getSource();
btn.setText("I've been clicked");
Edit:
Also you should avoid using this as your ActionListener since this means that you're likely having your GUI class implement an ActionListener which is asking the poor class to be too many things, to do too much. You're much better off either using anonymous inner classes or else even better use AbstractActions.
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.