I'm making a simple conversion tool to convert dollars to euro's and vice versa.
The whole purpose is just to experiment and learn this cool tool, java.
I have a JLabel at the top with an icon of a euro to indicate the starting currency. I have a button bellow this that I want to use to change that icon to a dollar one.
I am currently plying around with an ActionListener and trying different variations of setIcon/setIconImage (every itteration I can think of seeing that nothing has worked thus far).
public class MoneyConverter extends JFrame implements ActionListener{
//add label and icon showing base conversion currency
JLabel startcur = new JLabel("<--- Starting Curency", new ImageIcon("C:\\Users\\Russel\\Desktop\\1euro.gif"), SwingConstants.CENTER);
JButton euro = new JButton("Swap to Euro");
JButton dollar = new JButton("Swap to Dollar");
I then set up a
public MoneyConverter(){}
method and add all my components to a grid layout and add ActionLister's to my convert buttons.
e.g.
dollar.addActionListener(this);
euro.addActionListener(this);
After the usual code (setVisible and the likes that I will omit for your sake as I don't see it interfering with this, please let me know if I should include it all)
public void ActionPerformed (ActionEvent e){
Object source = e.getSource();
if (source.equals(euro)){
startcur.setIcon(new ImageIcon("C:\\Users\\Russel\\Desktop\\1.gif"));
}
}
This part has been changed many times and is the main reason for this post, how do I change this icon in the JLabel? - I will also be setting the conversion rate in here depending if they choose to start with dollars or euros. (Rate won't be actual rate.)
First, create and store a new ImageIcon
ImageIcon image = new ImageIcon(getClass().getResource("/nameOfImage.jpg"));
Then put this in your Action Listener
label.setIcon(image);
label.setText("");
You have to make sure you have a resource folder set up for your project. You can read how to do that in IntelliJ or Eclipse
You are also declaring the actionPerformed() wrong. I suggest reading up on this You should be doing it like this.
#Override
public void actionPerformed(ActionEvent e)
{
}
Conventionally, in java, method names start with a lower case letter and Classes start with an upper case.
The whole purpose is just to experiment and learn this cool tool, java.
Then I'll show you how to improve this program in a number of ways.
//Don't make your Swing class implement Actionlistener and add it as a
//listener to itself in the constructor before it's fully initialized
public class MoneyConverter extends JFrame {
//These don't have to be loaded at runtime, so make them into constants
//Java variables and methods follow thisNamingConvention
private static final Icon euroIcon = new ImageIcon("C:\\Users\\Russel\\Desktop\\1euro.gif");
private static final Icon dollarIcon = new ImageIcon("C:\\Users\\Russel\\Desktop\\1dollar.gif");
//These you probably want to use later so save them as private class variables
//Make them final so you can access them in the ActionListeners below
private final JLabel currencyLabel;
private final JButton euroButton;
private final JButton dollarButton;
public MoneyConverter() {
//These are declared final and are are therefore usually set first in constructor
this.currencyLabel = new JLabel("<--- Starting Curency", euroIcon, SwingConstants.CENTER);
this.euroButton = new JButton("Swap to Euro");
this.dollarButton = new JButton("Swap to Dollar");
//Write your own separate ActionListener for each button
euroButton.addActionListener(new ActionListener() {
#Override
public void run() {
currencyLabel.setIcon(euroIcon);
//These two are required for you to see the effect
//This should also be the solution to your initial problem
currencyLabel.revalidate();
currencyLabel.repaint();
}
});
dollarButton.addActionListener(new ActionListener() {
#Override
public void run() {
currencyLabel.setIcon(dollarIcon);
currencyLabel.revalidate();
currencyLabel.repaint();
}
});
//Add your components here using whatever layout manager you want.
}
public static void main(String []args){
//Start new Swing applications like this to prevent it from
//clogging the rest of the program
SwingUtilities.invokeLater(new Runnable() {
public void run() {
new MoneyConverter();
}
});
}
}
Related
Apparently my Google-fu skills are bit lacklustre and I can't figure out how to get JTextField when pressing a JButton.
Please note that I've removed some parts of the code for ease of reading.
If you see some variable that's not defined assume that it was part of that code.
As it stands, the code works fine.
public final class Main {
// Some removed code was here
private void prepareGUI() {
// Top right stuff
JPanel topRightPanel = new JPanel();
topRightPanel.setLayout(new FlowLayout());
JLabel topRightLabel = new JLabel("Address");
JTextField topRightTextField = new JTextField("", 15);
topRightTextField.setName("add_address");
JButton topRightButton = new JButton("Add");
topRightButton.setName("add_btn");
topRightPanel.add(topRightLabel);
topRightPanel.add(topRightTextField);
topRightPanel.add(topRightButton);
mainFrame.add(topRightPanel);
// The button in question. Very suggestive name, I know.
topRightButton.addActionListener(new GenericButtonListener());
genericButtonListener.setKernel(kernel);
// some other non relevant stuff here
mainFrame.setVisible(true);
}
}
public class GenericButtonListener implements ActionListener {
#Override
public void actionPerformed(ActionEvent e) {
JButton btn = (JButton) e.getSource();
String btnName = btn.getName();
if(btnName.toLowerCase().contains("add_btn")) {
addBtn(btn);
}
}
public void addBtn(JButton button){
SshFileIO sshFileIO = kernel.getFileIO();
// Get field text here
}
}
My current dilemma is how to get said textfield value inside GenericButtonListener.
I realize that I can use getText to get the text field value, however I don't have access to that variable inside the actionPerformed function.
I suppose this is more of a scoping problem rather than anything else.
I just need some pointing in the right direction, no hand holding required.
It's painfully obvious that I'm very new to Java.
Please try to get a reference of topRightTextField with the constructor of GenericButtonListener. Store as property of the class and use it inside actionPerformed.
Change this one:
topRightButton.addActionListener(new GenericButtonListener());
To this:
topRightButton.addActionListener(new GenericButtonListener(topRightTextField));
And inside class GenericButtonListener add field:
private JTextField topRightTextField;// set it in the constructor
And then use it inside of your method actionPerformed.
Have a nice coding and good luck!
private JButton jBtnDrawCircle = new JButton("Circle");
private JButton jBtnDrawSquare = new JButton("Square");
private JButton jBtnDrawTriangle = new JButton("Triangle");
private JButton jBtnSelection = new JButton("Selection");
How do I add action listeners to these buttons, so that from a main method I can call actionperformed on them, so when they are clicked I can call them in my program?
Two ways:
1. Implement ActionListener in your class, then use jBtnSelection.addActionListener(this); Later, you'll have to define a menthod, public void actionPerformed(ActionEvent e). However, doing this for multiple buttons can be confusing, because the actionPerformed method will have to check the source of each event (e.getSource()) to see which button it came from.
2. Use anonymous inner classes:
jBtnSelection.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
selectionButtonPressed();
}
} );
Later, you'll have to define selectionButtonPressed().
This works better when you have multiple buttons, because your calls to individual methods for handling the actions are right next to the definition of the button.
2, Updated. Since Java 8 introduced lambda expressions, you can say essentially the same thing as #2 but use fewer characters:
jBtnSelection.addActionListener(e -> selectionButtonPressed());
In this case, e is the ActionEvent. This works because the ActionListener interface has only one method, actionPerformed(ActionEvent e).
The second method also allows you to call the selectionButtonPressed method directly. In this case, you could call selectionButtonPressed() if some other action happens, too - like, when a timer goes off or something (but in this case, your method would be named something different, maybe selectionChanged()).
Your best bet is to review the Java Swing tutorials, specifically the tutorial on Buttons.
The short code snippet is:
jBtnDrawCircle.addActionListener( /*class that implements ActionListener*/ );
I don't know if this works but I made the variable names
public abstract class beep implements ActionListener {
public static void main(String[] args) {
JFrame f = new JFrame("beeper");
JButton button = new JButton("Beep me");
f.setVisible(true);
f.setSize(300, 200);
f.add(button);
button.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
// Insert code here
}
});
}
}
To add an action listener, you just call addActionListener from Abstract Button.
Sirs,
As an exercise to learn more about class and function accessibility (e.g. public, private, static, etc), I am wanting to write a Java GUI (in the Netbeans IDE) that has the following properties:
has only one jButton and one jTextField - no other GUI components.
pressing the jButton for the first time after launching the program
displays a "0" in the jTextField.
pressing the jButton again
increments the number in the jTextField by one (i.e. the jButton
plays the role of an incrementer).
The jButton cannot get the
existing text from the jTextField, read/parse the text, get the most
recent number, and then increment the number.
For example:
String someString = jTextField.getText();
int someInt = String.valueOf(someString);
someInt++;
String newString = new String();
newString = String.valueOf(someInt);
jTextField.setText()
is not allowed.
This project is much more difficult than it appears, given the requirements above. Based on the requirements, I am going to have to create a class somewhere else that can keep track of the counter value (remember, extracting the current counter value from the TextField is prohibited). However, since Netbeans seems to disallow calling class methods of objects that were instantiated elsewhere (outside the button), this seems impossible.
After all attempts, it seems that a GUI that meets the above 4 criterion is impossible in Netbeans, given its restrictions.
My best-failed-attempt-thus-far (if that makes any sense) goes like this:
private void IncrementButtonActionPerformed(...){
CountObject C = new CountObject();
int i = C.IncrementCounter();// CountObject has a method for this.
// line or two here to typecast i into a String
jTextField.setText("i");
However, this won't work because each time I re-press the IncrementButton, it will simply instantiate a new CountObject. Instantiating a CountObject outside of this IncrementButtonActionPerformed event handler and then calling the CountObject.IncrementCounter() method from within the event handler is disallowed, or so it seems.
So am I right in believing that the requirements 1-4 above simply cannot be done in Java Netbeans as stated?
Thanks,
the_photon
Simply create a counter int field and increment it in your button's ActionListener -- no need to get the text from the JTextField. Then the JTextField's text with the counter's value. Edit: actually with your requirements, do the reverse: set the JTextFields text with the current counter's value and then increment the counter.
import java.awt.event.ActionEvent;
import java.awt.event.KeyEvent;
import javax.swing.*;
public class SimpleGui extends JPanel {
private int counter = 0;
private JTextField textField = new JTextField(5);
private JButton incrementButton = new JButton(new IncrementAction("Increment", KeyEvent.VK_I));
public SimpleGui() {
textField.setFocusable(false);
add(textField);
add(incrementButton);
}
private class IncrementAction extends AbstractAction {
public IncrementAction(String name, int mnemonic) {
super(name);
putValue(MNEMONIC_KEY, mnemonic);
}
#Override
public void actionPerformed(ActionEvent e) {
textField.setText(String.valueOf(counter));
counter++;
}
}
private static void createAndShowGui() {
SimpleGui mainPanel = new SimpleGui();
JFrame frame = new JFrame("SimpleGui");
frame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
frame.getContentPane().add(mainPanel);
frame.pack();
frame.setLocationByPlatform(true);
frame.setVisible(true);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(() -> {
createAndShowGui();
});
}
}
I want my button to run a whole new class that will do different things inside. I don't know if that is even possible cause i'm really bad at java. My code looks like this at the moment:
public class MainMenu {
private class GardenActivities {
public GardenActivities() {
JFrame GardenAct = new JFrame();
GardenAct.setSize(400, 400);
GardenAct.setVisible(true);
}
}
public static void main(String[] args) {
JFrame choice = new JFrame();
choice.setSize(700, 500);
choice.setLocationRelativeTo(null);
choice.setTitle("Seeds");
choice.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
JPanel panel = new JPanel();
panel.setLayout(new GridLayout(0, 1));
JButton Labora = new JButton();
Labora.setText("Laboratory");
Labora.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent ev) {
GardenActivities();
}
});
JButton Garden = new JButton();
Garden.setText("Garden");
Garden.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent ev) {
}
});
choice.getContentPane().add(panel);
ButtonGroup group = new ButtonGroup();
group.add(Garden);
group.add(Labora);
panel.add(Garden);
panel.add(Labora);
choice.setVisible(true);
}
}
Just like I said. I need something to run my GardenActivities class just by pressing Garden button.
Your code doesn't compile, does it? When that happens, you need to post compilation errors with your question so that we can help you with them.
You need to add the key word new before the GardenActivities() statement.
#Override
public void actionPerformed(ActionEvent ev) {
new GardenActivities(); // here
}
Also, put the GardenActivities in its own file. There's no reason for making it a private inner class and many reasons not to do this.
Having said this, I recommend against having one JFrame create and display another JFrame since an application should have usually only one JFrame. Instead consider swapping JPanel "views" using a CardLayout, or if you must show a different window, consider showing the second dependent window as a modal or non-modal dialog.
Also more unsolicited advice: Your main method is doing way too much. Most of the code inside of the static main method should go inside the non-static main gui class, whatever that is, perhaps in its constructor or in an initGui() method that the constructor calls. The main method should just create an instance of the main gui class, make it visible, and that's about it.
And regarding:
I don't know if that is even possible cause i'm really bad at java.
Keep writing lots and lots of code, a ton of code, and keep reviewing tutorials and textbooks, and this will change.
I think that you just need to add:
new GardenActivities();
Into your JButton's actionPerformed() method.
Good Luck!
One way to do what you want, we make the GardenActivities class implement ActionListener itself.
Then your code would look something like this:
Garden.addActionListener(new GardenActivities());
Otherwise, your plan should work.
NOTE
See comments for opposing opinions about why one would want to leave the ActionListener in the anonymouse inner class and have it call into GardenActivities.
Thank you #HovercraftFullOfEels
As others have pointed out, this:
#Override
public void actionPerformed(ActionEvent ev)
{
GardenActivities();
}
Should look like:
#Override
public void actionPerformed(ActionEvent ev)
{
new GardenActivities();
}
There is no reason to create an inner class, and GardenActivities can be, and should be, its own class.
I am having a bit of problem regarding Swing. I have a JFrame called FrameMain. Inside it is a JPanel called panelChoices.
When FrameMain is called/created, it fills up the panelChoices object with a number of PanelEntries objects, which is a JPanel with a number of JButtons in it (it is a different class that I wrote).
What I want to do is when I click one of the buttons inside the PanelEntries object, I want to destroy/remove FrameMain, along with the rest of it components (including the PanelEntries object that contains the JButton).
I've tried using super but it returns the JPanel (the PanelEntries object) that holds the JButton and not FrameMain that holds them all together. How can I achieve this?
EDIT: It seems that I am not clear enough, so here's a bit more information from my work. I don't have the actual code right now because I am on a different machine but I hope this will help elaborate my question.
public class FrameMain() {
private JFrame frameMain;
private JPanel panelChoices;
public FrameMain(args) {
createGUI();
loadData();
}
private void createGUI() {
JFrame frameMain = new JFrame();
JPanel panelChoices = new JPanel(new GridLayout(1,1));
frameMain.add(panel);
// removed formatting and other design codes since they are not important.
pack();
}
private void loadData() {
boolean available;
for (int i = 1; i <= 10; i++) {
// do some if/else and give value to boolean available
PanelEntries panel = new PanelEntries(i, available);
frameMain.add(panel);
// more code here to handle data.
}
}
}
public class PanelEntries() extends JPanel {
public PanelEntries(int num, boolean avb) {
JButton button = new JButton("Button Number " + num);
button.setEnabled(avb);
add(button);
// add action listener to created button so that it calls 'nextScreen()' when clicked.
// more code
pack();
}
private void nextScreen() {
// destroy/dispose MainFrame here.
// See Notes.
AnotherFrame anotherFrame = new AnotherFrame();
}
}
Notes:
All classes are inside their own .java file.
I need to know how to dispose FrameMain from the button inside the PanelEntries object, not just disposing a JFrame.
As per the given information,
If you want to exit the application, its not a big deal use System.exit(0); :)
If you mean to dispose the frame, jframe.dispose();
If you want to remove a componet / all components you can use .remove(Component) / .removeAll() etc
If this did not help, please re-write your question with more information.