I am really struggling with making a program that has buttons on it and when a button is clicked, it calls a class to work. I have only been using Java for about 10 weeks now and I get the basics but I have not found any place that gives me an understanding of what I want to do here.
I have tried
public void mouseEntered(MouseEvent e) {
if (e.getButton()== MouseEvent.BUTTON3){
Object triangle;
Frame.class.getClass();
}
}
I have also tried
panel.addMouseListener(new MouseAdapter() {
if (e.getButton()== MouseEvent.BUTTON1) {
Frame.class.getClass(circle); }
Either way I have tried it I usually get an error unable to find object or The method getClass() in the type Objectis not applicable for the arguments (JButton).
Can anyone please help me try to figure out what I am doing wrong?
Thank you.
public class MainFrame extends JFrame {
private JButton button = new JButton("Run AnotherClass");
MainFrame() {
super();
this.setTitle("Demo App");
this.setSize(200,200);
this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
this.setLayout(new FlowLayout());
this.add(button);
button.addActionListener(new ButtonHandler());
}
public class ButtonHandler implements ActionListener {
public void actionPerformed(ActionEvent e) {
new AnotherClass();
}
}
public static void main(String[] args) {
new MainFrame().setVisible(true);
}
}
public class AnotherClass {
public AnotherClass() {
JOptionPane.showMessageDialog(null, "AnotherClass is in operation");
}
}
Related
I have a TabbedPane in a class called App and i want to run a method in this class. I added two tabs with a JPanel from the class Login and an empty one. Here is the class:
public class App {
private static JTabbedPane tabbedPane;
public JPanel mainPanel;
public App(){
tabbedPane.addTab("Login", new Login().mainPanel);
tabbedPane.addTab("test", new JPanel());
changeFocus(0);
}
public void changeFocus(int i){
//CODE HERE
}
}
Now i want to run a method called changeFocus() from an outer class. A added an actionListener to the Login class with a constructor like this:
public Login() {
logInButton.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
App.changeFocus(1);
}
});
}
Now i ask why this doesn´t work and changeFocus() must be static. And if i change it to static why the JTabbedPane cannot be static and throws out an error.
Simply pass App as an argument to Login's constructor:
tabbedPane.addTab("Login", new Login(this).mainPanel);
and then:
public Login(App app) {
logInButton.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
app.changeFocus(1);
}
});
}
public class A2 {
public class B implements ActionListener{
#Override
public void actionPerformed(ActionEvent e) {
System.out.println("Fing");
}
}
public class C implements ActionListener{
#Override
public void actionPerformed(ActionEvent e) {
System.out.println("Fang");
}
}
public class D implements ActionListener{
#Override
public void actionPerformed(ActionEvent e) {
System.out.println("Foom");
}
}
public A2(){
JButton a = new JButton("Fing");
JButton b = new JButton("Fang");
JButton c = new JButton("Foom");
a.addActionListener(new B());
b.addActionListener(new C());
c.addActionListener(new D());
}
public static void main(String[] args) {
A2 a2 = new A2();
}
The problem I encountered is quite simple, but complex. I want it to shorten the code without retouching its functionality. For example, the code is showing to many actionlisteners and actionperformed, and I was trying to make it one class pulling out System.out.println(); and putting in String value on it. However, the coding does not work in this simple ways. Please help me out to curtail this code as simple and increase the readability. Thanks.
It's impossible to know what things you could do, I'm personally a fan of self documenting code, so sometimes, you need to be careful when trying to optimise solutions.
My first thought might be to start with the Action's API, which allows you to design a self contained unit of work
public class CommonAction extends AbstractAction {
public CommonAction(String name) {
putValue(NAME, name);
putValue(SHORT_DESCRIPTION, "This is a tool tip for " + name);
}
#Override
public void actionPerformed(ActionEvent e) {
System.out.println(getValue(NAME));
}
}
You could extend it further to provide more customisation if you needed, overriding the actionPerformed method, but, that's up to you.
Then you just need to apply to your buttons...
public class A2 {
public A2() {
JButton a = new JButton(new CommonAction("Fing"));
JButton b = new JButton(new CommonAction("Fang"));
JButton c = new JButton(new CommonAction("Foom"));
}
}
Or your menu's or your key bindings, Action is a rather flexible API supported by a number of other components
You can define single class MyActionListener which implements ActionListener as shown below:
public class MyActionListener implements ActionListener {
private String input;
public MyActionListener(String input) {
this.input = input;
}
#Override
public void actionPerformed(ActionEvent e) {
System.out.println(input);
}
}
public A2(){
String[] inputs = {"Fing","Fang","Foom"};//Array of JButton inputs
for(int i=0;i<inputs.length;i++) {
JButton jButton = new JButton(inputs[i]);//create JButton instance
jButton.addActionListener(new MyActionListener(inputs[i]));
}
}
I want to initialize a Graphical User Interface (GUI) for the user to input a form. After this is accomplished i want to open a new GUI, but as soon as the first GUI pops-up the next one is initialized to.
Is there any way to solve this without using waits and notifies?
here is an example of my code:
public static void main(String[] args) {
new GUIForm();
// wait until the user inputs the complete form
new GUIWelcome();
}
It is really simple I woild like to keep it that way.
Create an Interface OnActionListener
public interface OnActionListener {
public void onAction();
}
Add these code in GUIForm class
private OnActionListener listener;
private JButton action;
public GUIForm(OnActionListener listener) {
this.listener = listener;
action = new JButton("Action");
action.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
GUIForm.this.listener.onAction();
}
});
}
Now you can achieve that
new GUIForm(new OnActionListener() {
#Override
public void onAction() {
new GUIWelcome();
}
});
You need to use some sort pub/sub mechanism. This in a nutshell is what you need:
public class PubSub {
public static void main(String[] args) {
JFrame frame1 = new JFrame("GUIForm");
frame1.setSize(640, 480);
JButton button = new JButton("User Input");
JFrame frame2 = new JFrame("Welcome");
frame2.setSize(320, 240);
button.addMouseListener(new MouseAdapter() {
#Override
public void mouseEntered(MouseEvent e) {
button.setCursor(new Cursor(Cursor.HAND_CURSOR));
}
#Override
public void mouseExited(MouseEvent e) {
button.setCursor(new Cursor(Cursor.DEFAULT_CURSOR));
}
#Override
public void mouseClicked(MouseEvent e) {
frame2.setVisible(true);
}
});
frame1.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame1.add(button);
frame1.setVisible(true);
}
}
This version uses JFrame's listeners, but you could implement your on callback mechanism to accomplish the same
i am in trouble with checking if the mouse has clicked with a JFrame. When i use public void mousePressed(MouseEvent e) to print something and i click with the mouse it doesn't print anything. It doesn't gives a error, it just prints nothing out. Here is my code :
import java.awt.event.MouseEvent;
import javax.swing.JFrame;
import javax.swing.JScrollPane;
import javax.swing.JTextArea;
public class tuna extends JFrame
{
private JTextArea textArea;
public static void main(String[] args)
{
//Run the program
tuna run = new tuna();
run.setDefaultCloseOperation(3);
run.setSize(1200, 1000);
run.setVisible(true);
}
public tuna()
{
super("Simple JFrame");
//add a simple JScrollPane
textArea = new JTextArea(10,10);
JScrollPane scrollPane = new JScrollPane(textArea);
textArea.setEditable(true);
add(scrollPane);
}
//This doesn't print anything when i am clicking in the JFrame
public void mousePressed(MouseEvent e)
{
if(e.getButton() == MouseEvent.BUTTON1)
{
System.out.println("left");
}
else if(e.getButton() == MouseEvent.BUTTON3)
{
System.out.println("right");
}
}
}
Thank you in advance.
You can make you own Mouse Listener and add it to textArea or another component.
For example like this:
public class tuna extends JFrame
{
private JTextArea textArea;
public static void main(String[] args)
{
//Run the program
tuna run = new tuna();
run.setDefaultCloseOperation(3);
run.setSize(1200, 1000);
run.setVisible(true);
}
public tuna()
{
super("Simple JFrame");
//add a simple JScrollPane
textArea = new JTextArea(10,10);
JScrollPane scrollPane = new JScrollPane(textArea);
textArea.setEditable(true);
textArea.addMouseListener(new CustomListener());
add(scrollPane);
}
//This doesn't print anything when i am clicking in the JFrame
public class CustomListener implements MouseListener {
#Override
public void mouseClicked(MouseEvent mouseEvent) {
if(mouseEvent.getButton() == MouseEvent.BUTTON1)
{
System.out.println("left");
}
else if(mouseEvent.getButton() == MouseEvent.BUTTON3)
{
System.out.println("right");
}
}
#Override
public void mousePressed(MouseEvent mouseEvent) {
}
#Override
public void mouseReleased(MouseEvent mouseEvent) {
}
#Override
public void mouseEntered(MouseEvent mouseEvent) {
}
#Override
public void mouseExited(MouseEvent mouseEvent) {
}
}
}
Well there are few issues, in your concept and source code
First you need a MouseListener, so in your case either you can
create a separate MouseListener or use the current JFrame class
itself, like this
public class Tuna extends JFrame implements MouseListener
Also I would recommend to follow proper naming convention and use Tuna instead of tuna.
Then the element you want to respond on the MouseEvents should be
register with the MouseListener created in first step, in your constructor.
textArea.addMouseListener(this);
Also make sure on what element you want to register your
MouseListener, currently your entire Frame is covered by TextArea,
so registering listener on JFrame won't help, instead add it on
JTextArea
Try using #Override annotation where ever possible, editor shows
appropriate compiler errors then, in your case you just wrote,
public void mousePressed(MouseEvent e)
instead of
#Override
public void mousePressed(MouseEvent e)
As this methods works only if you implement an MouseListener
Refer this link for more understanding,
https://docs.oracle.com/javase/tutorial/uiswing/events/mouselistener.html
i am constructing a word processor program as an assignment for my Java class in school and i am having a really hard time getting the popupmenu to work when i right click on my text area. I have already constructed the popup menu and have my textarea listening to my popuplistener and i have overridden the mouse pressed and mouse released functions with
class popupframe extends JFrame{
JMenuItem copy;
JMenuItem paste;
JTextArea textarea = new JTextArea();
JPopupMenu pop;
popupframe(){
Container cpane = getContentPane();
setSize(300 , 300);
setLocation(300, 300);
setTitle("Test");
JPopupMenu pop = new JPopupMenu();
copy = new JMenuItem("copy");
paste = new JMenuItem("paste");
textarea = new JTextArea("something goes here", 5, 5);
pop.add(copy);
pop.add(paste);
PopupListener popuplistener = new PopupListener();
textarea.addMouseListener(popuplistener);
}
class PopupListener extends MouseAdapter{
public void MousePressed(MouseEvent e){
popit(e);
}
public void MouseReleased(MouseEvent e){
popit(e);
}
private void popit(MouseEvent e){
if(e.isPopupTrigger()){
pop.show(e.getComponent(), e.getX(), e.getY());
}
}
}
}
I cannot see why it is not working but perhaps i am missing something crucial, please help!! much appreciated
Add the #Override annotation to the methods you think your are overriding...
class PopupListener extends MouseAdapter {
#Override
public void MousePressed(MouseEvent e) {
System.out.println("Pressed");
popit(e);
}
#Override
public void MouseReleased(MouseEvent e) {
System.out.println("Pressed");
popit(e);
}
You will now find that this fails to compile, but why? Because Java is case sensitive, and by convention, method names start with a lower case character
You'll find that something like...
class PopupListener extends MouseAdapter {
#Override
public void mousePressed(MouseEvent e) {
popit(e);
}
#Override
public void mouseReleased(MouseEvent e) {
popit(e);
}
#Override
public void mouseClicked(MouseEvent e) {
popit(e);
}
private void popit(MouseEvent e) {
if (e.isPopupTrigger()) {
pop.show(e.getComponent(), e.getX(), e.getY());
}
}
}
will work better. But having said that, you'll generally find
textarea.setComponentPopupMenu(pop);
significantly easier and less error prone (and it won't cause a NullPointerException like your example code will.