I created a program to display information about the presidents in Java. When I click the start button, it starts to move, but when I stop and click the start button again, it advance two pages at a t...

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I created a program to display information about the presidents in Java. When I click the start button, it starts to move, but when I stop and click the start button again, it advance two pages at a t...

I created a program to display information about the presidents in Java. When I click the start button, it starts to move, but when I stop and click the start button again, it advance two pages at a time. It has to change one page at a time. Please correct this error.

import java.awt.BorderLayout;

import java.awt.Color;

import java.awt.event.ActionEvent;

import java.awt.event.ActionListener;

import javax.swing.JButton;

import javax.swing.JFrame;

import javax.swing.JLabel;

import javax.swing.JPanel;

import javax.swing.Timer;

// Defines a class Map2 derived from JFrame

public class Map2 extends JFrame {

// Declares a JPanel object

JPanel panel;

// Declares a JLabel object

JLabel label;

// Declares a Timer object

Timer tm;

// Variable to toggle font style

int x = 1;

// Creates a font style

String pre1 = "<html> "

+ " 1789-1797 "

+ " <img src='https://presidenstory.com/usimag/phot2/washington.jpg' alt=\"Picture\" width=\'150px\' height=\'120px\'　> "

+ " George Washington "

+ " 1st US President "

+ " George Washington (February 22, 1732 – December 14, 1799) was an American political leader, military general, statesman, and Founding Father who also served as the first president of the United States from 1789 to 1797. He led Patriot forces to victory in the nation's War of Independence, and he presided at the Constitutional Convention of 1787 which established the new federal government. He has been called the \"Father of His Country\" for his manifold leadership in the formative days of the new nation. "

+ "</html>";

String pre2 = "<html> "

+ " 1797 - 1801 "

+ " <img src='https://presidenstory.com/usimag/phot2/adams.jpg' alt=\"Picture\" width=\'150px\' height=\'120px\'　> "

+ " John Adams "

+ " 2nd US President "

+ " John Adams (October 30, 1735 – July 4, 1826) was an American statesman, attorney, diplomat, writer, and Founding Father who served as the second president of the United States from 1797 to 1801. Before his presidency he was a leader of the American Revolution that achieved independence from Great Britain, and also served as the first vice president of the United States. "

+ "</html>";

String pre3 = "<html> "

+ " 1801 - 1809 "

+ " <img src='https://presidenstory.com/usimag/phot2/jefferson.jpg' alt=\"Picture\" width=\'150px\' height=\'120px\'　> "

+ " Thomas Jefferson "

+ " 3rd US President "

+ " Thomas Jefferson (April 13, 1743 – July 4, 1826) was an American statesman, diplomat, lawyer, architect, and Founding Father who served as the third president of the United States from 1801 to 1809. Previously, he had served as the second vice president of the United States from 1797 to 1801. "

+ " State - Virginia "

+ "</html>";

String pre4 = "<html> "

+ " 1809 - 1817 "

+ " <img src='https://presidenstory.com/usimag/phot2/madison.jpg' alt=\"Picture\" width=\'150px\' height=\'120px\'　> "

+ " James Madison "

+ " 4th US President "

+ " James Madison Jr. (March 16, 1751 – June 28, 1836) was an American statesman, lawyer, diplomat, philosopher, and Founding Father who served as the fourth president of the United States from 1809 to 1817. He is hailed as the \"Father of the Constitution\" for his pivotal role in drafting and promoting the United States Constitution and the United States Bill of Rights. He also co-wrote The Federalist Papers, co-founded the Democratic-Republican Party, and served as the fifth United States secretary of State from 1801 to 1809. "

+ "</html>";

String pre5 = "<html> "

+ " 1817 - 1825 "

+ " <img src='https://presidenstory.com/usimag/phot2/monroe.jpg' alt=\"Picture\" width=\'150px\' height=\'120px\'　> "

+ " James Monroe "

+ " 5th US President "

+ " James Monroe (April 28, 1758 – July 4, 1831) was an American statesman, lawyer, diplomat, and Founding Father who served as the fifth president of the United States from 1817 to 1825. A member of the Democratic-Republican Party, Monroe was the last president of the Virginia dynasty, and his presidency coincided with the Era of Good Feelings. "

+ " State - Virginia "

+ "</html>";

// Images Path In Array

String[] list = {pre1, pre2, pre3, pre4, pre5};

// Default constructor definition

public Map2() {

// Calls the JFrame parameterized constructor

super("Java SlideShow");

// Creates the panel

panel = new JPanel();

// Creates the label

label = new JLabel();

// Call The Function SetImageSize

SetImageSize(0);

// Creates the button

JButton start = new JButton("Start");

// Registers the start button for event handling using anonymous class

start.addActionListener(new ActionListener() {

@Override

// Overrides the method of ActionListenter interface

public void actionPerformed(ActionEvent e) {

// Set a timer

tm = new Timer(1000, new ActionListener() {

@Override

// Overrides the method of ActionListenter interface

public void actionPerformed(ActionEvent e) {

// Call The Function SetImageSize with index position style

SetImageSize(x);

// Increase the value by one

x += 1;

// Checks if x value is greater than or equals to

// list length

if(x >= list.length)

// Reset the x to 0

x = 0;

}// End of method

});// End of anonymous inner class for Timer

// Starts the timer

tm.start();

}// End of method

});// End of anonymous inner class for ActionListener

// Creates the button

JButton stop = new JButton("Stop");

// Registers the stop button for event handling using anonymous class

stop.addActionListener(new ActionListener() {

@Override

// Overrides the method of ActionListenter interface

public void actionPerformed(ActionEvent e) {

tm.stop();

}// End of method

});// End of anonymous inner class for ActionListener

// Adds the panel to south of the frame

add(panel, BorderLayout.SOUTH);

// Adds the button to panel

panel.add(start);

panel.add(stop);

// Adds the label to frame

add(label);

// Sets the frame properties

setSize(400, 600);

getContentPane().setBackground(Color.decode("#bdb67b"));

setLocationRelativeTo(null);

setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

setVisible(true);

}// End of default constructor

// Create a method to resize the image

public void SetImageSize(int i) {

label.setText(list[i]);

}// End of method

// main method definition

public static void main(String[] args) {

// Creates a anonymous object to calls default constructor

new Map2();

}// End of main method

}// End of class

engineering Computer-Science

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Answer

Answer #1

The problem with your code was that whenever the start button is clicked, you didn’t check if the timer is already running before starting it. Also, the timer was being recreated every time the start button is clicked, leaving the original timer task running in background. So I made three changes mainly. 1- Moved the timer initialization outside the action listener of start button click, so that the timer is created only once. 2- inside the action listener of start button, stopped the timer if already running before starting the timer. 3- inside the action listener of stop button, stopped the timer only if it is running.

Here is the completed code for this problem. Comments are included, go through it, learn how things work and let me know if you have any doubts or if you need anything to change. If you are satisfied with the solution, please rate the answer. Thanks

// Map2.java

import java.awt.BorderLayout;

import java.awt.Color;

import java.awt.event.ActionEvent;

import java.awt.event.ActionListener;

import javax.swing.JButton;

import javax.swing.JFrame;

import javax.swing.JLabel;

import javax.swing.JPanel;

import javax.swing.Timer;

// Defines a class Map2 derived from JFrame

public class Map2 extends JFrame {

// Declares a JPanel object

JPanel panel;

// Declares a JLabel object

JLabel label;

// Declares a Timer object

Timer tm;

// Variable to toggle font style

int x = 1;

// Creates a font style

String pre1 = "<html> "

+ " 1789-1797 "

+ " <img src='https://presidenstory.com/usimag/phot2/washington.jpg' alt=\"Picture\" width=\'150px\' height=\'120px\'?> "

+ " George Washington "

+ " 1st US President "

+ " George Washington (February 22, 1732 – December 14, 1799) was an American political leader, military general, statesman, and Founding Father who also served as the first president of the United States from 1789 to 1797. He led Patriot forces to victory in the nation's War of Independence, and he presided at the Constitutional Convention of 1787 which established the new federal government. He has been called the \"Father of His Country\" for his manifold leadership in the formative days of the new nation. "

+ "</html>";

String pre2 = "<html> "

+ " 1797 - 1801 "

+ " <img src='https://presidenstory.com/usimag/phot2/adams.jpg' alt=\"Picture\" width=\'150px\' height=\'120px\'?> "

+ " John Adams "

+ " 2nd US President "

+ " John Adams (October 30, 1735 – July 4, 1826) was an American statesman, attorney, diplomat, writer, and Founding Father who served as the second president of the United States from 1797 to 1801. Before his presidency he was a leader of the American Revolution that achieved independence from Great Britain, and also served as the first vice president of the United States. "

+ "</html>";

String pre3 = "<html> "

+ " 1801 - 1809 "

+ " <img src='https://presidenstory.com/usimag/phot2/jefferson.jpg' alt=\"Picture\" width=\'150px\' height=\'120px\'?> "

+ " Thomas Jefferson "

+ " 3rd US President "

+ " Thomas Jefferson (April 13, 1743 – July 4, 1826) was an American statesman, diplomat, lawyer, architect, and Founding Father who served as the third president of the United States from 1801 to 1809. Previously, he had served as the second vice president of the United States from 1797 to 1801. "

+ " State - Virginia "

+ "</html>";

String pre4 = "<html> "

+ " 1809 - 1817 "

+ " <img src='https://presidenstory.com/usimag/phot2/madison.jpg' alt=\"Picture\" width=\'150px\' height=\'120px\'?> "

+ " James Madison "

+ " 4th US President "

+ " James Madison Jr. (March 16, 1751 – June 28, 1836) was an American statesman, lawyer, diplomat, philosopher, and Founding Father who served as the fourth president of the United States from 1809 to 1817. He is hailed as the \"Father of the Constitution\" for his pivotal role in drafting and promoting the United States Constitution and the United States Bill of Rights. He also co-wrote The Federalist Papers, co-founded the Democratic-Republican Party, and served as the fifth United States secretary of State from 1801 to 1809. "

+ "</html>";

String pre5 = "<html> "

+ " 1817 - 1825 "

+ " <img src='https://presidenstory.com/usimag/phot2/monroe.jpg' alt=\"Picture\" width=\'150px\' height=\'120px\'?> "

+ " James Monroe "

+ " 5th US President "

+ " James Monroe (April 28, 1758 – July 4, 1831) was an American statesman, lawyer, diplomat, and Founding Father who served as the fifth president of the United States from 1817 to 1825. A member of the Democratic-Republican Party, Monroe was the last president of the Virginia dynasty, and his presidency coincided with the Era of Good Feelings. "

+ " State - Virginia "

+ "</html>";

// Images Path In Array

String[] list = { pre1, pre2, pre3, pre4, pre5 };

// Default constructor definition

public Map2() {

// Calls the JFrame parameterized constructor

super("Java SlideShow");

// Creates the panel

panel = new JPanel();

// Creates the label

label = new JLabel();

// Call The Function SetImageSize

SetImageSize(0);

// Creates the button

JButton start = new JButton("Start");

//creating the timer outside the action listener of button

tm = new Timer(1000, new ActionListener() {

@Override

// Overrides the method of ActionListenter interface

public void actionPerformed(ActionEvent e) {

// Call The Function SetImageSize with index position

// style

SetImageSize(x);

// Increase the value by one

x += 1;

// Checks if x value is greater than or equals to

// list length

if (x >= list.length)

// Reset the x to 0

x = 0;

}// End of method

});// End of anonymous inner class for Timer

tm.setInitialDelay(0);

// Registers the start button for event handling using anonymous class

start.addActionListener(new ActionListener() {

@Override

// Overrides the method of ActionListenter interface

public void actionPerformed(ActionEvent e) {

// if the timer is running when the start

// button is clicked, we should stop it

if (tm != null && tm.isRunning()) {

// stopping timer

tm.stop();

}

// Starts the timer

tm.start();

}// End of method

});// End of anonymous inner class for ActionListener

// Creates the button

JButton stop = new JButton("Stop");

// Registers the stop button for event handling using anonymous class

stop.addActionListener(new ActionListener() {

@Override

// Overrides the method of ActionListenter interface

public void actionPerformed(ActionEvent e) {

// here also, stopping the timer only if it is running

if (tm != null && tm.isRunning()) {

tm.stop();

}

}// End of method

});// End of anonymous inner class for ActionListener

// Adds the panel to south of the frame

add(panel, BorderLayout.SOUTH);

// Adds the button to panel

panel.add(start);

panel.add(stop);

// Adds the label to frame

add(label);

// Sets the frame properties

setSize(400, 600);

getContentPane().setBackground(Color.decode("#bdb67b"));

setLocationRelativeTo(null);

setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

setVisible(true);

}// End of default constructor

// Create a method to resize the image

public void SetImageSize(int i) {

label.setText(list[i]);

}// End of method

// main method definition

public static void main(String[] args) {

// Creates a anonymous object to calls default constructor

new Map2();

}// End of main method

}// End of class

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Can you fix my error? I created a program that changes labels every second in Java....

Can you fix my error? I created a program that changes labels every second in Java. But, it does not change. And, it will starts with second label. This is also an error. import java.awt.BorderLayout; import java.awt.Color; import java.awt.event.ActionEvent; import java.awt.event.ActionListener; import javax.swing.JButton; import javax.swing.JFrame; import javax.swing.JLabel; import javax.swing.JPanel; import javax.swing.Timer; public class Map2 extends JFrame{ JPanel panel; JLabel pic; Timer tm; int x = 0; String ly = "<html> " + " 111111111 ...

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I created a program to display information about the presidents in Java. When I click the start button, it starts to move, but when I stop and click the start button again, it advance two pages at a t...

Homework Answers

Add Answer to: I created a program to display information about the presidents in Java. When I click the start button, it starts to move, but when I stop and click the start button again, it advance two pages at a t...

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Add Answer to:
I created a program to display information about the presidents in Java. When I click the start button, it starts to move, but when I stop and click the start button again, it advance two pages at a t...