come fare un conto alla rovescia in java

Question

Sono un principiante (studente) in programmazione ed è stato assegnato per creare un gioco. Il gioco che sto facendo si chiama boggle. In cui il giocatore deve trovare le parole in una lavagna a caso in un dato momento. ma ho problemi con la creazione del timer. Questo è ciò che il mio timer dovrebbe fare:

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• input dinamico per il tempo (tempo impostato)
• conto alla rovescia da tempo di ingresso a 0
• quando o => saltare fuori dal ciclo

Tutto quello che devo sapere è come renderlo conto alla rovescia. Non penso di aver bisogno di un ActionListener perché inizia a spuntare nel momento in cui la classe viene creata.

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Qualsiasi aiuto, consiglio, collegamento, spinta nella giusta direzione, sarà accettato a braccia aperte. Vi ringrazio molto in anticipo per i vostri sforzi .. Sinceramente una persona riconoscente

Answer 1

Vedrete persone che usano la classe Timer per fare ciò. Sfortunatamente, non è sempre accurato. La soluzione migliore è quella di ottenere l'ora del sistema quando l'utente inserisce l'input, calcola l'ora del sistema di destinazione e controlla se l'ora del sistema ha superato l'ora del sistema di destinazione. Se lo è, quindi uscire dal ciclo.

Answer 2

import java.util.Scanner; 
import java.util.Timer; 
import java.util.TimerTask; 

public class Stopwatch { 
static int interval; 
static Timer timer; 

public static void main(String[] args) { 
    Scanner sc = new Scanner(System.in); 
    System.out.print("Input seconds => : "); 
    String secs = sc.nextLine(); 
    int delay = 1000; 
    int period = 1000; 
    timer = new Timer(); 
    interval = Integer.parseInt(secs); 
    System.out.println(secs); 
    timer.scheduleAtFixedRate(new TimerTask() { 

     public void run() { 
      System.out.println(setInterval()); 

     } 
    }, delay, period); 
} 

private static final int setInterval() { 
    if (interval == 1) 
     timer.cancel(); 
    return --interval; 
} 
} 

Prova questo.

Answer 3

è possibile creare un conto alla rovescia con applet, sotto è il codice,

import java.applet.*; 
    import java.awt.*; 
    import java.awt.event.*; 
    import javax.swing.*; 
    import javax.swing.Timer; // not java.util.Timer 
    import java.text.NumberFormat; 
    import java.net.*; 



/** 
    * An applet that counts down from a specified time. When it reaches 00:00, 
    * it optionally plays a sound and optionally moves the browser to a new page. 
    * Place the mouse over the applet to pause the count; move it off to resume. 
    * This class demonstrates most applet methods and features. 
    **/ 

public class Countdown extends JApplet implements ActionListener, MouseListener 
{ 
long remaining; // How many milliseconds remain in the countdown. 
long lastUpdate; // When count was last updated 
JLabel label; // Displays the count 
Timer timer; // Updates the count every second 
NumberFormat format; // Format minutes:seconds with leading zeros 
Image image; // Image to display along with the time 
AudioClip sound; // Sound to play when we reach 00:00 

// Called when the applet is first loaded 
public void init() { 
    // Figure out how long to count for by reading the "minutes" parameter 
    // defined in a <param> tag inside the <applet> tag. Convert to ms. 
    String minutes = getParameter("minutes"); 
    if (minutes != null) remaining = Integer.parseInt(minutes) * 60000; 
    else remaining = 600000; // 10 minutes by default 

    // Create a JLabel to display remaining time, and set some properties. 
    label = new JLabel(); 
    label.setHorizontalAlignment(SwingConstants.CENTER); 
    label.setOpaque(true); // So label draws the background color 

    // Read some parameters for this JLabel object 
    String font = getParameter("font"); 
    String foreground = getParameter("foreground"); 
    String background = getParameter("background"); 
    String imageURL = getParameter("image"); 

    // Set label properties based on those parameters 
    if (font != null) label.setFont(Font.decode(font)); 
    if (foreground != null) label.setForeground(Color.decode(foreground)); 
    if (background != null) label.setBackground(Color.decode(background)); 
    if (imageURL != null) { 
     // Load the image, and save it so we can release it later 
     image = getImage(getDocumentBase(), imageURL); 
     // Now display the image in the JLabel. 
     label.setIcon(new ImageIcon(image)); 
    } 

    // Now add the label to the applet. Like JFrame and JDialog, JApplet 
    // has a content pane that you add children to 
    getContentPane().add(label, BorderLayout.CENTER); 

    // Get an optional AudioClip to play when the count expires 
    String soundURL = getParameter("sound"); 
    if (soundURL != null) sound=getAudioClip(getDocumentBase(), soundURL); 

    // Obtain a NumberFormat object to convert number of minutes and 
    // seconds to strings. Set it up to produce a leading 0 if necessary 
    format = NumberFormat.getNumberInstance(); 
    format.setMinimumIntegerDigits(2); // pad with 0 if necessary 

    // Specify a MouseListener to handle mouse events in the applet. 
    // Note that the applet implements this interface itself 
    addMouseListener(this); 

    // Create a timer to call the actionPerformed() method immediately, 
    // and then every 1000 milliseconds. Note we don't start the timer yet. 
    timer = new Timer(1000, this); 
    timer.setInitialDelay(0); // First timer is immediate. 
} 

// Free up any resources we hold; called when the applet is done 
public void destroy() { if (image != null) image.flush(); } 

// The browser calls this to start the applet running 
// The resume() method is defined below. 
public void start() { resume(); } // Start displaying updates 

// The browser calls this to stop the applet. It may be restarted later. 
// The pause() method is defined below 
public void stop() { pause(); } // Stop displaying updates 

// Return information about the applet 
public String getAppletInfo() { 
    return "Countdown applet Copyright (c) 2003 by David Flanagan"; 
} 

// Return information about the applet parameters 
public String[][] getParameterInfo() { return parameterInfo; } 

// This is the parameter information. One array of strings for each 
// parameter. The elements are parameter name, type, and description. 
static String[][] parameterInfo = { 
    {"minutes", "number", "time, in minutes, to countdown from"}, 
    {"font", "font", "optional font for the time display"}, 
    {"foreground", "color", "optional foreground color for the time"}, 
    {"background", "color", "optional background color"}, 
    {"image", "image URL", "optional image to display next to countdown"}, 
    {"sound", "sound URL", "optional sound to play when we reach 00:00"}, 
    {"newpage", "document URL", "URL to load when timer expires"}, 
}; 

// Start or resume the countdown 
void resume() { 
    // Restore the time we're counting down from and restart the timer. 
    lastUpdate = System.currentTimeMillis(); 
    timer.start(); // Start the timer 
} 

// Pause the countdown 
void pause() { 
    // Subtract elapsed time from the remaining time and stop timing 
    long now = System.currentTimeMillis(); 
    remaining -= (now - lastUpdate); 
    timer.stop(); // Stop the timer 
} 

// Update the displayed time. This method is called from actionPerformed() 
// which is itself invoked by the timer. 
void updateDisplay() { 
    long now = System.currentTimeMillis(); // current time in ms 
    long elapsed = now - lastUpdate; // ms elapsed since last update 
    remaining -= elapsed; // adjust remaining time 
    lastUpdate = now; // remember this update time 

    // Convert remaining milliseconds to mm:ss format and display 
    if (remaining < 0) remaining = 0; 
    int minutes = (int)(remaining/60000); 
    int seconds = (int)((remaining)/1000); 
    label.setText(format.format(minutes) + ":" + format.format(seconds)); 

    // If we've completed the countdown beep and display new page 
    if (remaining == 0) { 
     // Stop updating now. 
     timer.stop(); 
     // If we have an alarm sound clip, play it now. 
     if (sound != null) sound.play(); 
     // If there is a newpage URL specified, make the browser 
     // load that page now. 
     String newpage = getParameter("newpage"); 
     if (newpage != null) { 
      try { 
       URL url = new URL(getDocumentBase(), newpage); 
       getAppletContext().showDocument(url); 
      } 
      catch(MalformedURLException ex) {  showStatus(ex.toString()); } 
     } 
    } 
} 

// This method implements the ActionListener interface. 
// It is invoked once a second by the Timer object 
// and updates the JLabel to display minutes and seconds remaining. 
public void actionPerformed(ActionEvent e) { updateDisplay(); } 

// The methods below implement the MouseListener interface. We use 
// two of them to pause the countdown when the mouse hovers over the timer. 
// Note that we also display a message in the statusline 
public void mouseEntered(MouseEvent e) { 
    pause(); // pause countdown 
    showStatus("Paused"); // display statusline message 
} 
public void mouseExited(MouseEvent e) { 
    resume(); // resume countdown 
    showStatus(""); // clear statusline 
} 
// These MouseListener methods are unused. 
public void mouseClicked(MouseEvent e) {} 
public void mousePressed(MouseEvent e) {} 
public void mouseReleased(MouseEvent e) {} 
}