How can we call the invokeLater() method in Java?

An invokeLater() method is a static method of the SwingUtilities class and it can be used to perform a task asynchronously in the AWT Event dispatcher thread. The SwingUtilities.invokeLater() method works like SwingUtilities.invokeAndWait() except that it puts the request on the event queue and returns immediately. An invokeLater() method does not wait for the block of code inside the Runnable referred by a target to execute.

Syntax

public static void invokeLater(Runnable target)

Example

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class InvokeLaterTest extends Object {
   private static void print(String msg) {
      String name = Thread.currentThread().getName();
      System.out.println(name + ": " + msg);
   }
   public static void main(String[] args) {
      final JLabel label= new JLabel("Initial text");
      JPanel panel = new JPanel(new FlowLayout());
      panel.add(label);
      JFrame f = new JFrame("InvokeLater Test");
      f.setContentPane(panel);
      f.setSize(400, 300);
      f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
      f.setLocationRelativeTo(null);
      f.setVisible(true);
      try {
         print("sleeping for 5 seconds");
         Thread.sleep(5000);
      } catch(InterruptedException ie) {
         print("interrupted while sleeping");
      }
      print("creating the code block for an event thread");
      Runnable setTextRun = new Runnable() {
         public void run() {
            try {
               Thread.sleep(100);
               print("about to do setText()");
               label.setText("New text");
            } catch(Exception e) {
               e.printStackTrace();
            }
         }
      };
      print("about to call invokeLater()");
      SwingUtilities.invokeLater(setTextRun);
      print("back from invokeLater()");
   }
}

Output

main: sleeping for 5 seconds
main: creating the code block for an event thread 
main: about to call invokeLater() 
main: back from invokeLater() 
AWT-EventQueue-0: about to do setText()

Raja

Published on 21-Aug-2019 13:53:48

• Related Questions & Answers
• Can we call the wait() method without acquiring the lock in Java?
• Can we call a constructor directly from a method in java?
• Can we call run() method directly instead of start() in Java
• How do we call a Java method recursively?
• Can we call methods of the superclass from a static method in java?
• Can we call Superclass’s static method from subclass in Java?
• How can we call garbage collection (GC) explicitly in Java?
• Can we call methods using this keyword in java?
• Can we overload the main method in Java?
• Can we override the static method in Java?
• Can we override the main method in java?
• Can we override the equals() method in Java?
• What will happen if we directly call the run() method in Java?
• When can we call @JsonAnyGetter and @JsonAnySetter annotations in Java?
• How can we call the documentation for NumPy and SciPy?