actionlistener

问题 package helloworld; import javax.swing.*; import java.awt.event.*; public class helloworld extends JFrame{ public static void main( String args[] ){ JFrame frame = new helloworld(); frame.setSize( 400, 200 ); frame.setDefaultCloseOperation( JFrame.EXIT_ON_CLOSE ); frame.setTitle( "HelloWorld" ); JPanel panel = new Panel(); frame.setContentPane( panel ); frame.setVisible( true ); } } class Panel extends JPanel { private JButton button, resetbutton; private JTextField textfield; public Panel(){

问题 package helloworld; import javax.swing.*; import java.awt.event.*; public class helloworld extends JFrame{ public static void main( String args[] ){ JFrame frame = new helloworld(); frame.setSize( 400, 200 ); frame.setDefaultCloseOperation( JFrame.EXIT_ON_CLOSE ); frame.setTitle( "HelloWorld" ); JPanel panel = new Panel(); frame.setContentPane( panel ); frame.setVisible( true ); } } class Panel extends JPanel { private JButton button, resetbutton; private JTextField textfield; public Panel(){

问题 I was reading different threads on the subject which suggested the Swing Timer class or SwingUtilities.InvokeLater ...but I am having a lot of trouble wrapping my head around them. I used atomicInteger to create my countdown timer and it works fine in the console. However, When I try to incorporate it in Swing, it only updates the starting and ending value (e.g. set a 5 sec countdown will display in the frame: "5" -> after 5 seconds -> "0". Is there any simple way for me to keep and "refresh"

问题 button.setOnAction(new EventHandler<ActionEvent>() { @Override public void handle(ActionEvent e) { label.setText("Accepted"); } }); In the code above we are defining what will happen when we press the button. This is all good but I wanna create new ActionListener and then add it to my button. Normally in JButton I can just add ActionListener like this: button.addActionListener(someControllerClass.createButtonListener()); In code above createButtonListener() returns ActionListener. My question

问题 Created a Program similar to paint where there is a rectangle whose movement inside the screen can be controlled by "w,a,s,d" keys and its size increased or decreased using the scroller on the mouse. There are also several buttons of various colours which when pressed fills the rectangular shape with the respective colours. Now the problem is after clicking any colour button the movement is stopped ie. the rectangle doesn't move. You can increase and decrease its size but you can't move with

问题 Created a Program similar to paint where there is a rectangle whose movement inside the screen can be controlled by "w,a,s,d" keys and its size increased or decreased using the scroller on the mouse. There are also several buttons of various colours which when pressed fills the rectangular shape with the respective colours. Now the problem is after clicking any colour button the movement is stopped ie. the rectangle doesn't move. You can increase and decrease its size but you can't move with

问题 I am learning Java and would really like to have a deeper understanding of what the ActionEvent e perameter means and stands for. When I code I don't just want to spit out lines that work, but I don't understand. I want to have a full understanding of concepts before I use them. So what specifically is it asking for and what do the two parts(ActionEvent and e) mean? class ButtonListener implements ActionListener{ @Override public void actionPerformed(ActionEvent e){ } } Thanks. 回答1:

问题 I am learning Java and would really like to have a deeper understanding of what the ActionEvent e perameter means and stands for. When I code I don't just want to spit out lines that work, but I don't understand. I want to have a full understanding of concepts before I use them. So what specifically is it asking for and what do the two parts(ActionEvent and e) mean? class ButtonListener implements ActionListener{ @Override public void actionPerformed(ActionEvent e){ } } Thanks. 回答1:

问题 I am learning Java and would really like to have a deeper understanding of what the ActionEvent e perameter means and stands for. When I code I don't just want to spit out lines that work, but I don't understand. I want to have a full understanding of concepts before I use them. So what specifically is it asking for and what do the two parts(ActionEvent and e) mean? class ButtonListener implements ActionListener{ @Override public void actionPerformed(ActionEvent e){ } } Thanks. 回答1:

问题 I am learning Java and would really like to have a deeper understanding of what the ActionEvent e perameter means and stands for. When I code I don't just want to spit out lines that work, but I don't understand. I want to have a full understanding of concepts before I use them. So what specifically is it asking for and what do the two parts(ActionEvent and e) mean? class ButtonListener implements ActionListener{ @Override public void actionPerformed(ActionEvent e){ } } Thanks. 回答1: