在Java程序中实现计时器

Question

I'm creating a java paint program and can't figure out how to implement a timer that starts when the GUI is opened so the user can see their time spent drawing so far. My code is pasted below. I'm a complete beginner and have searched all the oracle documents and can't understand them so any help is appreciated! Hopefully there's a simple way of implementing this.

I added a JLabel onto my toolbar so I can try and post the "Drawing Time: "+totalTime but it stays at 0 for some reason I don't know how to make it refresh every second...

Answer 1

I would try something like this:

Set up the Global Variables (Make sure you fix your imports)

public class MainWindow extends javax.swing.JFrame implements ActionListener{

//global variable for tracking time
Timer timer;
final int DELAY = 1000;   //the delay for the timer (1000 milliseconds)
int myCounter;

then initialize the timer and counter and make sure to send the info from the counter to your label

public MainWindow() {
    initComponents();

    //initialize the timer and the counter
    timer = new Timer(DELAY, this);
    timer.start();
    myCounter = 0;
}

//method needed for the timer, since this class implements ActionListener
//this method will get called however often the DELAY is set for
@Override
public void actionPerformed(ActionEvent e){
    myCounter++;
    labelOutput.setText(Integer.toString(myCounter));
}//end of method

This is a pretty basic example of setting up a timer, so if you just apply the steps taken in the code I've given you to your own application, you'll probably be able to get it working. Good luck!