如何制作计时器？

Question

I have this code:

if (main.isGoingLeft1)
{
    g.drawImage(playerLeft1,x,y,null);
    main.isGoingLeft2 = true;
}

I tried to put a Thread.sleep in there but it stops the whole game, so that's not a good idea.

I want to put a timer between drawImage and setting the boolean as true. So if you could tell me or show me how to make a timer, that would be awesome.

Answer 1

You'll need to use the javax.swing.Timer for doing animations.

Timer t=new Timer(2,new ActionListener(){
     public void actionPerformed(ActionEvent ae)
     {
      // your animation code
     }
});
t.start();

The above timer executes every 2 milliseconds ie it fires ActionEvent every 2ms. If you want to stop it you can use t.stop() method.

See javax.swing.Timer and also How to use swing timers

Answer 2

Hummm, based just in that piece of your code, it seems that it won't work. To use a timer like swing timer or java util timer will require that your have threads in your program.

With threads, there'll be code running in parallel, and you can prepare some of your classes to receive a signal from the timer and then take some action.

In the piece of code that you showed, seems that you want something to happen after some other thing, but after some delay. And you want that you program continue processing something else, but nothing seems to indicate that your code is prepared to run in parallel.

To do that, you'll have a thread taking care of the goingLeft1 and another to the goingLeft2, and they'll comunicate through messages, not just by setting an attribute directly.

Answer 3

yea, correctly said by java technical, you could use swing timer in swing based applications rather than using java.util.Timer.. benifit of using the swiing timer here is that you dont need to create a seperate thread to execute timer. your code freezes for X milliseconds because it is running on the same thread on which the whole code is running. if you want to display time elapsed in seconds, you may use something like this

Timer timer = new Timer (1000,new ActionListener()

{

public void actionPerformed(ActionEvent ae)

{

    endTime=System.currentTimeMillis();
    tempTime=(int)((endTime-startTime)/1000);
    if(tempTime>30)
    {
        timer.stop();
        displayResult();
    }
    someLabel.setText("Time left : "+(30-tempTime)+" seconds");
}

}

this code displays time remaining from 30 seconds (30,29,28 ...1) and then it stops.