java - 如何在 Java 中初始化计时器？

Question

我正在用 Java 创建一个需要帧动画的游戏程序，并且需要每 40 毫秒重新绘制一次帧。但是，我不太确定如何让 Timer 处理这些重绘。我试过这样的事情：

Timer timer = new Timer(null);

但是我想我需要在初始化程序中设置更新时间，对吗？我该如何去做，并在程序启动时让计时器运行？或者干脆就跑？我知道 null 不可能是正确的。帮助将不胜感激。

Answer 1

Timer timer = new Timer(50, this);
timer.start();

“50”是计时器关闭的频率，以毫秒为单位。...这调用了一个 actionListener

public void actionPerformed(ActionEvent e){
    //do stuff here
}

....然后停止计时器

timer.stop();

一个例子：

class MyPanel extends JPanel implements ActionListener{
    public Timer time1;
        public MyPanel() {
        time1 = new Timer(40,this);
        setBorder(BorderFactory.createLineBorder(Color.black));
     }
    public void actionPerformed (ActionEvent e){
            //do stuff here
            repaint();
    }
        public void paintComponent(Graphics g) {
        super.paintComponent(g);
        //your paint method
    }  
}

Answer 2

 Timer t = new Timer(delay, new ActionListener() {
                @Override
                public void actionPerformed(ActionEvent e) {
                  //Do your Stuff here
                }
            });

            t.start();

其中 delay 是整数值，它以毫秒为单位显示计时器的延迟，并在您希望时停止计时器

  t.stop();

Answer 3

您需要构建具有延迟的计时器和自定义动作侦听器。

class TimerAction implements ActionListener{

    boolean isItTimeForTic = true;

   @Override public void actionPerformed(ActionEvent e) {
      //this is the place to define logic which will be invoked after every DELAY ms
   }
}

然后你像这样使用它：

int delay = 1; //you set your delay here 
Timer timer = new Timer(delay, new TimerAction());
timer.start();

如果您希望您的计时器重新绘制一个框架，您可以修改您的 TimerAction 以引用框架，然后在 actionPerformed 中调用它的方法。

Answer 4

如果你正在创建一个游戏，你必须已经实现了 runnable。所以我建议你做类似的事情。

//1
    private boolean running = true;
    private long fps = 0;
  //  private static final int MAX_CPS = 50;
   // private static final long MS_PER_FRAME = 1000 / MAX_CPS;
    private static final long MS_PER_FRAME = 40;//in your case it is 40//cps is 25

    public void run(){
        while(running){
            long cycleStartTime = System.currentTimeMillis();

            gameUpdate();//for updating your game logic
            repaint();//for stuff like painting

            long timeSinceStart = (cycleStartTime - System.currentTimeMillis());
            if(timeSinceStart < MS_PER_FRAME){
                try{
                    fps = MS_PER_FRAME - timeSinceStart;
                    Thread.sleep(fps);
                }catch(InterruptedException e){
                    System.err.println("InterruptedException in run "+e);
                }catch(Exception e){
                    System.err.println("Exception in run "+e);
                }
            }//closig if
        }//closing while
    }//closing run


//Like in your case you want to paynt after constant time you can do somehting like
//2

  //  private static final int MAX_CPS = 25;
    private static final long MS_PER_FRAME = 40
    public void run(){
        while(running){
            gameUpdate();//for updating your game logic
            repaint();//for stuff like painting
                try{
                    Thread.sleep(MS_PER_FRAME);
                }catch(InterruptedException e){
                    System.err.println("InterruptedException in run "+e);
                }catch(Exception e){
                    System.err.println("Exception in run "+e);
                }
            }//closig if
        }//closing while
    }//closing run

我建议使用 1，因为它可以让游戏更加流畅