Java，无限循环的替代？ [英] Java, replacement for infinite loops?

问题描述

我正在制作一个通过阵列显示细胞生长的程序。当我按下开始按钮时，我已经得到它，数组在一段时间（真实）{}循环中每10秒更新一次。问题是我希望能够通过按下暂停按钮来停止循环，但是在循环中，它不会让我使用任何控件。我需要在orer中使用除了无限循环之外的其他东西来刷新帧。

I am making a program that shows cellular growth through an array. I have gotten it so when I press the start button, the array updates every 10 seconds in a while(true){} loop. The problem with that is I want to be able to stop the loop by pressing the pause button, but while in the loop, it wont let me use any of the controls. I need something other than a infinite loop in orer to refresh the frames.

我是一个新手，但我目前正在参加java课程。所以我掌握了一些语言。

I am a bit of a newbie, but I am in a java class at the moment. so I have some grasp of the language.

推荐答案

你需要的是使用计时器改变组件的状态（在这种情况下是细胞增长），然后调用 JComponent.repaint（）

What you need is use a Timer which changes the state of your component ( in this case the cellular growth ) and then call JComponent.repaint()

此计时器可以是取消进行暂停，然后重新启动它，你只需创建一个新的一个：

This timer can be cancelled to make the pause and then to restart it, you just create a new one:

所以你可以定义以下两种方法：

So you could define the following two methods:

private Timer timer;
...
public void startPaiting() {
    timer = new Timer();
    timer.schedule( new TimerTask(){
        public void run(){
            changeState();
            repaint();
        }
    },0,  10000 ); // 10 s. 
}

public void pause(){
    timer.cancel();
}

然后在暂停/恢复按钮中调用pause / startPaiting 方法：

And then in your "Pause/Resume" button invoke this "pause/startPaiting" methods:

if( e.getActionCommand().equals("Pause")){
    growPanel.pause();
    setText("Resume");
} else {
    growPanel.startPaiting();
    setText("Pause");
}

http://img512.imageshack.us/img512/7119/capturadepantalla201001.png

以下是完整的源代码它运行：

Here's the complete source code to see it running:

import javax.swing.*;
import java.awt.Graphics;
import java.awt.Point;
import java.awt.event.*;
import java.util.Timer;
import java.util.TimerTask;

public class Grow {

    public static void main( String [] args ) {
        JFrame frame = new JFrame();
        final GrowPanel growPanel = new GrowPanel();
        frame.add( growPanel );
        frame.add( new JPanel(){{
            add( new JButton("Pause"){{
                addActionListener( new ActionListener(){
                    public void actionPerformed( ActionEvent e ){
                        if( e.getActionCommand().equals("Pause")){
                            growPanel.pause();
                            setText("Resume");
                        } else {
                            growPanel.startPaiting();
                            setText("Pause");
                        }
                    }
                });
        }});}}, java.awt.BorderLayout.SOUTH );
        frame.setSize( 400, 300 );
        frame.setVisible( true );
    }
}

class GrowPanel extends JComponent {
    private int x;
    private int y;
    private Timer timer;
    GrowPanel() {
        x = 10;
        y = 10;
        startPaiting();
    }

    public void startPaiting() {
        timer = new Timer();
        timer.schedule( new TimerTask(){
            public void run(){
                changeState();
                repaint();
            }
        },0,  100 ); // or 10000 which is 10 s. 
    }

    public void pause(){
        timer.cancel();
    }

    public void paintComponent( Graphics g ){
        g.fillOval( x, y, 10, 10 );
    }
    private void changeState(){
            x+=10;
            if( x >= 400 ) {
                y+=10;
                x = 0;
            }
            if( y >= 300 ){
                y = 10;
            }
    }

}

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