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我有以下程序用于制作 JFrame，在框架上粘贴一个按钮，然后单击“启动按钮”以观看该按钮以抛物线弧线滑过框架。但是我的按钮没有出现。我已将按钮动作移动到一个单独的线程，并在 actionlistener 中调用该线程，但这似乎不起作用，因为我只看到按钮（要移动）出现然后显示在其端点。

package kinetic.energy.viewer;

import javax.swing.*;
import java.applet.*;

import java.awt.event.*;
import java.math.*;

public class KineticEnergyViewer  {


public static void main(String[] args) {
    final JFrame viewframe = new JFrame("Welcome to Gravitational Launcher");
    viewframe.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    viewframe.setSize(700,500);
    viewframe.setVisible(true);
    viewframe.setLayout(null);

    JButton launchbutton = new JButton("Launch");
    launchbutton.setSize(100,100);
    launchbutton.setLocation(600, 400);
    viewframe.add(launchbutton);

    final JButton rock = new JButton("YES!");
    rock.setSize(50,50);
    final GravitationalThread t = new GravitationalThread(9.8, (Math.PI)/4, 100, 500, 0, viewframe, rock);
    final Dumbthread g = new Dumbthread();
    launchbutton.addActionListener(new ActionListener()
                {
                //GravitationalThread t = new GravitationalThread(9.8, (Math.PI)/4, 100, 500, 0, viewframe, rock);
                public void actionPerformed(ActionEvent e){
                    g.run();
                    t.run();
                }
            });

}
}

--

package kinetic.energy.viewer;

import javax.swing.*;
import java.applet.*;

import java.awt.event.*;
import java.math.*;

public class KineticEnergyViewer  {


public static void main(String[] args) 
{
    final JFrame viewframe = new JFrame("Welcome to Gravitational Launcher");
    viewframe.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    viewframe.setSize(700,500);
    viewframe.setVisible(true);
    viewframe.setLayout(null);

    JButton launchbutton = new JButton("Launch");
    launchbutton.setSize(100,100);
    launchbutton.setLocation(600, 400);
    viewframe.add(launchbutton);

    final JButton rock = new JButton("YES!");
    rock.setSize(50,50);
    final GravitationalThread t = new GravitationalThread(9.8, (Math.PI)/4, 100, 500, 0, viewframe, rock);
    final Dumbthread g = new Dumbthread();
    launchbutton.addActionListener(new ActionListener()
                {
                //GravitationalThread t = new GravitationalThread(9.8, (Math.PI)/4, 100, 500, 0, viewframe, rock);
                public void actionPerformed(ActionEvent e){
                    g.run();
                    t.run();
                }
            });

}
}

一个可运行的类：

package kinetic.energy.viewer;

import java.lang.Thread.*;
import javax.swing.*;
import java.math.*;

public class GravitationalThread implements Runnable {
double grav, ang, vel,y,x;
JFrame targframe;
JButton targbutton;


public void run()
{
    double step = 0.01;
    double k = 0;
    double yoriginal = y;
    double xoriginal = x;
    while(y < 600 && x < 800)
    {
        System.out.println((int)x + " " + (int)y);

        y = yoriginal - vel*(Math.sin(ang))*k + (grav/2)*k*k;
        x = xoriginal + vel*(Math.cos(ang))*k;

        targframe.remove(targbutton);
        targbutton.setLocation((int)x, (int)y);
        targframe.add(targbutton);
        targframe.repaint();
        k = k + step;
        int j = 0;
        int i = 0;

        while(j < 10000)  
        {
            while(i < 10000)
            {
                i++;
            }

            j++;
        }
    }
}

GravitationalThread(double gravity, double angle, double velocity, double ypos, double xpos, JFrame whereat, JButton who)
{
    targbutton = who; //initialize variables
    targframe = whereat;
    grav = gravity;
    ang = angle;
    vel = velocity;
    y = ypos;
    x = xpos;
    targbutton.setLocation((int)x, (int)y);
    targframe.add(targbutton);
    targframe.validate();
}
}

和我正在尝试使用的空线程：

package kinetic.energy.viewer;

import java.lang.Thread.*;
import javax.swing.*;
import java.math.*;
public class Dumbthread implements Runnable {
Dumbthread()
{

}

public void run()
{
    int i = 0;
    while(i < 1000)
    {
        i = i + 1;
    }
}
}
4

1 回答 1

0 
g.run();
t.run();

不会导致GravitationalThread t和Dumbthread g运行在两个不同的线程中执行。它们将在调用它们的同一执行线程中运行。要在两个单独的执行线程中启动它们，您需要启动两个单独的线程，如下所示：

launchbutton.addActionListener(new ActionListener()
                {
                //GravitationalThread t = new GravitationalThread(9.8, (Math.PI)/4, 100, 500, 0, viewframe, rock);
                public void actionPerformed(ActionEvent e){
                    new Thread(g).start();
                    new Thread(t).start();
                }
            });
于 2013-10-24T13:23:38.933 回答