问空白java小程序
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Stack Overflow用户

提问于 2014-11-26 15:51:31

回答 2查看 183关注 0票数 0

我对java applet有个问题。我正在尝试制作一个简单的java小程序，看看它是如何工作的。

当我把所有的内容都放在一个类中时，一切看起来都很好，但是当我把它分成其他类时，applet窗口什么也没有显示：

头等舱：

package com.gmv.klinika;

import javax.swing.*;

/**
 * Created by gumovvy on 27.11.14.
 */
public class mainClass extends JApplet {
    OtherClass fr = new OtherClass();
    public void init() {
        fr.guiInit();

    }

}

二等舱：

package com.gmv.klinika;

import javax.swing.*;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

/**
 * Created by gumovvy on 27.11.14.
 */
public class OtherClass extends JFrame {
    JButton jbtnOne;
    JButton jbtnTwo;

    JLabel jlab;
    public void guiInit() {
        // Set the applet to use flow layout.
        setLayout(new FlowLayout());

        // Create two buttons and a label.
        jbtnOne = new JButton("One");
        jbtnTwo = new JButton("Two");

        jlab = new JLabel("Press a button.");

        // Add action listeners for the buttons.
        jbtnOne.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent le) {
                jlab.setText("Button One pressed.");
            }
        });

        jbtnTwo.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent le) {
                jlab.setText("Button Two pressed.");
            }
        });

        // Add the components to the applet's content pane.
        getContentPane().add(jbtnOne);
        getContentPane().add(jbtnTwo);
        getContentPane().add(jlab);
    }




}

你有什么想法吗？

原始类如下所示：

import javax.swing.*; 
import java.awt.*; 
import java.awt.event.*; 

/* 
This HTML can be used to launch the applet: 

<object code="MyApplet" width=240 height=100> 
</object> 

*/ 

public class MyApplet extends JApplet { 
  JButton jbtnOne; 
  JButton jbtnTwo; 

  JLabel jlab; 

  public void init() { 
    try { 
      SwingUtilities.invokeAndWait(new Runnable () { 
        public void run() { 
          guiInit(); // initialize the GUI 
        } 
      }); 
    } catch(Exception exc) { 
      System.out.println("Can't create because of "+ exc); 
    } 
  } 

  // Called second, after init().  Also called 
  // whenever the applet is restarted.  
  public void start() { 
    // Not used by this applet. 
  } 

  // Called when the applet is stopped. 
  public void stop() { 
    // Not used by this applet. 
  } 

  // Called when applet is terminated.  This is 
  // the last method executed. 
  public void destroy() { 
    // Not used by this applet. 
  } 

  // Setup and initialize the GUI.  
  private void guiInit() { 
    // Set the applet to use flow layout. 
    setLayout(new FlowLayout()); 

    // Create two buttons and a label. 
    jbtnOne = new JButton("One"); 
    jbtnTwo = new JButton("Two"); 

    jlab = new JLabel("Press a button."); 

    // Add action listeners for the buttons. 
    jbtnOne.addActionListener(new ActionListener() {      
      public void actionPerformed(ActionEvent le) {  
        jlab.setText("Button One pressed.");  
      }      
    });      

    jbtnTwo.addActionListener(new ActionListener() {      
      public void actionPerformed(ActionEvent le) {  
        jlab.setText("Button Two pressed.");  
      }      
    });      

    // Add the components to the applet's content pane. 
    getContentPane().add(jbtnOne); 
    getContentPane().add(jbtnTwo); 
    getContentPane().add(jlab);     
  } 
}

java

swing

applet

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回答 2

Stack Overflow用户

回答已采纳

发布于 2014-11-26 16:09:55

将您的OtherClass改为从JPanel扩展.

public class OtherClass extends JPanel {
    JButton jbtnOne;
    JButton jbtnTwo;

    JLabel jlab;
    public OtherClass() {
        // Set the applet to use flow layout.
        setLayout(new FlowLayout());

        // Create two buttons and a label.
        jbtnOne = new JButton("One");
        jbtnTwo = new JButton("Two");

        jlab = new JLabel("Press a button.");

        // Add action listeners for the buttons.
        jbtnOne.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent le) {
                jlab.setText("Button One pressed.");
            }
        });

        jbtnTwo.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent le) {
                jlab.setText("Button Two pressed.");
            }
        });

        // Add the components to the applet's content pane.
        add(jbtnOne);
        add(jbtnTwo);
        add(jlab);
    }
}

将OtherClass添加到MainClass..。

public class MainClass extends JApplet {
    OtherClass fr = new OtherClass();
    @Override
    public void init() {
        add(fr);
    }

}

从概念上讲，JAppelt不应该打开其他窗口，小程序应该是自包含的。由于不能将顶级容器(如JFrame )添加到其他容器中，所以很难进行扩展，因此我选择从JPanel扩展OtherClass的原因是……

票数 1

Stack Overflow用户

发布于 2014-11-26 16:01:41

这些线条看上去很可疑：

    // Set the applet to use flow layout.
    setLayout(new FlowLayout());

    ...

    // Add the components to the applet's content pane.
    getContentPane().add(jbtnOne);
    getContentPane().add(jbtnTwo);
    getContentPane().add(jlab);