Question

java myeclipse在面板上添加的按钮等控件怎么不能显示

import javax.swing.*;
import java.awt.*;
class FrameTest extends JFrame
{
public FrameTest()
{
super("面板");
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setVisible(true);
setSize(240,90);
}

}
class PanelTest extends FrameTest
{
JPanel panelobj;
public PanelTest()
{
panelobj=new JPanel();
panelobj.setBackground(Color.white);
getContentPane().add(panelobj);
}
}
class ButtonTest extends PanelTest
{
JButton buttonobj1;
JButton buttonobj2;
public ButtonTest()
{
buttonobj1=new JButton("按钮1");
buttonobj2=new JButton("按钮2");
buttonobj1.setEnabled(true);
buttonobj1.setVisible(true);
panelobj.add(buttonobj1);
panelobj.add(buttonobj2);
}
}
class FlowLayoutTest extends ButtonTest
{
FlowLayout layoutobj;
public FlowLayoutTest()
{
layoutobj=new FlowLayout();
getContentPane().setLayout(layoutobj);
}
}
public class j02_button {

/**
* @param args
*/
public static void main(String[] args) {
// TODO Auto-generated method stub
new FlowLayoutTest();
}

}

Answer 1

myeclipse中swing布局的问题导致控件不显示。

例子如下：

import java.awt.EventQueue;

import java.awt.FlowLayout;

import javax.swing.ImageIcon;

import javax.swing.JButton;

import javax.swing.JFrame;

import javax.swing.JPanel;

import javax.swing.UIManager;

import javax.swing.border.EmptyBorder;

public class JButtonDemo extends JFrame {

    

    

    private static final long serialVersionUID = 8651755261675396406L;

    private JPanel contentPane;

    

    

    public static void main(String[] args) {

        try {

            UIManager

                    .setLookAndFeel("com.sun.java.swing.plaf.nimbus.NimbusLookAndFeel");

        } catch (Throwable e) {

            e.printStackTrace();

        }

        EventQueue.invokeLater(new Runnable() {

            public void run() {

                try {

                    JButtonDemo frame = new JButtonDemo();

                    frame.setVisible(true);

                } catch (Exception e) {

                    e.printStackTrace();

                }

            }

        });

    }

    

    

    public JButtonDemo() {

        setTitle("按钮使用");// 设置窗体的标题

        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);// 设置窗体退出时操作

        setBounds(100, 100, 250, 100);// 设置窗体位置和大小

        contentPane = new JPanel();// 创建内容面板

        contentPane.setBorder(new EmptyBorder(5, 5, 5, 5));// 设置面板的边框

        setContentPane(contentPane);// 应用内容面板

        contentPane.setLayout(new FlowLayout(FlowLayout.CENTER, 5, 5));// 设置内容面板为流式布局

        

        JButton modifyButton = new JButton("修改");// 创建按钮

        modifyButton.setIcon(new ImageIcon(JButtonDemo.class

                .getResource("/images/modify.gif")));// 为按钮增加图标

        contentPane.add(modifyButton);// 在面板上增加按钮

        

        JButton deleteButton = new JButton("删除");// 创建按钮

        deleteButton.setIcon(new ImageIcon(JButtonDemo.class

                .getResource("/images/delete.gif")));// 为按钮增加图标

        contentPane.add(deleteButton);// 在面板上增加按钮

    }

    

}

运行效果：

Answer 2

好乱好纠结，我运行的没错啊，只是把第一个类名字改了，这个写得更简单一些
import javax.swing.*;
import java.awt.*;
public class FrameTest extends JFrame
{
JPanel panelobj;
JButton b1,b2;
public FrameTest()
{
super("面板");
panelobj=new JPanel();
b1=new JButton("1");b2=new JButton("2");
panelobj.add(b1);
panelobj.add(b2);
panelobj.setBackground(Color.white);
add(panelobj);
getContentPane().setLayout(new FlowLayout());
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setVisible(true);
setSize(240,90);
}

public static void main(String[] args) {
new FrameTest();

}

}

Answer 3

是你setVisible(true);
吧按钮隐藏掉了！　要把它设置为false!;

追问

我安你说的试了哈 还是没有显示呀

追答

是这里buttonobj1.setEnabled(true);
buttonobj1.setVisible(true);
改成false试试看！

Answer 4

我发现 运行后 放大面板 就会出现按钮