java - 如何为窗口添加滚动条？

Question

如何为我的窗口添加滚动 Pane ？

程序编译正确，但未创建窗口的滚动 Pane 。我真的不知道为什么会这样。我定义了 JScrollPane ，甚至使用 scrollPane = new JScrollPane

实现了它

我的错误在哪里？

下面是我的代码:

import java.awt.*;
import java.awt.Font;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.JScrollPane;
import java.awt.Dimension;
import javax.swing.JPanel;
import javax.swing.JFrame;
import javax.swing.JButton;

public class RegForm extends JFrame implements ItemListener{ 
JLabel l0,li,l1,l2,l3,l4,l5,l6,l7,l8,l9,l10,l11,l12,l13;
JButton b1,b2,b3,b4,b5;
JTextField t1,t2,t3,t4,t5,t6,t7,t8;
JTextArea a1,a2;
JComboBox<Integer> dd = new JComboBox<Integer>();
JComboBox<String> mm = new JComboBox<String>();
JComboBox<Integer> yyyy = new JComboBox<Integer>();
JComboBox<String> q = new JComboBox<String>();
JRadioButton rb1 = new JRadioButton( " Male ");
JRadioButton rb2 = new JRadioButton(" Female ");
JCheckBox cb1 = new JCheckBox (" C ");
JCheckBox cb2 = new JCheckBox (" C++ ");
JCheckBox cb3 = new JCheckBox (" Java ");
JCheckBox cb4 = new JCheckBox (" Oracle ");
JCheckBox cb5 = new JCheckBox (" Android ");
JCheckBox cb6 = new JCheckBox (" iOS ");
JCheckBox cb7 = new JCheckBox (" Web Designing ");
JCheckBox cb8 = new JCheckBox (" .Net ");
JCheckBox cb9 = new JCheckBox (" Same as Contact Address ");
JScrollPane scrollPane = new JScrollPane();
RegForm()
{

    l0 = new JLabel("REGISTRATION FORM");   
    Font f0 = new Font("Algerian",Font.ITALIC,20);
    l0.setFont(f0);
    l0.setBounds(600,10,250,50);
    scrollPane.add(l0);

    li = new JLabel(" * Fields are mandatory");
    Font fi = new Font("Arabic TypeSetting",Font.PLAIN,17);
    li.setFont(fi);
    li.setForeground(Color.RED);
    li.setBounds(10,50,150,30);
    scrollPane.add(li);


    l1 = new JLabel(" * FirstName: ");
    Font f1 = new Font("Bookman Old Style",Font.PLAIN,12);
    l1.setFont(f1);
    l1.setBounds(10,70,100,50);
    scrollPane.add(l1);

    t1 = new JTextField(20);
    t1.setBounds(165,85,140,20);
    scrollPane.add(t1);

    l2 = new JLabel("* Confirm FirstName: ");
    l2.setFont(f1);
    l2.setBounds(10,100,150,50);
    scrollPane.add(l2);

    t2 = new JTextField(20);
    t2.setBounds(165,115,140,20);
    scrollPane.add(t2);

    l3 = new JLabel(" Middle Name: ");
    l3.setFont(f1);
    l3.setBounds(15,130,120,50);
    scrollPane.add(l3);

    t3 = new JTextField(20);
    t3.setBounds(165,145,140,20);
    scrollPane.add(t3);

    l4 = new JLabel(" Confirm Middle Name: ");
    l4.setFont(f1);
    l4.setBounds(15,160,150,50);
    scrollPane.add(l4);

    t4 = new JTextField(20);
    t4.setBounds(165,175,140,20);
    scrollPane.add(t4);

    l5 = new JLabel(" * Sur Name: ");
    l5.setFont(f1);
    l5.setBounds(10,190,100,50);
    scrollPane.add(l5);

    t5 = new JTextField(20);
    t5.setBounds(165,205,140,20);
    scrollPane.add(t5);

    l6 = new JLabel(" * Confirm Sur Name: ");
    l6.setFont(f1); 
    l6.setBounds(10,220,150,50);
    scrollPane.add(l6);

    t6 = new JTextField(20);
    t6.setBounds(165,235,140,20);
    scrollPane.add(t6);

    l7 = new JLabel(" * DD / MM / YYYY" );
    Font f2 = new Font(" Comic Sans MS ",Font.ITALIC,12);
    l7.setFont(f2);
    l7.setBounds(10,260,150,50);
    scrollPane.add(l7);

    for(int j=1;j<=31;j++)
    dd.addItem(new Integer(j));
    dd.setBounds(165,275,47,20);
    scrollPane.add(dd);
    dd.addItemListener(this);

    mm.addItem("January");
    mm.addItem("February");
    mm.addItem("March");
    mm.addItem("April");
    mm.addItem("May");
    mm.addItem("June");
    mm.addItem("July");
    mm.addItem("August");
    mm.addItem("September");
    mm.addItem("October");
    mm.addItem("November");
    mm.addItem("December");
    mm.setBounds(212,275,90,20);
    scrollPane.add(mm);
    mm.addItemListener(this);

    for(int i=1990;i<=2016;i++)
    yyyy.addItem(new Integer(i));
    yyyy.setBounds(302,275,70,20);
    scrollPane.add(yyyy);
    yyyy.addItemListener(this);

    l8 = new JLabel(" Age: ");
    l8.setFont(f1);
    l8.setBounds(15,290,50,50);
    scrollPane.add(l8);

    t8 = new JTextField(10);
    t8.setBounds(165,305,50,20);
    scrollPane.add(t8);

    l9 = new JLabel(" Qualification ");
    l9.setFont(f1);
    l9.setBounds(15,320,120,50);
    scrollPane.add(l9);

    q.addItem(" B.Tech ");
    q.addItem(" M.Tech ");
    q.addItem(" MBA ");
    q.addItem(" MCA ");
    q.addItem(" Intermediate ");    
    q.addItem(" SSC "); 
    q.addItem(" Others ");
    q.setBounds(165,335,100,20);
    scrollPane.add(q);
    q.addItemListener(this);

    l10 = new JLabel(" Gender ");
    l10.setFont(f1);
    l10.setBounds(15,360,80,50);
    scrollPane.add(l10);

    rb1.setBounds(165,365,80,39);
    rb2.setBounds(250,365,80,39);

    ButtonGroup bg = new ButtonGroup();
    bg.add(rb1);
    bg.add(rb2);
    scrollPane.add(rb1);
    scrollPane.add(rb2);    

    l11 = new JLabel(" Courses Intrested: ");
    l11.setFont(f1);    
    l11.setBounds(15,450,150,50);
    scrollPane.add(l11);

    cb1.setBounds(165,390,100,50);
    scrollPane.add(cb1); 
    cb2.setBounds(285,390,100,50);
    scrollPane.add(cb2);
    cb3.setBounds(165,425,100,50);
    scrollPane.add(cb3);
    cb4.setBounds(285,425,100,50);
    scrollPane.add(cb4);
    cb5.setBounds(165,460,100,50);
    scrollPane.add(cb5);
    cb6.setBounds(285,460,100,50);
    scrollPane.add(cb6);
    cb7.setBounds(165,495,100,50);
    scrollPane.add(cb7);
    cb8.setBounds(285,495,100,50);
    scrollPane.add(cb8);
    cb9.setBounds(15,630,200,50);
    scrollPane.add(cb9);

    l12 = new JLabel(" Contact Address: ");
    l12.setFont(f1);
    l12.setBounds(15,550,150,50);
    scrollPane.add(l12);

    a1 = new JTextArea (5,20);
    a1.setBounds(165,545,250,80);
    scrollPane.add(a1);

    l13 = new JLabel(" Permenant Address: ");
    l13.setFont(f1);
    l13.setBounds(15,675,150,50);
    scrollPane.add(l13);

    a2 = new JTextArea (5,20);
    a2.setBounds(165,680,250,80);
    scrollPane.add(a2);

    cb9.addItemListener(this);


}

public void itemStateChanged(ItemEvent ie) 
{
    if(ie.getSource() == yyyy){
    int y = (Integer) ie.getItem();
    t8.setText(Integer.toString(2016-y));
    t8.setEditable(false);
    }
    if(cb9.isSelected()){
    a2.setText(a1.getText());
    a2.setEditable(false);
    }
}
public void actionPerformed(ActionEvent ae)
{   
    }

public static void main(String[] args)
{

    RegForm rf = new RegForm();
    rf.setTitle("Hai Hello");
    JScrollPane scrollPane = new JScrollPane();
       scrollPane.setHorizontalScrollBarPolicy(JScrollPane.HORIZONTAL_SCROLLBAR_NEVER);
                     scrollPane.setVerticalScrollBarPolicy(JScrollPane.VERTICAL_SCROLLBAR_AS_NEEDED);
scrollPane.setBounds(10,10,100,100);
JPanel contentPane = new JPanel();
contentPane.setPreferredSize(new Dimension(1500, 800));
contentPane.add(scrollPane);
rf.setContentPane(contentPane);
rf.pack();
rf.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
rf.setVisible(true);
}
}

Answer 1

scrollPane.add(l11);

切勿将组件直接添加到滚动 Pane 。

l1.setBounds(10,70,100,50);

不要使用 setBounds(...)。设置组件的大小/位置是布局管理器的工作。

基本逻辑是:

JPanel panel = new JPanel(); // set your layout manager for the panel.
panel.add( someComponent );
panel.add( anotherComponent );
JScrollPane scrollPane = new JScrollPane( panel );
frame.add( scrollPane );

阅读Swing Tutorial Swing 基础知识。本教程的每个部分都有工作示例。也许可以从如何使用滚动 Pane 部分开始。