jTable swing中的垂直滚动条未出现 [英] Vertical scrollbar in jTable swing does not appear
本文介绍了jTable swing中的垂直滚动条未出现的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！
问题描述
我有点新手，而且我想尝试一些涉及Jtable的代码. 我发现即使我添加了滚动条策略，垂直滚动条也似乎没有出现.代码简直是破旧的.(请事先警告您).但是，请您指出我需要在滚动条策略中添加的位置.我尝试在很多地方添加它，但似乎没有出现.
I am a bit new to swings, And i was trying to cough up some code involving Jtable. I find that even though i have added the scrollbar policy the vertical scrollbar does not seem to appear. THe code is pretty shabby.(warning u before hand). But could you please indicate where I need to put in the scrollbar policy. I have tried adding it at a lot of places and it just does not seem to appear.
另一个问题是我如何制作一个空表.就像每次单击处理按钮一样，我想刷新表格.您也可以将我指向这个方向吗?
the other question is how do i make an empty table. As in every time the process button is clicked, i would like to refresh the table. Could u point me in this direction as well.
使用说明:只需在常规节点文本字段中输入数字，例如5或10 然后点击处理按钮.
The directions for usage: just enter a number in the regular nodes textfield like 5 or 10 and click on the process button.
我的代码:
package ui;
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Component;
import java.awt.FlowLayout;
import java.awt.Font;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.FocusEvent;
import java.awt.event.FocusListener;
import java.util.Arrays;
import java.util.LinkedList;
import java.util.List;
import java.util.Map;
import java.util.Set;
import javax.swing.BorderFactory;
import javax.swing.Box;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTabbedPane;
import javax.swing.JTable;
import javax.swing.JTextField;
import javax.swing.UIManager;
import javax.swing.UIManager.LookAndFeelInfo;
import javax.swing.UnsupportedLookAndFeelException;
import javax.swing.table.DefaultTableModel;
import utils.ThroughputUtility;
/**
* @author Nathan
*
*/
public class EntryPoint extends JPanel{
public boolean isProcesed =false;
static JFrame frame;
JTabbedPane jTabbedPane = new JTabbedPane();
private static final long serialVersionUID = -6490905886388876629L;
public String messageTobeSent = null;
public int regularNodeCount =0;
public static final String MESSAGE_TO_BE_SENT =" Please Enter the message to be sent. ";
protected static final String ONE = "1";
Map<String,Double> regNodeThroughputMap ;
static JTable tableOfValues;
Object columnNames[] = { "<html><b>Regular Node Name</b></htm>", "<html><b>Throughput Value Obtained</b></html>"};
Object rowData[][] = null;
public EntryPoint() {
jTabbedPane.setTabPlacement(JTabbedPane.NORTH);
Font font = new Font("Verdana", Font.BOLD, 12);
jTabbedPane.setFont(font);
//Server Side Panel.
JPanel serverPanel = getServerPanel();
jTabbedPane.addTab("Server", serverPanel);
//Client side Panel.
JPanel clientPanel = getClientPanel();
jTabbedPane.addTab("Client", clientPanel);
}
private JPanel getClientPanel() {
//Heading Label
JPanel clientPanel = new JPanel();
JLabel RegularNodeLabel = new JLabel("<html><u>Throughput Optimization For Mobile BackBone Networks</u></html>");
RegularNodeLabel.setFont(new Font("Algerian",Font.BOLD,20));
RegularNodeLabel.setForeground(new Color(176,23,31));
clientPanel.add(RegularNodeLabel);
return clientPanel;
}
/**Server Side Code
* @return
*/
private JPanel getServerPanel() {
//Heading Label
JPanel serverPanel = new JPanel(new FlowLayout());
final Box verticalBox1 = Box.createVerticalBox();
Box horozontalBox1 = Box.createHorizontalBox();
Box verticalBox2forsep = Box.createVerticalBox();
Box horozontalBox2 = Box.createHorizontalBox();
JPanel heading = new JPanel(new FlowLayout(FlowLayout.CENTER));
JLabel backBoneNodeLabel = new JLabel("<html><u>Throughput Optimization For Mobile BackBone Networks</u></html>");
backBoneNodeLabel.setFont(new Font("Algerian",Font.BOLD,20));
backBoneNodeLabel.setForeground(new Color(176,23,31));
backBoneNodeLabel.setAlignmentX(Component.CENTER_ALIGNMENT);
//Indication of BackBone Node
JPanel body = new JPanel(new FlowLayout(FlowLayout.LEFT));
JLabel backBoneNodeID = new JLabel("Fixed BackBone Node");
backBoneNodeID.setFont(new Font("Algerian",Font.BOLD,16));
backBoneNodeID.setForeground(new Color(176,23,31));
backBoneNodeID.setAlignmentX(Component.CENTER_ALIGNMENT);
//Seperator
JLabel seperator = new JLabel(" ");
seperator.setFont(new Font("Algerian",Font.BOLD,20));
seperator.setForeground(new Color(176,23,31));
verticalBox2forsep.add(seperator);
//Message label
JLabel messageLabel = new JLabel("Please enter the Message to be sent: ");
messageLabel.setFont(new Font("Algerian",Font.BOLD,16));
messageLabel.setForeground(new Color(176,23,31));
messageLabel.setAlignmentX(Component.LEFT_ALIGNMENT);
//Message Text
final JTextField messageText = new JTextField(MESSAGE_TO_BE_SENT,25);
messageText.addFocusListener(new FocusListener() {
@Override
public void focusLost(FocusEvent arg0) {
// TODO Auto-generated method stub
}
@Override
public void focusGained(FocusEvent arg0) {
if(messageText.getText().trim().equalsIgnoreCase(MESSAGE_TO_BE_SENT.trim())){
messageText.setText("");
}
}
});
horozontalBox1.add(messageLabel);
horozontalBox1.add(messageText);
//Regular node attached to backbone nodes.
JLabel regularNodelabel = new JLabel("Number of Regular nodes to be attached to the backbone node. ");
regularNodelabel.setFont(new Font("Algerian",Font.BOLD,16));
regularNodelabel.setForeground(new Color(176,23,31));
regularNodelabel.setAlignmentX(Component.LEFT_ALIGNMENT);
//Regular Node text
final JTextField regularNodeText = new JTextField(ONE,5);
regularNodeText.addFocusListener(new FocusListener() {
@Override
public void focusLost(FocusEvent e) {
// TODO Auto-generated method stub
}
@Override
public void focusGained(FocusEvent e) {
if(regularNodeText.getText().trim().equalsIgnoreCase(ONE.trim())){
regularNodeText.setText("");
tableOfValues = new JTable(0,0);
}
}
});
horozontalBox2.add(regularNodelabel);
horozontalBox2.add(regularNodeText);
//Button for Processing.
JButton processbutton = new JButton("Process");
processbutton.setFont(new Font("Algerian",Font.BOLD,16));
processbutton.setForeground(new Color(176,23,31));
processbutton.setAlignmentX(Component.CENTER_ALIGNMENT);
//Processing on clciking process button
processbutton.addActionListener(new ActionListener() {
@Override
public void actionPerformed(ActionEvent e) {
isProcesed=false;
Runnable runThread = new Runnable() {
@Override
public void run() {
while(!isProcesed){
try {
Thread.sleep(50);
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
verticalBox1.add(tableOfValues);
isProcesed =false;
}
};
Thread processThread= new Thread(runThread);
processThread.start();
regularNodeCount = Integer.parseInt(regularNodeText.getText().trim());
regNodeThroughputMap = getThroughPutValues(regularNodeText.getText().trim());
System.out.println("Map obtained = "+regNodeThroughputMap);
tableOfValues = populateTable(regNodeThroughputMap);
isProcesed=true;
JScrollPane scrollPane = new JScrollPane(tableOfValues);
scrollPane.add(tableOfValues);
scrollPane.setVerticalScrollBarPolicy(JScrollPane.VERTICAL_SCROLLBAR_ALWAYS);
verticalBox1.add(scrollPane,BorderLayout.CENTER);
// verticalBox1.add(scrollPane);
}
});
verticalBox1.add(backBoneNodeID);
verticalBox1.add(verticalBox2forsep);
verticalBox1.add(horozontalBox1);
verticalBox1.add(verticalBox2forsep);
verticalBox1.add(horozontalBox2);
verticalBox1.add(verticalBox2forsep);
verticalBox1.add(processbutton);
heading.add(backBoneNodeLabel);
//body.add(backBoneNodeID);
body.add(verticalBox1);
serverPanel.add(heading);
serverPanel.add(body);
return serverPanel;
}
protected JTable populateTable(Map<String,Double> regNodeThroughputMap) {
/*{ { "Row1-Column1", "Row1-Column2", "Row1-Column3" },
{ "Row2-Column1", "Row2-Column2", "Row2-Column3" } }*/
rowData = new Object[regularNodeCount+1][2];
Set<Map.Entry<String, Double>> set = regNodeThroughputMap.entrySet();
for (Map.Entry<String, Double> me : set) {
System.out.println("key ="+me.getKey());
System.out.println("Value ="+me.getValue());
}
String[] keys = new String[regularNodeCount+2];
String[] values = new String[regularNodeCount+2];
List<String> keyList = new LinkedList<String>();
List<String> valueList = new LinkedList<String>();
keyList.add("");
valueList.add("");
for(String key:regNodeThroughputMap.keySet()){
keyList.add(key);
}
for(double value:regNodeThroughputMap.values()){
System.out.println(value);
valueList.add(Double.toString(value));
}
keyList.toArray(keys);
valueList.toArray(values);
System.out.println(Arrays.asList(keys));
System.out.println(Arrays.asList(values));
rowData[0][0] =columnNames[0];
rowData[0][1] =columnNames[1];
for(int i=1;i<=regularNodeCount;i++){
for(int j=0;j<2;j++){
if(j==0)
rowData[i][j]=keys[i];
if(j==1)
rowData[i][j]=values[i];
}
}
return new JTable(rowData, columnNames);
//Printing the array
/* for (int i =0; i < regularNodeCount; i++) {
for (int j = 0; j < 2; j++) {
System.out.print(" " + rowData[i][j]);
}
System.out.println("");
}
*/
}
protected Map<String, Double> getThroughPutValues(String regularNodeInput) {
return ThroughputUtility.generateMapofNodeAndThroughput(regularNodeInput);
}
protected static void createAndShowGUI() {
//Create and set up the window.
frame = new JFrame("Throughput Optimization for Mobile BackBone Networks");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
EntryPoint splitPaneDemo = new EntryPoint();
frame.getContentPane().add(splitPaneDemo.jTabbedPane);
JScrollPane sp = new JScrollPane(tableOfValues);
sp.setBorder(BorderFactory.createEmptyBorder());
sp.setVerticalScrollBarPolicy(JScrollPane.VERTICAL_SCROLLBAR_ALWAYS);
sp.setHorizontalScrollBarPolicy(JScrollPane .HORIZONTAL_SCROLLBAR_AS_NEEDED);
frame.setResizable(false);
//Display the window.
frame.pack();
frame.setVisible(true);
frame.setSize(800,600);
}
public static void main(String[] args) {
try {
for (LookAndFeelInfo info : UIManager.getInstalledLookAndFeels()) {
if ("Nimbus".equals(info.getName())) {
UIManager.setLookAndFeel(info.getClassName());
break;
}
}
} catch (UnsupportedLookAndFeelException e) {
e.printStackTrace();
} catch (ClassNotFoundException e) {
e.printStackTrace();
} catch (InstantiationException e) {
e.printStackTrace();
} catch (IllegalAccessException e) {
e.printStackTrace();
}
javax.swing.SwingUtilities.invokeLater(new Runnable() {
public void run() {
createAndShowGUI();
}
});
}
}
添加ThroughputUtility.java
Adding ThroughputUtility.java
package utils;
import java.util.LinkedHashMap;
import java.util.LinkedList;
import java.util.List;
import java.util.Map;
/**
* @author Nathan
*
*/
public class ThroughputUtility {
public static double MIN =5000;
public static double MAX =10000;
public static final double e =Math.E;
public static final double epsilon = 8.854187 *Math.pow(10,-12);
static int regularNodeCount;
static int counter ;
/**Generates the map of Node and ThroughPut values
* @param regularNodeInput
*/
public static Map<String,Double> generateMapofNodeAndThroughput(String regularNodeInput){
regularNodeCount = Integer.parseInt(regularNodeInput);
List<Double> randNodeDistances =getRandDistanceOfNodes(regularNodeCount);
Map<String,Double> nodeAndThroughputmap = getThroughputValuesForNodes(randNodeDistances);
System.out.println(nodeAndThroughputmap);
return nodeAndThroughputmap;
}
/** Obtains the throughput value based on the distances between
* the regular nodes and the backend Nodes.
* @param randNodeDistances
* @return
*/
private static Map<String, Double> getThroughputValuesForNodes(
List<Double> randNodeDistances) {
Map<String,Double> nodeAndThroughputmap = new LinkedHashMap<String, Double>();
for(double i : randNodeDistances){
double throughputValue = calculateThroughPut(i);
nodeAndThroughputmap.put("RegularNode :"+counter, throughputValue);
counter++;
}
return nodeAndThroughputmap;
}
private static double calculateThroughPut(double distanceij) {
double throughput = 1 /(e*regularNodeCount*distanceij*epsilon);
return throughput;
}
/**Generates the distance dij .
* @param regularNodeCount
* @return
*/
private static List<Double> getRandDistanceOfNodes(int regularNodeCount) {
List<Double> distnodeNumbers = new LinkedList<Double>();
for(int i=0;i<regularNodeCount;i++){
double randnodeNumber = MIN + (double)(Math.random() * ((MAX - MIN) + 1));
distnodeNumbers.add(randnodeNumber);
}
return distnodeNumbers;
}
public static void main(String[] args) {
ThroughputUtility.generateMapofNodeAndThroughput("5");
/*System.out.println(e);
System.out.println(epsilon);*/
}
}
推荐答案
为什么看不到滚动条的主要问题是将表添加到了多个容器中.
The main problem why you can't see the scroll bar is that you add the table to multiple containers.
单击按钮时，您将重新创建很多swing对象(为什么?)，然后启动一个线程以将表添加到框中(为什么?如果不知道您要做什么，请谨慎使用swing和多线程是做).之后(或之前，取决于线程运行的时间)，您可以将表添加到滚动窗格中.
when clicking the button, you recreate a lot of swing objects (why?), then you start a thread to add the table to the box (why?? be careful with swing and multithreading if you don't know what you are doing). after that (or before, depending on how long the thread is running) you add the table to the scrollpane.
滚动窗格不包含您的表，因为您只能使用一次.
the scrollpane does not contain your table, because you can only use it once.
一个快速修复方法是这样的: 一次创建所有GUI内容，将其保留在任何动作侦听器和内容之外.如果启动该应用程序，它应该只显示一个空表.不要将同一对象添加到多个容器中！您可以通过使用
A quick fix would be something like this: create all you GUI stuff once, leave it out of any action listeners and stuff. if you start the application, it should just show an empty table. don't add the same object into multiple containers! you can control the size of your table and scrollpane by using
table.setPreferredSize(new Dimension(width, height));
如果单击按钮(位于操作侦听器中)，则获取所有新数据并将其添加到表中.例如通过使用类似这样的东西.
if you click the button (that is in your action listener), get all the new data and add it it to the table. e.g. by using something like this.
tableOfValues.getModel().setValueAt(value, row, column);
或在需要时创建新的表模型:
or create a new table model if you have to:
tableOfValues.setModel(new DefaultTableModel(rowData, columnNames));
这就是我现在可以通过查看代码告诉你的全部信息……
That's all I can tell you for now by looking at the code...
在方法populateTable(...)中不要创建新表！如有必要，请使用上述代码来设置新模型，或者使用现有模型并修改其值.
edit: in the method populateTable(...) don't create a new table! use the above code to set a new model instead if you have to, or use an existing one and modify its values.
这篇关于jTable swing中的垂直滚动条未出现的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
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