我有一个正在进行的项目，它允许我创建模板和输入数据。有一点不起作用的是该表不是动态更新的。一旦我关闭应用程序并再次运行它，它只会刷新。是否有类似于UpdateUI的方法，它在您面前更新而无需退出应用程序并再次重新打开以查看更改？我有下面的代码，有人可以指出什么代码以及我将它放在课堂上的位置？谢谢。
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Font;
import java.awt.Insets;
import java.awt.Toolkit;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.Statement;
import java.util.ArrayList;
import java.util.Collections;
import javax.swing.JButton;
import javax.swing.JDialog;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JOptionPane;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTable;
import javax.swing.SwingConstants;
import javax.swing.border.EmptyBorder;
import javax.swing.border.LineBorder;
import javax.swing.event.CellEditorListener;
import javax.swing.event.ChangeEvent;
public class ViewTable extends JFrame {
private static final long serialVersionUID = 1L;
private static final String PREFERRED_LOOK_AND_FEEL = null;
private static String tableName;
private String[] columnNames;
private String[][] data;
private JPanel mainPanel;
private JTable tablePane;
private int dataX;
private int dataY;
public ViewTable(String tableName){
this.tableName=tableName;
initComponents();
loadDB();
displayTable();
/*setDefaultCloseOperation(CreateTemplate.DISPOSE_ON_CLOSE);
setSize(700,700);
setTitle("View Table");
setVisible(true);*/
Dimension dim = Toolkit.getDefaultToolkit().getScreenSize();
this.setSize(dim.width, dim.height);
this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
this.setVisible(true);
}
private void initComponents() {
mainPanel = new JPanel(new BorderLayout());
this.add(mainPanel);
mainPanel.setBackground(Color.gray);
JPanel topPanel = new JPanel(new BorderLayout());
topPanel.setBackground(Color.DARK_GRAY);
mainPanel.add(topPanel,BorderLayout.NORTH);
JLabel titleLabel = new JLabel(this.tableName);
titleLabel.setBorder(new LineBorder(Color.black));
titleLabel.setFont(new Font("Helvetica", Font.BOLD, 24));
titleLabel.setForeground(Color.white);
titleLabel.setHorizontalAlignment(SwingConstants.CENTER);
topPanel.add(titleLabel,BorderLayout.CENTER);
JPanel buttonPanel = new JPanel(new BorderLayout());
JButton exitButton = new JButton("Finish");
exitButton.addActionListener(new ActionListener(){
public void actionPerformed(ActionEvent event){
close_window();
}
});
exitButton.setBorder(new EmptyBorder(new Insets(20,20,20,20)));
buttonPanel.add(exitButton,BorderLayout.EAST);
JButton deleteButton = new JButton("Delete Entry");
deleteButton.addActionListener(new ActionListener(){
public void actionPerformed(ActionEvent event){
Object[] rows = new Object[dataX-1];
for (int r=0;r!=rows.length;r++){
rows[r] = data[r][0];
}
//JOptionPane delAsk = new JOptionPane("Delete entry:",JOptionPane.PLAIN_MESSAGE,JOptionPane.DEFAULT_OPTION,null,rows,rows[0]);
//delAsk.
//delAsk.set.InputDialogue(null,"Delete entry:","Delete",JOptionPane.PLAIN_MESSAGE,null,rows,rows[0]);
//JDialog dialog = delAsk.createDialog(null, "Delete");
//dialog.show();
//String del = (String)delAsk.getInputValue();
//System.out.println(del);
Object deleteRow
= JOptionPane.showInputDialog(null,"Which entry do you wish to delete",
"Delete Entry",JOptionPane.INFORMATION_MESSAGE,null,
rows,rows[0]);
int index = -1;
for(int i=0;i!=rows.length;i++){
if(rows[i].equals(deleteRow.toString())){ index = i; }
}
SQLCommands.SQLCommand("DELETE FROM "+tableName+" WHERE recID='"+index+"'");
initComponents();
loadDB();
displayTable();
tablePane.updateUI();
}
});
deleteButton.setBorder(new EmptyBorder(new Insets(20,20,20,20)));
buttonPanel.add(deleteButton,BorderLayout.WEST);
topPanel.add(buttonPanel,BorderLayout.EAST);
}
private void close_window(){ this.dispose(); }
private void loadDB(){
//get column names
columnNames = getColumnNames();
for (String S : columnNames){ System.out.println(S); }//JOptionPane.showInputDialog("Enter template name"); }
//Temp add new dummy data
//SQLCommands.SQLCommand("INSERT INTO "+tableName+" VALUES (1,'av', 'bv', 'cv', 'dv', 'ev')");
//use column names to populate data
String[] col = SQLCommands.returnSQLCommand("SELECT "+columnNames[0]+" FROM "+tableName+"");
dataX = col.length+1;
dataY = columnNames.length;
System.out.println(dataX+" "+dataY);
data = new String[dataX][dataY];
printTable(data);
System.out.println();
//e.g. data[4][0] => "SELECT Name FROM tableName"[4]
for(int j=0;j!=columnNames.length;j++){
String n = columnNames[j];
col = SQLCommands.returnSQLCommand("SELECT "+n+" FROM "+tableName+"");
for(int i=0; i!=col.length; i++){
data[i][j]=col[i];
}
}
for(int j=0;j!=dataY;j++){
data[dataX-1][j]="";
}
for(String D1[] : data){
for(String D : D1){
System.out.print(D+" ");
}
System.out.printf("\n");
}
/*columnNames = new String[2];
columnNames[0] = "col 1";
columnNames[1] = "col 2";
data = new String[2][2];
data[0][0] = "hello";
data[0][1] = "good bye";
dataX = 2;
dataY = 2;*/
}
private void displayTable(){
//use JTable
tablePane = new JTable(data,columnNames);
tablePane.setFillsViewportHeight(true);
tablePane.setShowHorizontalLines(true);
tablePane.setCellSelectionEnabled(true);
tablePane.setRowSelectionAllowed(true);
tablePane.getDefaultEditor(String.class).addCellEditorListener(new MyCellEditorListener(tablePane));
//new JScrollPane which uses the table
JScrollPane scrollPane = new JScrollPane(tablePane,JScrollPane.VERTICAL_SCROLLBAR_AS_NEEDED,JScrollPane.HORIZONTAL_SCROLLBAR_AS_NEEDED);
scrollPane.setBorder(new EmptyBorder(new Insets(15,15,15,15)));
//put JScrollpane in CENTER box
mainPanel.add(scrollPane,BorderLayout.CENTER);
}
public static String[] getColumnNames(){
Connection connection=null;
Statement statement=null;
ResultSet result = null;
String[] names=null;
try {
Class.forName("org.sqlite.JDBC");
connection = DriverManager
.getConnection("jdbc:sqlite:Media.db");
statement = connection.createStatement();
result = statement.executeQuery("PRAGMA table_info( "+tableName+" );");
ArrayList<String> nameList = new ArrayList<String>();
while(result.next()){
nameList.add(result.getString(2));
}
names = new String[nameList.toArray().length-1];
for (int i=1; i!=nameList.toArray().length; i++){
names[i-1] = (String)nameList.toArray()[i];
}
} catch (Exception e) {
e.printStackTrace();
} finally {
try {
statement.close();
connection.close();
} catch (Exception e) {
e.printStackTrace();
}
}
return names;
}
private class MyCellEditorListener implements CellEditorListener
{
private JTable table;
private String[][] datain;
public MyCellEditorListener(JTable table){
this.table = table;
setupDataIn();
}
private void setupDataIn(){
datain = new String[dataX][dataY];
for(int i=0; i!=dataX; i++){
for(int j=0; j!=dataY; j++){
datain[i][j]=data[i][j];
}
}
}
@Override
public void editingCanceled(ChangeEvent arg0) {
//Do Nothing
}
@Override
public void editingStopped(ChangeEvent e) {
// Update DB
printTable(data);
printTable(datain);
for(int i=0; i!=dataX; i++){
for(int j=0; j!=dataY; j++){
if(datain[i][j].equals(data[i][j])){
//DO Nothing
} else {
//Update or add new field
if(i==dataX-1){
System.out.println("new field");
String com = "INSERT INTO "+tableName+" VALUES ("+(dataX-1)+", ";
for(int y=0;y!=dataY;y++){
if(y==j){
com += "'"+data[i][j]+"', ";
} else {
com += "'', ";
}
}
com = com.substring(0, com.length()-2);
com+=")";
System.out.println(com);
SQLCommands.SQLCommand(com);
initComponents();
loadDB();
setupDataIn();
displayTable();
tablePane.updateUI();
break;
} else {
System.out.println("UPDATE "+tableName+" SET "+columnNames[j]+"='"+data[i][j]+"' WHERE recID="+i);
SQLCommands.SQLCommand("UPDATE "+tableName+" SET "+columnNames[j]+"='"+data[i][j]+"' WHERE recID="+i);
}
}
}
}
}
}
private void printTable(String[][] t){
for(String[] a : t){
for(String b: a){
System.out.print(b+" ");
}
System.out.println();
}
}
public static void main(String[] args){
String [] tableNames = SQLCommands.returnSQLCommand("SELECT name FROM sqlite_master");
new ViewTable(tableNames[tableNames.length -1]);
}
}
答案 0 :(得分：5)
您应该使用TableModel。结帐How to Use Tables。然后fireTableDataChanged()（或另一个适当的fire *方法）会通知您的表格有关更改。
也许Using JDBC with GUI API可能会有所帮助。它演示了JDBC和JTable的非常基本的集成。