如何使用java swing在jlist中的现有元素下添加新元素?
一、 我使用jlist显示我的数据库数据。该过程可以从数据库中获取数据并显示在jlist元素中。我需要通过单击事件在jlist元素下显示我的数据。示例:包含用户名的Jlist,单击特定用户后,它应在Jlist元素下方显示该用户的属性 如果有方法执行此过程,或者无法在特定jlist元素下显示,请建议我如何使用java swing在jlist中的现有元素下添加新元素?,java,swing,jlist,mouseclick-event,Java,Swing,Jlist,Mouseclick Event,一、 我使用jlist显示我的数据库数据。该过程可以从数据库中获取数据并显示在jlist元素中。我需要通过单击事件在jlist元素下显示我的数据。示例:包含用户名的Jlist,单击特定用户后,它应在Jlist元素下方显示该用户的属性 如果有方法执行此过程,或者无法在特定jlist元素下显示,请建议我 提前感谢。您首先要做的事情之一始终是第一件事,因为他们通常不这样做,请举例说明如何做到这一点 因此,现在需要基于MouseEvent(或点)为元素创建索引。有趣的是,在浏览JListJavaDocs
提前感谢。您首先要做的事情之一始终是第一件事,因为他们通常不这样做,请举例说明如何做到这一点 因此,现在需要基于
MouseEvent
(或点
)为元素创建索引。有趣的是,在浏览JList
JavaDocs时,我偶然发现了这个示例
MouseListener mouseListener = new MouseAdapter() {
public void mouseClicked(MouseEvent e) {
if (e.getClickCount() == 2) {
int index = list.locationToIndex(e.getPoint());
System.out.println("Double clicked on Item " + index);
}
}
};
list.addMouseListener(mouseListener);
好的,很好,我们知道JList
中元素的索引,我们可以使用它来获取物理元素,您可以使用它来查询数据库、查找属性,或者,如果您已经正确地完成了操作并将一个实际对象嵌入到模型中,则可以获取属性
向JList
/ListModel
动态添加元素的唯一方法是通过可变的ListModel
,如DefaultListModel
话虽如此,
JTable
和JTree
都将是显示复合信息的更好组件。您首先要做的事情之一始终是第一件事,而且它们通常都有这样做的示例
因此,现在需要基于MouseEvent
(或点
)为元素创建索引。有趣的是,在浏览JList
JavaDocs时,我偶然发现了这个示例
MouseListener mouseListener = new MouseAdapter() {
public void mouseClicked(MouseEvent e) {
if (e.getClickCount() == 2) {
int index = list.locationToIndex(e.getPoint());
System.out.println("Double clicked on Item " + index);
}
}
};
list.addMouseListener(mouseListener);
好的,很好,我们知道JList
中元素的索引,我们可以使用它来获取物理元素,您可以使用它来查询数据库、查找属性,或者,如果您已经正确地完成了操作并将一个实际对象嵌入到模型中,则可以获取属性
将元素动态添加到JList
/ListModel
的唯一方法是通过可变的ListModel
,如DefaultListModel
综上所述,
JTable
和JTree
都是显示复合信息的更好组件。这是动态树的工作示例,它将数据库作为节点加载,并将其表作为子节点加载。首先,您必须创建一个包含数据库的所有节点的根节点,然后在隐藏根节点之后,这会给您数据库列表的感觉。之后,当我们单击任何数据库节点时,它会在树中动态加载其表(注意:它只在单击数据库节点时加载表)
这是动态树的工作示例,它将数据库作为节点加载,并将其表作为子节点加载。首先,您必须创建一个根节点
节点,该节点包含数据库的所有节点,然后在隐藏根节点之后,这会给您数据库列表的感觉。之后,当我们单击任何数据库节点时,它会在树中动态加载其表(注意:它只在单击数据库节点时加载表)
@这是使用DefaultTreeCellRenderer
的树节点包含图像的示例
import java.awt.Component;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.util.ArrayList;
import java.util.List;
import javax.swing.ImageIcon;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JScrollPane;
import javax.swing.JTree;
import javax.swing.event.TreeSelectionEvent;
import javax.swing.event.TreeSelectionListener;
import javax.swing.tree.DefaultMutableTreeNode;
import javax.swing.tree.DefaultTreeCellRenderer;
import javax.swing.tree.DefaultTreeModel;
public class DatabaseTree implements TreeSelectionListener {
JFrame frame;
DefaultTreeModel treeModel;
DefaultTreeCellRenderer cellRenderer;
JScrollPane pane;
JTree tree;
Connection connection;
PreparedStatement pst;
ResultSet rs;
List<String> databaseNode = new ArrayList<String>();
public DatabaseTree() {
// JFrame.setDefaultLookAndFeelDecorated(true);
frame = new JFrame();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
DefaultMutableTreeNode root = new DefaultMutableTreeNode();
root.setUserObject(new JLabel("Databases", new ImageIcon("/images/g.jpg"), JLabel.CENTER));
treeModel = new DefaultTreeModel(root);
try {
Class.forName("com.mysql.jdbc.Driver");
connection = DriverManager.getConnection("jdbc:mysql://localhost:3306/ganesh", "root",
"admina");
pst = connection.prepareStatement("show databases");
rs = pst.executeQuery();
while (rs.next()) {
String text = rs.getString(1);
databaseNode.add(text);
root.add(new DefaultMutableTreeNode(new JLabel(text, new ImageIcon("/images/g.jpg"),
JLabel.CENTER)));
}
} catch (Exception e) {
e.printStackTrace();
}
tree = new JTree(treeModel);
tree.setCellRenderer(new MyTreeCellRenderer());
tree.addTreeSelectionListener(this);
tree.setRootVisible(true);
tree.expandRow(0);
pane = new JScrollPane(tree);
frame.setContentPane(pane);
frame.setVisible(true);
}
public static void main(String args[]) {
new DatabaseTree();
}
@Override
public void valueChanged(TreeSelectionEvent e) {
DefaultMutableTreeNode node = (DefaultMutableTreeNode) e.getPath().getLastPathComponent();
String text = ((JLabel) node.getUserObject()).getText();
JLabel label = null;
if (databaseNode.contains(text)) {
if (node.getChildCount() == 0) {
try {
pst = connection.prepareStatement("show tables in " + text);
rs = pst.executeQuery();
while (rs.next()) {
String data = rs.getString(1);
label = new JLabel(data);
node.add(new DefaultMutableTreeNode(label));
}
} catch (Exception ee) {
ee.printStackTrace();
}
}
}
}
class MyTreeCellRenderer extends DefaultTreeCellRenderer {
JLabel label;
@Override
public Component getTreeCellRendererComponent(JTree tree, Object value, boolean selected,
boolean expanded, boolean leaf, int row,
boolean hasFocus) {
DefaultMutableTreeNode node = (DefaultMutableTreeNode) value;
label = (JLabel) node.getUserObject();
if (selected) {
label.setBackground(backgroundSelectionColor);
label.setForeground(textSelectionColor);
} else {
label.setBackground(backgroundNonSelectionColor);
label.setForeground(textNonSelectionColor);
}
return label;
}
}
}
导入java.awt.Component;
导入java.sql.Connection;
导入java.sql.DriverManager;
导入java.sql.PreparedStatement;
导入java.sql.ResultSet;
导入java.util.ArrayList;
导入java.util.List;
导入javax.swing.ImageIcon;
导入javax.swing.JFrame;
导入javax.swing.JLabel;
导入javax.swing.JScrollPane;
导入javax.swing.JTree;
导入javax.swing.event.TreeSelectionEvent;
导入javax.swing.event.TreeSelectionListener;
导入javax.swing.tree.DefaultMutableTreeNode;
导入javax.swing.tree.DefaultTreeCellRenderer;
导入javax.swing.tree.DefaultTreeModel;
公共类DatabaseTree实现TreeSelectionListener{
JFrame框架;
默认树模型树模型;
DefaultTreeCellRenderer-cellRenderer;
JScrollPane;
JTree树;
连接;
编制报表pst;
结果集rs;
List databaseNode=新建ArrayList();
公共数据库树(){
//JFrame.setDefaultLookAndFeelDecorated(true);
frame=新的JFrame();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
DefaultMutableTreeNode根=新的DefaultMutableTreeNode();
setUserObject(新的JLabel(“数据库”,新的ImageIcon(“/images/g.jpg”),JLabel.CENTER));
treeModel=新的DefaultTreeModel(根);
试一试{
Class.forName(“com.mysql.jdbc.Driver”);
connection=DriverManager.getConnection(“jdbc:mysql://localhost:3306/ganesh“,”根“,
“行政管理”);
pst=connection.prepareStatement(“显示数据库”);
rs=pst.executeQuery();
while(rs.next()){
String text=rs.getString(1);
databaseNode.add(文本);
添加(新的DefaultMutableTreeNode(新的JLabel(文本,新的图像图标(“/images/g.jpg”),
JLabel.CENTER),;
}
}捕获(例外e){
e、 printStackTrace();
}
树=新的JTree(树模型);
setCellRenderer(新的MyTreeCellRenderer());
addTreeSelectionListener(这个);
tree.setRootVisible(true);
tree.expandRow(0);
窗格=新的JScrollPane(树);
frame.setContentPane(窗格);
frame.setVisible(true);
}
公共静态void main(字符串参数[]){
新建数据库树();
}
@凌驾
公共作废值已更改(TreeSelection事件e){
DefaultMutableTreeNode=(DefaultMutableTreeNode)e.getPath().getLastPathComponent();
字符串文本=((JLabel)node.getUserObject()).getText();
JLabel标签=null;
if(databaseNode.contains(text)){
if(node.getChildCount()==0){
试一试{
pst=connection.prepareStatement(“在“+文本中显示表格”);
rs=pst。
import java.awt.Component;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.util.ArrayList;
import java.util.List;
import javax.swing.ImageIcon;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JScrollPane;
import javax.swing.JTree;
import javax.swing.event.TreeSelectionEvent;
import javax.swing.event.TreeSelectionListener;
import javax.swing.tree.DefaultMutableTreeNode;
import javax.swing.tree.DefaultTreeCellRenderer;
import javax.swing.tree.DefaultTreeModel;
public class DatabaseTree implements TreeSelectionListener {
JFrame frame;
DefaultTreeModel treeModel;
DefaultTreeCellRenderer cellRenderer;
JScrollPane pane;
JTree tree;
Connection connection;
PreparedStatement pst;
ResultSet rs;
List<String> databaseNode = new ArrayList<String>();
public DatabaseTree() {
// JFrame.setDefaultLookAndFeelDecorated(true);
frame = new JFrame();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
DefaultMutableTreeNode root = new DefaultMutableTreeNode();
root.setUserObject(new JLabel("Databases", new ImageIcon("/images/g.jpg"), JLabel.CENTER));
treeModel = new DefaultTreeModel(root);
try {
Class.forName("com.mysql.jdbc.Driver");
connection = DriverManager.getConnection("jdbc:mysql://localhost:3306/ganesh", "root",
"admina");
pst = connection.prepareStatement("show databases");
rs = pst.executeQuery();
while (rs.next()) {
String text = rs.getString(1);
databaseNode.add(text);
root.add(new DefaultMutableTreeNode(new JLabel(text, new ImageIcon("/images/g.jpg"),
JLabel.CENTER)));
}
} catch (Exception e) {
e.printStackTrace();
}
tree = new JTree(treeModel);
tree.setCellRenderer(new MyTreeCellRenderer());
tree.addTreeSelectionListener(this);
tree.setRootVisible(true);
tree.expandRow(0);
pane = new JScrollPane(tree);
frame.setContentPane(pane);
frame.setVisible(true);
}
public static void main(String args[]) {
new DatabaseTree();
}
@Override
public void valueChanged(TreeSelectionEvent e) {
DefaultMutableTreeNode node = (DefaultMutableTreeNode) e.getPath().getLastPathComponent();
String text = ((JLabel) node.getUserObject()).getText();
JLabel label = null;
if (databaseNode.contains(text)) {
if (node.getChildCount() == 0) {
try {
pst = connection.prepareStatement("show tables in " + text);
rs = pst.executeQuery();
while (rs.next()) {
String data = rs.getString(1);
label = new JLabel(data);
node.add(new DefaultMutableTreeNode(label));
}
} catch (Exception ee) {
ee.printStackTrace();
}
}
}
}
class MyTreeCellRenderer extends DefaultTreeCellRenderer {
JLabel label;
@Override
public Component getTreeCellRendererComponent(JTree tree, Object value, boolean selected,
boolean expanded, boolean leaf, int row,
boolean hasFocus) {
DefaultMutableTreeNode node = (DefaultMutableTreeNode) value;
label = (JLabel) node.getUserObject();
if (selected) {
label.setBackground(backgroundSelectionColor);
label.setForeground(textSelectionColor);
} else {
label.setBackground(backgroundNonSelectionColor);
label.setForeground(textNonSelectionColor);
}
return label;
}
}
}