如何使用 SWT 和 MySql 在树视图中显示列表值

Question

请原谅我的英语不好。 java 和 SWT 的新功能。我试图在 SWT 中而不是在 jface 中显示树视图。从数据库获取值，我应该显示树视图。

树状视图，

模板 - 页码 - 布局编号-

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.ResultSetMetaData;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import org.eclipse.swt.SWT;
import org.eclipse.swt.layout.FillLayout;
import org.eclipse.swt.widgets.Display;
import org.eclipse.swt.widgets.Shell;
import org.eclipse.swt.widgets.Tree;
import org.eclipse.swt.widgets.TreeItem;

public class TreeEx 
{
    static final String JDBC_DRIVER = "com.mysql.jdbc.Driver";  
    static final String DB_URL = "jdbc:mysql://localhost/Tree";
    static final String USER = "root";
    static final String PASS = "root123";

    public static void main(String[] args) 
    {
        Connection conn = null;
        Statement stmt = null;

        int TemplateID=0;
        int templateId =0 ;
        int  pageNumber = 0;
        int PageNumber=0;
        int layoutId = 0;
        int LayoutId=0;
List<Integer> a1 = new ArrayList();
        List a2 = new ArrayList();
        List a3 = new ArrayList();
    try
        {

            Class.forName("com.mysql.jdbc.Driver");


            System.out.println("Connecting to a selected database...");
            conn = DriverManager.getConnection(DB_URL, USER, PASS);

            System.out.println("Creating statement...");
            stmt = conn.createStatement();

            String sql = "SELECT templateID,PageNumber,layoutid FROM templatepage, templatelayout WHERE  templatelayout.pageid = templatepage.PageNumber";

            String sql1="SELECT count(distinct templateID )TemplateID FROM templatepage, templatelayout WHERE  templatelayout.pageid = templatepage.PageNumber";

            String sql2="SELECT count(distinct PageNumber )PageNumber FROM templatepage, templatelayout WHERE  templatelayout.pageid = templatepage.PageNumber";

            String sql3="SELECT count(distinct layoutid )LayoutId FROM templatepage, templatelayout WHERE  templatelayout.pageid = templatepage.PageNumber";
    ResultSet rs = stmt.executeQuery(sql);
while(rs.next())
            {
    templateId=rs.getInt("templateID");
                    pageNumber=rs.getInt("PageNumber");
                    layoutId=rs.getInt("layoutid");
a1.add(rs.getInt("templateID"));
                    a2.add(rs.getInt("PageNumber"));
                    a3.add(rs.getInt("layoutid"));
    System.out.print("templateID: " + templateId);
                    System.out.print(", PageNumber: " + pageNumber);
                    System.out.print(", layoutid: " + layoutId+"\n");
System.out.println(a1);
            }     
                rs.close();

                ResultSet rs1 = stmt.executeQuery(sql1);
                while(rs1.next())
                {
                    TemplateID=rs1.getInt("TemplateID");
                    System.out.println("Distinct TemplateID"+TemplateID);
                }
                rs1.close();

                ResultSet rs2 = stmt.executeQuery(sql2);
                while(rs2.next())
                {
                    PageNumber=rs2.getInt("PageNumber");
                    System.out.println("Distinct PageNumber"+PageNumber);
                }
                rs2.close();

                ResultSet rs3 = stmt.executeQuery(sql3);
                while(rs3.next())
                {
                    LayoutId=rs3.getInt("LayoutId");
                    System.out.println("Distinct LayoutId"+LayoutId);
                }
                rs3.close();
            }
            catch(SQLException se)
            {
                se.printStackTrace();
            }
            catch(Exception e)
            {
                e.printStackTrace();
            }
            finally
            {
                try
                {
                    if(stmt!=null)
                        conn.close();
                }catch(SQLException se)
                {
                }
                try
                {
                    if(conn!=null)
                        conn.close();
                }
                catch(SQLException se)
                {
                    se.printStackTrace();
                }
            }
            Display display = new Display();

            Shell shell = new Shell(display);
            shell.setText("SWT Trees");
            shell.setLayout(new FillLayout());
            shell.setSize(400, 300);

            Tree tree = new Tree(shell, SWT.BORDER | SWT.H_SCROLL | SWT.V_SCROLL);

            for (int i = 0; i <TemplateID; i++) 
        {
            TreeItem treeItem = new TreeItem(tree, 0);
            treeItem.setText("template "+a1);

            for (int j = 0; j <PageNumber; j++) 
            {
                TreeItem subTreeItem = new TreeItem(treeItem, SWT.NONE);
                subTreeItem.setText("pageNumber " +a2);

                for (int k = 0; k <LayoutId; k++) 
                {
                    TreeItem subSubTreeItem = new TreeItem(subTreeItem, SWT.NONE);
                    subSubTreeItem.setText("layoutid "+a3);
                    System.out.println("**********"+layoutId);
                }
            }
        }
            shell.open();
            while (!shell.isDisposed()) 
            {
                if (!display.readAndDispatch())
                    display.sleep();
            }
            display.dispose();
    }
}

我的代码显示如下，

Temaple[1,1,1]
   PageNumber[1,1,1,]
      layoutid[1,2,3]
      layoutid[1,2,3]
      layoutid[1,2,3]

It should be 

Template1
    Pagenumber1
       layoutid3
       layoutid3
        layoutid3

Answer 1

好的。很难找出问题所在，因为有一些不相关的代码。首先，请不要发送 SQL 查询，尝试对问题建模。但。如果是这样，请在 finally{} 块中调用类似 close() 的方法。 ;)

问题是您有 for 循环，但您没有以正确的方式执行它。您循环了三次，但值与您使用的值相同（完整的 ArrayList）。你通过 a1 得到完整的数组；使用 get() 方法获取实际元素或使用 for-each 循环！

treeItem.setText("template " + a1.get(i));

如何使用 SWT 和 MySql 在树视图中显示列表值

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