Question

我需要安装一个屏幕，其中包含我从数据库中搜索过的信息。为此，我搜索了信息并存储在ArrayList中。我需要使用for循环来浏览ArrayList和每个循环以挂载JTextArea。

我尝试让for循环通过ArrayList然后安装屏幕，但我无法做任何事情。

屏幕代码：

import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
import java.sql.*;
import java.util.*;

public class TelaSugestao extends JFrame implements ActionListener {
   public void actionPerformed(ActionEvent e) {}

   private JTextArea txtArea;

   private Sugestao sugestao;
   private Connection conn;

   public TelaSugestao(Connection conn) {
      super("Tela sugestao");

      txtArea = new JTextArea(3,3);

      this.conn = conn;

      Container caixa = getContentPane();
      caixa.setLayout(new FlowLayout());

      caixa.add(txtArea);

      setSize(432,400);
      setLocationRelativeTo(null);
      setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
      setVisible(true);
   }

   // Trying to mount the screen every time the For runs the ArrayList.
   public void montaTela() {
      Sugestao sugestao = new Sugestao(); 
      ArrayList<Sugestao> listaSugestao = sugestao.carregaSugestao(conn);
      for (int i = 0; i < listaSugestao.size(); i++) {

      }
   }
}

我正在寻找这种方式的数据库信息：

public ArrayList<Sugestao> carregaSugestao(Connection conn) {
    String sqlSelect = "Select id, sugestao from tabelaTeste where id_sugestao = ?";
    ArrayList<Sugestao> listaSugestao = new ArrayList<>();

    try (PreparedStatement stm = conn.prepareStatement(sqlSelect);) {
        stm.setInt(1, getIdSugestao());
        try (ResultSet rs = stm.executeQuery();) {
            while (rs.next()){
                Sugestao s = new Sugestao();
                s.setIdSugestao(rs.getInt("id_sugestao"));
                s.setSugestao(rs.getString("sugestao")); 
                listaSugestao.add(s);
                guardaSugestao = carregaSugestao(conn);
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
    } catch (SQLException e1) {
        System.out.print(e1.getStackTrace());
    }
    return listaSugestao;
}

请您解释一下如何做到这一点？

Answer 1

从构造函数中删除这两行：metadataWindow::metadataWindow(QWidget *parent) : QWidget(parent) { this->setupUI(); // not shown here, but just basic QLabel stuff } void metadataWindow::setupListener() { const char *metadata_file = "/tmp/my-pipe-file"; // vvvvv This here is blocking vvvvvv FILE *fd = fopen(metadata_file, "r"); pipe = new QTextStream(fd); streamReader = new QSocketNotifier(fileno(fd), QSocketNotifier::Read, qApp); QObject::connect(streamReader, SIGNAL(activated(int)), this, SLOT(onData())); streamReader->setEnabled(true); }方法现在更改为：

txtArea = new JTextArea(3,3); caixa.add(txtArea);

并调用方法：public void montaTela(Container pane){ Sugestao sugestao = new Sugestao(); ArrayList<Sugestao> listaSugestao = sugestao.carregaSugestao(conn); for(int i = 0; i < listaSugestao.size(); i++){ txtArea=new JTextArea(); //add Text to your txtArea with .append(string) pane.add(txtarea); } }＆lt; - 需要在构造函数中调用。否则为内容窗格制作一个getter

我有一个Java的GUI，我不知道如何继续

1 个答案: