嗨，为什么我的左JTextField没有显示文本提示符，而我的右JTextField为什么呢？
我正在谈论的gname被称为JTextField。
正在运行的fid称为JTextField。
一旦有人按下JButton搜索，该程序就应该在sql数据库中搜索两个import java.awt.BorderLayout;
import java.awt.CardLayout;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.FlowLayout;
import java.awt.Font;
import java.awt.Frame;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JTextField;
import javax.swing.border.LineBorder;
import org.jdesktop.swingx.prompt.PromptSupport;
import com.mysql.jdbc.PreparedStatement;
public class errorbrowser implements ActionListener{
JFrame frame = new JFrame();
JPanel contentPanel = new JPanel(new CardLayout());
private String db_host = "localhost";
private String db_port = "3306";
private String db_user = "root";
private String db_pass = "password";
private String db_base = "errormanager";
private static final String DRIVER = "com.mysql.jdbc.Driver";
private java.sql.Connection connection = null;
errorbrowser(){
JPanel searchsite = new JPanel(new BorderLayout(5,6));
searchsite.setBackground(Color.DARK_GRAY);
JPanel searchbar = new JPanel(new FlowLayout());
searchbar.setBackground(Color.DARK_GRAY);
// searchbar.setBorder(new LineBorder(Color.WHITE, 3));
JTextField gname = new JTextField(10);
JTextField fid = new JTextField(10);
PromptSupport.setPrompt("Gerätebezeichnung",gname);
gname.setOpaque(false);
gname.setBorder(javax.swing.BorderFactory.createEmptyBorder());
gname.setForeground(Color.WHITE);
gname.setFont(new Font("Dialog BOLD",Font.BOLD, 17));
PromptSupport.setPrompt("FehlerID",fid);
fid.setOpaque(false);
fid.setBorder(javax.swing.BorderFactory.createEmptyBorder());
fid.setForeground(Color.WHITE);
fid.setFont(new Font("Dialog BOLD", Font.BOLD, 17));
searchbar.add(gname);
searchbar.add(fid);
searchsite.add(searchbar, BorderLayout.NORTH);
JButton search = new JButton("Search");
search.setPreferredSize(new Dimension(100,60));
search.setMaximumSize(new Dimension(100,60));
search.setMaximumSize(new Dimension(100,60));
searchsite.add(search,BorderLayout.CENTER);
search.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
String gerätename = gname.getText();
String fehlerid = fid.getText();
System.out.println("suche startet");
try {
PreparedStatement st = (PreparedStatement) connection
.prepareStatement("Select gerätebezeichnung, fehlerid from rational where gerätebezeichnung=? and fehlerid=?");
st.setString(1, gerätename);
st.setString(2, fehlerid);
ResultSet results = st.executeQuery();
if(results.next()) {
System.out.println("Fehler gefunden!");
}else {
System.out.println("Fehler nicht gefunden");
}
}catch(SQLException sqlException) {
sqlException.printStackTrace();
}
}
});
JPanel textbox = new JPanel();
contentPanel.add(searchsite);
frame.add(contentPanel);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setSize(600,400);
frame.setVisible(true);
}
public static void main(String[] args) {
errorbrowser app = new errorbrowser();
try {
//Verbindung herstellen
app.createConnection();
}catch(SQLException e) {
System.err.println("SQL Fehler - "+ e.getLocalizedMessage());
e.printStackTrace();
}catch(ClassNotFoundException e) {
System.err.println("Der Datenbank treiber wurde nicht gefunden. - " + e.getLocalizedMessage());
e.printStackTrace();
}
}
public void createConnection() throws SQLException, ClassNotFoundException{
//Treiber initialisieren
Class.forName(DRIVER);
//Url für die Verbindung zu der Datenbank
String mySqlUrl = "jdbc:mysql://" + db_host + ":" + db_port + "/" + db_base;
//Verbindung herstellen
connection = DriverManager.getConnection(mySqlUrl,db_user,db_pass);
}
public void showAll(String nameOfTable)throws SQLException{
String query = "Select * FROM " + nameOfTable;
java.sql.Statement stmt = connection.createStatement();
ResultSet rs = stmt.executeQuery(query);
int columns = rs.getMetaData().getColumnCount();
System.out.println("Alle Einträge zu den Personen ");
System.out.println();
// Ich zeige die Tabellenspaltennamen an
for(int i = 1;i<=columns;i++) {
System.out.print(rs.getMetaData().getColumnLabel(i)+"\t\t");
}
System.out.println();
System.out.println();
//Ich zeige den Inhalt der Tabelle an
while(rs.next()) {
for(int j = 1;j<=columns;j++) {
System.out.print(rs.getString(j)+"\t\t");
}
System.out.println();
}
//Ich schließe die Streams wieder und gebe die Tabelle wieder frei
rs.close();
stmt.close();
}
//Ich schließe die Verbindung zu der Datenbank und gebe de Port am PC frei
public void closeProgramm() throws SQLException{
this.connection.close();
}
@Override
public void actionPerformed(ActionEvent arg0) {
// TODO Auto-generated method stub
}
}
值。
我正在使用swingx库中包含的Prompt Api。
编辑：进一步测试后，我发现当我按下“搜索”按钮时，两个提示均可见。我不知道为什么会这样或怎么发生。
这是我的代码：
class TrainOneModel答案 0 :(得分：1)
提示正在起作用，但焦点位于左侧的TextBox上，这使其不可见。
您可以在开始时将焦点保持在TextBox之外（例如将焦点保持在JButton上）
设置好帧后，您可以像这样保持焦点：
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setSize(600,400);
frame.setVisible(true);
search.requestFocus();//set your focus on button
}