我想創建一個很好的JFrame登錄面板

Question

因此，現在我試圖創建一個基本的登錄GUI。我想看起來像這樣

   UserID        Password 
    <EDITABLE AREA FOR USERID>   <EDITABLE AREA FOR Password> 
    "Error Msg displayed here if there exists error, otherwise NO SPACE" 
          [Login Button] 

下面是我目前正在嘗試使用的代碼來實現此目的。我明白目前沒有任何功能，我將在稍後添加監聽器並提供功能。我目前的問題是，間距似乎已關閉，我不知道如何改善它。

public class Login extends JFrame{ 

    /** 
    * 
    */ 
    private static final long serialVersionUID = 1023608189590961526L; 

    JTextField userName, passWord, userNameLabel, passWordLabel; 
    JTextField errorMsg; 
    JButton login; 
    JPanel userNamePanel, passWordPanel, errorMsgPanel, loginPanel; 
    public Login(String Title){ 
     super(Title);//Set Frame Title 

     login = new JButton("Login"); 
     initTextFields(); 
     setLayout(new GridBagLayout()); 

     userNamePanel = new JPanel(new GridBagLayout()); 
     passWordPanel = new JPanel(new GridBagLayout()); 
     GridBagConstraints constraints = new GridBagConstraints(); 
      constraints.fill = GridBagConstraints.BOTH; 
      constraints.weightx = 1; 
      constraints.weighty = 1; 
      constraints.gridwidth = GridBagConstraints.REMAINDER; 
      constraints.gridx = 0; 
      constraints.gridy = 0; 
     userNamePanel.add(userNameLabel, constraints); 
     passWordPanel.add(passWordLabel, constraints); 
      constraints.gridy++; 
     userNamePanel.add(userName, constraints); 
     passWordPanel.add(passWord, constraints); 
     constraints.gridwidth = GridBagConstraints.RELATIVE; 
     constraints.fill = GridBagConstraints.NONE; 
     this.add(userNamePanel, constraints); 
      constraints.gridwidth = GridBagConstraints.REMAINDER; 
      constraints.gridx = 2; 
     this.add(passWordPanel, constraints); 
      constraints.gridy++; 
      constraints.gridy++; 
      constraints.gridx--; 
     this.add(login, constraints); 
      constraints.gridwidth = GridBagConstraints.REMAINDER; 
      constraints.gridx = 0; 
      constraints.gridy--; 
     this.add(errorMsg, constraints); 
     errorMsg.setVisible(false); 



    } 

    private boolean initTextFields(){ 
     userName = new JTextField(20); 
     passWord = new JTextField(20); 
     userNameLabel = new JTextField("UserID", 20); 
      userNameLabel.setBorder(javax.swing.BorderFactory.createEmptyBorder()); 
      userNameLabel.setEditable(false); 
      userNameLabel.setHorizontalAlignment(JTextField.CENTER); 
     passWordLabel = new JTextField("Password", 20); 
      passWordLabel.setBorder(javax.swing.BorderFactory.createEmptyBorder()); 
      passWordLabel.setEditable(false); 
      passWordLabel.setHorizontalAlignment(JTextField.CENTER); 
     errorMsg = new JTextField("", 50); 
      errorMsg.setBorder(javax.swing.BorderFactory.createEmptyBorder()); 
      errorMsg.setEditable(false); 
      errorMsg.setForeground(Color.red); 
      passWordLabel.setHorizontalAlignment(JTextField.CENTER); 

      return true; 
    } 

} 

我在我的主要方法的初始化這個如下：

Login testLog = new Login("Login GUI"); 
     testLog.setSize(525, 200);// Sets the Frame Size 
     testLog.setMinimumSize(new Dimension(525,200)); 
     testLog.setResizable(false);//Makes the size fixed 
     testLog.setLocationRelativeTo(null); // Make the Frame appear centered 
     testLog.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);//Tells program to exit when the 'x'(close) button is pressed 
     testLog.pack(); 
     testLog.setVisible(true); 

Answer 1

試試這個：

import java.awt.Color; 
import java.awt.GridBagConstraints; 
import java.awt.GridBagLayout; 

import javax.swing.JButton; 
import javax.swing.JFrame; 
import javax.swing.JPanel; 
import javax.swing.JTextField; 

public class Login extends JFrame{ 

    /** 
    * 
    */ 
    private static final long serialVersionUID = 1023608189590961526L; 

    JTextField userName, passWord, userNameLabel, passWordLabel; 
    JTextField errorMsg; 
    JButton login; 
    JPanel userNamePanel, passWordPanel, errorMsgPanel, loginPanel; 
    public Login(String Title){ 
     super(Title);//Set Frame Title 

     login = new JButton("Login"); 
     initTextFields(); 
     setLayout(new GridBagLayout()); 

     userNamePanel = new JPanel(new GridBagLayout()); 
     passWordPanel = new JPanel(new GridBagLayout()); 
     GridBagConstraints constraints = new GridBagConstraints(); 
      constraints.fill = GridBagConstraints.NONE; 
      constraints.weightx = 1; 
      constraints.weighty = 1; 

      constraints.gridx = 0; 
      constraints.gridy = 0; 
     userNamePanel.add(userNameLabel, constraints); 
     passWordPanel.add(passWordLabel, constraints); 
      constraints.gridy++; 
     userNamePanel.add(userName, constraints); 
     passWordPanel.add(passWord, constraints); 
     constraints.gridwidth = GridBagConstraints.RELATIVE; 
     constraints.weighty = 0.01; 
     this.add(userNamePanel, constraints); 
      constraints.gridwidth = GridBagConstraints.REMAINDER; 
      constraints.gridx = 2; 
     this.add(passWordPanel, constraints); 
      constraints.gridy++; 
      constraints.gridx = 0; 
      constraints.anchor = GridBagConstraints.NORTH; 
     this.add(login, constraints); 
      constraints.gridy++; 
     this.add(errorMsg, constraints); 
     errorMsg.setVisible(false); 


    } 

    private boolean initTextFields(){ 
     userName = new JTextField(20); 
     passWord = new JTextField(20); 
     userNameLabel = new JTextField("UserID", 20); 
      userNameLabel.setBorder(javax.swing.BorderFactory.createEmptyBorder()); 
      userNameLabel.setEditable(false); 
      userNameLabel.setHorizontalAlignment(JTextField.CENTER); 
     passWordLabel = new JTextField("Password", 20); 
      passWordLabel.setBorder(javax.swing.BorderFactory.createEmptyBorder()); 
      passWordLabel.setEditable(false); 
      passWordLabel.setHorizontalAlignment(JTextField.CENTER); 
     errorMsg = new JTextField("", 50); 
      errorMsg.setBorder(javax.swing.BorderFactory.createEmptyBorder()); 
      errorMsg.setEditable(false); 
      errorMsg.setForeground(Color.red); 
      passWordLabel.setHorizontalAlignment(JTextField.CENTER); 

      return true; 
    } 

}