Java 从JFrame获取输入
我有点困惑,到底该如何编程。我有一个扩展了JFrame的类,它有两个文本字段。我希望能够从JFrame获取输入。不知怎的,只是等待我的主课的输入…有什么想法吗Java 从JFrame获取输入,java,swing,class,Java,Swing,Class,我有点困惑,到底该如何编程。我有一个扩展了JFrame的类,它有两个文本字段。我希望能够从JFrame获取输入。不知怎的,只是等待我的主课的输入…有什么想法吗 import java.awt.BorderLayout; import java.awt.event.ActionEvent; import java.awt.event.ActionListener; import javax.swing.JFrame; import javax.swing.JTextField; public
import java.awt.BorderLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JFrame;
import javax.swing.JTextField;
public class mainMaybe extends JFrame{
JTextField login;
JTextField pass;
public mainMaybe() throws InterruptedException{
login = new JTextField();
pass = new JTextField();
pass.addActionListener(new ActionListener(){
public void actionPerformed(ActionEvent arg0) {
System.out.println("DO SOMETHING");
}
});
add(login,BorderLayout.NORTH);
add(pass,BorderLayout.SOUTH);
pack();
setVisible(true);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}
public void returnEmail(){
//SOME HOW WAIT FOR THE ACTION LISTENER?
}
public static void main(String[] args) throws InterruptedException {
new mainMaybe().returnEmail();
//CONTROL SHOULD STAY WITH mainMaybe until an email is returned
}
}
我认为你的设计方法是错误的。在JavaGUI(和大多数类似的技术)中,您不会说“等待电子邮件地址”,而是说“收到电子邮件地址时告诉我”
在文本框中添加一个监听器,这在一定程度上是成功的——基本上,您希望一个监听器在文本框中的值更改时“激发”。侦听器的实现做了一些事情—在您的简单示例中,将电子邮件地址写入控制台,然后退出。Java Swing基于
事件驱动体系结构的概念。因此,事件触发动作,并根据这些事件执行某种操作
这将是一个很好的起点,可以开始理解并实现您希望在UI及其相应行为方面实现的目标。所以我建议你读一读,然后试着解决你想要实现的目标
我不太确定你想要实现什么,但如果我是你,我会有两个文本字段,可能会附加一些标签和一个“提交”按钮。我会在这个按钮上添加一个ActionListener
,以执行某种操作
也许安可以帮你开始。请看一下这段代码:
package com.test;
import javax.swing.JOptionPane;
public class SimpleUI extends javax.swing.JFrame {
/**
* Creates new form SimpleUI
*/
public SimpleUI() {
initComponents();
}
private void initComponents() {
mainPanel = new javax.swing.JPanel();
labelName = new javax.swing.JLabel();
textName = new javax.swing.JTextField();
jLabel1 = new javax.swing.JLabel();
textPassword = new javax.swing.JPasswordField();
jButton1 = new javax.swing.JButton();
setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);
mainPanel.setBorder(javax.swing.BorderFactory.createEmptyBorder(2, 2, 2, 2));
labelName.setText("Name: ");
jLabel1.setText("Password: ");
jButton1.setText("Submit");
jButton1.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
jButton1ActionPerformed(evt);
}
});
javax.swing.GroupLayout mainPanelLayout = new javax.swing.GroupLayout(mainPanel);
mainPanel.setLayout(mainPanelLayout);
mainPanelLayout.setHorizontalGroup(
mainPanelLayout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(mainPanelLayout.createSequentialGroup()
.addGroup(mainPanelLayout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addComponent(labelName)
.addComponent(jLabel1))
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
.addGroup(mainPanelLayout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING, false)
.addComponent(textName)
.addComponent(textPassword, javax.swing.GroupLayout.DEFAULT_SIZE, 195, Short.MAX_VALUE))
.addGap(18, 18, 18)
.addComponent(jButton1)
.addGap(0, 65, Short.MAX_VALUE))
);
mainPanelLayout.setVerticalGroup(
mainPanelLayout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(mainPanelLayout.createSequentialGroup()
.addContainerGap()
.addGroup(mainPanelLayout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
.addComponent(labelName)
.addComponent(textName, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE))
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
.addGroup(mainPanelLayout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
.addComponent(jLabel1)
.addComponent(textPassword, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
.addComponent(jButton1))
.addContainerGap(15, Short.MAX_VALUE))
);
javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
getContentPane().setLayout(layout);
layout.setHorizontalGroup(
layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addComponent(mainPanel, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
);
layout.setVerticalGroup(
layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addComponent(mainPanel, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
);
pack();
}
/**
* This is the method that is called when an action is performed.
* Over here I just simply show an error message if any of the text fields are empty or just show their names.
*/
private void jButton1ActionPerformed(java.awt.event.ActionEvent evt) {
String name = textName.getText();
String password = String.valueOf(textPassword.getPassword());
if("".equals(password) || "".equals(name)){
JOptionPane.showMessageDialog(this, "Name or password is empty!", "Incorrect Input", JOptionPane.ERROR_MESSAGE);
}else{
JOptionPane.showMessageDialog(this, "Hello "+name+" with password "+password, "Incorrect Input", JOptionPane.PLAIN_MESSAGE);
}
}
/**
* @param args the command line arguments
*/
public static void main(String args[]) {
try {
javax.swing.UIManager.setLookAndFeel("com.sun.java.swing.plaf.windows.WindowsLookAndFeel");
} catch (ClassNotFoundException ex) {
java.util.logging.Logger.getLogger(SimpleUI.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (InstantiationException ex) {
java.util.logging.Logger.getLogger(SimpleUI.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (IllegalAccessException ex) {
java.util.logging.Logger.getLogger(SimpleUI.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (javax.swing.UnsupportedLookAndFeelException ex) {
java.util.logging.Logger.getLogger(SimpleUI.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
}
/* Create and display the form */
java.awt.EventQueue.invokeLater(new Runnable() {
public void run() {
new SimpleUI().setVisible(true);
}
});
}
private javax.swing.JButton jButton1;
private javax.swing.JLabel jLabel1;
private javax.swing.JLabel labelName;
private javax.swing.JPanel mainPanel;
private javax.swing.JTextField textName;
private javax.swing.JPasswordField textPassword;
}
注意:我使用NetBeans IDE生成了这段代码,因此我不需要处理太多关于布局或其他方面的问题。如果您想了解布局,这里有一个有趣的教程:
我的主要想法是向你展示事件是如何触发的。因此,我所做的是在我的“提交”按钮中添加了一个actionlistener
,当有人点击按钮时,我执行某种操作。希望您能了解情况。另一种方法,使用模态对话框(或者两个)
好的,那么在事件被触发之后…我如何告诉我的“main”以及我如何告诉这个main等待事件被触发?我已经用SSCCE更新了我的答案,看一看。希望这有帮助:)我喜欢这个解决方案。它真的很不一样而且很短。但出于某种原因,我不喜欢用多个对话框来打扰我的用户。我知道这是个人喜好的问题,但我会让我的用户通过一个简单的用户界面,而不是向他抛出多个对话框。你怎么看?@Sujay“不喜欢用多个对话框来打扰我的用户”完全同意这一点。只想显示两种不同类型的输入对话框。我喜欢第一个字段的简单性,但第二个字段更容易显示这两个字段(可能需要一个面板)。顺便说一句,你的回答是最好的。你完全应该得到这个“剔”@安德烈霍姆森-谢谢!我只是想了解其他人对使用对话框的看法:)@Sujay:设计越少越好。@trashgood:有道理。谢谢
import javax.swing.*;
public class LoginPrompt {
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
@Override
public void run() {
String username = JOptionPane.showInputDialog(null, "User Name");
System.out.println("Username: " + username);
JPasswordField passwordField = new JPasswordField(8);
// a bit quirky, we need to tab to the field
JOptionPane.showMessageDialog(null, passwordField, "Password",
JOptionPane.QUESTION_MESSAGE);
char[] password = null;
password = passwordField.getPassword();
System.out.println("Password: " + String.valueOf(password));
}
});
}
}