Question

现在，我只是测试以确保按钮有效...但这是我的代码，用于扩展使用Pascal三角形的二项式的applet！我有实际计算部分的等式，我只需要知道如何存储来自JTextFields的信息！谢谢！

import java.applet.Applet;     
import java.awt.*;     
import java.awt.event.*;     
import java.applet.*;     
import javax.swing.*;   
import java.text.DecimalFormat;  
import java.util.ArrayList;  
import javax.swing.Action; 

public class BinomialExpander extends JApplet implements ActionListener 
{   
  JLabel welcome;    
  JLabel directions;  
  JLabel example;    

  JLabel instructions;    
  JLabel startOfBinomial;    
  JLabel plusSign;    
  JLabel forExponent;    
  JLabel endOfBinomial;    

  JTextField txtFirst;    
  JTextField firstVar;    
  JTextField txtSecond;    
  JTextField secondVar;    
  JTextField exp;    


  JLabel lblExpanded;     
  JLabel outputExpanded;      
  double degreesFahrenheit;     
  FlowLayout layout;    
  Timer timer;    

  Button compute;    

  private int[] pascal1 = {1,1};    
  private int[] pascal2 = {1,2,1};    
  private int[] pascal3 = {1,3,3,1};    
  private int[] pascal4 = {1,4,6,4,1};    
  private int[] pascal5 = {1,5,10,10,5,1};    
  private int[] pascal6 = {1,6,15,20,15,6,1};    
  private int[] pascal7 = {1,7,21,35,35,21,7,1};    
  private int[] pascal8 = {1,8,28,56,70,56,28,8,1};    
  private int[] pascal9 = {1,9,36,84,126,84,36,9,1};    
  private int[] pascal10 = {1,10,45,120,210,120,45,10,1};    

  public void init()     
  {    
      Container c = getContentPane();     
      c.setBackground(Color.cyan);    

      layout = new FlowLayout();    
      layout.setAlignment(FlowLayout.LEFT);    
      c.setLayout(layout);    
      setSize(500,175);    

      welcome = new JLabel("Welcome to the Binomial Expander Applet!");    
      directions = new JLabel("Enter binomial in the form: '(number)(variable) + (number)(variable)^exponent'.");    
      example = new JLabel("Example: (4a + 2)^2.");    
      // instantiate JLabel object for Degrees Fahrenheit
      instructions = new JLabel("Enter the first number of your binomial(if there is a variable, add it into the second box):");
      // instantiate JTextField object for the degrees fahrenheit
      startOfBinomial = new JLabel(" (");
      txtFirst = new JTextField(4);
      // instantiate JLabel object for Degrees Celesius
      firstVar = new JTextField(4);
      plusSign = new JLabel(" + ");
      txtSecond = new JTextField(4);
      secondVar = new JTextField(4);
      endOfBinomial = new JLabel(")");
      forExponent = new JLabel("^");
      forExponent.setFont(new Font("Times New Roman", Font.BOLD, 9));
      exp = new JTextField(2);
      compute = new Button("Compute!");
      compute.addActionListener(this);
      lblExpanded = new JLabel("Your expanded binomial is: ");
      // JLabel to display the equivalent degrees Celsius
      outputExpanded = new JLabel("");
      c.add(welcome);
      c.add(directions);
      c.add(example);
      c.add(instructions);
      c.add(startOfBinomial);
      //CALL the addActionListener() method on the JTextField object 
      // for the degrees Fahrenheit
      txtFirst.addActionListener(this);
      // Add the textbox the celsius label and output label
      c.add(txtFirst);
      c.add(firstVar);
      c.add(plusSign);
      c.add(txtSecond);
      c.add(secondVar);
      c.add(endOfBinomial);
      c.add(forExponent);
      c.add(exp);
      c.add(compute);
      c.add(lblExpanded);
      c.add(outputExpanded);
     // timer = new Timer(1, this);
     // timer.start();
  }

  public void actionPerformed(ActionEvent event)     
  {    
      if (event.getSource() == compute)      
      {    
          outputExpanded.setText(expand());    
      }    
}
  public String expand()    
  {    
     String x = "callingComputing";    
     return x;    
  }    
}

Answer 1

yourTextField。getText()返回一个String，你可以像使用任何其他String一样使用它，将它存储在数组中，教它唱歌，飞行和享受生活。相反，您可以使用yourTextField.setText（）在JLabel，textfield等中显示内容。

Answer 2

JTextField扩展JTextComponent，其中包含处理文字操作的API。

正如其他答案所建议的那样，使用setText将当前文本替换为新文本。

另请阅读官方教程以了解How to Use Text Fields

Answer 3

JTextField txtName = new JTextField();
JButton btn = new JButton();

在动作执行方法中添加此

String name = txtname.getText();

此语句返回在单击按钮

之前在文本字段中输入的文本

您创建了一个类，您将在其中存储数据，并在Frame类中创建该对象，即将为数据类提供GUI的类，然后在提交按钮的动作侦听器中创建。框架将getText（）返回的字符串分配给对象的字段

例如：你想从文本字段中获取输入名称和年龄，创建一个Person类

public class Person{
public String name;
public int age;
}

现在创建一个GUI类

public PersonFrame extends JFrame{

public person;
public PersonFrame(){
person = new Person();
JTextField txtName = new JTextField();
JButton btn = new JButton();

btn.addActionListener(new ActionListener(){
public void actionPerformed(ActionEvent e){
  person.name = txtName.getText();
  person.age = Integer.parseInt(txtAge.getText()); //as the textfield returns a String always
}
});
}

} 并避免使用

  if (event.getSource() == compute)      
      {    
          outputExpanded.setText(expand());    
      }

如果你有100个按钮，那么编写嵌套的if-else语句来检查生成事件的按钮是愚蠢的！

请记住，swing是为提供用户界面而设计的，您需要一个类的对象来存储数据！对于java教程，请访问here

如何存储textFields中的信息？

3 个答案: