Java 将ActionListener添加到JButtons
尝试实现ActionListener时，我收到以下错误 我不想让Java 将ActionListener添加到JButtons,java,actionlistener,Java,Actionlistener,尝试实现ActionListener时，我收到以下错误 我不想让EmployeesApplet抽象化，因为它不需要。 下面是我的代码，请注意，我注释掉了实现ActionListener，并将JButtons添加为ActionListener import javax.swing.*; import java.awt.*; import java.awt.event.*; public class EmployeesApplet extends JApplet //implements Acti
EmployeesApplet抽象化，因为它不需要。
下面是我的代码，请注意，我注释掉了实现ActionListener
，并将JButtons
添加为ActionListener
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
public class EmployeesApplet extends JApplet //implements ActionListener
{
public JButton sd = new JButton ("Salaried");
public JButton hr = new JButton ("Hourly");
public JButton cm = new JButton ("Commissioned");
public JButton cl = new JButton ("Clear");
private final int FIELDS = 8,
FIELD_WIDTH = 20;
private String[] strings = new String[FIELDS];
private TextFieldWithLabel[] tf = new TextFieldWithLabel[FIELDS];
private JTextArea ta = new JTextArea(5,25);
public void init()
{
String[] s = {"First Name", "Last Name", "Employee ID", "(a) Salaried: Weekly Salary", "(b1) Hourly 1: Rate Per Hour",
"(b2) Hourly 2: Hours Worked" , "(c1) Commissioned: Rate", "(c2) Commissioned: Gross Sales" };
//----------------------
// Set up the Structure
//----------------------
Container c = getContentPane();
JPanel f = new JPanel(new FlowLayout());
JPanel b = new JPanel(new BorderLayout(2,0));
JPanel glb = new JPanel(new GridLayout(8,1,0,2));
JPanel gtf = new JPanel(new GridLayout(8,1,0,2));
JPanel flb = new JPanel(new FlowLayout());
// Add FlowLayout to the container
c.add(f);
// Add BorderLayout to the FlowLayout
f.add(b);
//---------------------------------------
//Add JPanels to the BorderLayout regions
//---------------------------------------
// Add JLables to GridLayout in West
b.add(glb, BorderLayout.WEST);
for (int i = 0; i < tf.length; i++)
{
tf[i] = new TextFieldWithLabel(s[i], FIELD_WIDTH);
glb.add(tf[i].getLabel());
}
// Add JTextFeilds to GridLayout in East
b.add(gtf, BorderLayout.EAST);
for (int i = 0; i < tf.length; i++)
{
tf[i] = new TextFieldWithLabel(s[i], FIELD_WIDTH);
tf[i].getTextField();
gtf.add(tf[i].getTextField());
}
// Add JButtons to FlowLayout in South
b.add(flb, BorderLayout.SOUTH);
flb.add(sd);
flb.add(hr);
flb.add(cm);
flb.add(cl);
//sd.addActionListener(this);
//hr.addActionListener(this);
//cm.addActionListener(this);
//cl.addActionListener(this);
// Add JTextArea and make it not editable
f.add(ta);
ta.setEditable(false);
}
public void readFields()
{
}
public void fieldsExist()
{
}
public void fieldsEmpty()
{
}
public void actionPerformed()
{
}
}
import javax.swing.*；
导入java.awt.*；
导入java.awt.event.*；
公共类EmployeesApplet扩展了JApplet//实现了ActionListener
{
公共JButton sd=新JButton（“受薪”）；
公共按钮hr=新按钮（“每小时”）；
公共按钮cm=新按钮（“委托”）；
公共按钮cl=新按钮（“清除”）；
专用最终整型字段=8，
字段宽度=20；
私有字符串[]字符串=新字符串[字段]；
私有TextFieldWithLabel[]tf=新TextFieldWithLabel[FIELDS]；
私人JTextArea ta=新JTextArea（5,25）；
公共void init（）
{
字符串[]s={“名字”、“姓氏”、“员工ID”，“（a）领薪：周工资”，“b1）小时工资1：每小时费率”，
“（b2）每小时2：工作小时数”，“（c1）委托：费率”，“（c2）委托：总销售额”}；
//----------------------
//建立结构
//----------------------
容器c=getContentPane（）；
JPanel f=newjpanel（newflowlayout（））；
JPanel b=新JPanel（新边界布局（2,0））；
JPanel glb=新JPanel（新网格布局（8,1,0,2））；
JPanel gtf=新JPanel（新网格布局（8,1,0,2））；
JPanel flb=新的JPanel（新的FlowLayout（））；
//将FlowLayout添加到容器中
c、 添加（f）；
//将BorderLayout添加到FlowLayout
f、 添加（b）；
//---------------------------------------
//将JPanel添加到BorderLayout区域
//---------------------------------------
//将JLables添加到西部的GridLayout
b、 添加（glb，BorderLayout.WEST）；
for（int i=0；i
您的actionPerformed
方法需要一个ActionEvent
作为参数：
public void actionPerformed(ActionEvent e) {
}
否则，您将不会被重写-您将只创建一个新方法。由于ActionListener
是一个接口，因此需要实现接口中定义的所有方法，因此会出现错误
actionPerformed
方法是用ActionEvent
参数声明的，用于传递有关事件的方法详细信息（哪个组件触发了事件，等等）。如果没有ActionEvent
参数，就无法轻松收集此类信息。执行操作时，将创建一个ActionEvent
对象，并填充事件信息，然后调用actionPerformed
方法，将ActionEvent
对象作为参数传入。您的actionPerformed
方法需要一个ActionEvent
作为参数：
public void actionPerformed(ActionEvent e) {
}
否则，您将不会被重写-您将只创建一个新方法。由于ActionListener
是一个接口，因此需要实现接口中定义的所有方法，因此会出现错误
actionPerformed
方法是用ActionEvent
参数声明的，用于传递有关事件的方法详细信息（哪个组件触发了事件，等等）。如果没有ActionEvent
参数，就无法轻松收集此类信息。执行操作时，将创建一个ActionEvent
对象，并填充事件信息，然后调用actionPerformed
方法，将ActionEvent
对象作为参数传入。您的类正在实现接口ActionListener
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
public class EmployeesApplet extends JApplet //implements ActionListener
{
public JButton sd = new JButton ("Salaried");
public JButton hr = new JButton ("Hourly");
public JButton cm = new JButton ("Commissioned");
public JButton cl = new JButton ("Clear");
private final int FIELDS = 8,
FIELD_WIDTH = 20;
private String[] strings = new String[FIELDS];
private TextFieldWithLabel[] tf = new TextFieldWithLabel[FIELDS];
private JTextArea ta = new JTextArea(5,25);
public void init()
{
String[] s = {"First Name", "Last Name", "Employee ID", "(a) Salaried: Weekly Salary", "(b1) Hourly 1: Rate Per Hour",
"(b2) Hourly 2: Hours Worked" , "(c1) Commissioned: Rate", "(c2) Commissioned: Gross Sales" };
//----------------------
// Set up the Structure
//----------------------
Container c = getContentPane();
JPanel f = new JPanel(new FlowLayout());
JPanel b = new JPanel(new BorderLayout(2,0));
JPanel glb = new JPanel(new GridLayout(8,1,0,2));
JPanel gtf = new JPanel(new GridLayout(8,1,0,2));
JPanel flb = new JPanel(new FlowLayout());
// Add FlowLayout to the container
c.add(f);
// Add BorderLayout to the FlowLayout
f.add(b);
//---------------------------------------
//Add JPanels to the BorderLayout regions
//---------------------------------------
// Add JLables to GridLayout in West
b.add(glb, BorderLayout.WEST);
for (int i = 0; i < tf.length; i++)
{
tf[i] = new TextFieldWithLabel(s[i], FIELD_WIDTH);
glb.add(tf[i].getLabel());
}
// Add JTextFeilds to GridLayout in East
b.add(gtf, BorderLayout.EAST);
for (int i = 0; i < tf.length; i++)
{
tf[i] = new TextFieldWithLabel(s[i], FIELD_WIDTH);
tf[i].getTextField();
gtf.add(tf[i].getTextField());
}
// Add JButtons to FlowLayout in South
b.add(flb, BorderLayout.SOUTH);
flb.add(sd);
flb.add(hr);
flb.add(cm);
flb.add(cl);
//sd.addActionListener(this);
//hr.addActionListener(this);
//cm.addActionListener(this);
//cl.addActionListener(this);
// Add JTextArea and make it not editable
f.add(ta);
ta.setEditable(false);
}
public void readFields()
{
}
public void fieldsExist()
{
}
public void fieldsEmpty()
{
}
public void actionPerformed()
{
}
}
因此你有两个选择。。。使类抽象或实现方法actionPerformed
第一个看起来像你需要的
所以试着做一些类似的事情：
public class EmployeesApplet extends JApplet implements ActionListener {
....
....
@Override
public void actionPerformed(ActionEvent e) {
// TODO Auto-generated method stub
}
您的类正在实现接口ActionListener
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
public class EmployeesApplet extends JApplet //implements ActionListener
{
public JButton sd = new JButton ("Salaried");
public JButton hr = new JButton ("Hourly");
public JButton cm = new JButton ("Commissioned");
public JButton cl = new JButton ("Clear");
private final int FIELDS = 8,
FIELD_WIDTH = 20;
private String[] strings = new String[FIELDS];
private TextFieldWithLabel[] tf = new TextFieldWithLabel[FIELDS];
private JTextArea ta = new JTextArea(5,25);
public void init()
{
String[] s = {"First Name", "Last Name", "Employee ID", "(a) Salaried: Weekly Salary", "(b1) Hourly 1: Rate Per Hour",
"(b2) Hourly 2: Hours Worked" , "(c1) Commissioned: Rate", "(c2) Commissioned: Gross Sales" };
//----------------------
// Set up the Structure
//----------------------
Container c = getContentPane();
JPanel f = new JPanel(new FlowLayout());
JPanel b = new JPanel(new BorderLayout(2,0));
JPanel glb = new JPanel(new GridLayout(8,1,0,2));
JPanel gtf = new JPanel(new GridLayout(8,1,0,2));
JPanel flb = new JPanel(new FlowLayout());
// Add FlowLayout to the container
c.add(f);
// Add BorderLayout to the FlowLayout
f.add(b);
//---------------------------------------
//Add JPanels to the BorderLayout regions
//---------------------------------------
// Add JLables to GridLayout in West
b.add(glb, BorderLayout.WEST);
for (int i = 0; i < tf.length; i++)
{
tf[i] = new TextFieldWithLabel(s[i], FIELD_WIDTH);
glb.add(tf[i].getLabel());
}
// Add JTextFeilds to GridLayout in East
b.add(gtf, BorderLayout.EAST);
for (int i = 0; i < tf.length; i++)
{
tf[i] = new TextFieldWithLabel(s[i], FIELD_WIDTH);
tf[i].getTextField();
gtf.add(tf[i].getTextField());
}
// Add JButtons to FlowLayout in South
b.add(flb, BorderLayout.SOUTH);
flb.add(sd);
flb.add(hr);
flb.add(cm);
flb.add(cl);
//sd.addActionListener(this);
//hr.addActionListener(this);
//cm.addActionListener(this);
//cl.addActionListener(this);
// Add JTextArea and make it not editable
f.add(ta);
ta.setEditable(false);
}
public void readFields()
{
}
public void fieldsExist()
{
}
public void fieldsEmpty()
{
}
public void actionPerformed()
{
}
}
因此你有两个选择。。。使类抽象或实现方法actionPerformed
第一个看起来像你需要的
所以试着做一些类似的事情：
public class EmployeesApplet extends JApplet implements ActionListener {
....
....
@Override
public void actionPerformed(ActionEvent e) {
// TODO Auto-generated method stub
}
那么为了实现ActionListener，有没有actionPerformed方法？是的，您建议添加该参数解决了问题，我现在只是想理解我的回答，解释了如何解决问题，以及为什么需要该参数。那么，为了实现ActionListener，是否需要actionPerformed方法？是的，您添加该参数的建议解决了问题，我现在只是想理解它。我编辑了我的答案，解释了如何解决问题，以及为什么需要该参数。@beeee没有ActionEvent e
，如何