Java ActionListener 错误：类型不兼容
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Java ActionListener error: incompatible types
提问by benharris
I'm having some trouble setting up an ActionListener on a JButton, here is the code...
我在 JButton 上设置 ActionListener 时遇到了一些问题，这是代码...
package pipes;
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class PipesUI extends javax.swing.JFrame {
Main main = new Main();
JButton addPipeButton = new JButton("Add Pipe");
public PipesUI(){
addUI();
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}
private void addUI(){
addPipeButton.addActionListener(this);
}
public void actionPerformed(ActionEvent e){
if (e.getSource()==addPipeButton)
main.addPipe();
else
;
}
public static void main(String args[]) {
PipesUI pipesUI = new PipesUI(); // create an instance of the menu
pipesUI.setSize(500,500);
pipesUI.setVisible(true);
}
}
The error is on the line addPipeButton.addActionListener(this);
错误在行 addPipeButton.addActionListener(this);
The (this) it doesn't seem to like, the error says 'incompatible types: PipesUI cannot be converted to ActionListener'
(this) 它似乎不喜欢，错误说“不兼容的类型：PipesUI 无法转换为 ActionListener”
Any help would be great thanks.
任何帮助都会非常感谢。
采纳答案by rgettman
You created your actionPerformedmethod, but you didn't declare your class as an ActionListener. Implement that interface:
您创建了actionPerformed方法，但没有将类声明为ActionListener. 实现该接口：
public class PipesUI extends javax.swing.JFrame implements ActionListener {
回答by nanofarad
I'm guessing you saw addActionListener(this)in another place and decided to use it here. That other place was a completely different context, as thiswas an instance of ActionListner.
我猜你addActionListener(this)在另一个地方看到过并决定在这里使用它。另一个地方是一个完全不同的环境，就像thisActionListner 的一个实例。
Do as follows:
执行以下操作：
addPipeButton.addActionListener(new ActionListner(){
public void actionPerformed(ActionEvent e){
//handle `e`
}
});
Edit: You already have ActionListenermethods in your class. In thiscase, you can use:
编辑：您ActionListener的课程中已经有了方法。在这种情况下，您可以使用：
public class PipesUI extends javax.swing.JFrame implements ActionListener {
回答by Markus Koivisto
One possible solution:
一种可能的解决方案：
public class PipesUI extends javax.swing.JFrame implements ActionListener{
//implement the relevant methods
Another:
其他：
private void addUI(){
addPipeButton.addActionListener(new ActionListener(){
//anonymous actionlistener implementation
};
}
and so on and so forth.
等等等等。
回答by Sage
addPipeButton.addActionListener(this);
Within an instance method or a constructor, thisis a reference to the current object — the object whose method or constructor is being called. So, the addActionListener(ActionListener)method is expecting an implemented instance of interface ActionListener. When you are passing thisto addActionListenerfunction, which is currently referencing the instance of PipesUIwasn't implemented with ActionListener.
在实例方法或构造函数中，this是对当前对象的引用——正在调用其方法或构造函数的对象。因此，该addActionListener(ActionListener)方法需要一个已实现的 interface 实例ActionListener。当您传递this给addActionListener函数时，该函数当前引用的实例PipesUI未使用ActionListener.
Implement the ActionListeneras follows:
执行ActionListener如下：
public class PipesUI extends javax.swing.JFrame implements ActionListener
{
//your code
@Override
public void actionPerformed(ActionEvent e) {
// your code
}
}
But from your code i don't see you have added the addPipeButtonto any container. Just add the button to your frame PipesUIusing add(addPipeButton)as shown follows:
但是从您的代码中，我没有看到您已将其添加addPipeButton到任何容器中。只需PipesUI使用add(addPipeButton)如下所示将按钮添加到您的框架中：
private void addUI(){
add(addPipeButton); <--- adding pipe button
addPipeButton.addActionListener(this);
}
This Jframe.add(addPipeButton)will add the addPipeButtonbutton to the frame's content pane which has BorderLayoutas default layout manager.
这Jframe.add(addPipeButton)会将addPipeButton按钮添加到框架的内容窗格中，该窗格具有BorderLayout默认布局管理器。
