java - 如何将 ActionListener 添加到 ArrayList 中的按钮？

Question

我正在开发一个项目，其中解析程序从输入文件中读取数据，对其进行标记，然后从中构建一个 GUI。在本例中，它是一个计算器 GUI。我现在正在尝试编写计算器操作的代码，但在向计算器按钮添加 ActionListener 时遇到问题。它们存储在 ArrayList 中，当我尝试使用 addActionListener() 函数时，我收到以下错误:

ActionListener error

下面是我的构建器文件代码:

import java.awt.*;
import java.awt.event.*;
import java.util.*;
import javax.swing.*;

public class GUIBuilder implements ActionListener {
    //Declare variables
    boolean[] function = new boolean[4];
    double[] temp = {0, 0};
    static JFrame outputFrame;  //Declare GUI window frame
    static JPanel panel1, panel2, panel3, panel4;  //Declare GUI panel variables
    static Container container;  //Declare GUI container variable
    static JTextField textField;  //Declare GUI text field variable
    static ArrayList<JButton> button;
    static ArrayList<JLabel> label;
    static ArrayList<JRadioButton> radio;
    static GUIParser guiParser;  //Create instance of GUIParser 

    public static void main(String[] args) throws Exception {

    //Instantiates a GUIParser object
    guiParser = new GUIParser();

    //Instantiates ArrayList objects
    button = new ArrayList<>();
    label = new ArrayList<>();      
    radio = new ArrayList<>();

    //Instantiates a GUIBuilder object that invokes frameConstructor() method
    GUIBuilder guiBuilder = new GUIBuilder();
    guiBuilder.frameConstructor();  
    }

    public void frameConstructor() {

    //Instantiates a JFrame object
    outputFrame = new JFrame();

    //Sets window size
    outputFrame.setSize(this.guiParser.getWindowWidth(),this.guiParser.getWindowHeight());  //Sets size of outputFrame to the return value of getWindowWidth method

    //Sets window name
    outputFrame.setTitle(this.guiParser.getWindowName());  //Sets title of window to return value of getWindowName method
    outputFrame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);  //Sets the default close operation to exit

    container = outputFrame.getContentPane();
    if (this.guiParser.getWindowLayout() == 0) { //If return value of getWindowLayout is 0, use flow layout
            container.setLayout(new FlowLayout());
    } else { //If return value is other than 0, use grid layout
            if (this.guiParser.getHorizontalSpace() != 0 && this.guiParser.getVerticalSpace() != 0) {  //If return values of getHorizontalSpace and getVerticalSpace are zero, create Grid layout with these dimensions
        container.setLayout(new GridLayout
        (this.guiParser.getNumRows(),this.guiParser.getNumColumns(),
        this.guiParser.getHorizontalSpace(),this.guiParser.getVerticalSpace()));
            } else {  //Otherwise create a Grid layout with these dimensions
                container.setLayout(new GridLayout
        (this.guiParser.getNumRows(),this.guiParser.getNumColumns()));
            }
    }

    //Instantiates new JPanel objects
    panel1 = new JPanel();
    panel2 = new JPanel();
    panel3 = new JPanel();
    panel4 = new JPanel();
    if (this.guiParser.getPanelLayout() == 0) { //If return value of getPanelLayout is zero, use flow layout
            panel1.setLayout(new FlowLayout());
            panel2.setLayout(new FlowLayout());
            panel3.setLayout(new FlowLayout());
        } else { //Otherwise use grid layout, set dimensions according to input values
            if (this.guiParser.getHorizontalSpace() != 0 && this.guiParser.getVerticalSpace() != 0) {
        panel1.setLayout(new GridLayout
                    (this.guiParser.getNumRows(),this.guiParser.getNumColumns(),
                        this.guiParser.getHorizontalSpace(),this.guiParser.getVerticalSpace()));
        panel2.setLayout(new GridLayout
                    (this.guiParser.getNumRows(),this.guiParser.getNumColumns(),
            this.guiParser.getHorizontalSpace(),this.guiParser.getVerticalSpace()));
        panel3.setLayout(new GridLayout
                    (this.guiParser.getNumRows(),this.guiParser.getNumColumns(),
            this.guiParser.getHorizontalSpace(),this.guiParser.getVerticalSpace()));
        panel4.setLayout(new GridLayout
                    (this.guiParser.getNumRows(),this.guiParser.getNumColumns(),
            this.guiParser.getHorizontalSpace(),this.guiParser.getVerticalSpace()));
            } else {
        panel1.setLayout(new GridLayout
                    (this.guiParser.getNumRows(),this.guiParser.getNumColumns()));
        panel2.setLayout(new GridLayout
                    (this.guiParser.getNumRows(),this.guiParser.getNumColumns()));
        panel3.setLayout(new GridLayout
                    (this.guiParser.getNumRows(),this.guiParser.getNumColumns()));
        panel4.setLayout(new GridLayout
                    (this.guiParser.getNumRows(),this.guiParser.getNumColumns()));
            }
    }

    //Instantiates a JTextField object and sets text field width with the return value of getTextWidth()   
    textField = new JTextField("", this.guiParser.getTextWidth());
    container.add(textField);  //Add the text field to the Jframe container
    panel1.add(textField);  //Add the text field to panel 1

    //Walk through the buttonList array and add buttons to the container and panel 2
    int i = 0;
    Iterator<String> iterator = this.guiParser.getButtonList().iterator();
    while (iterator.hasNext()) {
            button.add(new JButton(iterator.next()));
            container.add(button.get(i));
            panel2.add(button.get(i));
            button.addActionListener(this);
            i++;
    }

    //Walk through the radioList array and add radio buttons to the container and panel 3
    i = 0;
    iterator = this.guiParser.getRadioList().iterator();
    while (iterator.hasNext()) {
            radio.add(new JRadioButton(iterator.next()));
            container.add(radio.get(i));
            panel3.add(radio.get(i));
            i++;
    }

    //Walk through the labelList array and add labels to the container and panel 4
    i = 0;
    iterator = this.guiParser.getLabelList().iterator();
    while (iterator.hasNext()) {
            label.add(new JLabel(iterator.next()));
            container.add(label.get(i));
            panel4.add(label.get(i));
            i++;
    }

        //Add each panel to the output frame and set its visibility
    outputFrame.add(panel1);
    outputFrame.add(panel2);
    outputFrame.add(panel3);
    outputFrame.setVisible(true);
        for(i = 0; i < 16; i++){

        }
    }

    public void clear(){
        try{
            textField.setText("");
            for(int i = 0; i < 4; i++){
                function[i] = false;
            }
            for(int i = 0; i < 2; i++){
                temp[i] = 0;
            }
        } catch(NullPointerException e){

        }
    }


    public void calcResult(){
        double result = 0;
        temp[1] = Double.parseDouble(textField.getText());
        String temp0 = Double.toString(temp[0]);
        String temp1 = Double.toString(temp[1]);
        try{
            if(temp0.contains("-")){
                String[] temp00 = temp0.split("-", 2);
                temp[0] = (Double.parseDouble(temp00[1]) * -1);
            }
            if(temp1.contains("-")){
                String[] temp11 = temp1.split("-", 2);
                temp[1] = (Double.parseDouble(temp11[1]) * -1);
            }
        } catch(ArrayIndexOutOfBoundsException e){

        }
        try{
            if(function[2] == true){
                result = temp[0] * temp[1];
            } else if(function[3] == true){
                result = temp[0] / temp[1];
            } else if(function[0] == true){
                result = temp[0] + temp[1];
            } else if(function[1] == true){
                result = temp[0] - temp[1];
            }
            textField.setText(Double.toString(result));
            for(int i = 0; i < 4; i++){
                function[i] = false;
            }
        } catch(NumberFormatException e){

        }
    }

    @Override
    public void actionPerformed( ActionEvent ae) {
        if(ae.getSource() == button.get(0)){
            textField.setText("1");
        }
        if(ae.getSource() == button.get(1)){
            textField.setText(textField.getText().concat("2"));
        }
        if(ae.getSource() == button.get(2)){
            textField.setText(textField.getText().concat("3"));
        }
        if(ae.getSource() == button.get(3)){
            textField.setText(textField.getText().concat("4"));
        }
        if(ae.getSource() == button.get(4)){
            textField.setText(textField.getText().concat(""));
        }
        if(ae.getSource() == button.get(5)){
            textField.setText(textField.getText().concat("1"));
        }
        if(ae.getSource() == button.get(6)){
            textField.setText(textField.getText().concat("1"));
        }
        if(ae.getSource() == button.get(7)){
            textField.setText(textField.getText().concat("1"));
        }
        if(ae.getSource() == button.get(8)){
            textField.setText(textField.getText().concat("1"));
        }
        if(ae.getSource() == button.get(9)){
            textField.setText(textField.getText().concat("1"));
        }
        if(ae.getSource() == button.get(10)){
            textField.setText(textField.getText().concat("1"));
        }
        if(ae.getSource() == button.get(11)){
            textField.setText(textField.getText().concat("1"));
        }
        if(ae.getSource() == button.get(12)){
            textField.setText(textField.getText().concat("1"));
        }
        if(ae.getSource() == button.get(13)){
            textField.setText(textField.getText().concat("1"));
        }
        if(ae.getSource() == button.get(14)){
            textField.setText(textField.getText().concat("1"));
        }
        if(ae.getSource() == button.get(15)){
            textField.setText(textField.getText().concat("1"));
        }
    }    
}

Answer 1

您的 button.addActionListener(this); 应该是 button.get(i).addActionListener(this);。

话虽这么说，您应该保留对在每次迭代中创建的按钮的引用，而不是每次随后在该循环中修改它时从 ArrayList 中检索它:

while (iterator.hasNext()) {
        JButton newButton = new JButton(iterator.next());
        button.add(newButton);
        container.add(newButton);
        panel2.add(newButton);
        newButton.addActionListener(this);
}