这是我的第一个 GUI 程序，我似乎无法弄清楚为什么会出现此错误。我已将 actionListener 接口(interface)设置为 main.c 中的内部类。我尝试将所有引用该类的代码放在课后，但根据我读过的其他一些帖子，我没有运气。
Assig4.java:57: error: cannot find symbol ActionListener listener2 = new MListener(); ^ symbol: class MListener location: class Assig4 LINE 57 FOR REFERENCE: ActionListener listener2 = new MListener();
//import section
import java.awt.*;
import java.awt.event.*;
import java.io.File;
import java.io.IOException;
import java.lang.reflect.Array;
import java.util.ArrayList;
import java.util.*;
import javax.swing.*;
public class Assig4 {
public static void main (String [] args) throws IOException
{
/* variables */
String ballotsFile = args[0]; // gets the file name from command line
JFrame theWindow; //assign variable name for main window
ArrayList <Ballot> ballotsAr = new ArrayList<>(); //creates array for jpanel ballot objects
int numBallots=0;
int counter = 0; //to count each file read in loop
JButton login, submitVote;
//voter variables
ArrayList <Integer> voterIdList = new ArrayList<>();
ArrayList <String> voterNames = new ArrayList<>();
ArrayList <Boolean> voterVoted = new ArrayList<>();
/*create window*/
theWindow = new JFrame ("Voting E Machine");
theWindow.setLayout(new FlowLayout());
/* read in ballot info and create ballot objects*/
numBallots = readInBallotFile(ballotsFile, numBallots, ballotsAr);
/*read in data from voter file*/
try {
// method that accesses the file
readInVoterFile(voterIdList, voterNames, voterVoted);
}
catch (Exception e)
{}
/*create action listener object */
ActionListener listener2 = new MListener();
/*add Ballot panels*/
addPanels(theWindow, ballotsAr);
/*add local components*/
submitVote = new JButton("Submit Vote(s)");
submitVote.setEnabled(false);
submitVote.addActionListener(listener2);
login = new JButton("Login");
login.addActionListener(listener2);
theWindow.add(submitVote);
theWindow.add(login);
/*pack and set window to visible*/
theWindow.pack();
theWindow.setVisible(true);
/*actionListener class to handle login and vote submissions*/
class MListenter implements ActionListener
{
public void actionPerformed(ActionEvent ae)
{
//if submitVote button is clicked
if (ae.getSource() == submitVote)
{
//tally results
//update voter file local variables including false to true for voted
//write data to temp file
//delete original file
//change temp file name to previous file name
}
//if login button is clicked
if (ae.getSource() == login)
{
String userEntryIdString;
int userEntryId;
boolean registered=false;
do {
userEntryIdString = JOptionPane.showInputDialog("Enter your voter ID number: ");
userEntryId = Integer.parseInt(userEntryIdString);
//check id number against registered citizens
for (int v =0; v < voterIdList.size(); v++)
{
if (userEntryId == voterIdList.get(v))
{
registered = true;
}
} // end of loop to check id against id list
if (registered)
{
//enable buttons
for (int j = 0; j<ballotsAr.size(); j++)
{
ballotsAr.get(j).enableCandidateButtons();
}
submitVote.setEnabled(true);
}
else if (!registered)
System.out.println("Invalid ID number. Please try again. ");
} while (!registered);
} //end of if login button is clicked
} //end of action performed method
}// end of actionlistener
} //end of main
public static int readInBallotFile(String ballotsFile, int numBallots, ArrayList<Ballot> ballotsAr) throws IOException
{
int counter = 0;
//objects - open and setup scanner for file
File myfile = new File (ballotsFile);
Scanner textScan = new Scanner(myfile); // reads in date from text file
numBallots = Integer.parseInt(textScan.nextLine()); //read in first line (number of ballots) and parse to int
while (textScan.hasNextLine()) //one ballot's data for each loop
{
//read in each ballot's info
//take the first line as a string
String [] tempStr = textScan.nextLine().split(":");
//parse line into proper data values
int tempId = Integer.parseInt(tempStr[0]); //take first value for id
String tempCategory = tempStr[1]; // take second value as category type
String [] tempCandidates = tempStr[2].split(","); // takes the arbitrary number of candidates and splits into separate string variables
//create ballot object
ballotsAr.add(new Ballot(tempId,tempCategory,tempCandidates));
counter++; //adds counter to while loop
} // end of loop to read in ballot text file contents
textScan.close(); //closes ballots.txt file
return numBallots;
} //end of read in ballot file method
public static void addPanels(JFrame theWindow, ArrayList <Ballot> ballotsAr)
{
for (int i =0; i<ballotsAr.size();i++)
{
theWindow.add(ballotsAr.get(i));
}
}
public static void readInVoterFile(ArrayList <Integer> _voterIdList, ArrayList <String> _voterNames, ArrayList <Boolean> _voterVoted) throws IOException
{
int counter = 0;
//objects - open and setup scanner for file
File myfile = new File ("voters.txt");
Scanner textScan = new Scanner(myfile); // reads in date from text file
while (textScan.hasNextLine()) //one voter's data for each loop
{
//take the first line as a string
String [] tempStr = textScan.nextLine().split(":");
//parse line into proper data values
_voterIdList.add(Integer.parseInt(tempStr[0])); //take first value for voter id
_voterNames.add(tempStr[1]); // take second value as voter name
_voterVoted.add(Boolean.parseBoolean(tempStr[2]));
counter++; //adds counter to while loop
} // end of loop to read in voter text file contents
textScan.close(); //closes ballots.txt file
} // end of voter read in method
} // end of class
最佳答案
您拼错了其中一个。
ActionListener listener2 = new MListener();
class MListenter implements ActionListener
注意类名中额外的“t”。
关于java - 找不到符号 Action 监听器引用变量，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/33850168/