Calling a method from another class

I'm trying to be able to access the methods in the variable mineGui from the class Minebutton.



MinesweeperGUI (mineGui is from this class).

Code:

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package MSweep;


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


public class MinesweeperGUI extends JFrame {
 
  private  Minebutton[][] mineGrid;
  private static JPanel GUI;
  private int rows;
  private int cols;
  private boolean minesSet = false;
  private static int totalMines;
  private int flaggedMines = 0;
  private int unopenedBoxes;
  private int setMines;
  private int count = 0;
  private int qNum = 1;
  private int checkRow;
  private int checkCol;
  private int[][] queueList = new int[10][2];
 
 
 
 
 
  public MinesweeperGUI() {
   
   
    //GRID Variables Declared (Rows, Columns, Mines)
   
    rows = 8;
    cols = 8;
    totalMines = 10;
    setMines = 0;
    mineGrid = new Minebutton[20][20];
    unopenedBoxes = (rows * cols);
    int[][] queueList = new int[unopenedBoxes][2];
   
    //Create initial Grid
   
    for (int i = 0; i < rows; i++ ){
      for (int j = 0; j < cols; j++ ) {
        mineGrid[i][j] = new Minebutton(i, j);
      }
    }
   
   
   
   
    //Create GUI
   
    GUI = new JPanel();
    GUI.setLayout(new GridLayout(rows, cols, 0, 0));
   
    drawGrid();
   
   
    add(GUI);                             
    setTitle("Minesweeper");
    setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    setLocationRelativeTo(null);         
    setSize(350,350);
   
   
    //Set mines
   
    if (minesSet == false){
      while (setMines < totalMines) {
        int mineRow = ((int)(Math.random() * (rows) ));
        int mineCol = ((int)(Math.random() * (cols) ));
        if (mineGrid[mineRow][mineCol].getMined() == false) {
          mineGrid[mineRow][mineCol].setMined(true);
          setMines += 1;
        }
      }
     
      minesSet = true;
    }
   
   
   
   
   
    //Draw Grid
   
  }
 
  public static void main() {
    MinesweeperGUI mineGui = new MinesweeperGUI();
    mineGui.setVisible(true);
   
   
  } // end main()
 
  public void drawGrid() {
   
    GUI.removeAll();
   
    for (int i = 0; i < rows; i++ )
      for (int j = 0; j < cols; j++ )
    {
      GUI.add(mineGrid[i][j].getFace());
    }
   
   
    GUI.updateUI();
   
   
   
  }
 
 
  public void Opening(int checkRow, int checkCol) {
    setQNum(getQNum() - 1);
    mineGrid[checkRow][checkCol].setOpened(true);
    unopenedBoxes =- 1;
    count = 0;
    if (unopenedBoxes == ((rows * cols) - totalMines))
      Win();
    for ( int i = 0; i < 3; i++ ) {
      for ( int j = 0; j < 3; j++ ) {
        try{
          if (mineGrid[(checkRow + (i - 1))][(checkCol + (j - 1))].getOpened() == false) {
            if (mineGrid[(checkRow + (i - 1))][(checkCol + (j - 1))].getMined() == true)
              count += 1;
            mineGrid[checkRow][checkCol].setShown(Integer.toString(count));
            if (count > 0){
              if (mineGrid[(checkRow + (i - 1))][(checkCol + (j - 1))].getOpened() == false) {
                if (mineGrid[(checkRow + (i - 1))][(checkCol + (j - 1))].getMined() == false) {
                  makeQueue(qNum, (checkRow + (i - 1)), (checkCol + (j - 1)));
                  qNum += 1;
                }
              }
            }
           
            else{
              runQueue(qNum);
             
            }
           
          }
        }
        catch (ArrayIndexOutOfBoundsException e){
          System.out.println("Skipped out of bounds button");
        }
      }
    }
   
  }
 
  public void makeQueue (int place, int qRow, int qCol){
    queueList[place][0] = qRow;
    queueList[place][1] = qCol;
  }
 
  public void runQueue(int placeHold){
    while (placeHold != 0){
      Opening(queueList[placeHold][0], queueList[placeHold][1]);
    }
  }
 
  public void addGoodFlag(){
    flaggedMines =+ 1;
    if (flaggedMines == totalMines){
      Win();
    }
  }
 
  public void remGoodFlag(){
    flaggedMines =- 1;
  }
 
  public static void Lose(){
    Object[]options = {"Okay", "Quit"};
    JOptionPane.showOptionDialog(null, "Would you like to play again", "You lost!", JOptionPane.DEFAULT_OPTION, JOptionPane.QUESTION_MESSAGE, null, options, options[0]);
  }
  public static void Win(){
    Object[]options = {"Okay", "Quit"};
    JOptionPane.showOptionDialog(null, "Would you like to play again", "You win!", JOptionPane.DEFAULT_OPTION, JOptionPane.QUESTION_MESSAGE, null, options, options[0]);
  }
 
  public int getQNum(){
    return qNum;
  }
 
  public void setQNum(int setQNum){
    qNum = setQNum;
  }
}

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I try to access mineGui on lines 97, 117, and 121 of Minesquare

Code:

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package MSweep;
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import java.util.*;
import MSweep.MinesweeperGUI.*;


public class Minebutton{
  private boolean mined;
  private int minecount;
  private boolean opened;
  private String shown;
  private int[] location = new int[2];
  private JButton showBtn;
  private JLabel showLbl;
 
 
 
  public Minebutton(int row, int col) {
    setMined (false);
    setOpened (false);
    setShown (" ");
    setMinecount (0);
    setLocation (row, col);
    showBtn = new JButton(getShown());
    showLbl = new JLabel(getShown());
   
   
    showBtn.setBorder(BorderFactory.createLineBorder(Color.BLACK, 1));
    showLbl.setBorder(BorderFactory.createLineBorder(Color.BLACK, 1));
   
    showLbl.setHorizontalAlignment(JTextField.CENTER);
   
  }
 
  //Getters and Setters
 
  public boolean getMined(){
    return mined;
  }
 
  public void setMined(boolean setmined){
    this.mined = setmined;
  }
 
  public boolean getOpened(){
    return opened;
  }
 
  public void setOpened(boolean setopened){
    this.opened = setopened;
  }
 
  public String getShown(){
    return shown;
  }
 
  public void setShown(String setShown){
    this.shown = setShown;
  }
 
  public int getMinecount(){
    return minecount;
  }
 
  public void setMinecount(int setMinecount){
    this.minecount = setMinecount;
  }
 
  public JComponent getFace() {
    if (getOpened() == true)
      return showLbl;
    else
      return showBtn;
  }
 
  public void setLocation(int setRow, int setCol) {
    this.location[0] = setRow;
    this.location[1] = setCol;
  }
 
  public int[] getLocation(){
    return location;
  }
 

 
  public void actionPerformed(ActionEvent e){
   
    setOpened(true);
   
    if (mined == true){
  MinesweeperGUI.Lose();
    }
    else
      mineGui.Opening(location[0], location[1]);
   
  }
 
      class RightClicker extends MouseAdapter {

        public void mousePressed(MouseEvent e) {
            if (e.isMetaDown()) {

                JButton B = (JButton) e.getSource();
                nextSymbol(B);
            }
        }
    }

    public void nextSymbol(JButton B) {

        if (B.getText() == " ") {
            B.setText("F");
  if (mined == true)
            mineGui.addGoodFlag();
        } else if (B.getText() == "F") {
            B.setText("?");
  if (mined == true)
            mineGui.remGoodFlag();
        } else if (B.getText() == "F") {
            B.setText("?");
        } else {
            B.setText(" ");
        }
    }
 
 
}

---

I get the following errors when I compile.

Code:

---

3 errors found:
File: C:\...\MSweep\Minebutton.java  [line: 97]
Error: C:\...\MSweep\Minebutton.java:97: cannot find symbol
symbol  : variable mineGui
location: class MSweep.Minebutton
File: C:\...\MSweep\Minebutton.java  [line: 117]
Error: C:\...MSweep\Minebutton.java:117: cannot find symbol
symbol  : variable mineGui
location: class MSweep.Minebutton
File: C:\...\MSweep\Minebutton.java  [line: 121]
Error: C:\...\MSweep\Minebutton.java:121: cannot find symbol
symbol  : variable mineGui
location: class MSweep.Minebutton

---

This is probably unrelated to your question, but I don't think the following lines do what you expect them to do:

Code:

---

    unopenedBoxes =- 1;
    flaggedMines =- 1;
    flaggedMines =+ 1;

---

These are legal, but x =- 1 parses as x = -1. If you want to do compound assignment, the equals sign has to go on the right: += or -=.

Alternatively, since you're incrementing and decrementing by 1, you can use the ++ and -- operators.

Edit: Also, you're comparing strings with ==. This also won't provide the result you're expecting, since it compares object references instead of string content. Use .equals() instead.

Your mineGui is a local variable (declared inside a method) in the MinesweeperGUI class. So you can't access it inside other class even if you have the imports declared.

Either make mineGui as instance variable in MinesweeperGUI class or re-declare it in the class where you want to use it.

Hope that helps,

Goldest

Quote:

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Originally Posted by Iron Lion

This is probably unrelated to your question, but I don't think the following lines do what you expect them to do:

Code:

---

    unopenedBoxes =- 1;
    flaggedMines =- 1;
    flaggedMines =+ 1;

---

These are legal, but x =- 1 parses as x = -1. If you want to do compound assignment, the equals sign has to go on the right: += or -=.

Alternatively, since you're incrementing and decrementing by 1, you can use the ++ and -- operators.

Edit: Also, you're comparing strings with ==. This also won't provide the result you're expecting, since it compares object references instead of string content. Use .equals() instead.

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Thank's for catching this! Would have taken me forever to figure that out.

Quote:

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Originally Posted by goldest

Your mineGui is a local variable (declared inside a method) in the MinesweeperGUI class. So you can't access it inside other class even if you have the imports declared.

Either make mineGui as instance variable in MinesweeperGUI class or re-declare it in the class where you want to use it.

Hope that helps,

Goldest

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How would I make an instance variable?

Also, thank you both for your responses!

Quote:

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Originally Posted by andrewche

How would I make an instance variable?

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An instance variable is a non-static variable that is declared in the class, not in a constructor, method or other block:

Code:

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class Foo
  private int bar = 3;  // **** I'm an instance variable!! ****

  public Foo() {
    int spam = 2; // *** I'm not since I'm local to a constructor
  }

  public void baz() {
    int barlicious = 100; // *** also not an instance variable as I'm declared in a method
  }
}

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Some details about variable types in Java : Java Variable Types

Have a look!

Goldest