I need to get Keyboard input as well as mouse input on a JButton

Question

I need to get Keyboard input as well as mouse input on a JButton
I have attempted to implement KeyListener. I get the keyCode but I need it to go in to the same String variable as my Actionlistener section.

Answer 1

Here is the code I have trouble with getting keyboard input as wells as mouse input into the same variable.
public class Calctester extends JFrame
implements ActionListener, KeyListener
private double var1, var2;//var1 and var2 are used to perform calculation
String operand1 = "";//takes first input until an operator is pressed
String operand2 = "";//takes input after operator is invoked
double result;//is used to store the result
boolean flag = false;//to signal operator pressed
boolean decimalFlag = false;//to signal decimal pressed
String stringInput;//used as a temporary store for all entry to allow for conditions to be evaluated
char ch; //used to store the operator for comparison//Reason is pre does not compare using string
String pre = "";//used to store the operator
double mem; //will hold memory operation values
double vMod; //Temporary store for var2 to be used with percent operations
//Creates buttons
JButton btn0 = new JButton("0");
JButton btn1 = new JButton("1");
JButton btn2 = new JButton("2");
JButton btn3 = new JButton("3");
JButton btn4 = new JButton("4");
JButton btn5 = new JButton("5");
JButton btn6 = new JButton("6");
JButton btn7 = new JButton("7");
JButton btn8 = new JButton("8");
JButton btn9 = new JButton("9");
JButton btnC = new JButton("C");
JButton btnCE = new JButton("CE");
JButton btnBkpSpc = new JButton("Backspace");
JButton btnPlus = new JButton("+");
JButton btnMinus = new JButton("-");
JButton btnMultiply = new JButton("*");
JButton btnDivide = new JButton("/");
JButton btnEquals = new JButton("=");
JButton btnPeriod = new JButton(".");
JButton btnPlusMinus = new JButton("+/-");
JButton btnSqrt = new JButton("sqrt");
JButton btnMod = new JButton("%");
JButton btnOneOverX = new JButton("1/x");
JButton btnMC = new JButton("MC");
JButton btnMR = new JButton("MR");
JButton btnMS = new JButton("MS");
JButton btnMPlus = new JButton("M+");
//Displays Text area for Display
JTextField txtArea = new JTextField("0.");//The calculation display area set to 0.
JTextField mArea = new JTextField();//to display memory operations
//Default constructor
Calctester()
//Defines a content pane
Container c = getContentPane();
//Defines the layout of the frame and sets it to null to allow absolute positioning
c.setLayout(null);
//Defines event handling
btn0.addActionListener(this);
btn1.addActionListener(this);
btn2.addActionListener(this);
btn3.addActionListener(this);
btn4.addActionListener(this);
btn5.addActionListener(this);
btn6.addActionListener(this);
btn7.addActionListener(this);
btn8.addActionListener(this);
btn9.addActionListener(this);
btnC.addActionListener(this);
btnCE.addActionListener(this);
btnBkpSpc.addActionListener(this);
btnPlus.addActionListener(this);
btnMinus.addActionListener(this);
btnDivide.addActionListener(this);
btnMultiply.addActionListener(this);
btnEquals.addActionListener(this);
btnPeriod.addActionListener(this);
btnPlusMinus.addActionListener(this);
btnSqrt.addActionListener(this);
btnMod.addActionListener(this);
btnOneOverX.addActionListener(this);
btnMR.addActionListener(this);
btnMS.addActionListener(this);
btnMPlus.addActionListener(this);
btnMC.addActionListener(this);
btn1.addKeyListener(this);
//Adds the buttons to the frame and sets the font of the label to be
//logical font Dialog,plain as opposed to Bold and the label size to 12
//Also sets the border type of aech button
c.add(btn0).setFont(new Font("Dialog", Font.PLAIN, 12));
btn0.setBorder(new BevelBorder(BevelBorder.RAISED));
c.add(btn1).setFont(new Font("Dialog", Font.PLAIN, 12));
btn1.setBorder(new BevelBorder(BevelBorder.RAISED));
c.add(btn2).setFont(new Font("Dialog", Font.PLAIN, 12));
btn2.setBorder(new BevelBorder(BevelBorder.RAISED));
c.add(btn3).setFont(new Font("Dialog", Font.PLAIN, 12));
btn3.setBorder(new BevelBorder(BevelBorder.RAISED));
c.add(btn4).setFont(new Font("Dialog", Font.PLAIN, 12));
btn4.setBorder(new BevelBorder(BevelBorder.RAISED));
c.add(btn5).setFont(new Font("Dialog", Font.PLAIN, 12));
btn5.setBorder(new BevelBorder(BevelBorder.RAISED));
c.add(btn6).setFont(new Font("Dialog", Font.PLAIN, 12));
btn6.setBorder(new BevelBorder(BevelBorder.RAISED));
c.add(btn7).setFont(new Font("Dialog", Font.PLAIN, 12));
btn7.setBorder(new BevelBorder(BevelBorder.RAISED));
c.add(btn8).setFont(new Font("Dialog", Font.PLAIN, 12));
btn8.setBorder(new BevelBorder(BevelBorder.RAISED));
c.add(btn9).setFont(new Font("Dialog", Font.PLAIN, 12));
btn9.setBorder(new BevelBorder(BevelBorder.RAISED));
c.add(btnC).setFont(new Font("Dialog", Font.PLAIN, 12));
btnC.setBorder(new BevelBorder(BevelBorder.RAISED));
c.add(btnCE).setFont(new Font("Helvetica", Font.PLAIN, 12));
btnCE.setBorder(new BevelBorder(BevelBorder.RAISED));
c.add(btnBkpSpc).setFont(new Font("Dialog", Font.PLAIN, 12));
btnBkpSpc.setBorder(new BevelBorder(BevelBorder.RAISED));
c.add(btnPlus).setFont(new Font("Dialog", Font.PLAIN, 12));
btnPlus.setBorder(new BevelBorder(BevelBorder.RAISED));
c.add(btnMinus).setFont(new Font("Dialog", Font.PLAIN, 12));
btnMinus.setBorder(new BevelBorder(BevelBorder.RAISED));
c.add(btnMultiply).setFont(new Font("Dialog", Font.PLAIN, 12));
btnMultiply.setBorder(new BevelBorder(BevelBorder.RAISED));
c.add(btnDivide).setFont(new Font("Dialog", Font.PLAIN, 12));
btnDivide.setBorder(new BevelBorder(BevelBorder.RAISED));
c.add(btnEquals).setFont(new Font("Dialog", Font.PLAIN, 12));
btnEquals.setBorder(new BevelBorder(BevelBorder.RAISED));
c.add(btnPeriod).setFont(new Font("Dialog", Font.PLAIN, 12));
btnPeriod.setBorder(new BevelBorder(BevelBorder.RAISED));
c.add(btnPlusMinus).setFont(new Font("Dialog", Font.PLAIN, 12));
btnPlusMinus.setBorder(new BevelBorder(BevelBorder.RAISED));
c.add(btnMod).setFont(new Font("Albertus Medium", Font.PLAIN, 12));
btnMod.setBorder(new BevelBorder(BevelBorder.RAISED));
c.add(btnSqrt).setFont(new Font("Microsoft San Serif", Font.PLAIN, 11));
btnSqrt.setBorder(new BevelBorder(BevelBorder.RAISED));
c.add(btnOneOverX).setFont(new Font("Dialog", Font.PLAIN, 12));
btnOneOverX.setBorder(new BevelBorder(BevelBorder.RAISED));
c.add(btnMC).setFont(new Font("Dialog", Font.PLAIN, 12));
btnMC.setBorder(new BevelBorder(BevelBorder.RAISED));
c.add(btnMS).setFont(new Font("Dialog", Font.PLAIN, 12));
btnMS.setBorder(new BevelBorder(BevelBorder.RAISED));
c.add(btnMR).setFont(new Font("Dialog", Font.PLAIN, 12));
btnMR.setBorder(new BevelBorder(BevelBorder.RAISED));
c.add(btnMPlus).setFont(new Font("Dialog", Font.PLAIN, 12));
btnMPlus.setBorder(new BevelBorder(BevelBorder.RAISED));
//sets the color of the label of the buttons
btnC.setForeground(Color.red);
btnCE.setForeground(Color.red);
btnBkpSpc.setForeground(Color.red);
btnDivide.setForeground(Color.red);
btnMultiply.setForeground(Color.red);
btnMinus.setForeground(Color.red);
btnPlus.setForeground(Color.red);
btnMC.setForeground(Color.red);
btnMR.setForeground(Color.red);
btnMS.setForeground(Color.red);
btnMPlus.setForeground(Color.red);
btnEquals.setForeground(Color.red);
btn0.setForeground(Color.blue);
btn1.setForeground(Color.blue);
btn2.setForeground(Color.blue);
btn3.setForeground(Color.blue);
btn4.setForeground(Color.blue);
btn5.setForeground(Color.blue);
btn6.setForeground(Color.blue);
btn7.setForeground(Color.blue);
btn8.setForeground(Color.blue);
btn9.setForeground(Color.blue);
btnPlusMinus.setForeground(Color.blue);
btnSqrt.setForeground(Color.blue);
btnMod.setForeground(Color.blue);
btnOneOverX.setForeground(Color.blue);
btn0.setFocusPainted(false);
btnPlus.setFocusPainted(false);
btnEquals.setFocusPainted(false);
//The display text area and the memory operation text area
c.add(txtArea);
txtArea.setBorder(new BevelBorder(BevelBorder.LOWERED));
txtArea.setBounds(7,0,240,25);//To provide a Text box @ the top of the frame
txtArea.setEditable(false);
txtArea.setBackground(Color.white);
c.add(mArea);
mArea.setBounds(13, 35, 28, 25);
mArea.setEditable(false);
mArea.setBorder(new BevelBorder(BevelBorder.LOWERED));
setSize(260,251);//size of the frame
setTitle("Calculator"); //Title
setVisible(true); //this makes the frame visible on the screen
setResizable(false); //this disallow resizing of the frame
setDefaultCloseOperation(EXIT_ON_CLOSE);//to close app
//instead of the above method you can use the WindowsListener which extennds other classes and implements other interfaces.
setLocation(300,200);//positioning of the window on the screen
txtArea.setHorizontalAlignment(JTextField.RIGHT);//sets the text in the text field to the right
mArea.setHorizontalAlignment(JTextField.CENTER);//centers the label
JMenu editMenu = new JMenu("Edit");//creates menu
JMenuItem copy = new JMenuItem("Copy Ctrl+C");//creates menu item
copy.addActionListener(this);//event handling
JMenuItem paste = new JMenuItem("Paste Ctrl+V");//creates menu
paste.addActionListener(this);//event handling
JMenuBar myMenu = new JMenuBar();//declares a menu bar
setJMenuBar(myMenu);//adds the menu bar to the frame
editMenu.setBorderPainted(false);//removes the border shadow around the menu bar
myMenu.setBorderPainted(false);//removes the border shadow around menu bar
//adds menu items to the menu, sets the font and font size.
editMenu.add(paste).setFont(new Font("Dialog", Font.PLAIN, 12));//
editMenu.add(copy).setFont(new Font("Dialog", Font.PLAIN, 12));
myMenu.add(editMenu).setFont(new Font("Dialog", Font.PLAIN, 12));
JMenu viewMenu = new JMenu("View");//creates menu
JMenuItem sci = new JMenuItem("Scientific");//creates menu item
sci.addActionListener(this);//event handling
JMenuItem std = new JMenuItem("Standard");//creates menu item
//adds menu items to the menu, sets the font and font size.
viewMenu.add(sci).setFont(new Font("Dialog", Font.PLAIN, 12));
viewMenu.add(std).setFont(new Font("Dialog", Font.PLAIN, 12));
myMenu.add(viewMenu).setFont(new Font("Dialog", Font.PLAIN, 12));
JMenu helpMenu = new JMenu("Help");//creates menu
JMenuItem helpTopics = new JMenuItem("Help Topics");//creates menu item
JMenuItem aboutCalc = new JMenuItem("About Calculator");//creates menu item
helpTopics.addActionListener(this);//event handling
//helpTopics.setBorder(new BevelBorder(BevelBorder.RAISED));
helpTopics.setBorder(LineBorder.createGrayLineBorder());
//adds menu items to the menu, sets the font and font size.
helpMenu.add(helpTopics).setFont(new Font("Dialog", Font.PLAIN, 12));
helpMenu.add(aboutCalc).setFont(new Font("Dialog", Font.PLAIN, 12));
myMenu.add(helpMenu).setFont(new Font("Dialog", Font.PLAIN, 12));
//aboutCalc.setBorder(new BevelBorder(BevelBorder.RAISED));
aboutCalc.setBorder(LineBorder.createGrayLineBorder());
//aboutCalc.setActionCommand("Nothing here right now");
//Setting absolute positions for the buttons.
btn0.setBounds(50, 160, 35, 28);
btn1.setBounds(50, 130, 35, 28);
btn2.setBounds(90, 130, 35, 28);
btn3.setBounds(130, 130, 35, 28);
btn4.setBounds(50, 100, 35, 28);
btn5.setBounds(90, 100, 35, 28);
btn6.setBounds(130, 100, 35, 28);
btn7.setBounds(50, 70, 35, 28);
btn8.setBounds(90, 70, 35, 28);
btn9.setBounds(130, 70, 35, 28);
btnC.setBounds(180, 35, 63, 28);
btnCE.setBounds(115, 35, 63, 28);
btnBkpSpc.setBounds(50, 35, 63, 28);
btnPlus.setBounds(170, 160, 35, 28);
btnMinus.setBounds(170, 130, 35, 28);
btnMultiply.setBounds(170, 100, 35, 28);
btnDivide.setBounds(170, 70, 35, 28);
btnEquals.setBounds(210, 160, 35, 28);
btnPeriod.setBounds(130, 160, 35, 28);
btnPlusMinus.setBounds(90, 160, 35, 28);
btnMC.setBounds(8, 70, 35, 28);
btnMR.setBounds(8, 100, 35, 28);
btnMS.setBounds(8, 130, 35, 28);
btnMPlus.setBounds(8, 160, 35, 28);
btnSqrt.setBounds(210, 70, 35, 28);
btnMod.setBounds(210, 100, 35, 28);
btnOneOverX.setBounds(210, 130, 35, 28);
// btn7.addKeyListener(this);
try
UIManager.setLookAndFeel("javax.swing.plaf.metal.MetalLookAndFeel");
SwingUtilities.updateComponentTreeUI(this);
catch (Exception e)
System.out.println("Could not load Metal Look and Feel");
public void keyReleased(KeyEvent e)
//btn1 = txtArea.getRegisteredKeyStrokes();
// System.out.println(1);
// keyTyped();
public void keyPressed(KeyEvent e)
//if (e.getActionCommand().equals("1"));
//(e.getKeyText().compareTo("1"));
//(e.getKeyCode().equals("1"));
//else
System.out.println("Error");
//keyTyped();
public void keyTyped(KeyEvent e)
//displayInfo(e, "KEY TYPED: ");
System.err.println("KeyTyped >>> " + e.KEY_TYPED);
//keyEvent.keyTyped();
// e.KEY_TYPED;
/* protected void displayInfo (KeyEvent e, string s)
{KeyCodeString;
int keyCode = e.getKeyCode();
keyCodeString = "key code " + keyCode
+ "("
+ KeyEvent.getKeyText(keyCode);
public void actionPerformed(ActionEvent e)
stringInput = e.getActionCommand();
System.out.println("First stringInput action performed>>" +stringInput);
System.out.println("First pre action performed>>" +pre);
if (stringInput == "C")
operand1 = "";
operand2 = "";
var1 = 0;
var2 = 0;
var1 = result;
txtArea.setText("0.");
flag = false;//to force the operations to jump to operand 1 and go through the loop as normal
pre = "";
if (stringInput == "CE")
operand2 = "";
var2 = 0;
txtArea.setText("0.");
flag = true;//to force the operations to jump to operand 1 and go through the loop as normal
if (stringInput == "MR")
if (var1 != 0)
txtArea.setText(Double.toString(var1));
mArea.setText("M");
System.err.println("mem@operand1 >> "+ mem );
else if (var2 != 0)
txtArea.setText(Double.toString(var2));
mArea.setText("M");
System.err.println("mem @ mR else>> "+ mem );
if (stringInput == "MS")
mArea.setText("M");
if (operand1 != "")
mem = var1;
else if (operand2 != "")
mem = var2;
else
mem = 0;
if (stringInput == "MC")
mArea.setText("");//to clear the text area display
mem = 0;//to reset the variable
if (stringInput == "M+")
mArea.setText("M");
flag = true;//to force the operations to jump to operand 2 and go through the loop as normal
if (stringInput == "=")
//result = evaluate();
txtArea.setText(Double.toString(result));
System.out.println("Equals>>" +stringInput);
System.out.println("Equals>>" +pre);
System.err.println("The flag at equals is " + flag);
if (stringInput == "+"||stringInput == "-"||stringInput == "/"||
stringInput == "*"||stringInput == "=")
pre = pre.concat(stringInput);
System.out.println("Second action perfo/check for operator>>" +stringInput);
System.out.println("Second pre action perfo/check for operator>>" +pre);
operand2 = "";
System.err.println("The flag at +,- etc is " + flag);
if(!flag &&(stringInput == "*"|| stringInput == "/"))
var2 = 1;
stringInput = "";
flag = true;
if(!flag)
stringInput = pre;
System.out.println("if flag true/stringInput" +stringInput);
System.out.println("flag true/pre" +pre);
else
//These statements extract the operator
stringInput = pre.valueOf(pre.charAt(pre.length()-2));
ch = pre.charAt(pre.length()-2);
System.out.println("@ position -2 stringInput" + pre.valueOf(pre.charAt(pre.length()-2)));
System.out.println("@ position -2 pre" + pre.charAt(pre.length()-2));
result = evaluate();
var2 = 0;
operand2 = "";
txtArea.setText(Double.toString(result));
System.out.println("Total is " + result);
flag = true;
if(!flag &&(stringInput == "*"|| stringInput == "/"))
var2 = 1;
stringInput = "";
flag = true;
if (stringInput == "%")
//evaluate();
txtArea.setText(Double.toString(result));
System.err.println("mem @ mR else>> "+ result + " %" );
if (stringInput == "1/x")
if (operand1 != "")
txtArea.setText(Double.toString(1/var1));
//System.err.println("mem@operand1 >> "+ mem );
else if (operand2 != "")
operand2 = "";
txtArea.setText(Double.toString(1/var2));
//System.err.println(">> "+ mem );
if (Character.isDigit(stringInput.charAt(0))||stringInput == ".")
System.out.println(operand1);
if (stringInput == "." && operand1 == "")
operand1 = "0";
System.out.print("fail op1");
if (stringInput == "." && operand2 == "")
System.out.print("fail op2");
operand2 = "0";
if (flag==false)
operand1 = operand1.concat(stringInput);
result = Double.parseDouble(operand1);
System.out.println("op1 =>" + operand1);
txtArea.setText(operand1);
//result = var1;
System.out.println("result after var1 = result " + result);
else
operand2 = operand2.concat(stringInput);
var2 = Double.parseDouble(operand2);
//var2 = vMod;
System.out.println("op2 =>" + operand2);
txtArea.setText(" ");//to clear the text area
txtArea.setText(operand2);//to display the second number if (operators == "+")
System.out.println("result after var2 " + result);
public double evaluate()
if (ch == '+' )
result = result + var2;
if (ch == '-' )
result = result - var2;
if (ch == '/' )
result = result / var2;
if (ch == '*' )
result = result * var2;
if (ch == '%')
var2 = Double.parseDouble(operand2);
result = result/vMod*100;
System.out.println("% "+ result);
return result;
public static void main(String [] args)
Calctester x = new Calctester();
}