Java Simple Calculator program design _java

To write an application that simulates a calculator, using the Panel and grid layout, add a text box, 10 number buttons (0~9), 4 subtraction buttons, an equal sign button, a purge button, a square root button, a backspace button that asks the calculation formula and results to be displayed in a text box. The implementation effect is shown in the following illustration.

Java Simple Calculator Code:

Import javax.swing.*; 
Import Javax.swing.JTextField; 
Import java.awt.*; 
Import java.awt.event.*; 
Import java.lang.*; 
 
 
Import Java.awt.Color; public class Ex5_2 extends JFrame implements ActionListener {private JPanel = new P1 ();//create panel private JPanel 
  el P2 = new JPanel ();   Private JTextField T1;   Text box 1 is used to display input information private JTextField T2;    Text box 2 is used to display the result information private JLabel label;      tag Information StringBuffer str;         The string displayed by the display is double x,y;           Both x and y are operands int z; Z indicates that the operator was clicked. 0 means "+", 1 means "-", 2 means "*", 3 means "/" private JButton b[] = new JBUTTON[12]; Create an array with 12 buttons private JButton b1,b2,b3,b4,b5,b6,b7,b8;   Arithmetic function button public ex5_2 () {super ("simple Calculator"); Window name Container c = Getcontentpane (); 
    Create a content panel object t1 = new JTextField (30); T1.seteditable (FALSE); 
    Can only be displayed, cannot edit t2 = new JTextField (30); T2.seteditable (FALSE); Can only display, cannot edit label = new JLabel ("Welcome to the wizard version of the calculator ^_^ o~ efforts!" 
    "); Label.setforeground (Color.Blue);  
 
    Creates an empty string buffer str=new stringbuffer (); P2.add (label);   Add tags to panel p2.add (T2);   Add text box to panel p2.add (T1); Add a text box to the panel p2.setlayout (new GridLayout (4,1)); 
      The panel layout is set to label 4 rows of 1 columns for (int i=0;i<10;i++)//buttons for the 0~9 number in the array and registers the listener {String s= "" +i;   
      b[i]= new JButton (s);   
    B[i].addactionlistener (this); //Instantiate each button b[10]= new JButton ("-/+"); 
    b[11]= New JButton (".");    b1= New JButton ("/"); 
    b2= New JButton ("Back");    b3= New JButton ("*"); 
    b4= new JButton ("C");    b5= New JButton ("+"); 
    b6= new JButton ("Sqrt");    b7= New JButton ("-"); 
     
    b8= new JButton ("="); 
    Sets the button foreground color for (int i=0;i<12;i++) {b[i].setforeground (Color.Blue);  } b1.setforeground (color.red); 
    B3.setforeground (color.red);  B5.setforeground (color.red); 
    B7.setforeground (color.red);  B2.setforeground (Color.Blue); 
    B4.setforeground (Color.Blue);   B6.setforeground (color.red); B8.setForeground (Color.Blue); Add to Panel P1.add (B[7]); P1.add (B[8]); P1.add (b[9]); P1.add (B1); 
    P1.add (B2); P1.add (B[4]); P1.add (B[5]); P1.add (B[6]); P1.add (B3); 
    P1.add (B4); P1.add (b[1]); P1.add (b[2]); P1.add (B[3]); P1.add (B5); 
    P1.add (B6); P1.add (B[0]); P1.add (b[10]); 
    P1.add (b[11]);p 1.add (B7);p 1.add (B8); 
 
     
    P1.setlayout (New GridLayout (4,5,5,5)); Register Listener B[10].addactionlistener (this); 
    B[11].addactionlistener (this); B1.addactionlistener (this); 
    B2.addactionlistener (this); B3.addactionlistener (this); 
    B4.addactionlistener (this); B5.addactionlistener (this); 
    B6.addactionlistener (this); B7.addactionlistener (this); 
   
    B8.addactionlistener (this); 
    Add the Panel to the content panel C.add (p2); 
    C.add (p1); C.setlayout (New FlowLayout ()); Set to Sequential layout setdefaultcloseoperation (jframe.exit_on_close);  Sets the window Close action setvisible (TRUE); Set to Visible setresizable (false);  Prohibit the adjustment of frame size setSize (400,300); 
 
 Set Window Size}  
  The Main method implementation creates a window public static void main (string[] args) {ex5_2 f = new Ex5_2 ();} 
      button event handling public void actionperformed (ActionEvent e) {try {if (E.getsource () ==b4)//select "C" Clear 0 { T1.settext ("0");  Clear the text box 0 t1.sethorizontalalignment (jtextfield.right); Text aligned to right str.setlength (0); Empties the string buffer to prepare to receive the new input operand} else if (E.getsource () ==b[10])//click "+ +" to select whether the input count is positive or negative {X=double.parsedoub 
      Le (T1.gettext (). Trim ());//trim function is to remove the space T1.settext ("" + (x)) in the string; 
    T1.sethorizontalalignment (Jtextfield.right); 
      else if (E.getsource () ==b5)//Click the plus button to get X's value and Z's value and empty Y's value {x=double.parsedouble (T1.gettext (). Trim ()); 
      Str.setlength (0); 
      y=0d; 
    z=0; 
      else if (E.getsource () ==b7)//Click the minus button to get X's value and Z's value and empty Y's value {x=double.parsedouble (T1.gettext (). Trim ()); 
      Str.setlength (0); 
      y=0d; 
    Z=1; 
    else if (E.getsource () ==b3)//Click the multiplication button to get X's value and Z's value and empty Y's value {  X=double.parsedouble (T1.gettext (). Trim ()); 
      Str.setlength (0); 
      y=0d; 
    z=2; 
      else if (E.getsource () ==b1)/Click the Division button to get the value of X and Z and empty the value of y {x=double.parsedouble (T1.gettext (). Trim ()); 
      Str.setlength (0); 
      y=0d; 
    z=3; 
      else if (E.getsource () ==b8)//Click the equals button to output the computed result {str.setlength (0); Switch (z) {case 0:t1.settext ("" + (X+y)); 
        T1.sethorizontalalignment (Jtextfield.right); Case 1:t1.settext ("" + (x-y)); 
        T1.sethorizontalalignment (Jtextfield.right); Case 2:t1.settext ("" + (X*y)); 
        T1.sethorizontalalignment (Jtextfield.right); Case 3:t1.settext ("" + (x/y)); 
      T1.sethorizontalalignment (Jtextfield.right); } else if (E.getsource () ==b[11])//click. button to enter a decimal {if (T1.gettext). Trim (). IndexOf ('. ')! =-1)//Determine if the string already contains the decimal point {} else//If there is no decimal point {if (T1.gettext (). Trim (). Equals ("0")//if the first time 
        Displayed as 0 {  T1.settext (Str.append (E.getactioncommand ()). ToString ()); 
        T1.sethorizontalalignment (Jtextfield.right); else if (T1.gettext (). Trim (). Equals ("")///If initially displayed as empty then do no action {} else {T1.s  
          Ettext (Str.append (E.getactioncommand ()). ToString ()); 
        T1.sethorizontalalignment (Jtextfield.right); 
    }} y=0d;  
      else if (E.getsource () ==b6)//square root {x=double.parsedouble (T1.gettext (). Trim ()); 
        if (x<0) {t1.settext ("number format exception"); 
      T1.sethorizontalalignment (Jtextfield.right); 
        else {t1.settext ("" +math.sqrt (x)); 
      T1.sethorizontalalignment (Jtextfield.right); 
      } str.setlength (0); 
    y=0d; else {if (E.getsource () ==b[0])//If you select "0" this number key {if (T1.gettext ()). Trim (). Equals ("0")) If the display of the display is zero operation {} else T1.settext (Str.append (E.getactioncommand) (). ToString ()); 
          T1.sethorizontalalignment (Jtextfield.right);  
      Y=double.parsedouble (T1.gettext (). Trim ());  
        else if (E.getsource () ==b2)//Selected is the back key {if (!t1.gettext). Trim (). Equals ("0")//If the display is not 0 {if (Str.length ()!=1) {T1.settext (Str.delete (Str.length () -1,str.length ()). ToString ()) 
        ;//May throw string out of bounds exception t1.sethorizontalalignment (jtextfield.right); 
          else {T1.settext ("0"); t1.sethorizontalalignment (jtextfield.right);  
        Str.setlength (0);  
      } y=double.parsedouble (T1.gettext (). Trim ());  
        else {t1.settext (Str.append (E.getactioncommand ()). ToString ()); 
        T1.sethorizontalalignment (Jtextfield.right); 
        Y=double.parsedouble (T1.gettext (). Trim ()); 
    '} ' catch (NumberFormatException E1) {t1.settext ("number format exception"); T1.sethorizontalalignment (JTEXTFIELD.Right); 
    catch (Stringindexoutofboundsexception E1) {t1.settext ("string index out of Bounds");  
  T1.sethorizontalalignment (jtextfield.right);} 

 } 
}

Run Effect chart:

A Java Simple calculator program design is so complete, hope this article can write calculator to have inspiration, this is only a simple calculator, everybody still can continue to play, perfect calculator function.