Pertama, kita perlu ktahui ada pakage apa saja dlm sbuah aplikasi yg akan kita bangun, dan dalam aplikasi yg ini hanya ada 3 pakage, yaitu : pakege form, pakage entitas, pakage main..

disetiap pakage akan berisi class'nya masing..
pakage form = Berisi semua source form yg akan kita bangun termasuk even2'a..
pakage entitas = Berisi semua source entitas utk menghubungkan antara entitas dgn form..
pakage main = sbnarnya ini tidak begitu penting, hanya utk running program slm msih dalam tahap pembangunan..



Tahap pertama Desain Form :
[Image: 79302091.png]

Langsung memberikan nama variable disetiap Swing..

Tahap kedua setting running program melalui class main :
Code:
package calculatorujicoba;

import Tampilan.TampilanUtama;

/*
* Programmer : Fajar Musti Prawira
*
* Created on 11 Nov 11, 21:28:41
*/

public class CalculatorUjicoba {

    /**
     * @param args the command line arguments
     */
    public static void main(String[] args) {
        // TODO code application logic here
        TampilanUtama Tu = new TampilanUtama();
        Tu.setVisible(true);
        Tu.setLocationRelativeTo(null);
    }
}

Tahap ketiga Buat class entitas :
PHP Code:
package Entitas;

/*
 * Programmer : Fajar Musti Prawira
 *
 * Created on 11 Nov 11, 21:28:41
 */

public class EntitiCalcu {
    int operator = 0;
    double nilai1;
    double nilai2;
    double result;
    
    public void setNilai(String nl){
        if (!nl.equals("")){
            if(operator==0){
                nilai1= Double.valueOf(nl);
            }else{
                nilai2= Double.valueOf(nl);
            }
        }
    }

    public void setOperator(int operator) {
        this.operator = operator;
    }

    public double getResult() {
        return result;
    }

    public void setResult(double hasil) {
        this.result = hasil;
    }
    
    public void proses(){
        switch(operator){
            case 1:
                result = nilai1 + nilai2;
                break;
            case 2:
                result = nilai1 - nilai2;
                break;
            case 3:
                result = nilai1 * nilai2;
                break;
            case 4:
                result = nilai1 / nilai2;
                break;
            case 5:
                result = nilai1 % nilai2;
                break;
            case 6:
                result = 1/nilai1;
                break;
            }
        nilai1=result;
    }
} 

Sebelum kita memberikan event di setiap swing, maka trlbh dahulu kita membuat methode..
Code:
//Menurunkan
    EntitiCalcu model = new EntitiCalcu();
    String oper="";
    
    //Ambil nilai
    public void getOper(javax.swing.JButton button){
        oper+=button.getText();
        model.setNilai(oper);
        resultHasil.setText(oper);
    }
    
    private void getOperator(int opt){
        model.setOperator(opt);
        oper="";
    }
    
     private void proses(){
        DecimalFormat df = new DecimalFormat("#,###.########");
        model.proses();
        oper="";
        resultHasil.setText(df.format(model.getResult())+"");
    }

Lanjutkan Memberikan event di setiap butoon..
sesuai namanya yaaa..
Code:
private void bnt_tambahActionPerformed(java.awt.event.ActionEvent evt) {                                           
// TODO add your handling code here:
    getOperator(1);
}                                          

private void bnt_kurangActionPerformed(java.awt.event.ActionEvent evt) {                                           
// TODO add your handling code here:
    getOperator(2);
}                                          

private void bnt_kaliActionPerformed(java.awt.event.ActionEvent evt) {                                         
// TODO add your handling code here:
    getOperator(3);
}                                        

private void bnt_bagiActionPerformed(java.awt.event.ActionEvent evt) {                                         
// TODO add your handling code here:
    getOperator(4);
}                                        

private void bnt_persenActionPerformed(java.awt.event.ActionEvent evt) {                                           
// TODO add your handling code here:
    getOperator(5);
}                                          

private void bnt_samadengaActionPerformed(java.awt.event.ActionEvent evt) {                                              
// TODO add your handling code here:
    proses();
}                                             

private void bnt_1ActionPerformed(java.awt.event.ActionEvent evt) {                                      
// TODO add your handling code here:
    getOper(bnt_1);
}                                     

private void bnt_2ActionPerformed(java.awt.event.ActionEvent evt) {                                      
// TODO add your handling code here:
    getOper(bnt_2);
}                                     

private void bnt_3ActionPerformed(java.awt.event.ActionEvent evt) {                                      
// TODO add your handling code here:
    getOper(bnt_3);
}                                     

private void bnt_4ActionPerformed(java.awt.event.ActionEvent evt) {                                      
// TODO add your handling code here:
    getOper(bnt_4);
}                                     

private void bnt_5ActionPerformed(java.awt.event.ActionEvent evt) {                                      
// TODO add your handling code here:
    getOper(bnt_5);
}                                     

private void bnt_6ActionPerformed(java.awt.event.ActionEvent evt) {                                      
// TODO add your handling code here:
    getOper(bnt_6);
}                                     

private void bnt_7ActionPerformed(java.awt.event.ActionEvent evt) {                                      
// TODO add your handling code here:
    getOper(bnt_7);
}                                     

private void bnt_8ActionPerformed(java.awt.event.ActionEvent evt) {                                      
// TODO add your handling code here:
    getOper(bnt_8);
}                                     

private void bnt_9ActionPerformed(java.awt.event.ActionEvent evt) {                                      
// TODO add your handling code here:
    getOper(bnt_9);
}                                     

private void bnt_titikActionPerformed(java.awt.event.ActionEvent evt) {                                          
// TODO add your handling code here:
    getOper(bnt_titik);
}                                         

private void bnt_0ActionPerformed(java.awt.event.ActionEvent evt) {                                      
// TODO add your handling code here:
    getOper(bnt_0);
}                                     

private void bnt_cActionPerformed(java.awt.event.ActionEvent evt) {                                      
// TODO add your handling code here:
    if(oper.length()>1){
        oper = oper.substring(0, oper.length()-1);
        model.setNilai(oper);
        resultHasil.setText(oper);
    }else{
        oper = "";
        model.setNilai(oper);
        resultHasil.setText("0");
    }
}                                     

private void bnt_ACActionPerformed(java.awt.event.ActionEvent evt) {                                       
// TODO add your handling code here:
    oper ="";
    model.setOperator(0);
    model.setResult(0);
    resultHasil.setText("0");
}

SELESAI, GOOD JOB Bahagia