Java GUI

Here are my codes for GUI system. The button cancel and new order did not erase the calculation for previous order. help me.

btnorder.addActionListener(this);

apple.addActionListener(this);

orange.addActionListener(this);

pear.addActionListener(this);

guava.addActionListener(this);

peach.addActionListener(this);

mango.addActionListener(this);

btnpay.addActionListener(this);

btncancel.addActionListener(this);

txtcharge.addActionListener(this);

}

public void actionPerformed(ActionEvent e) {

//declare variables using suitable data type into price for each fruit and quantity

double a;

Object obj = e.getSource(); //return the object if any event occurred

double priceapple = 0;

double priceorange = 0;

double pricepear = 0;

double priceguava = 0;

double pricepeach = 0;

double pricemango = 0;

int countapple = 0;

int countorange = 0;

int countpear = 0;

int countguava = 0;

int countpeach = 0;

int countmango = 0;

if(obj == apple) { //count for apples

txtname.setText("Apple"); //fruits name

txtprice.setText("RM 10.00"); //fruit price

txtquantity.setText("1"); //fruit quantity

++countapple; //for count

priceapple = countapple * 10.0; //count apple price

display.append(" Apple" + " " + countapple++ + " " + "RM" + df.format(priceapple));

}

totalprice += priceapple ; //total price of apple

if(obj == orange) { //count for oranges

txtname.setText("Orange"); //fruit name

txtprice.setText("RM 9.00"); //fruit price

txtquantity.setText("1"); //fruit quantity

++countorange; //for count

priceorange = countorange * 9.0; //count orange price

display.append(" Orange" + " " + countorange++ + " " + "RM" + df.format(priceorange));

}

totalprice += priceorange; //total price of orange

if(obj == pear) { //count for pears

txtname.setText("Pear"); //fruit name

txtprice.setText("RM 12.00"); //fruit price

txtquantity.setText("1"); //fruit quantity

++countpear; //for count

pricepear = countpear * 12.0; //count pear price

display.append(" Pear" + " " + countpear++ + " " + "RM" + df.format(pricepear));

}

totalprice += pricepear; //total price of pear

if(obj == guava) { //count for guava

txtname.setText("Guava"); //fruit name

txtprice.setText("RM 7.00"); //fruit price

txtquantity.setText("1"); //fruit quantity

++countguava; //for count

priceguava = countguava * 7.0; //count guava price

display.append(" Guava" + " " + countguava++ + " " + "RM" + df.format(priceguava));

}

totalprice += priceguava; //total price of guava

if(obj == peach) { //count for peach

txtname.setText("Peach"); //fruit name

txtprice.setText("RM 15.00"); //fruit price

txtquantity.setText("1"); //fruit quantity

++countpeach; //for count

pricepeach = countpeach * 15.0; //count peach price

display.append(" Peach" + " " + countpeach++ + " " + "RM" + df.format(pricepeach));

}

totalprice += pricepeach; //total price of peach

if(obj == mango) { //count for mango

txtname.setText("Mango"); //fruit name

txtprice.setText("RM 9.00"); //fruit price

txtquantity.setText("1"); //fruit quantity

++countmango; //for count

pricemango = countmango * 9.0; //count mango price

display.append(" Mango" + " " + countmango++ + " " + "RM" + df.format(pricemango));

}

totalprice += pricemango; //total price of mango

String tp = df.format(totalprice);

txtcharge.setText("RM 1.00"); //set price

double t = 1.00;

a = t + totalprice;

txtsubtotal.setText("RM" + tp); //for subtotal using setText

txttotal.setText("RM" + df.format(a)); //for total using setText

if(obj == btnorder) { //for button order

txtname.setText("");

txtprice.setText("");

txtquantity.setText("");

display.setText("");

//txttotal.setText("");

txtsubtotal.setText("");

txtcharge.setText("");

txttotal.setText("");

lblpay.setText("");

}

if(obj == btnpay) { // for button pay

lblpay.setText("The total charge is RM " + df.format(a)); //the set text with total price

}

else if (obj == btncancel) { //for button cancel

txtname.setText("");

txtprice.setText("");

txtquantity.setText("");

display.setText("");

//txttotal.setText("");

txtsubtotal.setText("");

txtcharge.setText("");

txttotal.setText("");

lblpay.setText("");

}

}

public static void main(String[] args) {

// TODO Auto-generated method stub

frushi b = new frushi();

b.setTitle("Frushi");

b.setSize(1000,600);

b.setVisible(true);

}

}