Thread: adding numbers in table

java.jpg

hello . can somebody help me how can I add the numbers in quantity where it will automatically put in total?
im using netbeans.

just want the codes for how to add the listed quantity? hope you can help me

i tried this

jLabel8.setText(String.valueOf(Double.parseDouble( txtQuantity.getText()) + Double.parseDouble(txtQuantity.getText())));

i tried this

if(txtQuantity.getText().equals("")){
txtAmount.setText("");
}
else {
txtAmount.setText(String.valueOf(Double.parseDoubl e(txtQuantity.getText()) * 250));

but the Amount keeps changing into the quantity im putting it must be the sum of quantity

--- Update ---

it should be like this . First, I will put quantity: 12 then the amount will be 250 * 12 = 3000 , but when i change it in any number example 124 the amount change but total must be 124 + 12 = 136 so i want it like that hope you understand my grammar is not good

hmmm.

what i mean is every time i input quantity it will keep adding and getting the sum. so that i can use that total in exchange for txtAmount.setText(String.valueOf(Double.parseDoubl e(*txtQuantity--this should be replace by the TotalQty*.getText()) * 250));