I need a little help with a calculator program

Question

I tried to do a calculator program. I added the buttons and a textfield to show the user's income and output as well. My problem starts when somebody write for example "5+2". It is a String value what a tried to transform to int value to calculate the sum (Integer.parseInt(textfield.getText()). After that I would like to transform the result back String value to add this value to the textfield (String.instanceof(Integer.parseInt(textfield.getText().But I always get a NumberformatException. Anybody can help?

Answer 1

try this ,

String numberone = edittext.getText().toString();
String numbertwo = edittext1.getText().toString();

int addition = Integer.parseInt(numberone) + Integer.parseint(numbertwo);

TextView.setText(String.valueof(addition));

Answer 2

because you can't parse 5+2 as one int because 5 is one integer, + is operator and 2 is another integer. You could try to threat that string as array of characters and parse his first and second character.

Answer 3

you're welcome 😁

Answer 4

Thank you to all the help. I will try your suggestions.