Adding value from textfield - javafx

Question

I a m creating a java application and I have a problem.
Here is the code.
package javastackoverflow;
import javafx.application.Application;
import javafx.geometry.Pos;
import javafx.scene.Scene;
import javafx.scene.control.Button;
import javafx.scene.control.Label;
import javafx.scene.control.TextField;
import javafx.scene.layout.FlowPane;
import javafx.stage.Stage;
public class Javastackoverflow extends Application {
TextField deduct2;
Label text;
double ammount = 0.0;
#Override
public void start(Stage primaryStage) {
Button btn = new Button();
btn.setText("Apply");
text = new Label(Double.toString(ammount));
btn.setOnAction((e->{
double getamount = Double.parseDouble(deduct2.getText());
text.setText(Double.toString(getamount)+ ammount);
//this is where the program is suppose to get the amount and add it to amount, notice the + sign.
}))
;
deduct2 = new TextField();
FlowPane root = new FlowPane();
root.setAlignment(Pos.CENTER);
root.getChildren().addAll(btn,deduct2,text);
Scene scene = new Scene(root, 400, 450);
primaryStage.setTitle("Yo Stack");
primaryStage.setScene(scene);
primaryStage.show();
}
/**
* #param args the command line arguments
*/
public static void main(String[] args) {
launch(args);
}
}
What it is suppose to do
When the user enters a number into the textfield the program is suppose to
to take that number and add it to ammount = 0;
My problem
But when ever the using enters a new number the text changes to That number. Remember I would like it to add to the currant number like (currant number = 23; user enters new Number) new number = 3; I would like results to equal = 26 but right now the program shows the result 3;
What I think
I think the problem is in the onAction() method.
I think that the text.setText() method is displaying the currant text entered into the textfield, rather then adding it to ammount.
I alse don't think I am using the correct operator from this line of code. That may be part of the problem.
text.setText(Double.toString(getamount)+ ammount);
notice how I use the + sign, that + adds the getamount to ammount..or its supposed to. But when I change that plus sign to - or * I get this error
===============================
bad operand types for binary operator '*'
first type: String
second type: TextField
===============================
As you can probably tell I really would like this code to be correct so if you don't understand something please comment before you report me. Then I can change it fast. Thank you!

Answer 1

You are adding the amount to the getAmount variable when amount = 0.0
Try adding the new value to getAmount
package javastackoverflow;
import javafx.application.Application;
import javafx.geometry.Pos;
import javafx.scene.Scene;
import javafx.scene.control.Button;
import javafx.scene.control.Label;
import javafx.scene.control.TextField;
import javafx.scene.layout.FlowPane;
import javafx.stage.Stage;
public class Javastackoverflow extends Application {
TextField deduct2;
Label text;
double getamount = 0.0; //Edit 1
#Override
public void start(Stage primaryStage) {
Button btn = new Button();
btn.setText("Apply");
text = new Label(Double.toString(ammount));
btn.setOnAction((e->{
getamount += Double.parseDouble(deduct2.getText()); //Edit 2
text.setText(Double.toString(getamount));
//this is where the program is suppose to get the amount and add it to amount, notice the + sign.
}))
;
deduct2 = new TextField();
FlowPane root = new FlowPane();
root.setAlignment(Pos.CENTER);
root.getChildren().addAll(btn,deduct2,text);
Scene scene = new Scene(root, 400, 450);
primaryStage.setTitle("Yo Stack");
primaryStage.setScene(scene);
primaryStage.show();
}
/**
* #param args the command line arguments
*/
public static void main(String[] args) {
launch(args);
}
}