import javafx.application.Application;
import javafx.event.ActionEvent;
import javafx.event.EventHandler;
import javafx.geometry.Pos;
import javafx.scene.control.Button;
import javafx.scene.control.TextField;
import javafx.scene.layout.HBox;
import javafx.scene.layout.VBox;
import javafx.stage.Stage;
import javafx.scene.Scene;

public class Kalkulator extends Application{
    TextField res;
    TextField t1, t2;
    @Override
    public void start(Stage stage) {
        VBox rootPane = new VBox();
        HBox textPane = new HBox();
        textPane.setAlignment(Pos.CENTER);
         t1 = new TextField();
         t2 = new TextField();

        textPane.getChildren().addAll(t1, t2);

        HBox buttonPane = new HBox();
        buttonPane.setAlignment(Pos.CENTER);

        Button plus = new Button("+");
        Button min = new Button("-");
        Button mult = new Button("X");
        Button div = new Button("/");

        ButtonHandler h = new ButtonHandler();
        plus.setOnAction(h);
        min.setOnAction(h);
        mult.setOnAction(h);
        div.setOnAction(h);

        res = new TextField("Result");
        
        buttonPane.getChildren().addAll(plus, min, mult, div, res);
        rootPane.getChildren().addAll(textPane, buttonPane);
        stage.setScene(new Scene(rootPane, 200, 100));
        
        stage.show();

    }
    private class ButtonHandler implements EventHandler<ActionEvent> {
        @Override
        public void handle(ActionEvent e) {
            Button tmp = (Button) e.getSource();
            Double num1=0.0, num2=0.0;
            try {
                num1 = Double.parseDouble(t1.getText());
                num2 = Double.parseDouble(t2.getText());
            }
            catch (NumberFormatException exe) {
                System.out.println("Dette er ikke tall!");
                return;
            }
            String op = tmp.getText();
            double sum = 0;
            switch (op) {
                case "+":
                    sum = num1+num2;
                    break;
                case "-":
                    sum=num1-num2;
                    break;
                case "X":
                    sum=num1*num2;
                    break;
                case "/":
                    sum=num1/num2;
                    break;
            }
            res.setText(""+sum);
        }
    }
}