So I'm a college student presently learning Java and JavaFX by myself, with some help from you all.
I'm trying to start by making a relatively simple calculator, customizing it with some CSS. My program works fine, the only real problem is the lag whenever I actually calculate what I want. So I'll go, "5 + 5 =" and as soon as I hit equals it lags and then shows "10". Not sure why and I haven't found much on it.
Thanks for the help in advance.
NOTE: If you have any other suggestions to help me improve my code, feel free to post it. I have a long way to go.
import javafx.application.Application;
import javafx.scene.control.*;
import javafx.scene.input.*;
import javafx.scene.Scene;
import javafx.stage.Stage;
import javafx.geometry.Insets;
import javafx.scene.layout.*;
import javafx.scene.text.Font;
import javax.script.ScriptEngineManager;
import java.math.BigDecimal;
import javax.script.ScriptEngine;
public class practice3 extends Application {
Stage window;
Button plus,
minus,
divide,
multiply,
clear,
zero,
one,
two,
three,
four,
five,
six,
seven,
eight,
nine,
decimal,
equals;
TextField display;
double total,
num1;
String input = "";
String equationInput = ""; //equationInput will store all data up to a symbol is pressed
Label equation;
public static void main(String[] args) {
launch(args);
}
@Override
public void start(Stage primaryStage) throws Exception {
window = primaryStage;
window.setTitle("Simple Calculator");
//Display Text Field
display = new TextField();
display.setEditable(false);
display.setPrefHeight(70);
display.setFont(Font.font("Verdana", 50));
equation = new Label();
equation.setPrefHeight(70);
equation.setFont(Font.font("Verdana", 12));
equation.setText(equationInput);
equation.setPrefWidth(209);
equation.setPadding(new Insets(0, 0, 3, 3));
//Buttons
plus = new Button("+");
plus.setPrefSize(70, 70);
plus.setOnAction(e - >operationButton("+"));
minus = new Button("-");
minus.setPrefSize(70, 70);
minus.setOnAction(e - >operationButton("-"));
divide = new Button("/");
divide.setPrefSize(70, 70);
divide.setOnAction(e->operationButton("/"));
multiply = new Button("*");
multiply.setPrefSize(70, 70);
multiply.setOnAction(e->operationButton("*"));
clear = new Button("C");
clear.setPrefSize(70, 70);
clear.setOnAction(e->clearButton());
equals = new Button("=");
equals.setPrefSize(70, 70);
equals.setOnAction(e->{
try {
calculate();
} catch(Exception e1) {
System.out.println("Error in code.");
}
});
decimal = new Button(".");
decimal.setPrefSize(70, 70);
decimal.setOnAction(e->decimalButton());
//Numbers
one = new Button("1");
one.setPrefSize(70, 70);
one.setOnAction(e->numberButton("1"));
two = new Button("2");
two.setPrefSize(70, 70);
two.setOnAction(e->numberButton("2"));
three = new Button("3");
three.setPrefSize(70, 70);
three.setOnAction(e->numberButton("3"));
four = new Button("4");
four.setPrefSize(70, 70);
four.setOnAction(e->numberButton("4"));
five = new Button("5");
five.setPrefSize(70, 70);
five.setOnAction(e->numberButton("5"));
six = new Button("6");
six.setPrefSize(70, 70);
six.setOnAction(e->numberButton("6"));
seven = new Button("7");
seven.setPrefSize(70, 70); //WidthxHeight
seven.setOnAction(e->numberButton("7"));
eight = new Button("8");
eight.setPrefSize(70, 70);
eight.setOnAction(e->numberButton("8"));
nine = new Button("9");
nine.setPrefSize(70, 70);
nine.setOnAction(e->numberButton("9"));
zero = new Button("0");
zero.setPrefSize(70, 70);
zero.setOnAction(e->numberButton("0"));
BorderPane layout = new BorderPane();
GridPane grid = new GridPane();
layout.setCenter(grid);
layout.setTop(display);
//Setting Constraints for Buttons and Equation Display
grid.setConstraints(seven, 0, 1);
grid.setConstraints(eight, 1, 1);
grid.setConstraints(nine, 2, 1);
grid.setConstraints(clear, 3, 0);
grid.setConstraints(four, 0, 2);
grid.setConstraints(five, 1, 2);
grid.setConstraints(six, 2, 2);
grid.setConstraints(plus, 3, 1);
grid.setConstraints(one, 0, 3);
grid.setConstraints(two, 1, 3);
grid.setConstraints(three, 2, 3);
grid.setConstraints(minus, 3, 2);
grid.setConstraints(decimal, 0, 4);
grid.setConstraints(zero, 1, 4);
grid.setConstraints(multiply, 3, 3);
grid.setConstraints(divide, 3, 4);
grid.setConstraints(equals, 2, 4);
grid.setConstraints(equation, 0, 0, 3, 1);
display.setStyle("-fx-focus-color: transparent;");
grid.getChildren().addAll(seven, eight, nine, clear, four, five, six, plus, one, two, three, minus, decimal, zero, multiply, divide, equals, equation);
layout.setPadding(new Insets(5, 5, 5, 5));
display.setText("0");
Scene scene = new Scene(layout, 290, 462);
//Keyboard Events
scene.addEventHandler(KeyEvent.KEY_PRESSED, (key) -> {
if (key.getCode() == KeyCode.DIGIT1 || key.getCode() == KeyCode.NUMPAD1) {
numberButton("1");
}
else if (key.getCode() == KeyCode.DIGIT2 || key.getCode() == KeyCode.NUMPAD2) {
numberButton("2");
}
else if (key.getCode() == KeyCode.DIGIT3 || key.getCode() == KeyCode.NUMPAD3) {
numberButton("3");
}
else if (key.getCode() == KeyCode.DIGIT4 || key.getCode() == KeyCode.NUMPAD4) {
numberButton("4");
}
else if (key.getCode() == KeyCode.DIGIT5 || key.getCode() == KeyCode.NUMPAD5) {
numberButton("5");
}
else if (key.getCode() == KeyCode.DIGIT6 || key.getCode() == KeyCode.NUMPAD6) {
numberButton("6");
}
else if (key.getCode() == KeyCode.DIGIT7 || key.getCode() == KeyCode.NUMPAD7) {
numberButton("7");
}
else if (key.getCode() == KeyCode.DIGIT8 || key.getCode() == KeyCode.NUMPAD8) {
numberButton("8");
}
else if (key.getCode() == KeyCode.DIGIT9 || key.getCode() == KeyCode.NUMPAD9) {
numberButton("9");
}
else if (key.getCode() == KeyCode.DIGIT0 || key.getCode() == KeyCode.NUMPAD0) {
numberButton("0");
}
else if (key.getCode() == KeyCode.PERIOD || key.getCode() == KeyCode.DECIMAL) {
decimalButton();
}
else if (key.getCode() == KeyCode.ADD) {
operationButton("+");
}
else if (key.getCode() == KeyCode.SUBTRACT) {
operationButton("-");
}
else if (key.getCode() == KeyCode.MULTIPLY) {
operationButton("*");
}
else if (key.getCode() == KeyCode.DIVIDE) {
operationButton("/");
}
else if (key.getCode() == KeyCode.EQUALS) {
try {
calculate();
} catch(Exception e1) {
System.out.println("Error in code.");
}
}
else if (key.getCode() == KeyCode.C) {
clearButton();
}
});
scene.getStylesheets().add("practice3.css");
equation.getStyleClass().add("equation-label");
//End
window.setScene(scene);
window.show();
}
private void clearButton() {
input = "";
total = 0;
num1 = 0;
equationInput = "";
display.setText("0");
equation.setText("");
}
private void numberButton(String value) {
input += value;
display.setText(input);
}
private void decimalButton() {
int check;
if (input.indexOf(".") == -1) {
if (input == "") {
input += "0.";
display.setText(input);
}
else {
input += ".";
display.setText(input);
}
}
}
private void operationButton(String symbol) {
equationInput += input;
input = "";
if (symbol == "+") {
equationInput += " + ";
}
else if (symbol == "-") {
equationInput += " - ";
}
else if (symbol == "*") {
equationInput += " * ";
}
else if (symbol == "/") {
equationInput += " / ";
}
equation.setText(equationInput);
display.setText("0");
}
private void calculate() throws Exception {
String answer = "0";
double answer1;
Object eval;
equationInput += input;
input = "";
ScriptEngineManager mgr = new ScriptEngineManager();
ScriptEngine engine = mgr.getEngineByName("JavaScript");
eval = engine.eval(equationInput);
answer1 = new BigDecimal(eval.toString()).doubleValue();
answer = String.valueOf(answer1);
equationInput += " = ";
display.setText(answer);
equation.setText(equationInput);
}
}
Also, I would like to mention that I'm not very good at organization yet so if anything seems confusing feel free to ask!
