I'm stuck on figuring out how to add a decimal place function to a very simple calculator gui I am building. The current implementation I have for the makeDecimalButton function throws an error at runtime. Should I not be parsing the decimal to a double? Maybe I should be using BigDecimal? Any help is appreciated.
import javafx.application.Application;
import javafx.beans.binding.Bindings;
import javafx.beans.property.*;
import javafx.event.ActionEvent;
import javafx.event.EventHandler;
import javafx.geometry.Pos;
import javafx.scene.Scene;
import javafx.scene.control.*;
import javafx.scene.input.KeyEvent;
import javafx.scene.layout.*;
import javafx.stage.Stage;
import javafx.stage.StageStyle;
import java.util.HashMap;
import java.util.Map;
public class Calculator extends Application {
private static final String[][] template = {
{ "7", "8", "9", "/" },
{ "4", "5", "6", "*" },
{ "1", "2", "3", "-" },
{ "0", "C", "=", "+", "." } };
private final Map<String, Button> accelerators = new HashMap<>();
private DoubleProperty stackValue = new SimpleDoubleProperty();
private DoubleProperty value = new SimpleDoubleProperty();
private enum Operation {
NOOP, ADD, SUBTRACT, MULTIPLY, DIVIDE
}
private Operation curOp = Operation.NOOP;
private Operation stackOp = Operation.NOOP;
public static void main(String[] args) {
launch(args);
}
@Override
public void start(Stage stage) {
final TextField screen = createScreen();
final TilePane buttons = createButtons();
stage.setTitle("Calculator");
stage.initStyle(StageStyle.UTILITY);
stage.setResizable(false);
stage.setScene(new Scene(createLayout(screen, buttons)));
stage.show();
}
private VBox createLayout(TextField screen, TilePane buttons) {
final VBox layout = new VBox(20);
layout.setAlignment(Pos.CENTER);
layout.setStyle("-fx-background-color: black; -fx-padding: 20; -fx-font-size: 20;");
layout.getChildren().setAll(screen, buttons);
handleAccelerators(layout);
screen.prefWidthProperty().bind(buttons.widthProperty());
return layout;
}
private void handleAccelerators(VBox layout) {
layout.addEventFilter(KeyEvent.KEY_PRESSED, new EventHandler<KeyEvent>() {
@Override
public void handle(KeyEvent keyEvent) {
Button activated = accelerators.get(keyEvent.getText());
if (activated != null) {
activated.fire();
}
}
});
}
private TextField createScreen() {
final TextField screen = new TextField();
screen.setStyle("-fx-background-color: white;");
screen.setAlignment(Pos.CENTER_RIGHT);
screen.setEditable(false);
screen.textProperty().bind(Bindings.format("%f", value));
return screen;
}
private TilePane createButtons() {
TilePane buttons = new TilePane();
buttons.setVgap(7);
buttons.setHgap(7);
buttons.setPrefColumns(template[0].length);
for (String[] r : template) {
for (String s : r) {
buttons.getChildren().add(createButton(s));
}
}
return buttons;
}
private Button createButton(final String s) {
Button button = makeStandardButton(s);
if (s.matches("[0-9]")) {
makeNumericButton(s, button);
} else {
final ObjectProperty<Operation> triggerOp = determineOperand(s);
if (triggerOp.get() != Operation.NOOP) {
makeOperandButton(button, triggerOp);
} else if ("C".equals(s)) {
makeClearButton(button);
} else if ("=".equals(s)) {
makeEqualsButton(button);
} else if (".".equals(s)) {
makeDecimalButton(button);
}
}
return button;
}
private void makeDecimalButton(Button button) {
button.setStyle("-fx-base: mistyrose;");
button.setOnAction(new EventHandler<ActionEvent>() {
@Override
public void handle(ActionEvent actionEvent) {
value.set(value.get() + Double.parseDouble("."));
}
});
}
private ObjectProperty<Operation> determineOperand(String s) {
final ObjectProperty<Operation> triggerOp = new SimpleObjectProperty<>(Operation.NOOP);
switch (s) {
case "+":
triggerOp.set(Operation.ADD);
break;
case "-":
triggerOp.set(Operation.SUBTRACT);
break;
case "*":
triggerOp.set(Operation.MULTIPLY);
break;
case "/":
triggerOp.set(Operation.DIVIDE);
break;
}
return triggerOp;
}
private void makeOperandButton(Button button, final ObjectProperty<Operation> triggerOp) {
button.setStyle("-fx-base: lightgray;");
button.setOnAction(new EventHandler<ActionEvent>() {
@Override
public void handle(ActionEvent actionEvent) {
curOp = triggerOp.get();
}
});
}
private Button makeStandardButton(String s) {
Button button = new Button(s);
button.setStyle("-fx-base: beige;");
accelerators.put(s, button);
button.setMaxSize(Double.MAX_VALUE, Double.MAX_VALUE);
return button;
}
private void makeNumericButton(final String s, Button button) {
button.setOnAction(new EventHandler<ActionEvent>() {
@Override
public void handle(ActionEvent actionEvent) {
if (curOp == Operation.NOOP) {
value.set(value.get() * 10 + Integer.parseInt(s));
} else {
stackValue.set(value.get());
value.set(Integer.parseInt(s));
stackOp = curOp;
curOp = Operation.NOOP;
}
}
});
}
private void makeClearButton(Button button) {
button.setStyle("-fx-base: mistyrose;");
button.setOnAction(new EventHandler<ActionEvent>() {
@Override
public void handle(ActionEvent actionEvent) {
value.set(0);
}
});
}
private void makeEqualsButton(Button button) {
button.setStyle("-fx-base: ghostwhite;");
button.setOnAction(new EventHandler<ActionEvent>() {
@SuppressWarnings("incomplete-switch")
@Override
public void handle(ActionEvent actionEvent) {
switch (stackOp) {
case ADD:
value.set(stackValue.get() + value.get());
break;
case SUBTRACT:
value.set(stackValue.get() - value.get());
break;
case MULTIPLY:
value.set(stackValue.get() * value.get());
break;
case DIVIDE:
value.set(stackValue.get() / value.get());
break;
}
}
});
}
}
