Designing Graphical Interfaces - Beginning Java Programming: The Object-Oriented Approach - page 549

double mass;
double height;
try {
mass = Double.parseDouble(txtMass.getText());
height = Double.parseDouble(txtHeight.getText());
} catch (NumberFormatException e) {
JOptionPane.showMessageDialog(self,
"Please enter a valid number for mass and height.",
"Input error",
JOptionPane.ERROR_MESSAGE);
return;
}
double result = calculateBMI(mass, height);
JOptionPane.showMessageDialog(self,
"Your BMI is: " + (Math.round(result*100.0)/100.0),
"Your BMI result",
JOptionPane.PLAIN_MESSAGE);
}
});
*/
}
@Override
public void start(Stage stage) throws Exception {
VBox vbox = new VBox(10);
Label lblTitle = new Label("BMI Calculator");
lblTitle.setFont(Font.font(18));
vbox.getChildren().add(lblTitle);
vbox.getChildren().add(new Label("Your mass (kg):"));
vbox.getChildren().add(txtMass);
vbox.getChildren().add(new Label("Your height (cm):"));
vbox.getChildren().add(txtHeight);
vbox.getChildren().add(btnCalc);
Scene scene = new Scene(new Group(vbox));
stage.setTitle("JavaFX BMI Calculator");
stage.setScene(scene);
stage.sizeToScene();
stage.show();
}
protected double calculateBMI(double mass, double height) {
return mass / Math.pow(height/100.0, 2.0);
}
public static void main(String[] args) {
Application.launch(args);
}
}