Question

JavaFX Programming

Develop a temperature converter GUI JavaFX application that consists of two labels and two text fields. Typing a temperature into the Celsius field and then pressing the "Enter" key causes the equivalent Fahrenheit temperature to appear in the Fahrenheit field and vice versa. Temperature Converter Celsius 100 Fahrenheit 212.0 Typing a non-numeric value into either field causes the following error dialog to appear: Message Error, input must be numerical OK Formulas are simple: Celsius to Fahrenheit F = 9/5 (°C) +32 Fahrenheit to Celsius C = 5/9 (°F -32)

Answer 1

Here is the answer for your question in Java Programming Language using JavaFX

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CODE :

import javafx.application.Application; import javafx.event.ActionEvent; import javafx.geometry.Insets; import javafx.scene.Scene; import javafx.scene.control.*; import javafx.scene.control.Alert.AlertType; import javafx.scene.layout.GridPane; import javafx.stage.Stage; public class TemperatureConverter extends Application{ //Required scene variable Scene Window; //Required variables double celsius = 0.00,fahrenheit = 0.00;    //Main method() public static void main(String[] args){ launch(args); } //Method to execute on pressing enter public static double onEnter(ActionEvent e,String s,double input){ //Required variable double result = 0; //If the string is "celsius" if(s.compareToIgnoreCase("celsius") == 0){ //Calculates fahrenheit value of the input result = (((9*input)/5) + 32); }    else if(s.compareToIgnoreCase("fahrenheit") == 0){ //Else if the input is "fahrenheit" //Calculates celsius of the input result = (5*(input - 32))/9; } //Returns result return result; }    //Start method @Override public void start(Stage primaryStage) throws Exception { //Set title for the Stage object primaryStage.setTitle("Temperature Converter");    //Required components of the GUI and their styings Label celsiusLbl = new Label("Celcius "); celsiusLbl.setPadding(new Insets(0,0,0,10)); celsiusLbl.setStyle("-fx-font-weight: bold"); Label fahrenheitLbl = new Label("Fahrenheit "); fahrenheitLbl.setStyle("-fx-font-weight: bold");    TextField celsiusTxt = new TextField(); TextField fahrenheitTxt = new TextField(); //Binding event for first textbox celsiusTxt.setOnAction((ActionEvent e)->{    //Read text from first text box to string 'input' String input = celsiusTxt.getText(); //To handle exception try{ //If input is not null if(input.compareTo("") !=0) //Parse input to double celsius = Double.parseDouble(input); //Call onEnter method and calculate fahrenheit fahrenheit = TemperatureConverter.onEnter(e,"celsius",celsius); //Display fahrenheit in sen=cond textbox fahrenheitTxt.setText(String.valueOf(fahrenheit)); } catch(Exception ex){ //If input is not double then exception will be catched here    //Create object of alert class Alert alert = new Alert(AlertType.INFORMATION); //Display contents in the alert object alert.setHeaderText(null); alert.setTitle("Error"); alert.setContentText("Error, input must be numerical"); alert.showAndWait(); }    });    //Binding event for second textbox fahrenheitTxt.setOnAction((ActionEvent e)->{ //Read text from second text box to string 'input' String input = fahrenheitTxt.getText(); //To handle exception    try{ //If input is not null if(input.compareTo("") != 0) //Parse input to double fahrenheit = Double.parseDouble(input); //Call onEnter method and calculate celsius celsius = TemperatureConverter.onEnter(e,"fahrenheit",fahrenheit); //Display celsius in first textbox celsiusTxt.setText(String.valueOf(celsius)); } catch(Exception ex){ //If input is not double then exception will be catched here    //Create object of alert class Alert alert = new Alert(AlertType.INFORMATION); //Display contents in the alert object alert.setHeaderText(null); alert.setTitle("Error"); alert.setContentText("Error, input must be numerical"); alert.showAndWait(); }       });    //GridPane Object to set components GridPane g = new GridPane(); //Set components in repsective columns g.addColumn(0,celsiusLbl); g.addColumn(1,celsiusTxt); g.addColumn(2,fahrenheitLbl); g.addColumn(3,fahrenheitTxt);    //Set horizontal gap g.setHgap(10);    //Initialize Window Window = new Scene(g,500,50);    //Add Window to stage object primaryStage.setScene(Window); primaryStage.show();    } }

SCREENSHOTS :

Please see the screehsots of the code below for the indentations of the code.

1 2 3 4 5 ç import juvafx.application. Application; import javafx.event. ActionEvent; import javafx.geometry.Insets; import javafx.scene. Scene; import javafx.scene.control.*; import javafx.scene.control.Alert. AlertType; import javafx.scene.layout. GridPane; import javafx. stage. Stage; 6 7 8 9 public class TemperatureConverter extends Application { 10 ll 12 13 14 15 16 17 //Required scene variable Scene Window; // Required variables double celsius = 0.00, fahrenheit = 0.00; CO 마 19 20 21 22 23 24 25 26 27 28 29 30 31 32 //Main method() public static void main(String[] args) { Launch(args); } //Method to execute on pressing enter public static double on Enter (ActionEvent e, String s, double input) { // Required variable double result = 0; //If the string is "celsius" if(s.compare toIgnoreCase("celsius") == 0){ //Calculates fahrenheit value of the input result - (((9* input)/5) + 32); } *) { else if(s.compareToIgnoreCase("fahrenheit") //Else if the input is "fahrenheit" //Calculates celsius of the input

33 34 35 36 result (5*(input - 32))/9; } // Returns result return result; } 38 39 40 1 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 //Start method @Override public void start(Stage primaryStage) throws Exception { // Set title for the Stage object primaryStage.setTitle("Temperature Converter"); //Required components of the GUI and their styings Label celsiusLbl = new Label("Celcius "); celsiusLbl.setPadding(new Insets(0,0,0,10)); celsiusLbl.setStyle("-fx-font-weight: bold"); Label fahrenheitlbl = new Label("Fahrenheit "); fahrenheitlbl.setStyle("-fx-font-weight: bold"); TextField celsiusTxt = new TextField(); TextField fahrenheittxt = new TextField(); //Binding event for first textbox celsiusTxt.setOnAction((ActionEvent e) ->{ //Read text from first text box to string 'input' String input celsiusTxt.getText(); //To handle exception try{ //If input is not null if(input.compareTo("") !=0) //Parse input to double

67 celsius Double.parseDouble(input); 7/Call on Enter method and calculate fahrenheit fahrenheit = TemperatureConverter.onEnter(e,"celsius", celsius); //Display fahrenheit in sen=cond textbox fahrenheittxt.setText(String.valueOf (Fahrenheit)); 68 69 } 70 71 72 73 74 75 catch(Exception ex) { // If input is not double then exception will be catched here // Create object of alert class Alert alert = new Alert (AlertType . INFORMATION); //Display contents in the alert object alert.setHeaderText(null); alert.setTitle("Error"); alert.setContent Text("Error, input must be numerical"); alert.showAndwait(); 76 77 78 79 80 ܢܟ }); 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 //Binding event for second textbox fahrenheittxt.setOnAction((ActionEvent e)->{ //Read text from second text box to string 'input' String input = fahrenheittxt.getText(); //To handle exception try{ //If input is not null if(input.compareTo("") != 0) //Parse input to double fahrenheit = Double.parseDouble(input); //Call on Enter method and calculate celsius celsius TemperatureConverter.onEnter(e,"fahrenheit", fahrenheit);

//Display celsius in first textbox celsiusTxt.setText(String.valueof (celsius)); 98 99 } catch(Exception ex){ // If input is not double then exception will be catched here //Create object of alert class Alert alert = new Alert (Alert Type . INFORMATION); //Display contents in the alert object alert.setHeaderText(null); alert.setTitle("Error"); alert.setContentText("Error, input must be numerical"); alert.showAndWait(); } }); 100 101 102 103 104 105 106 107 108 109 110 ill 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 //GridPane object to set components GridPane g = new GridPane(); // Set components in repsective columns g.addColumn(e, celsiuslbl); g.addColumn(1, celsiusTxt); g.addColumn(2, fahrenheitlbl); g.addColumn(3, fahrenheittxt); // Set horizontal gap g.setHgap(10); //Initialize Window Window = new Scene(g, 500, 50);

- 128 129 130 131 132 133 134 135 // Add Window to stage object primaryStage.setScene (Window); primaryStage.show(); ܝܟ ܢܟ

OUTPUT :

Initial Output

х Temperature Converter Celcius Fahrenheit

If given valid value

х Temperature Converter Celcius 100 Fahrenheit

After clicking "Enter" in first text box

Х Temperature Converter Celcius 100 Fahrenheit 212.0

Similary for Fahrenheit

Temperature Converter - Celcius Fahrenheit 320

Temperature Converter x Celcius 160.0 Fahrenheit 320

If given wrong input

Temperature Converter Celcius abcd Fahrenheit Error X Error input must be numerical .- OK

Any doubts regarding this can be explained with pleasure :)