Question

Write a Java application with a JavaFXGUI that takes a String input by the user and shows whether the string contains all 26 letters of the (English version of the Latin) alphabet. For example, "Pack my box with five dozen liquor jugs" contains all 26 letters, but "The quick frown box jumps over the hazy log" does not contain a d. It does not matter whether one or more letters appear more than once.

The GUI needs, at minimum, a label to say "Enter String: ", a TextBox to take input for the String, a label to show the answer ("String contains all 26 letters" or "String does not contain all 26 letters", and a button to trigger the method to determine the outcome.

Hints:

• Use toLowerCase() or toUpperCase() on the characters from the String so that you do not have to worry about case.
• *Absolutely don't* write 26 different statements to test all 26 letters. You can use a loop and cast (int) the loop counter to a char; upper case A is Unicode character 65.
• String has a contains() method much like the one in List.

Answer 1

/************************

GuiApp.java

********************/

package gui.fx;

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

public class GuiApp extends Application {
  
public static void main(String[] args) {
launch(args);
}
  
@Override
public void start(Stage primaryStage) {
primaryStage.setTitle("String Check");
  
Label lbl1 = new Label("Enter String:"); //label
  
TextField txt = new TextField(); //Text field where string will be input
txt.setPrefSize(400, 40);
txt.setMaxWidth(400); //max width is set to 400
  
Label lbl2 = new Label(""); //label for showing final outcome
  
Button btn = new Button(); //button : on click of this final outcome will be shown
btn.setText("Get Result");
btn.setOnAction(new EventHandler<ActionEvent>() { //this will be triggered when button is clicked
@Override
public void handle(ActionEvent event) {
String textToCheck = txt.getText(); //get the text from textfield
String result = checkResult(textToCheck); //get the result by calling checkResult() method
lbl2.setText(result);//set the outcome in lbl2
}
});
  
  
//add all the above in a VBox
VBox root = new VBox(20); //VBox will put all the children with a vertical gap of 20
root.getChildren().add(lbl1);//add lbl1
root.getChildren().add(txt);//add text field
root.getChildren().add(btn);//add the button
root.getChildren().add(lbl2);//add lbl2 to show the outcome
  
primaryStage.setScene(new Scene(root, 500, 300));
primaryStage.show();
}
  
/**
* The method checks whether the given text contains all the 26 letters or not
* @param text
* @return
*/
private String checkResult(String text){
   String result = null;
   String tempText = text.toLowerCase(); //converts text into all lower case
   boolean isLetterPresent = true;
   for(char currentLetter = 'a' ; currentLetter <='z'; currentLetter++){ //loop through each letter from a to z
       //System.out.println(String.valueOf(currentLetter));
       if(!tempText.contains(String.valueOf(currentLetter))){ //if tempText doesnot contain the current character
           isLetterPresent = false;//set the letter is not present
           break; //it will brak out of the loop
       }
   }
  
   //set result based on whether ll letter is found or not
   if(isLetterPresent){
       result = "String contains all 26 letters";
   }else{
       result = "String does not contain all 26 letters";
   }
  
   return result;
}
}

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OUTPUT

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