[Video] Java Fx Programming - Creating Java Fx Login Application

official-hord (60)in #utopian-io • 6 years ago

Repository

https://github.com/dmlloyd/openjdk

What Will I Learn?

Creating Java Fx Login Application

Create UI
Button Event Handling;
1. Lambda Expression
2. Method Reference
Database Connection
Login Trial Counter

Requirements

Basic Understanding of Java
Intelli J Idea IDE or any other IDE of Choice
Sqlite Studio and Sqlite-Jdbc library

Difficulty

Intermediate

Description

In this tutorial I have explained the process of building a login application with Java Fx, code and video below. It is required to download the tools used as they are mandatory for code to work. Questions would be addressed.

Code Segment 1
Creating the UI

   VBox root = new VBox();
        root.setPadding(new Insets(10));
        root.setAlignment(Pos.CENTER);
connect = databaseConnection();

        TextField usernamefield = new TextField();
        PasswordField passwordField = new PasswordField();
        Button loginbtn = new Button("Login/Sign IN");
        Label outputlabel = new Label("This displays the output");

root.getChildren().addAll(usernamefield,passwordField,loginbtn,outputlabel);
        primaryStage.setTitle("Login App");
        primaryStage.setScene(new Scene(root, 300, 150));
        primaryStage.show();

Code Segment 2
Connection to Database

public static Connection databaseConnection(){
        try{
          Class.forName("org.sqlite.JDBC");
          Connection connect = DriverManager.getConnection("jdbc:sqlite:UserDetails.db");
          System.out.print("Database Connected");
return connect;


        }catch(Exception e){

            e.printStackTrace();
            return null;
        }
    }

Code Segment 3
Login with Lambda Expression

 loginbtn.setOnAction(e ->{

            String username = usernamefield.getText();
            String password = passwordField.getText();

try{

    String sql = "Select * from Login where Username = ? and Password =?";
    pst = connect.prepareStatement(sql);
    pst.setString(1, username);
    pst.setString(2, password);
    rst = pst.executeQuery();
    if(rst.next()){

        outputlabel.setText("User details are correct");
    }
    else{

        outputlabel.setText("User details are incorrect");
 loginattempts.set(loginattempts.add(1).get());
        if(loginattempts.get()>2){

            usernamefield.setEditable(false);
            passwordField.setEditable(false);

            timer();
            outputlabel.setText("Please try again");
            usernamefield.setEditable(true);
            passwordField.setEditable(true);


        }
    }

Code Segment 4
Timer method

private void timer(){
// this method handles counting the seconds after maximum trials nuumber is reached.
        long start = System.currentTimeMillis();
       long end = start + maxattempts *1000;
        while(System.currentTimeMillis()<end){

        }
    }

Code Segment 5
Imports and Variables

import javafx.beans.property.IntegerProperty;
import javafx.beans.property.SimpleIntegerProperty;
import javafx.fxml.FXMLLoader;
import javafx.geometry.Insets;
import javafx.geometry.Pos;
import javafx.scene.Parent;
import javafx.scene.Scene;
import javafx.scene.control.Button;
import javafx.scene.control.Label;
import javafx.scene.control.PasswordField;
import javafx.scene.control.TextField;
import javafx.scene.layout.VBox;
import javafx.stage.Stage;
import java.sql.*;


// Create the username and password to be used for validation before database validation.
private static String user = "Username";
    private static String pass = "Password";
    
// Create [Integer property](https://docs.oracle.com/javase/8/javafx/api/javafx/beans/property/IntegerProperty.html) used in the restriction after specified maximum trials.
private final static IntegerProperty loginattempts = new SimpleIntegerProperty();
    private int maxattempts = 5;

// Create variables required for database connection and validation [More information](https://docs.oracle.com/javase/7/docs/api/java/sql/Connection.html)
Connection connect = null;
PreparedStatement pst = null;
ResultSet rst =null;