Getting User Input

How to get the user input in Java?

You can use any of the following options based on the requirements.

Scanner class

import java.util.Scanner; 
//...
Scanner scan = new Scanner(System.in);
String s = scan.next();
int i = scan.nextInt();

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BufferedReader and InputStreamReader classes

import java.io.BufferedReader;
import java.io.InputStreamReader;
//...
BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
String s = br.readLine();
int i = Integer.parseInt(s);

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DataInputStream class

import java.io.DataInputStream;
//...
DataInputStream dis = new DataInputStream(System.in);
int i = dis.readInt();

The readLine method from the DataInputStream class has been deprecated. To get String value, you should use the previous solution with BufferedReader

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Console class

import java.io.Console;
//...
Console console = System.console();
String s = console.readLine();
int i = Integer.parseInt(console.readLine());

Apparently, this method does not work well in some IDEs.

How to get the input from user?

You can make a function that takes the user input and converts it to the actual name you need as such;

def get_group_name_from_id(id):
    if id == "0":
        return "All_Groups"
    elif id == "1":
        return "Caltech"
    elif id == "2":
        return "KKI"
    elif id == "3":
        return "Leuven"
    else:
        return "an invalid option"

group_id = input("Which group you want to analyze: \n 0-All_Groups \n 1-Caltech \n 2-KKI \n 3-Leuven")
group_name = get_group_name_from_id(group_id)
print("You have chosen:", group_name, "!")

Getting user input while a timer is counting and updating the console

I ended up using async and learning a bit in the process. Here's the code. And BTW it is a lot lighter weight than my threaded verssion. My Macbook pro fans spin up to max speed when I run the threaded version. But I can barely hear them at all with the async version.

import sys
import asyncio
from count_timer import CountTimer
from blessed import Terminal

def count():
    if counter.remaining > 10:
        print(
            term.bold
            + term.green
            + term.move_x(0)
            + term.move_up
            + term.clear_eol
            + str(round(counter.remaining, 3))
        )
    elif counter.remaining > 5:
        print(
            term.bold
            + term.yellow2
            + term.move_x(0)
            + term.move_up
            + term.clear_eol
            + str(round(counter.remaining, 3))
        )
    elif counter.remaining > 0:
        print(
            term.bold
            + term.red
            + term.move_x(0)
            + term.move_up
            + term.clear_eol
            + str(round(counter.remaining, 3))
        )
    else:
        print(
            term.bold
            + term.magenta
            + term.move_x(0)
            + term.move_up
            + term.clear_eol
            + "TIME'S UP!"
        )

def kb_input():
    if counter.remaining <= 0:
        return
    with term.cbreak():
        key = term.inkey(timeout=0.01).lower()
        if key:
            if key == "q":
                print(
                    term.bold
                    + term.magenta
                    + term.move_x(0)
                    + term.move_up
                    + term.clear_eol
                    + "Quitting..."
                )
                sys.exit()
            elif key == "r":
                counter.reset(duration=float(duration))
                counter.start()
            elif key == " ":
                counter.pause() if counter.running else counter.resume()

async def main():
    global counter
    global term
    global duration

    duration = input("Enter countdown timer duration: ")
    counter = CountTimer(duration=float(duration))
    counter.start()
    term = Terminal()

    def _run_executor_count():
        count()

    def _run_executor_kb_input():
        kb_input()

    while counter.remaining > 0:
        await asyncio.get_event_loop().run_in_executor(None, _run_executor_count)
        await asyncio.get_event_loop().run_in_executor(None, _run_executor_kb_input)

    await asyncio.get_event_loop().run_in_executor(None, _run_executor_count)

def async_main_entry():
    asyncio.get_event_loop().run_until_complete(main())

if __name__ == "__main__":
    async_main_entry()

How to get user input from contenteditable div in a grid?

https://codepen.io/codmitu/pen/LYegzNN?editors=0011

html:

<p>absolute</p>
<div contenteditable="true" style="border: 5px solid; padding: 5px"></div>
<button>check</button>

js:

const pText = document.querySelector("p").innerText
const div = document.querySelector("div")
const button = document.querySelector("button")

button.addEventListener("click", () => {
  const text = div.textContent
  //checking for numbers
  if (text.match(/\d/gi)) {
    div.innerText = text
    return 
  }

    div.innerHTML = ""
    text.split("").forEach(letter => {
    if (pText.includes(letter)) {
      div.innerHTML += `<span style="color: green">${letter}</span>`
    } else {
      div.innerHTML += `<span style="color: grey">${letter}</span>`
    }
  })
})

//blur the div if text is longer than 8 letters
div.addEventListener("keydown", (e) => {
   if (div.innerText.length > 7 || e.keyCode == 32) {
     div.blur()
   }
})

//clear on focus
div.addEventListener("focus", () => {
   div.innerHTML = ""
})

Get User Input and show it on field - Java

Below code is a rewrite of your GUI application.

import java.awt.BorderLayout;
import java.awt.EventQueue;
import java.awt.Font;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.KeyEvent;

import javax.swing.ButtonGroup;
import javax.swing.JButton;
import javax.swing.JCheckBox;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JPasswordField;
import javax.swing.JRadioButton;
import javax.swing.JScrollPane;
import javax.swing.JTextArea;
import javax.swing.JTextField;

public class Login {
    private JCheckBox c1;
    private JPasswordField confirmPasswordText;
    private JPasswordField passwordText;
    private JRadioButton femaleButton;
    private JRadioButton maleButton;
    private JTextArea textArea;
    private JTextField emailText;
    private JTextField nameText;

    private void createAndDisplayGui() {
        JFrame frame = new JFrame("Registration");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.add(createHeading(), BorderLayout.PAGE_START);
        frame.add(createForm(), BorderLayout.CENTER);
        frame.add(createButtonsPanel(), BorderLayout.PAGE_END);
        frame.pack();
        frame.setLocationByPlatform(true);
        frame.setVisible(true);
    }

    private JButton createButton(String text,
                                 int mnemonic,
                                 ActionListener listener) {
        JButton button = new JButton(text);
        button.setMnemonic(mnemonic);
        button.addActionListener(listener);
        return button;
    }

    private JPanel createButtonsPanel() {
        JPanel buttonsPanel = new JPanel();
        buttonsPanel.add(createButton("Submit", KeyEvent.VK_S, this::submit));
        return buttonsPanel;
    }

    private JPanel createForm() {
        JPanel form = new JPanel(new GridBagLayout());
        GridBagConstraints gbc = new GridBagConstraints();
        gbc.anchor = GridBagConstraints.LINE_START;
        gbc.gridx = 0;
        gbc.gridy = 0;
        gbc.insets.bottom = 5;
        gbc.insets.left = 10;
        gbc.insets.right = 10;
        gbc.insets.top = 0;
        JLabel nameLabel = new JLabel("Name");
        form.add(nameLabel, gbc);
        gbc.gridx = 1;
        nameText = new JTextField(16);
        form.add(nameText, gbc);
        gbc.gridy = 1;
        form.add(createRadioButtons(), gbc);
        gbc.gridx = 0;
        gbc.gridy = 2;
        JLabel eMailLabel = new JLabel("E-mail");
        form.add(eMailLabel, gbc);
        gbc.gridx = 1;
        emailText = new JTextField(16);
        form.add(emailText, gbc);
        gbc.gridx = 0;
        gbc.gridy = 3;
        JLabel passwordLabel = new JLabel("Password");
        form.add(passwordLabel, gbc);
        gbc.gridx = 1;
        passwordText = new JPasswordField(16);
        form.add(passwordText, gbc);
        gbc.gridx = 0;
        gbc.gridy = 4;
        JLabel confirmLabel = new JLabel("Confirm password");
        form.add(confirmLabel, gbc);
        gbc.gridx = 1;
        confirmPasswordText = new JPasswordField(16);
        form.add(confirmPasswordText, gbc);
        gbc.gridx = 1;
        gbc.gridy = 5;
        c1 = new JCheckBox("I agree to websites rules!");
        form.add(c1, gbc);
        gbc.gridx = 1;
        gbc.gridy = 6;
        textArea = new JTextArea(2, 30);
        textArea.setEditable(false);
        textArea.setFocusable(false);
        JScrollPane scrollPane = new JScrollPane(textArea);
        form.add(scrollPane, gbc);
        return form;
    }

    private JPanel createHeading() {
        JPanel heading = new JPanel();
        JLabel label = new JLabel("REGISTRATION FORM");
        label.setFont(label.getFont().deriveFont(Font.BOLD, 14.0f));
        heading.add(label);
        return heading;
    }

    private JPanel createRadioButtons() {
        JPanel radioButtons = new JPanel();
        ButtonGroup group = new ButtonGroup();
        maleButton = new JRadioButton("Male");
        maleButton.setSelected(true);
        radioButtons.add(maleButton);
        group.add(maleButton);
        femaleButton = new JRadioButton("Female");
        radioButtons.add(femaleButton);
        group.add(femaleButton);
        return radioButtons;
    }

    private void submit(ActionEvent event) {
        textArea.setText("");
        String name = nameText.getText();
        textArea.append(name);
        String gender;
        if (maleButton.isSelected()) {
            gender = "male";
        }
        else {
            gender = "female";
        }
        textArea.append(", " + gender);
        String email = emailText.getText();
        textArea.append(", " + email);
        String password = new String(passwordText.getPassword());
        textArea.append(", " + password);
        String confirmPassword = new String(confirmPasswordText.getPassword());
        textArea.append(", " + confirmPassword);
        textArea.append(", " + c1.isSelected());
    }

    public static void main(String[] args) {
        EventQueue.invokeLater(() -> new Login().createAndDisplayGui());
    }
}

• Usually you use a layout manager rather than setting it to null. Refer to Laying Out Components Within a Container
• You need to group JRadioButtons in a ButtonGroup to ensure that only one can be selected. Refer to How to Use Buttons, Check Boxes, and Radio Buttons
• Method getText is deprecated for JPasswordField. Refer to How to Use Password Fields.
• I chose to display the user inputs in a JTextArea in a JScrollPane but there are other options. Refer to Using Text Components and How to Use Scroll Panes.
• Since Java 8, the ActionListener interface can be implemented via a method reference.

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