B4J Tutorials

EDIT: If the message length is equal to the pad length, you have to pad to the next multiple. E.g. 16 bytes would be padded to 32 because one would not know how long the message was because the...

 

Wikipedia: Google Authenticator

Most websites where you have to log in offer to protect your account by using a multi-factor authentication. Here you can use an app like Google...

 

Disclaimer:
None of the techniques used here are new to our community and you may have seen the 'Trick' used by me before.

The Problem:
We are using classes more frequently, especially with...

 

Edit: XUI2D version of Tetris: https://www.b4x.com/android/forum/threads/xui2d-tetris.107698/

...

 

*** Contents ***
Intro
Acknowledgements
Disclaimer
Environment
Conventions used in this post
Making it work
Compiling and running your programs
A semi-automated way to get your B4J UI...

 

The example here uses a Bezier curve which is one of a lot of possible curves.
But the text drawing routine works on any list of points.
The attached .zip has all the code (140 lines)...

 

I've written a tutorial about database modelling and how long queries in a good designed db environment should take. This is a example about using huge databases. What it does:

- creates two...

 

This little tutorial is about signing and verifying data you send/receive between apps (= all "programs", even websites). You can use it in B4A without a change (I don't know how B4i works, but I...

 

- Changed to B4x as the subs can be used in B4A, too
- "Send File" added (new Button to send a file to the other client)


This tutorial is based on Erel's Asyncstreams example...

 

New video tutorial:


Resumable subs is a new feature added in B4J v5.50 / B4i v4.00 / B4A v7.00. It dramatically simplifies the handling of asynchronous tasks.
(This feature is a...

 

Many years ago I needed to sniff a connection and I didn't have a free sniffer available and I didn't know how to create one .... So after a long reflection I decided to create a Proxy Server in...

 

The latest IDE update adds support for grouping files and modules.

Groups

You can add groups with a right click...

 

This document is intended to add a little understanding as to how Resumable Subs actually work under the bonnet and is intended as a complement to how they are used as Erel explains in his...

 

FontAwesome and Material Icons are two free icon sets including more than 1500 icons.
They are implemented as regular font files which means that each icon is a regular character...

 

Here is a customer support chat demo of FirebaseFirestore for B4J

• It listens to
  1. Chats
  2. Chat
  3. Products
  4. Sales
  5. Customers

You can further add...

 

Since retiring some time ago, I have been thinking about creating stories that involve
computer operated robots which carry out actions and speech - like actors in a drama.

It would have at least...

 

Short one.

You can configure the IDE to show a list of external file editors. The list shows when you right click on a file in the Files tab...

 

I made 7 examples how to exchange data between B4x apps and php. I use the POSTSTRING method as it is simple, secure (get-methods will be logged with the data autmatically on the server...

 

Custom views are implemented as B4X classes or in a library.
A custom view includes a set of properties that can be set...

 

B4J v10.00 includes support for "code snippets". This feature will be added to the other tools in the next updates.
A code snippet is a piece of code that can be added to your code in very few...