B4J Tutorials

pyvips is a very powerful image manipulation library. It can manipulate very large images. I've created a modified "HugeImageView" based on it as an example. It can show 1-2 GB images...

 

First post, first issue:
I'm in the process of developing an ABM application. For testing purposes, I uploaded the application on my test server. The application may start fine, but when loading...

 

PyBridge is a framework that allows accessing Python libraries from within B4J.

It works by starting a Python process that connects to the B4J process. The Python process receives commands from...

 

Hi all,

here a simple shooter game using B4J WebGL libary and cannon.js physic engine.

Note that really I use cannon-es that is a port of cannon.js to use inside Javascript ES6 modules.

Note...

 

PyBridge must be accessed from a single thread. In server solutions, each handler runs in its own thread so we need to add some barriers to ensure proper usage.

The way to implement it is by...

 

This sophisticated project does one thing - the user clicks on a hardware button, connected to the RPi, and a notification appears on the PC.

The setup:
RPi running Mosquitto broker...

 

Hi all,

this code will show how to make a simple 3D game, with gravity and collisions by code without use any physics engine.

I want to remember that with WebGL library you can use more than one...

 

Hi there

NB: Where possible, please include a simple project that demonstrates your use case.

Do you have any questions about SithasoDaisy UI Toolkit?

You can shoot it here...

 

Getting the RPi 5 to work with B4J is very simple.

I've tested it with the recommended 64 bit Raspbian OS (bookworm).

1. Download and unpack the Linux ARM Full JDK (21)...

 

NOTE: This isnt recommened for everyone, this is just something that works for me. Removing support for specific platforms could cause your app to stop working.

I use SQLite for a lot of...

 

I've posted in the past a few examples of a simple chat app based on BLE: https://www.b4x.com/android/forum/threads/ble-chat-connecting-android-and-ios.66543/#content
A new version of this...

 

This Thread is about the german Post and their free Api Service for Postalstamps and other Services...

 

Hi Fam

SithasoDaisy5 Demo incl Preferences Dialog Forms Builder

SithasoDaisy5 Open Source

Before you start this tutorial, please ensure that your dev environment is setup by...

 

B4JPackager11 is a utility written in B4J that uses the underlying Java tools to create a standalone package that doesn't depend on any other software being installed.
It works with OpenJDK 11 and...

 

This was the first time I faced something like this and it was Chrome's fault. Here is what happened:

I added in a .js file a new javascript function. When I tried to call it, Chrome was saying...

 

Hi Fam

SithasoDaisy5 Demo

Before you start this tutorial, please ensure that your dev environment is setup by following this tutorial...

 

Now I have a windows 11 PC and thanks to a prod from one of @Cableguy posts on another thread, I finally got round to looking at an alternative to my Replacement Titlebar lib.

This...

 

But if to make lots of preparations:
0. Do not forget to include into the B4J library folder file: www.b4x.com/b4j/files/bluecove-2.1.1-SNAPSHOT.jar

1. Install Linux Bluetooth Bluecove...

 

A friend of mine created a docker image for me to debug apps on my server quickly and easily.
I am happy to share this with you.

https://hub.docker.com/r/o0shojo0o/b4jbridge

 

This example is based on: https://scikit-learn.org/stable/auto_examples/linear_model/plot_ols.html
The steps are:

1. Read the CSV file with StringUtils.
2. Take the BMI and target columns...